diff options
Diffstat (limited to 'security/apparmor/domain.c')
| -rw-r--r-- | security/apparmor/domain.c | 1853 |
1 files changed, 1292 insertions, 561 deletions
diff --git a/security/apparmor/domain.c b/security/apparmor/domain.c index 01b7bd669a88..267da82afb14 100644 --- a/security/apparmor/domain.c +++ b/security/apparmor/domain.c @@ -1,3 +1,4 @@ +// SPDX-License-Identifier: GPL-2.0-only /* * AppArmor security module * @@ -5,225 +6,498 @@ * * Copyright (C) 2002-2008 Novell/SUSE * Copyright 2009-2010 Canonical Ltd. - * - * This program is free software; you can redistribute it and/or - * modify it under the terms of the GNU General Public License as - * published by the Free Software Foundation, version 2 of the - * License. */ #include <linux/errno.h> -#include <linux/fdtable.h> +#include <linux/fs.h> #include <linux/file.h> #include <linux/mount.h> #include <linux/syscalls.h> -#include <linux/tracehook.h> #include <linux/personality.h> +#include <linux/xattr.h> +#include <linux/user_namespace.h> #include "include/audit.h" #include "include/apparmorfs.h" -#include "include/context.h" +#include "include/cred.h" #include "include/domain.h" #include "include/file.h" #include "include/ipc.h" #include "include/match.h" #include "include/path.h" #include "include/policy.h" +#include "include/policy_ns.h" -/** - * aa_free_domain_entries - free entries in a domain table - * @domain: the domain table to free (MAYBE NULL) - */ -void aa_free_domain_entries(struct aa_domain *domain) -{ - int i; - if (domain) { - if (!domain->table) - return; - - for (i = 0; i < domain->size; i++) - kzfree(domain->table[i]); - kzfree(domain->table); - domain->table = NULL; - } -} +static const char * const CONFLICTING_ATTACH_STR = "conflicting profile attachments"; +static const char * const CONFLICTING_ATTACH_STR_IX = + "conflicting profile attachments - ix fallback"; +static const char * const CONFLICTING_ATTACH_STR_UX = + "conflicting profile attachments - ux fallback"; /** * may_change_ptraced_domain - check if can change profile on ptraced task - * @task: task we want to change profile of (NOT NULL) - * @to_profile: profile to change to (NOT NULL) + * @to_cred: cred of task changing domain + * @to_label: profile to change to (NOT NULL) + * @info: message if there is an error * - * Check if the task is ptraced and if so if the tracing task is allowed + * Check if current is ptraced and if so if the tracing task is allowed * to trace the new domain * * Returns: %0 or error if change not allowed */ -static int may_change_ptraced_domain(struct task_struct *task, - struct aa_profile *to_profile) +static int may_change_ptraced_domain(const struct cred *to_cred, + struct aa_label *to_label, + const char **info) { struct task_struct *tracer; - struct aa_profile *tracerp = NULL; + struct aa_label *tracerl = NULL; + const struct cred *tracer_cred = NULL; + int error = 0; rcu_read_lock(); - tracer = ptrace_parent(task); - if (tracer) + tracer = ptrace_parent(current); + if (tracer) { /* released below */ - tracerp = aa_get_task_profile(tracer); - + tracerl = aa_get_task_label(tracer); + tracer_cred = get_task_cred(tracer); + } /* not ptraced */ - if (!tracer || unconfined(tracerp)) + if (!tracer || unconfined(tracerl)) goto out; - error = aa_may_ptrace(tracer, tracerp, to_profile, PTRACE_MODE_ATTACH); + error = aa_may_ptrace(tracer_cred, tracerl, to_cred, to_label, + PTRACE_MODE_ATTACH); out: rcu_read_unlock(); - aa_put_profile(tracerp); + aa_put_label(tracerl); + put_cred(tracer_cred); + if (error) + *info = "ptrace prevents transition"; return error; } +/**** TODO: dedup to aa_label_match - needs perm and dfa, merging + * specifically this is an exact copy of aa_label_match except + * aa_compute_perms is replaced with aa_compute_fperms + * and policy->dfa with file->dfa + ****/ +/* match a profile and its associated ns component if needed + * Assumes visibility test has already been done. + * If a subns profile is not to be matched should be prescreened with + * visibility test. + */ +static inline aa_state_t match_component(struct aa_profile *profile, + struct aa_profile *tp, + bool stack, aa_state_t state) +{ + struct aa_ruleset *rules = profile->label.rules[0]; + const char *ns_name; + + if (stack) + state = aa_dfa_match(rules->file->dfa, state, "&"); + if (profile->ns == tp->ns) + return aa_dfa_match(rules->file->dfa, state, tp->base.hname); + + /* try matching with namespace name and then profile */ + ns_name = aa_ns_name(profile->ns, tp->ns, true); + state = aa_dfa_match_len(rules->file->dfa, state, ":", 1); + state = aa_dfa_match(rules->file->dfa, state, ns_name); + state = aa_dfa_match_len(rules->file->dfa, state, ":", 1); + return aa_dfa_match(rules->file->dfa, state, tp->base.hname); +} + /** - * change_profile_perms - find permissions for change_profile - * @profile: the current profile (NOT NULL) - * @ns: the namespace being switched to (NOT NULL) - * @name: the name of the profile to change to (NOT NULL) - * @request: requested perms - * @start: state to start matching in + * label_compound_match - find perms for full compound label + * @profile: profile to find perms for + * @label: label to check access permissions for + * @stack: whether this is a stacking request + * @state: state to start match in + * @subns: whether to do permission checks on components in a subns + * @request: permissions to request + * @perms: perms struct to set * - * Returns: permission set + * Returns: 0 on success else ERROR + * + * For the label A//&B//&C this does the perm match for A//&B//&C + * @perms should be preinitialized with allperms OR a previous permission + * check to be stacked. */ -static struct file_perms change_profile_perms(struct aa_profile *profile, - struct aa_namespace *ns, - const char *name, u32 request, - unsigned int start) +static int label_compound_match(struct aa_profile *profile, + struct aa_label *label, bool stack, + aa_state_t state, bool subns, u32 request, + struct aa_perms *perms) { - struct file_perms perms; + struct aa_ruleset *rules = profile->label.rules[0]; + struct aa_profile *tp; + struct label_it i; struct path_cond cond = { }; - unsigned int state; - if (unconfined(profile)) { - perms.allow = AA_MAY_CHANGE_PROFILE | AA_MAY_ONEXEC; - perms.audit = perms.quiet = perms.kill = 0; - return perms; - } else if (!profile->file.dfa) { - return nullperms; - } else if ((ns == profile->ns)) { - /* try matching against rules with out namespace prepended */ - aa_str_perms(profile->file.dfa, start, name, &cond, &perms); - if (COMBINED_PERM_MASK(perms) & request) - return perms; + /* find first subcomponent that is visible */ + label_for_each(i, label, tp) { + if (!aa_ns_visible(profile->ns, tp->ns, subns)) + continue; + state = match_component(profile, tp, stack, state); + if (!state) + goto fail; + goto next; } - /* try matching with namespace name and then profile */ - state = aa_dfa_match(profile->file.dfa, start, ns->base.name); - state = aa_dfa_match_len(profile->file.dfa, state, ":", 1); - aa_str_perms(profile->file.dfa, state, name, &cond, &perms); + /* no component visible */ + *perms = allperms; + return 0; + +next: + label_for_each_cont(i, label, tp) { + if (!aa_ns_visible(profile->ns, tp->ns, subns)) + continue; + state = aa_dfa_match(rules->file->dfa, state, "//&"); + state = match_component(profile, tp, false, state); + if (!state) + goto fail; + } + *perms = *(aa_lookup_condperms(current_fsuid(), rules->file, state, + &cond)); + aa_apply_modes_to_perms(profile, perms); + if ((perms->allow & request) != request) + return -EACCES; - return perms; + return 0; + +fail: + *perms = nullperms; + return -EACCES; } /** - * __attach_match_ - find an attachment match - * @name - to match against (NOT NULL) - * @head - profile list to walk (NOT NULL) - * - * Do a linear search on the profiles in the list. There is a matching - * preference where an exact match is preferred over a name which uses - * expressions to match, and matching expressions with the greatest - * xmatch_len are preferred. + * label_components_match - find perms for all subcomponents of a label + * @profile: profile to find perms for + * @label: label to check access permissions for + * @stack: whether this is a stacking request + * @start: state to start match in + * @subns: whether to do permission checks on components in a subns + * @request: permissions to request + * @perms: an initialized perms struct to add accumulation to * - * Requires: @head not be shared or have appropriate locks held + * Returns: 0 on success else ERROR * - * Returns: profile or NULL if no match found + * For the label A//&B//&C this does the perm match for each of A and B and C + * @perms should be preinitialized with allperms OR a previous permission + * check to be stacked. */ -static struct aa_profile *__attach_match(const char *name, - struct list_head *head) +static int label_components_match(struct aa_profile *profile, + struct aa_label *label, bool stack, + aa_state_t start, bool subns, u32 request, + struct aa_perms *perms) { - int len = 0; - struct aa_profile *profile, *candidate = NULL; + struct aa_ruleset *rules = profile->label.rules[0]; + struct aa_profile *tp; + struct label_it i; + struct aa_perms tmp; + struct path_cond cond = { }; + aa_state_t state = 0; - list_for_each_entry(profile, head, base.list) { - if (profile->flags & PFLAG_NULL) + /* find first subcomponent to test */ + label_for_each(i, label, tp) { + if (!aa_ns_visible(profile->ns, tp->ns, subns)) continue; - if (profile->xmatch && profile->xmatch_len > len) { - unsigned int state = aa_dfa_match(profile->xmatch, - DFA_START, name); - u32 perm = dfa_user_allow(profile->xmatch, state); - /* any accepting state means a valid match. */ - if (perm & MAY_EXEC) { - candidate = profile; - len = profile->xmatch_len; - } - } else if (!strcmp(profile->base.name, name)) - /* exact non-re match, no more searching required */ - return profile; + state = match_component(profile, tp, stack, start); + if (!state) + goto fail; + goto next; } - return candidate; + /* no subcomponents visible - no change in perms */ + return 0; + +next: + tmp = *(aa_lookup_condperms(current_fsuid(), rules->file, state, + &cond)); + aa_apply_modes_to_perms(profile, &tmp); + aa_perms_accum(perms, &tmp); + label_for_each_cont(i, label, tp) { + if (!aa_ns_visible(profile->ns, tp->ns, subns)) + continue; + state = match_component(profile, tp, stack, start); + if (!state) + goto fail; + tmp = *(aa_lookup_condperms(current_fsuid(), rules->file, state, + &cond)); + aa_apply_modes_to_perms(profile, &tmp); + aa_perms_accum(perms, &tmp); + } + + if ((perms->allow & request) != request) + return -EACCES; + + return 0; + +fail: + *perms = nullperms; + return -EACCES; } /** - * find_attach - do attachment search for unconfined processes - * @ns: the current namespace (NOT NULL) - * @list: list to search (NOT NULL) - * @name: the executable name to match against (NOT NULL) + * label_match - do a multi-component label match + * @profile: profile to match against (NOT NULL) + * @label: label to match (NOT NULL) + * @stack: whether this is a stacking request + * @state: state to start in + * @subns: whether to match subns components + * @request: permission request + * @perms: Returns computed perms (NOT NULL) * - * Returns: profile or NULL if no match found + * Returns: the state the match finished in, may be the none matching state */ -static struct aa_profile *find_attach(struct aa_namespace *ns, - struct list_head *list, const char *name) +static int label_match(struct aa_profile *profile, struct aa_label *label, + bool stack, aa_state_t state, bool subns, u32 request, + struct aa_perms *perms) { - struct aa_profile *profile; + int error; + + *perms = nullperms; + error = label_compound_match(profile, label, stack, state, subns, + request, perms); + if (!error) + return error; + + *perms = allperms; + return label_components_match(profile, label, stack, state, subns, + request, perms); +} + +/******* end TODO: dedup *****/ - read_lock(&ns->lock); - profile = aa_get_profile(__attach_match(name, list)); - read_unlock(&ns->lock); +/** + * change_profile_perms - find permissions for change_profile + * @profile: the current profile (NOT NULL) + * @target: label to transition to (NOT NULL) + * @stack: whether this is a stacking request + * @request: requested perms + * @start: state to start matching in + * @perms: Returns computed perms (NOT NULL) + * + * + * Returns: permission set + * + * currently only matches full label A//&B//&C or individual components A, B, C + * not arbitrary combinations. Eg. A//&B, C + */ +static int change_profile_perms(struct aa_profile *profile, + struct aa_label *target, bool stack, + u32 request, aa_state_t start, + struct aa_perms *perms) +{ + if (profile_unconfined(profile)) { + perms->allow = AA_MAY_CHANGE_PROFILE | AA_MAY_ONEXEC; + perms->audit = perms->quiet = perms->kill = 0; + return 0; + } - return profile; + /* TODO: add profile in ns screening */ + return label_match(profile, target, stack, start, true, request, perms); } /** - * separate_fqname - separate the namespace and profile names - * @fqname: the fqname name to split (NOT NULL) - * @ns_name: the namespace name if it exists (NOT NULL) + * aa_xattrs_match - check whether a file matches the xattrs defined in profile + * @bprm: binprm struct for the process to validate + * @profile: profile to match against (NOT NULL) + * @state: state to start match in * - * This is the xtable equivalent routine of aa_split_fqname. It finds the - * split in an xtable fqname which contains an embedded \0 instead of a : - * if a namespace is specified. This is done so the xtable is constant and - * isn't re-split on every lookup. + * Returns: number of extended attributes that matched, or < 0 on error + */ +static int aa_xattrs_match(const struct linux_binprm *bprm, + struct aa_profile *profile, aa_state_t state) +{ + int i; + struct dentry *d; + char *value = NULL; + struct aa_attachment *attach = &profile->attach; + int size, value_size = 0, ret = attach->xattr_count; + + if (!bprm || !attach->xattr_count) + return 0; + might_sleep(); + + /* transition from exec match to xattr set */ + state = aa_dfa_outofband_transition(attach->xmatch->dfa, state); + d = bprm->file->f_path.dentry; + + for (i = 0; i < attach->xattr_count; i++) { + size = vfs_getxattr_alloc(&nop_mnt_idmap, d, attach->xattrs[i], + &value, value_size, GFP_KERNEL); + if (size >= 0) { + struct aa_perms *perms; + + /* + * Check the xattr presence before value. This ensure + * that not present xattr can be distinguished from a 0 + * length value or rule that matches any value + */ + state = aa_dfa_null_transition(attach->xmatch->dfa, + state); + /* Check xattr value */ + state = aa_dfa_match_len(attach->xmatch->dfa, state, + value, size); + perms = aa_lookup_perms(attach->xmatch, state); + if (!