From 223981db9bafb80f558162c148f261e2ff043dbe Mon Sep 17 00:00:00 2001 From: Casey Schaufler Date: Tue, 12 Sep 2023 13:56:54 -0700 Subject: AppArmor: Add selfattr hooks Add hooks for setselfattr and getselfattr. These hooks are not very different from their setprocattr and getprocattr equivalents, and much of the code is shared. Signed-off-by: Casey Schaufler Acked-by: John Johansen [PM: forward ported beyond v6.6 due merge window changes] Signed-off-by: Paul Moore --- security/apparmor/include/procattr.h | 2 +- security/apparmor/lsm.c | 91 +++++++++++++++++++++++++++++++++--- security/apparmor/procattr.c | 10 ++-- 3 files changed, 92 insertions(+), 11 deletions(-) (limited to 'security') diff --git a/security/apparmor/include/procattr.h b/security/apparmor/include/procattr.h index 31689437e0e1..03dbfdb2f2c0 100644 --- a/security/apparmor/include/procattr.h +++ b/security/apparmor/include/procattr.h @@ -11,7 +11,7 @@ #ifndef __AA_PROCATTR_H #define __AA_PROCATTR_H -int aa_getprocattr(struct aa_label *label, char **string); +int aa_getprocattr(struct aa_label *label, char **string, bool newline); int aa_setprocattr_changehat(char *args, size_t size, int flags); #endif /* __AA_PROCATTR_H */ diff --git a/security/apparmor/lsm.c b/security/apparmor/lsm.c index 093da0a9dbd8..8165f80c10ff 100644 --- a/security/apparmor/lsm.c +++ b/security/apparmor/lsm.c @@ -776,6 +776,55 @@ static int apparmor_sb_pivotroot(const struct path *old_path, return error; } +static int apparmor_getselfattr(unsigned int attr, struct lsm_ctx __user *lx, + size_t *size, u32 flags) +{ + int error = -ENOENT; + struct aa_task_ctx *ctx = task_ctx(current); + struct aa_label *label = NULL; + size_t total_len = 0; + char *value; + + switch (attr) { + case LSM_ATTR_CURRENT: + label = aa_get_newest_label(cred_label(current_cred())); + break; + case LSM_ATTR_PREV: + if (ctx->previous) + label = aa_get_newest_label(ctx->previous); + break; + case LSM_ATTR_EXEC: + if (ctx->onexec) + label = aa_get_newest_label(ctx->onexec); + break; + default: + error = -EOPNOTSUPP; + break; + } + + if (label) { + error = aa_getprocattr(label, &value, false); + if (error > 0) { + total_len = ALIGN(struct_size(lx, ctx, error), 8); + if (total_len > *size) + error = -E2BIG; + else if (lx) + error = lsm_fill_user_ctx(lx, value, error, + LSM_ID_APPARMOR, 0); + else + error = 1; + } + kfree(value); + } + + aa_put_label(label); + + *size = total_len; + if (error < 0) + return error; + return 1; +} + static int apparmor_getprocattr(struct task_struct *task, const char *name, char **value) { @@ -795,7 +844,7 @@ static int apparmor_getprocattr(struct task_struct *task, const char *name, error = -EINVAL; if (label) - error = aa_getprocattr(label, value); + error = aa_getprocattr(label, value, true); aa_put_label(label); put_cred(cred); @@ -803,8 +852,7 @@ static int apparmor_getprocattr(struct task_struct *task, const char *name, return error; } -static int apparmor_setprocattr(const char *name, void *value, - size_t size) +static int do_setattr(u64 attr, void *value, size_t size) { char *command, *largs = NULL, *args = value; size_t arg_size; @@ -835,7 +883,7 @@ static int apparmor_setprocattr(const char *name, void *value, goto out; arg_size = size - (args - (largs ? largs : (char *) value)); - if (strcmp(name, "current") == 0) { + if (attr == LSM_ATTR_CURRENT) { if (strcmp(command, "changehat") == 0) { error = aa_setprocattr_changehat(args, arg_size, AA_CHANGE_NOFLAGS); @@ -850,7 +898,7 @@ static int apparmor_setprocattr(const char *name, void *value, error = aa_change_profile(args, AA_CHANGE_STACK); } else goto fail; - } else if (strcmp(name, "exec") == 0) { + } else if (attr == LSM_ATTR_EXEC) { if (strcmp(command, "exec") == 0) error = aa_change_profile(args, AA_CHANGE_ONEXEC); else if (strcmp(command, "stack") == 0) @@ -870,13 +918,42 @@ out: fail: ad.subj_label = begin_current_label_crit_section(); - ad.info = name; + if (attr == LSM_ATTR_CURRENT) + ad.info = "current"; + else if (attr == LSM_ATTR_EXEC) + ad.info = "exec"; + else + ad.info = "invalid"; ad.error = error = -EINVAL; aa_audit_msg(AUDIT_APPARMOR_DENIED, &ad, NULL); end_current_label_crit_section(ad.subj_label); goto out; } +static int apparmor_setselfattr(unsigned int attr, struct lsm_ctx *ctx, + size_t size, u32 flags) +{ + int rc; + + if (attr != LSM_ATTR_CURRENT && attr != LSM_ATTR_EXEC) + return -EOPNOTSUPP; + + rc = do_setattr(attr, ctx->ctx, ctx->ctx_len); + if (rc > 0) + return 0; + return rc; +} + +static int apparmor_setprocattr(const char *name, void *value, + size_t size) +{ + int attr = lsm_name_to_attr(name); + + if (attr) + return do_setattr(attr, value, size); + return -EINVAL; +} + /** * apparmor_bprm_committing_creds - do task cleanup on committing new creds * @bprm: binprm for the exec (NOT NULL) @@ -1424,6 +1501,8 @@ static struct security_hook_list apparmor_hooks[] __ro_after_init = { LSM_HOOK_INIT(file_lock, apparmor_file_lock), LSM_HOOK_INIT(file_truncate, apparmor_file_truncate), + LSM_HOOK_INIT(getselfattr, apparmor_getselfattr), + LSM_HOOK_INIT(setselfattr, apparmor_setselfattr), LSM_HOOK_INIT(getprocattr, apparmor_getprocattr), LSM_HOOK_INIT(setprocattr, apparmor_setprocattr), diff --git a/security/apparmor/procattr.c b/security/apparmor/procattr.c index 197d41f9c32b..e3857e3d7c6c 100644 --- a/security/apparmor/procattr.c +++ b/security/apparmor/procattr.c @@ -20,6 +20,7 @@ * aa_getprocattr - Return the label information for @label * @label: the label to print label info about (NOT NULL) * @string: Returns - string containing the label info (NOT NULL) + * @newline: indicates that a newline should be added * * Requires: label != NULL && string != NULL * @@ -27,7 +28,7 @@ * * Returns: size of string placed in @string else error code on failure */ -int aa_getprocattr(struct aa_label *label, char **string) +int aa_getprocattr(struct aa_label *label, char **string, bool newline) { struct aa_ns *ns = labels_ns(label); struct aa_ns *current_ns = aa_get_current_ns(); @@ -57,11 +58,12 @@ int aa_getprocattr(struct aa_label *label, char **string) return len; } - (*string)[len] = '\n'; - (*string)[len + 1] = 0; + if (newline) + (*string)[len++] = '\n'; + (*string)[len] = 0; aa_put_ns(current_ns); - return len + 1; + return len; } /** -- cgit