(perms->allow & MAY_EXEC)) { + ret = -EINVAL; + goto out; + } + } + /* transition to next element */ + state = aa_dfa_outofband_transition(attach->xmatch->dfa, state); + if (size < 0) { + /* + * No xattr match, so verify if transition to + * next element was valid. IFF so the xattr + * was optional. + */ + if (!state) { + ret = -EINVAL; + goto out; + } + /* don't count missing optional xattr as matched */ + ret--; + } + } + +out: + kfree(value); + return ret; +} + +/** + * find_attach - do attachment search for unconfined processes + * @bprm: binprm structure of transitioning task + * @ns: the current namespace (NOT NULL) + * @head: profile list to walk (NOT NULL) + * @name: to match against (NOT NULL) + * @info: info message if there was an error (NOT NULL) * - * Either the profile or namespace name may be optional but if the namespace - * is specified the profile name termination must be present. This results - * in the following possible encodings: - * profile_name\0 - * :ns_name\0profile_name\0 - * :ns_name\0\0 + * Do a linear search on the profiles in the list. There is a matching + * preference where an exact match is preferred over a name which uses + * expressions to match, and matching expressions with the greatest + * xmatch_len are preferred. * - * NOTE: the xtable fqname is pre-validated at load time in unpack_trans_table + * Requires: @head not be shared or have appropriate locks held * - * Returns: profile name if it is specified else NULL + * Returns: label or NULL if no match found */ -static const char *separate_fqname(const char *fqname, const char **ns_name) +static struct aa_label *find_attach(const struct linux_binprm *bprm, + struct aa_ns *ns, struct list_head *head, + const char *name, const char **info) { - const char *name; + int candidate_len = 0, candidate_xattrs = 0; + bool conflict = false; + struct aa_profile *profile, *candidate = NULL; + + AA_BUG(!name); + AA_BUG(!head); + + rcu_read_lock(); +restart: + list_for_each_entry_rcu(profile, head, base.list) { + struct aa_attachment *attach = &profile->attach; - if (fqname[0] == ':') { - /* In this case there is guaranteed to be two \0 terminators - * in the string. They are verified at load time by - * by unpack_trans_table + if (profile->label.flags & FLAG_NULL && + &profile->label == ns_unconfined(profile->ns)) + continue; + + /* Find the "best" matching profile. Profiles must + * match the path and extended attributes (if any) + * associated with the file. A more specific path + * match will be preferred over a less specific one, + * and a match with more matching extended attributes + * will be preferred over one with fewer. If the best + * match has both the same level of path specificity + * and the same number of matching extended attributes + * as another profile, signal a conflict and refuse to + * match. */ - *ns_name = fqname + 1; /* skip : */ - name = *ns_name + strlen(*ns_name) + 1; - if (!*name) - name = NULL; - } else { - *ns_name = NULL; - name = fqname; + if (attach->xmatch->dfa) { + unsigned int count; + aa_state_t state; + struct aa_perms *perms; + + state = aa_dfa_leftmatch(attach->xmatch->dfa, + attach->xmatch->start[AA_CLASS_XMATCH], + name, &count); + perms = aa_lookup_perms(attach->xmatch, state); + /* any accepting state means a valid match. */ + if (perms->allow & MAY_EXEC) { + int ret = 0; + + if (count < candidate_len) + continue; + + if (bprm && attach->xattr_count) { + long rev = READ_ONCE(ns->revision); + + if (!aa_get_profile_not0(profile)) + goto restart; + rcu_read_unlock(); + ret = aa_xattrs_match(bprm, profile, + state); + rcu_read_lock(); + aa_put_profile(profile); + if (rev != + READ_ONCE(ns->revision)) + /* policy changed */ + goto restart; + /* + * Fail matching if the xattrs don't + * match + */ + if (ret < 0) + continue; + } + /* + * TODO: allow for more flexible best match + * + * The new match isn't more specific + * than the current best match + */ + if (count == candidate_len && + ret <= candidate_xattrs) { + /* Match is equivalent, so conflict */ + if (ret == candidate_xattrs) + conflict = true; + continue; + } + + /* Either the same length with more matching + * xattrs, or a longer match + */ + candidate = profile; + candidate_len = max(count, attach->xmatch_len); + candidate_xattrs = ret; + conflict = false; + } + } else if (!strcmp(profile->base.name, name)) { + /* + * old exact non-re match, without conditionals such + * as xattrs. no more searching required + */ + candidate = profile; + goto out; + } + } + + if (!candidate || conflict) { + if (conflict) + *info = CONFLICTING_ATTACH_STR; + rcu_read_unlock(); + return NULL; } - return name; +out: + candidate = aa_get_newest_profile(candidate); + rcu_read_unlock(); + + return &candidate->label; } static const char *next_name(int xtype, const char *name) @@ -235,362 +509,696 @@ static const char *next_name(int xtype, const char *name) * x_table_lookup - lookup an x transition name via transition table * @profile: current profile (NOT NULL) * @xindex: index into x transition table + * @name: returns: name tested to find label (NOT NULL) * - * Returns: refcounted profile, or NULL on failure (MAYBE NULL) + * Returns: refcounted label, or NULL on failure (MAYBE NULL) + * @name will always be set with the last name tried */ -static struct aa_profile *x_table_lookup(struct aa_profile *profile, u32 xindex) +struct aa_label *x_table_lookup(struct aa_profile *profile, u32 xindex, + const char **name) { - struct aa_profile *new_profile = NULL; - struct aa_namespace *ns = profile->ns; + struct aa_ruleset *rules = profile->label.rules[0]; + struct aa_label *label = NULL; u32 xtype = xindex & AA_X_TYPE_MASK; int index = xindex & AA_X_INDEX_MASK; - const char *name; + const char *next; - /* index is guaranteed to be in range, validated at load time */ - for (name = profile->file.trans.table[index]; !new_profile && name; - name = next_name(xtype, name)) { - struct aa_namespace *new_ns; - const char *xname = NULL; + AA_BUG(!name); - new_ns = NULL; + /* index is guaranteed to be in range, validated at load time */ + /* TODO: move lookup parsing to unpack time so this is a straight + * index into the resultant label + */ + for (next = rules->file->trans.table[index]; next; + next = next_name(xtype, next)) { + const char *lookup = (*next == '&') ? next + 1 : next; + *name = next; if (xindex & AA_X_CHILD) { - /* release by caller */ - new_profile = aa_find_child(profile, name); - continue; - } else if (*name == ':') { - /* switching namespace */ - const char *ns_name; - xname = name = separate_fqname(name, &ns_name); - if (!xname) - /* no name so use profile name */ - xname = profile->base.hname; - if (*ns_name == '@') { - /* TODO: variable support */ - ; - } - /* released below */ - new_ns = aa_find_namespace(ns, ns_name); - if (!new_ns) - continue; - } else if (*name == '@') { - /* TODO: variable support */ + /* TODO: switich to parse to get stack of child */ + struct aa_profile *new = aa_find_child(profile, lookup); + + if (new) + /* release by caller */ + return &new->label; continue; - } else { - /* basic namespace lookup */ - xname = name; } - - /* released by caller */ - new_profile = aa_lookup_profile(new_ns ? new_ns : ns, xname); - aa_put_namespace(new_ns); + label = aa_label_parse(&profile->label, lookup, GFP_KERNEL, + true, false); + if (!IS_ERR_OR_NULL(label)) + /* release by caller */ + return label; } - /* released by caller */ - return new_profile; + return NULL; } /** - * x_to_profile - get target profile for a given xindex + * x_to_label - get target label for a given xindex * @profile: current profile (NOT NULL) + * @bprm: binprm structure of transitioning task * @name: name to lookup (NOT NULL) * @xindex: index into x transition table + * @lookupname: returns: name used in lookup if one was specified (NOT NULL) + * @info: info message if there was an error (NOT NULL) * - * find profile for a transition index + * find label for a transition index * - * Returns: refcounted profile or NULL if not found available + * Returns: refcounted label or NULL if not found available */ -static struct aa_profile *x_to_profile(struct aa_profile *profile, - const char *name, u32 xindex) +static struct aa_label *x_to_label(struct aa_profile *profile, + const struct linux_binprm *bprm, + const char *name, u32 xindex, + const char **lookupname, + const char **info) { - struct aa_profile *new_profile = NULL; - struct aa_namespace *ns = profile->ns; + struct aa_label *new = NULL; + struct aa_label *stack = NULL; + struct aa_ns *ns = profile->ns; u32 xtype = xindex & AA_X_TYPE_MASK; + /* Used for info checks during fallback handling */ + const char *old_info = NULL; switch (xtype) { case AA_X_NONE: /* fail exec unless ix || ux fallback - handled by caller */ - return NULL; + *lookupname = NULL; + break; + case AA_X_TABLE: + /* TODO: fix when perm mapping done at unload */ + /* released by caller + * if null for both stack and direct want to try fallback + */ + new = x_table_lookup(profile, xindex, lookupname); + if (!new || **lookupname != '&') + break; + stack = new; + new = NULL; + fallthrough; /* to X_NAME */ case AA_X_NAME: if (xindex & AA_X_CHILD) /* released by caller */ - new_profile = find_attach(ns, &profile->base.profiles, - name); + new = find_attach(bprm, ns, &profile->base.profiles, + name, info); else /* released by caller */ - new_profile = find_attach(ns, &ns->base.profiles, - name); - break; - case AA_X_TABLE: - /* released by caller */ - new_profile = x_table_lookup(profile, xindex); + new = find_attach(bprm, ns, &ns->base.profiles, + name, info); + *lookupname = name; break; } + /* fallback transition check */ + if (!new) { + if (xindex & AA_X_INHERIT) { + /* (p|c|n)ix - don't change profile but do + * use the newest version + */ + if (*info == CONFLICTING_ATTACH_STR) { + *info = CONFLICTING_ATTACH_STR_IX; + } else { + old_info = *info; + *info = "ix fallback"; + } + /* no profile && no error */ + new = aa_get_newest_label(&profile->label); + } else if (xindex & AA_X_UNCONFINED) { + new = aa_get_newest_label(ns_unconfined(profile->ns)); + if (*info == CONFLICTING_ATTACH_STR) { + *info = CONFLICTING_ATTACH_STR_UX; + } else { + old_info = *info; + *info = "ux fallback"; + } + } + /* We set old_info on the code paths above where overwriting + * could have happened, so now check if info was set by + * find_attach as well (i.e. whether we actually overwrote) + * and warn accordingly. + */ + if (old_info && old_info != CONFLICTING_ATTACH_STR) { + pr_warn_ratelimited( + "AppArmor: find_attach (from profile %s) audit info \"%s\" dropped", + profile->base.hname, old_info); + } + } + + if (new && stack) { + /* base the stack on post domain transition */ + struct aa_label *base = new; + + new = aa_label_merge(base, stack, GFP_KERNEL); + /* null on error */ + aa_put_label(base); + } + + aa_put_label(stack); /* released by caller */ - return new_profile; + return new; } -/** - * apparmor_bprm_set_creds - set the new creds on the bprm struct - * @bprm: binprm for the exec (NOT NULL) - * - * Returns: %0 or error on failure - */ -int apparmor_bprm_set_creds(struct linux_binprm *bprm) +static struct aa_label *profile_transition(const struct cred *subj_cred, + struct aa_profile *profile, + const struct linux_binprm *bprm, + char *buffer, struct path_cond *cond, + bool *secure_exec) { - struct aa_task_cxt *cxt; - struct aa_profile *profile, *new_profile = NULL; - struct aa_namespace *ns; - char *buffer = NULL; - unsigned int state; - struct file_perms perms = {}; - struct path_cond cond = { - file_inode(bprm->file)->i_uid, - file_inode(bprm->file)->i_mode - }; - const char *name = NULL, *target = NULL, *info = NULL; - int error = cap_bprm_set_creds(bprm); - if (error) - return error; - - if (bprm->cred_prepared) - return 0; + struct aa_ruleset *rules = profile->label.rules[0]; + struct aa_label *new = NULL; + struct aa_profile *new_profile = NULL; + const char *info = NULL, *name = NULL, *target = NULL; + aa_state_t state = rules->file->start[AA_CLASS_FILE]; + struct aa_perms perms = {}; + bool nonewprivs = false; + int error = 0; - cxt = cred_cxt(bprm->cred); - BUG_ON(!cxt); + AA_BUG(!profile); + AA_BUG(!bprm); + AA_BUG(!buffer); - profile = aa_get_profile(aa_newest_version(cxt->profile)); - /* - * get the namespace from the replacement profile as replacement - * can change the namespace - */ - ns = profile->ns; - state = profile->file.start; - - /* buffer freed below, name is pointer into buffer */ - error = aa_path_name(&bprm->file->f_path, profile->path_flags, &buffer, - &name, &info); + error = aa_path_name(&bprm->file->f_path, profile->path_flags, buffer, + &name, &info, profile->disconnected); if (error) { - if (profile->flags & - (PFLAG_IX_ON_NAME_ERROR | PFLAG_UNCONFINED)) + if (profile_unconfined(profile) || + (profile->label.flags & FLAG_IX_ON_NAME_ERROR)) { + AA_DEBUG(DEBUG_DOMAIN, "name lookup ix on error"); error = 0; + new = aa_get_newest_label(&profile->label); + } name = bprm->filename; goto audit; } - /* Test for onexec first as onexec directives override other - * x transitions. - */ - if (unconfined(profile)) { - /* unconfined task */ - if (cxt->onexec) - /* change_profile on exec already been granted */ - new_profile = aa_get_profile(cxt->onexec); - else - new_profile = find_attach(ns, &ns->base.profiles, name); - if (!new_profile) - goto cleanup; - /* - * NOTE: Domain transitions from unconfined are allowed - * even when no_new_privs is set because this aways results - * in a further reduction of permissions. + if (profile_unconfined(profile)) { + new = find_attach(bprm, profile->ns, + &profile->ns->base.profiles, name, &info); + /* info set -> something unusual that we should report + * Currently this is only conflicting attachments, but other + * infos added in the future should also be logged by default + * and only excluded on a case-by-case basis */ - goto apply; + if (info) { + /* Because perms is never used again after this audit + * we don't need to care about clobbering it + */ + perms.audit |= MAY_EXEC; + perms.allow |= MAY_EXEC; + /* Don't cause error if auditing fails */ + (void) aa_audit_file(subj_cred, profile, &perms, + OP_EXEC, MAY_EXEC, name, target, new, cond->uid, + info, error); + } + if (new) { + AA_DEBUG(DEBUG_DOMAIN, "unconfined attached to new label"); + return new; + } + AA_DEBUG(DEBUG_DOMAIN, "unconfined exec no attachment"); + return aa_get_newest_label(&profile->label); } /* find exec permissions for name */ - state = aa_str_perms(profile->file.dfa, state, name, &cond, &perms); - if (cxt->onexec) { - struct file_perms cp; - info = "change_profile onexec"; - if (!(perms.allow & AA_MAY_ONEXEC)) - goto audit; - - /* test if this exec can be paired with change_profile onexec. - * onexec permission is linked to exec with a standard pairing - * exec\0change_profile - */ - state = aa_dfa_null_transition(profile->file.dfa, state); - cp = change_profile_perms(profile, cxt->onexec->ns, - cxt->onexec->base.name, - AA_MAY_ONEXEC, state); - - if (!(cp.allow & AA_MAY_ONEXEC)) - goto audit; - new_profile = aa_get_profile(aa_newest_version(cxt->onexec)); - goto apply; - } - + state = aa_str_perms(rules->file, state, name, cond, &perms); if (perms.allow & MAY_EXEC) { /* exec permission determine how to transition */ - new_profile = x_to_profile(profile, name, perms.xindex); - if (!new_profile) { - if (perms.xindex & AA_X_INHERIT) { - /* (p|c|n)ix - don't change profile but do - * use the newest version, which was picked - * up above when getting profile - */ - info = "ix fallback"; - new_profile = aa_get_profile(profile); - goto x_clear; - } else if (perms.xindex & AA_X_UNCONFINED) { - new_profile = aa_get_profile(ns->unconfined); - info = "ux fallback"; - } else { - error = -ENOENT; - info = "profile not found"; - /* remove MAY_EXEC to audit as failure */ - perms.allow &= ~MAY_EXEC; + new = x_to_label(profile, bprm, name, perms.xindex, &target, + &info); + if (new && new->proxy == profile->label.proxy && info) { + /* Force audit on conflicting attachment fallback + * Because perms is never used again after this audit + * we don't need to care about clobbering it + */ + if (info == CONFLICTING_ATTACH_STR_IX + || info == CONFLICTING_ATTACH_STR_UX) + perms.audit |= MAY_EXEC; + /* hack ix fallback - improve how this is detected */ + goto audit; + } else if (!new) { + if (info) { + pr_warn_ratelimited( + "AppArmor: %s (from profile %s) audit info \"%s\" dropped on missing transition", + __func__, profile->base.hname, info); + } + info = "profile transition not found"; + /* remove MAY_EXEC to audit as failure or complaint */ + perms.allow &= ~MAY_EXEC; + if (COMPLAIN_MODE(profile)) { + /* create null profile instead of failing */ + goto create_learning_profile; } + error = -EACCES; } } else if (COMPLAIN_MODE(profile)) { - /* no exec permission - are we in learning mode */ - new_profile = aa_new_null_profile(profile, 0); +create_learning_profile: + /* no exec permission - learning mode */ + new_profile = aa_new_learning_profile(profile, false, name, + GFP_KERNEL); if (!new_profile) { error = -ENOMEM; info = "could not create null profile"; } else { error = -EACCES; - target = new_profile->base.hname; + new = &new_profile->label; } perms.xindex |= AA_X_UNSAFE; } else /* fail exec */ error = -EACCES; - /* - * Policy has specified a domain transition, if no_new_privs then - * fail the exec. - */ - if (bprm->unsafe & LSM_UNSAFE_NO_NEW_PRIVS) { - aa_put_profile(new_profile); - error = -EPERM; - goto cleanup; + if (!new) + goto audit; + + + if (!(perms.xindex & AA_X_UNSAFE)) { + if (DEBUG_ON) { + dbg_printk("apparmor: setting AT_SECURE for %s profile=", + name); + aa_label_printk(new, GFP_KERNEL); + dbg_printk("\n"); + } + *secure_exec = true; } - if (!new_profile) - goto audit; +audit: + aa_audit_file(subj_cred, profile, &perms, OP_EXEC, MAY_EXEC, name, + target, new, + cond->uid, info, error); + if (!new || nonewprivs) { + aa_put_label(new); + return ERR_PTR(error); + } - if (bprm->unsafe & LSM_UNSAFE_SHARE) { - /* FIXME: currently don't mediate shared state */ - ; + return new; +} + +static int profile_onexec(const struct cred *subj_cred, + struct aa_profile *profile, struct aa_label *onexec, + bool stack, const struct linux_binprm *bprm, + char *buffer, struct path_cond *cond, + bool *secure_exec) +{ + struct aa_ruleset *rules = profile->label.rules[0]; + aa_state_t state = rules->file->start[AA_CLASS_FILE]; + struct aa_perms perms = {}; + const char *xname = NULL, *info = "change_profile onexec"; + int error = -EACCES; + + AA_BUG(!profile); + AA_BUG(!onexec); + AA_BUG(!bprm); + AA_BUG(!buffer); + + if (profile_unconfined(profile)) { + /* change_profile on exec already granted */ + /* + * NOTE: Domain transitions from unconfined are allowed + * even when no_new_privs is set because this always results + * in a further reduction of permissions. + */ + return 0; } - if (bprm->unsafe & (LSM_UNSAFE_PTRACE | LSM_UNSAFE_PTRACE_CAP)) { - error = may_change_ptraced_domain(current, new_profile); - if (error) { - aa_put_profile(new_profile); - goto audit; + error = aa_path_name(&bprm->file->f_path, profile->path_flags, buffer, + &xname, &info, profile->disconnected); + if (error) { + if (profile_unconfined(profile) || + (profile->label.flags & FLAG_IX_ON_NAME_ERROR)) { + AA_DEBUG(DEBUG_DOMAIN, "name lookup ix on error"); + error = 0; } + xname = bprm->filename; + goto audit; } - /* Determine if secure exec is needed. - * Can be at this point for the following reasons: - * 1. unconfined switching to confined - * 2. confined switching to different confinement - * 3. confined switching to unconfined - * - * Cases 2 and 3 are marked as requiring secure exec - * (unless policy specified "unsafe exec") - * - * bprm->unsafe is used to cache the AA_X_UNSAFE permission - * to avoid having to recompute in secureexec + /* find exec permissions for name */ + state = aa_str_perms(rules->file, state, xname, cond, &perms); + if (!(perms.allow & AA_MAY_ONEXEC)) { + info = "no change_onexec valid for executable"; + goto audit; + } + /* test if this exec can be paired with change_profile onexec. + * onexec permission is linked to exec with a standard pairing + * exec\0change_profile */ - if (!(perms.xindex & AA_X_UNSAFE)) { - AA_DEBUG("scrubbing environment variables for %s profile=%s\n", - name, new_profile->base.hname); - bprm->unsafe |= AA_SECURE_X_NEEDED; + state = aa_dfa_null_transition(rules->file->dfa, state); + error = change_profile_perms(profile, onexec, stack, AA_MAY_ONEXEC, + state, &perms); + if (error) { + perms.allow &= ~AA_MAY_ONEXEC; + goto audit; } -apply: - target = new_profile->base.hname; - /* when transitioning profiles clear unsafe personality bits */ - bprm->per_clear |= PER_CLEAR_ON_SETID; -x_clear: - aa_put_profile(cxt->profile); - /* transfer new profile reference will be released when cxt is freed */ - cxt->profile = new_profile; - - /* clear out all temporary/transitional state from the context */ - aa_clear_task_cxt_trans(cxt); + if (!(perms.xindex & AA_X_UNSAFE)) { + if (DEBUG_ON) { + dbg_printk("apparmor: setting AT_SECURE for %s label=", + xname); + aa_label_printk(onexec, GFP_KERNEL); + dbg_printk("\n"); + } + *secure_exec = true; + } audit: - error = aa_audit_file(profile, &perms, GFP_KERNEL, OP_EXEC, MAY_EXEC, - name, target, cond.uid, info, error); + return aa_audit_file(subj_cred, profile, &perms, OP_EXEC, + AA_MAY_ONEXEC, xname, + NULL, onexec, cond->uid, info, error); +} -cleanup: - aa_put_profile(profile); - kfree(buffer); +/* ensure none ns domain transitions are correctly applied with onexec */ - return error; +static struct aa_label *handle_onexec(const struct cred *subj_cred, + struct aa_label *label, + struct aa_label *onexec, bool stack, + const struct linux_binprm *bprm, + char *buffer, struct path_cond *cond, + bool *unsafe) +{ + struct aa_profile *profile; + struct aa_label *new; + int error; + + AA_BUG(!label); + AA_BUG(!onexec); + AA_BUG(!bprm); + AA_BUG(!buffer); + + /* TODO: determine how much we want to loosen this */ + error = fn_for_each_in_ns(label, profile, + profile_onexec(subj_cred, profile, onexec, stack, + bprm, buffer, cond, unsafe)); + if (error) + return ERR_PTR(error); + + new = fn_label_build_in_ns(label, profile, GFP_KERNEL, + stack ? aa_label_merge(&profile->label, onexec, + GFP_KERNEL) + : aa_get_newest_label(onexec), + profile_transition(subj_cred, profile, bprm, + buffer, cond, unsafe)); + if (new) + return new; + + /* TODO: get rid of GLOBAL_ROOT_UID */ + error = fn_for_each_in_ns(label, profile, + aa_audit_file(subj_cred, profile, &nullperms, + OP_CHANGE_ONEXEC, + AA_MAY_ONEXEC, bprm->filename, NULL, + onexec, GLOBAL_ROOT_UID, + "failed to build target label", -ENOMEM)); + return ERR_PTR(error); } /** - * apparmor_bprm_secureexec - determine if secureexec is needed - * @bprm: binprm for exec (NOT NULL) + * apparmor_bprm_creds_for_exec - Update the new creds on the bprm struct + * @bprm: binprm for the exec (NOT NULL) + * + * Returns: %0 or error on failure * - * Returns: %1 if secureexec is needed else %0 + * TODO: once the other paths are done see if we can't refactor into a fn */ -int apparmor_bprm_secureexec(struct linux_binprm *bprm) +int apparmor_bprm_creds_for_exec(struct linux_binprm *bprm) { - int ret = cap_bprm_secureexec(bprm); + struct aa_task_ctx *ctx; + struct aa_label *label, *new = NULL; + const struct cred *subj_cred; + struct aa_profile *profile; + char *buffer = NULL; + const char *info = NULL; + int error = 0; + bool unsafe = false; + vfsuid_t vfsuid = i_uid_into_vfsuid(file_mnt_idmap(bprm->file), + file_inode(bprm->file)); + struct path_cond cond = { + vfsuid_into_kuid(vfsuid), + file_inode(bprm->file)->i_mode + }; + + subj_cred = current_cred(); + ctx = task_ctx(current); + AA_BUG(!cred_label(bprm->cred)); + AA_BUG(!ctx); - /* the decision to use secure exec is computed in set_creds - * and stored in bprm->unsafe. + label = aa_get_newest_label(cred_label(bprm->cred)); + + /* + * Detect no new privs being set, and store the label it + * occurred under. Ideally this would happen when nnp + * is set but there isn't a good way to do that yet. + * + * Testing for unconfined must be done before the subset test */ - if (!ret && (bprm->unsafe & AA_SECURE_X_NEEDED)) - ret = 1; + if ((bprm->unsafe & LSM_UNSAFE_NO_NEW_PRIVS) && !unconfined(label) && + !ctx->nnp) + ctx->nnp = aa_get_label(label); - return ret; -} + /* buffer freed below, name is pointer into buffer */ + buffer = aa_get_buffer(false); + if (!buffer) { + error = -ENOMEM; + goto done; + } -/** - * apparmor_bprm_committing_creds - do task cleanup on committing new creds - * @bprm: binprm for the exec (NOT NULL) - */ -void apparmor_bprm_committing_creds(struct linux_binprm *bprm) -{ - struct aa_profile *profile = __aa_current_profile(); - struct aa_task_cxt *new_cxt = cred_cxt(bprm->cred); + /* Test for onexec first as onexec override other x transitions. */ + if (ctx->onexec) + new = handle_onexec(subj_cred, label, ctx->onexec, ctx->token, + bprm, buffer, &cond, &unsafe); + else + new = fn_label_build(label, profile, GFP_KERNEL, + profile_transition(subj_cred, profile, bprm, + buffer, + &cond, &unsafe)); + + AA_BUG(!new); + if (IS_ERR(new)) { + error = PTR_ERR(new); + goto done; + } else if (!new) { + error = -ENOMEM; + goto done; + } - /* bail out if unconfined or not changing profile */ - if ((new_cxt->profile == profile) || - (unconfined(new_cxt->profile))) - return; + /* Policy has specified a domain transitions. If no_new_privs and + * confined ensure the transition is to confinement that is subset + * of the confinement when the task entered no new privs. + * + * NOTE: Domain transitions from unconfined and to stacked + * subsets are allowed even when no_new_privs is set because this + * always results in a further reduction of permissions. + */ + if ((bprm->unsafe & LSM_UNSAFE_NO_NEW_PRIVS) && + !unconfined(label) && + !aa_label_is_unconfined_subset(new, ctx->nnp)) { + error = -EPERM; + info = "no new privs"; + goto audit; + } - current->pdeath_signal = 0; + if (bprm->unsafe & LSM_UNSAFE_SHARE) { + /* FIXME: currently don't mediate shared state */ + ; + } - /* reset soft limits and set hard limits for the new profile */ - __aa_transition_rlimits(profile, new_cxt->profile); -} + if (bprm->unsafe & (LSM_UNSAFE_PTRACE)) { + /* TODO: test needs to be profile of label to new */ + error = may_change_ptraced_domain(bprm->cred, new, &info); + if (error) + goto audit; + } -/** - * apparmor_bprm_commited_cred - do cleanup after new creds committed - * @bprm: binprm for the exec (NOT NULL) - */ -void apparmor_bprm_committed_creds(struct linux_binprm *bprm) -{ - /* TODO: cleanup signals - ipc mediation */ - return; + if (unsafe) { + if (DEBUG_ON) { + dbg_printk("setting AT_SECURE for %s label=", + bprm->filename); + aa_label_printk(new, GFP_KERNEL); + dbg_printk("\n"); + } + bprm->secureexec = 1; + } + + if (label->proxy != new->proxy) { + /* when transitioning clear unsafe personality bits */ + if (DEBUG_ON) { + dbg_printk("apparmor: clearing unsafe personality bits. %s label=", + bprm->filename); + aa_label_printk(new, GFP_KERNEL); + dbg_printk("\n"); + } + bprm->per_clear |= PER_CLEAR_ON_SETID; + } + aa_put_label(cred_label(bprm->cred)); + /* transfer reference, released when cred is freed */ + set_cred_label(bprm->cred, new); + +done: + aa_put_label(label); + aa_put_buffer(buffer); + + return error; + +audit: + error = fn_for_each(label, profile, + aa_audit_file(current_cred(), profile, &nullperms, + OP_EXEC, MAY_EXEC, + bprm->filename, NULL, new, + vfsuid_into_kuid(vfsuid), info, error)); + aa_put_label(new); + goto done; } /* * Functions for self directed profile change */ -/** - * new_compound_name - create an hname with @n2 appended to @n1 - * @n1: base of hname (NOT NULL) - * @n2: name to append (NOT NULL) + +/* helper fn for change_hat * - * Returns: new name or NULL on error + * Returns: label for hat transition OR ERR_PTR. Does NOT return NULL */ -static char *new_compound_name(const char *n1, const char *n2) +static struct aa_label *build_change_hat(const struct cred *subj_cred, + struct aa_profile *profile, + const char *name, bool sibling) { - char *name = kmalloc(strlen(n1) + strlen(n2) + 3, GFP_KERNEL); - if (name) - sprintf(name, "%s//%s", n1, n2); - return name; + struct aa_profile *root, *hat = NULL; + const char *info = NULL; + int error = 0; + + if (sibling && PROFILE_IS_HAT(profile)) { + root = aa_get_profile_rcu(&profile->parent); + } else if (!sibling && !PROFILE_IS_HAT(profile)) { + root = aa_get_profile(profile); + } else { + info = "conflicting target types"; + error = -EPERM; + goto audit; + } + + hat = aa_find_child(root, name); + if (!hat) { + error = -ENOENT; + if (COMPLAIN_MODE(profile)) { + hat = aa_new_learning_profile(profile, true, name, + GFP_KERNEL); + if (!hat) { + info = "failed null profile create"; + error = -ENOMEM; + } + } + } + aa_put_profile(root); + +audit: + aa_audit_file(subj_cred, profile, &nullperms, OP_CHANGE_HAT, + AA_MAY_CHANGEHAT, + name, hat ? hat->base.hname : NULL, + hat ? &hat->label : NULL, GLOBAL_ROOT_UID, info, + error); + if (!hat || (error && error != -ENOENT)) + return ERR_PTR(error); + /* if hat && error - complain mode, already audited and we adjust for + * complain mode allow by returning hat->label + */ + return &hat->label; +} + +/* helper fn for changing into a hat + * + * Returns: label for hat transition or ERR_PTR. Does not return NULL + */ +static struct aa_label *change_hat(const struct cred *subj_cred, + struct aa_label *label, const char *hats[], + int count, int flags) +{ + struct aa_profile *profile, *root, *hat = NULL; + struct aa_label *new; + struct label_it it; + bool sibling = false; + const char *name, *info = NULL; + int i, error; + + AA_BUG(!label); + AA_BUG(!hats); + AA_BUG(count < 1); + + if (PROFILE_IS_HAT(labels_profile(label))) + sibling = true; + + /*find first matching hat */ + for (i = 0; i < count && !hat; i++) { + name = hats[i]; + label_for_each_in_ns(it, labels_ns(label), label, profile) { + if (sibling && PROFILE_IS_HAT(profile)) { + root = aa_get_profile_rcu(&profile->parent); + } else if (!sibling && !PROFILE_IS_HAT(profile)) { + root = aa_get_profile(profile); + } else { /* conflicting change type */ + info = "conflicting targets types"; + error = -EPERM; + goto fail; + } + hat = aa_find_child(root, name); + aa_put_profile(root); + if (!hat) { + if (!COMPLAIN_MODE(profile)) + goto outer_continue; + /* complain mode succeed as if hat */ + } else if (!PROFILE_IS_HAT(hat)) { + info = "target not hat"; + error = -EPERM; + aa_put_profile(hat); + goto fail; + } + aa_put_profile(hat); + } + /* found a hat for all profiles in ns */ + goto build; +outer_continue: + ; + } + /* no hats that match, find appropriate error + * + * In complain mode audit of the failure is based off of the first + * hat supplied. This is done due how userspace interacts with + * change_hat. + */ + name = NULL; + label_for_each_in_ns(it, labels_ns(label), label, profile) { + if (!list_empty(&profile->base.profiles)) { + info = "hat not found"; + error = -ENOENT; + goto fail; + } + } + info = "no hats defined"; + error = -ECHILD; + +fail: + label_for_each_in_ns(it, labels_ns(label), label, profile) { + /* + * no target as it has failed to be found or built + * + * change_hat uses probing and should not log failures + * related to missing hats + */ + /* TODO: get rid of GLOBAL_ROOT_UID */ + if (count > 1 || COMPLAIN_MODE(profile)) { + aa_audit_file(subj_cred, profile, &nullperms, + OP_CHANGE_HAT, + AA_MAY_CHANGEHAT, name, NULL, NULL, + GLOBAL_ROOT_UID, info, error); + } + } + return ERR_PTR(error); + +build: + new = fn_label_build_in_ns(label, profile, GFP_KERNEL, + build_change_hat(subj_cred, profile, name, + sibling), + aa_get_label(&profile->label)); + if (!new) { + info = "label build failed"; + error = -ENOMEM; + goto fail; + } /* else if (IS_ERR) build_change_hat has logged error so return new */ + + return new; } /** @@ -598,139 +1206,176 @@ static char *new_compound_name(const char *n1, const char *n2) * @hats: vector of hat names to try changing into (MAYBE NULL if @count == 0) * @count: number of hat names in @hats * @token: magic value to validate the hat change - * @permtest: true if this is just a permission test + * @flags: flags affecting behavior of the change + * + * Returns %0 on success, error otherwise. * * Change to the first profile specified in @hats that exists, and store * the @hat_magic in the current task context. If the count == 0 and the * @token matches that stored in the current task context, return to the * top level profile. * - * Returns %0 on success, error otherwise. + * change_hat only applies to profiles in the current ns, and each profile + * in the ns must make the same transition otherwise change_hat will fail. */ -int aa_change_hat(const char *hats[], int count, u64 token, bool permtest) +int aa_change_hat(const char *hats[], int count, u64 token, int flags) { - const struct cred *cred; - struct aa_task_cxt *cxt; - struct aa_profile *profile, *previous_profile, *hat = NULL; - char *name = NULL; - int i; - struct file_perms perms = {}; - const char *target = NULL, *info = NULL; + const struct cred *subj_cred; + struct aa_task_ctx *ctx = task_ctx(current); + struct aa_label *label, *previous, *new = NULL, *target = NULL; + struct aa_profile *profile; + struct aa_perms perms = {}; + const char *info = NULL; int error = 0; + /* released below */ + subj_cred = get_current_cred(); + label = aa_get_newest_cred_label(subj_cred); + previous = aa_get_newest_label(ctx->previous); + /* - * Fail explicitly requested domain transitions if no_new_privs. - * There is no exception for unconfined as change_hat is not - * available. + * Detect no new privs being set, and store the label it + * occurred under. Ideally this would happen when nnp + * is set but there isn't a good way to do that yet. + * + * Testing for unconfined must be done before the subset test */ - if (current->no_new_privs) - return -EPERM; + if (task_no_new_privs(current) && !unconfined(label) && !ctx->nnp) + ctx->nnp = aa_get_label(label); - /* released below */ - cred = get_current_cred(); - cxt = cred_cxt(cred); - profile = aa_cred_profile(cred); - previous_profile = cxt->previous; + /* return -EPERM when unconfined doesn't have children to avoid + * changing the traditional error code for unconfined. + */ + if (unconfined(label)) { + struct label_it i; + bool empty = true; - if (unconfined(profile)) { - info = "unconfined"; - error = -EPERM; - goto audit; + rcu_read_lock(); + label_for_each_in_ns(i, labels_ns(label), label, profile) { + empty &= list_empty(&profile->base.profiles); + } + rcu_read_unlock(); + + if (empty) { + info = "unconfined can not change_hat"; + error = -EPERM; + goto fail; + } } if (count) { - /* attempting to change into a new hat or switch to a sibling */ - struct aa_profile *root; - root = PROFILE_IS_HAT(profile) ? profile->parent : profile; - - /* find first matching hat */ - for (i = 0; i < count && !hat; i++) - /* released below */ - hat = aa_find_child(root, hats[i]); - if (!hat) { - if (!COMPLAIN_MODE(root) || permtest) { - if (list_empty(&root->base.profiles)) - error = -ECHILD; - else - error = -ENOENT; - goto out; - } + new = change_hat(subj_cred, label, hats, count, flags); + AA_BUG(!new); + if (IS_ERR(new)) { + error = PTR_ERR(new); + new = NULL; + /* already audited */ + goto out; + } - /* - * In complain mode and failed to match any hats. - * Audit the failure is based off of the first hat - * supplied. This is done due how userspace - * interacts with change_hat. - * - * TODO: Add logging of all failed hats - */ + /* target cred is the same as current except new label */ + error = may_change_ptraced_domain(subj_cred, new, &info); + if (error) + goto fail; - /* freed below */ - name = new_compound_name(root->base.hname, hats[0]); - target = name; - /* released below */ - hat = aa_new_null_profile(profile, 1); - if (!hat) { - info = "failed null profile create"; - error = -ENOMEM; - goto audit; - } - } else { - target = hat->base.hname; - if (!PROFILE_IS_HAT(hat)) { - info = "target not hat"; - error = -EPERM; - goto audit; - } + /* + * no new privs prevents domain transitions that would + * reduce restrictions. + */ + if (task_no_new_privs(current) && !unconfined(label) && + !aa_label_is_unconfined_subset(new, ctx->nnp)) { + /* not an apparmor denial per se, so don't log it */ + AA_DEBUG(DEBUG_DOMAIN, + "no_new_privs - change_hat denied"); + error = -EPERM; + goto out; } - error = may_change_ptraced_domain(current, hat); - if (error) { - info = "ptraced"; + if (flags & AA_CHANGE_TEST) + goto out; + + target = new; + error = aa_set_current_hat(new, token); + if (error == -EACCES) + /* kill task in case of brute force attacks */ + goto kill; + } else if (previous && !(flags & AA_CHANGE_TEST)) { + /* + * no new privs prevents domain transitions that would + * reduce restrictions. + */ + if (task_no_new_privs(current) && !unconfined(label) && + !aa_label_is_unconfined_subset(previous, ctx->nnp)) { + /* not an apparmor denial per se, so don't log it */ + AA_DEBUG(DEBUG_DOMAIN, + "no_new_privs - change_hat denied"); error = -EPERM; - goto audit; + goto out; } - if (!permtest) { - error = aa_set_current_hat(hat, token); - if (error == -EACCES) - /* kill task in case of brute force attacks */ - perms.kill = AA_MAY_CHANGEHAT; - else if (name && !error) - /* reset error for learning of new hats */ - error = -ENOENT; - } - } else if (previous_profile) { - /* Return to saved profile. Kill task if restore fails + /* Return to saved label. Kill task if restore fails * to avoid brute force attacks */ - target = previous_profile->base.hname; - error = aa_restore_previous_profile(token); - perms.kill = AA_MAY_CHANGEHAT; - } else - /* ignore restores when there is no saved profile */ - goto out; - -audit: - if (!permtest) - error = aa_audit_file(profile, &perms, GFP_KERNEL, - OP_CHANGE_HAT, AA_MAY_CHANGEHAT, NULL, - target, GLOBAL_ROOT_UID, info, error); + target = previous; + error = aa_restore_previous_label(token); + if (error) { + if (error == -EACCES) + goto kill; + goto fail; + } + } /* else ignore @flags && restores when there is no saved profile */ out: - aa_put_profile(hat); - kfree(name); - put_cred(cred); + aa_put_label(new); + aa_put_label(previous); + aa_put_label(label); + put_cred(subj_cred); + + return error; + +kill: + info = "failed token match"; + perms.kill = AA_MAY_CHANGEHAT; + +fail: + fn_for_each_in_ns(label, profile, + aa_audit_file(subj_cred, profile, &perms, OP_CHANGE_HAT, + AA_MAY_CHANGEHAT, NULL, NULL, target, + GLOBAL_ROOT_UID, info, error)); + + goto out; +} + + +static int change_profile_perms_wrapper(const char *op, const char *name, + const struct cred *subj_cred, + struct aa_profile *profile, + struct aa_label *target, bool stack, + u32 request, struct aa_perms *perms) +{ + struct aa_ruleset *rules = profile->label.rules[0]; + const char *info = NULL; + int error = 0; + + if (!error) + error = change_profile_perms(profile, target, stack, request, + rules->file->start[AA_CLASS_FILE], + perms); + if (error) + error = aa_audit_file(subj_cred, profile, perms, op, request, + name, + NULL, target, GLOBAL_ROOT_UID, info, + error); return error; } +static const char *stack_msg = "change_profile unprivileged unconfined converted to stacking"; + /** * aa_change_profile - perform a one-way profile transition - * @ns_name: name of the profile namespace to change to (MAYBE NULL) - * @hname: name of profile to change to (MAYBE NULL) - * @onexec: whether this transition is to take place immediately or at exec - * @permtest: true if this is just a permission test + * @fqname: name of profile may include namespace (NOT NULL) + * @flags: flags affecting change behavior * * Change to new profile @name. Unlike with hats, there is no way * to change back. If @name isn't specified the current profile name is @@ -740,111 +1385,197 @@ out: * * Returns %0 on success, error otherwise. */ -int aa_change_profile(const char *ns_name, const char *hname, bool onexec, - bool permtest) +int aa_change_profile(const char *fqname, int flags) { - const struct cred *cred; - struct aa_profile *profile, *target = NULL; - struct aa_namespace *ns = NULL; - struct file_perms perms = {}; - const char *name = NULL, *info = NULL; - int op, error = 0; + struct aa_label *label, *new = NULL, *target = NULL; + struct aa_profile *profile; + struct aa_perms perms = {}; + const char *info = NULL; + const char *auditname = fqname; /* retain leading & if stack */ + bool stack = flags & AA_CHANGE_STACK; + struct aa_task_ctx *ctx = task_ctx(current); + const struct cred *subj_cred = get_current_cred(); + int error = 0; + char *op; u32 request; - if (!hname && !ns_name) + label = aa_get_current_label(); + + /* + * Detect no new privs being set, and store the label it + * occurred under. Ideally this would happen when nnp + * is set but there isn't a good way to do that yet. + * + * Testing for unconfined must be done before the subset test + */ + if (task_no_new_privs(current) && !unconfined(label) && !ctx->nnp) + ctx->nnp = aa_get_label(label); + + if (!fqname || !*fqname) { + aa_put_label(label); + AA_DEBUG(DEBUG_DOMAIN, "no profile name"); return -EINVAL; + } - if (onexec) { + if (flags & AA_CHANGE_ONEXEC) { request = AA_MAY_ONEXEC; - op = OP_CHANGE_ONEXEC; + if (stack) + op = OP_STACK_ONEXEC; + else + op = OP_CHANGE_ONEXEC; } else { request = AA_MAY_CHANGE_PROFILE; - op = OP_CHANGE_PROFILE; + if (stack) + op = OP_STACK; + else + op = OP_CHANGE_PROFILE; } - cred = get_current_cred(); - profile = aa_cred_profile(cred); - - /* - * Fail explicitly requested domain transitions if no_new_privs - * and not unconfined. - * Domain transitions from unconfined are allowed even when - * no_new_privs is set because this aways results in a reduction - * of permissions. + /* This should move to a per profile test. Requires pushing build + * into callback */ - if (current->no_new_privs && !unconfined(profile)) { - put_cred(cred); - return -EPERM; - } - - if (ns_name) { - /* released below */ - ns = aa_find_namespace(profile->ns, ns_name); - if (!ns) { - /* we don't create new namespace in complain mode */ - name = ns_name; - info = "namespace not found"; - error = -ENOENT; - goto audit; - } - } else - /* released below */ - ns = aa_get_namespace(profile->ns); - - /* if the name was not specified, use the name of the current profile */ - if (!hname) { - if (unconfined(profile)) - hname = ns->unconfined->base.hname; - else - hname = profile->base.hname; + if (!stack && unconfined(label) && + label == &labels_ns(label)->unconfined->label && + aa_unprivileged_unconfined_restricted && + /* TODO: refactor so this check is a fn */ + cap_capable(current_cred(), &init_user_ns, CAP_MAC_OVERRIDE, + CAP_OPT_NOAUDIT)) { + /* regardless of the request in this case apparmor + * stacks against unconfined so admin set policy can't be + * by-passed + */ + stack = true; + perms.audit = request; + (void) fn_for_each_in_ns(label, profile, + aa_audit_file(subj_cred, profile, &perms, op, + request, auditname, NULL, target, + GLOBAL_ROOT_UID, stack_msg, 0)); + perms.audit = 0; } - perms = change_profile_perms(profile, ns, hname, request, - profile->file.start); - if (!(perms.allow & request)) { - error = -EACCES; - goto audit; + if (*fqname == '&') { + stack = true; + /* don't have label_parse() do stacking */ + fqname++; } + target = aa_label_parse(label, fqname, GFP_KERNEL, true, false); + if (IS_ERR(target)) { + struct aa_profile *tprofile; - /* released below */ - target = aa_lookup_profile(ns, hname); - if (!target) { - info = "profile not found"; - error = -ENOENT; - if (permtest || !COMPLAIN_MODE(profile)) + info = "label not found"; + error = PTR_ERR(target); + target = NULL; + /* + * TODO: fixme using labels_profile is not right - do profile + * per complain profile + */ + if ((flags & AA_CHANGE_TEST) || + !COMPLAIN_MODE(labels_profile(label))) goto audit; /* released below */ - target = aa_new_null_profile(profile, 0); - if (!target) { + tprofile = aa_new_learning_profile(labels_profile(label), false, + fqname, GFP_KERNEL); + if (!tprofile) { info = "failed null profile create"; error = -ENOMEM; goto audit; } + target = &tprofile->label; + goto check; } + /* + * self directed transitions only apply to current policy ns + * TODO: currently requiring perms for stacking and straight change + * stacking doesn't strictly need this. Determine how much + * we want to loosen this restriction for stacking + * + * if (!stack) { + */ + error = fn_for_each_in_ns(label, profile, + change_profile_perms_wrapper(op, auditname, + subj_cred, + profile, target, stack, + request, &perms)); + if (error) + /* auditing done in change_profile_perms_wrapper */ + goto out; + + /* } */ + +check: /* check if tracing task is allowed to trace target domain */ - error = may_change_ptraced_domain(current, target); - if (error) { - info = "ptrace prevents transition"; + error = may_change_ptraced_domain(subj_cred, target, &info); + if (error && !fn_for_each_in_ns(label, profile, + COMPLAIN_MODE(profile))) goto audit; + + /* TODO: add permission check to allow this + * if ((flags & AA_CHANGE_ONEXEC) && !current_is_single_threaded()) { + * info = "not a single threaded task"; + * error = -EACCES; + * goto audit; + * } + */ + if (flags & AA_CHANGE_TEST) + goto out; + + /* stacking is always a subset, so only check the nonstack case */ + if (!stack) { + new = fn_label_build_in_ns(label, profile, GFP_KERNEL, + aa_get_label(target), + aa_get_label(&profile->label)); + /* + * no new privs prevents domain transitions that would + * reduce restrictions. + */ + if (task_no_new_privs(current) && !unconfined(label) && + !aa_label_is_unconfined_subset(new, ctx->nnp)) { + /* not an apparmor denial per se, so don't log it */ + AA_DEBUG(DEBUG_DOMAIN, + "no_new_privs - change_hat denied"); + error = -EPERM; + goto out; + } } - if (permtest) - goto audit; + if (!(flags & AA_CHANGE_ONEXEC)) { + /* only transition profiles in the current ns */ + if (stack) + new = aa_label_merge(label, target, GFP_KERNEL); + if (IS_ERR_OR_NULL(new)) { + info = "failed to build target label"; + if (!new) + error = -ENOMEM; + else + error = PTR_ERR(new); + new = NULL; + perms.allow = 0; + goto audit; + } + error = aa_replace_current_label(new); + } else { + if (new) { + aa_put_label(new); + new = NULL; + } - if (onexec) - error = aa_set_current_onexec(target); - else - error = aa_replace_current_profile(target); + /* full transition will be built in exec path */ + aa_set_current_onexec(target, stack); + } audit: - if (!permtest) - error = aa_audit_file(profile, &perms, GFP_KERNEL, op, request, - name, hname, GLOBAL_ROOT_UID, info, error); + error = fn_for_each_in_ns(label, profile, + aa_audit_file(subj_cred, + profile, &perms, op, request, auditname, + NULL, new ? new : target, + GLOBAL_ROOT_UID, info, error)); - aa_put_namespace(ns); - aa_put_profile(target); - put_cred(cred); +out: + aa_put_label(new); + aa_put_label(target); + aa_put_label(label); + put_cred(subj_cred); return error; } |