From f9df6458218f4fe8a1c3bf0af89c1fa9eaf0db39 Mon Sep 17 00:00:00 2001 From: Andrew Perepechko Date: Thu, 24 Dec 2015 11:09:41 -0500 Subject: selinux: export validatetrans decisions Make validatetrans decisions available through selinuxfs. "/validatetrans" is added to selinuxfs for this purpose. This functionality is needed by file system servers implemented in userspace or kernelspace without the VFS layer. Writing "$oldcontext $newcontext $tclass $taskcontext" to /validatetrans is expected to return 0 if the transition is allowed and -EPERM otherwise. Signed-off-by: Andrew Perepechko CC: andrew.perepechko@seagate.com Acked-by: Stephen Smalley Signed-off-by: Paul Moore --- security/selinux/include/classmap.h | 2 +- security/selinux/include/security.h | 3 ++ security/selinux/selinuxfs.c | 80 +++++++++++++++++++++++++++++++++++++ security/selinux/ss/services.c | 34 ++++++++++++---- 4 files changed, 111 insertions(+), 8 deletions(-) diff --git a/security/selinux/include/classmap.h b/security/selinux/include/classmap.h index 5a4eef59aeff..ef83c4b85a33 100644 --- a/security/selinux/include/classmap.h +++ b/security/selinux/include/classmap.h @@ -21,7 +21,7 @@ struct security_class_mapping secclass_map[] = { { "compute_av", "compute_create", "compute_member", "check_context", "load_policy", "compute_relabel", "compute_user", "setenforce", "setbool", "setsecparam", - "setcheckreqprot", "read_policy", NULL } }, + "setcheckreqprot", "read_policy", "validate_trans", NULL } }, { "process", { "fork", "transition", "sigchld", "sigkill", "sigstop", "signull", "signal", "ptrace", "getsched", "setsched", diff --git a/security/selinux/include/security.h b/security/selinux/include/security.h index 223e9fd15d66..38feb55d531a 100644 --- a/security/selinux/include/security.h +++ b/security/selinux/include/security.h @@ -187,6 +187,9 @@ int security_node_sid(u16 domain, void *addr, u32 addrlen, int security_validate_transition(u32 oldsid, u32 newsid, u32 tasksid, u16 tclass); +int security_validate_transition_user(u32 oldsid, u32 newsid, u32 tasksid, + u16 tclass); + int security_bounded_transition(u32 oldsid, u32 newsid); int security_sid_mls_copy(u32 sid, u32 mls_sid, u32 *new_sid); diff --git a/security/selinux/selinuxfs.c b/security/selinux/selinuxfs.c index c02da25d7b63..0dc407dac3b9 100644 --- a/security/selinux/selinuxfs.c +++ b/security/selinux/selinuxfs.c @@ -116,6 +116,7 @@ enum sel_inos { SEL_DENY_UNKNOWN, /* export unknown deny handling to userspace */ SEL_STATUS, /* export current status using mmap() */ SEL_POLICY, /* allow userspace to read the in kernel policy */ + SEL_VALIDATE_TRANS, /* compute validatetrans decision */ SEL_INO_NEXT, /* The next inode number to use */ }; @@ -653,6 +654,83 @@ static const struct file_operations sel_checkreqprot_ops = { .llseek = generic_file_llseek, }; +static ssize_t sel_write_validatetrans(struct file *file, + const char __user *buf, + size_t count, loff_t *ppos) +{ + char *oldcon = NULL, *newcon = NULL, *taskcon = NULL; + char *req = NULL; + u32 osid, nsid, tsid; + u16 tclass; + int rc; + + rc = task_has_security(current, SECURITY__VALIDATE_TRANS); + if (rc) + goto out; + + rc = -ENOMEM; + if (count >= PAGE_SIZE) + goto out; + + /* No partial writes. */ + rc = -EINVAL; + if (*ppos != 0) + goto out; + + rc = -ENOMEM; + req = kzalloc(count + 1, GFP_KERNEL); + if (!req) + goto out; + + rc = -EFAULT; + if (copy_from_user(req, buf, count)) + goto out; + + rc = -ENOMEM; + oldcon = kzalloc(count + 1, GFP_KERNEL); + if (!oldcon) + goto out; + + newcon = kzalloc(count + 1, GFP_KERNEL); + if (!newcon) + goto out; + + taskcon = kzalloc(count + 1, GFP_KERNEL); + if (!taskcon) + goto out; + + rc = -EINVAL; + if (sscanf(req, "%s %s %hu %s", oldcon, newcon, &tclass, taskcon) != 4) + goto out; + + rc = security_context_str_to_sid(oldcon, &osid, GFP_KERNEL); + if (rc) + goto out; + + rc = security_context_str_to_sid(newcon, &nsid, GFP_KERNEL); + if (rc) + goto out; + + rc = security_context_str_to_sid(taskcon, &tsid, GFP_KERNEL); + if (rc) + goto out; + + rc = security_validate_transition_user(osid, nsid, tsid, tclass); + if (!rc) + rc = count; +out: + kfree(req); + kfree(oldcon); + kfree(newcon); + kfree(taskcon); + return rc; +} + +static const struct file_operations sel_transition_ops = { + .write = sel_write_validatetrans, + .llseek = generic_file_llseek, +}; + /* * Remaining nodes use transaction based IO methods like nfsd/nfsctl.c */ @@ -1759,6 +1837,8 @@ static int sel_fill_super(struct super_block *sb, void *data, int silent) [SEL_DENY_UNKNOWN] = {"deny_unknown", &sel_handle_unknown_ops, S_IRUGO}, [SEL_STATUS] = {"status", &sel_handle_status_ops, S_IRUGO}, [SEL_POLICY] = {"policy", &sel_policy_ops, S_IRUGO}, + [SEL_VALIDATE_TRANS] = {"validatetrans", &sel_transition_ops, + S_IWUGO}, /* last one */ {""} }; ret = simple_fill_super(sb, SELINUX_MAGIC, selinux_files); diff --git a/security/selinux/ss/services.c b/security/selinux/ss/services.c index ebb5eb3c318c..ebda97333f1b 100644 --- a/security/selinux/ss/services.c +++ b/security/selinux/ss/services.c @@ -778,8 +778,8 @@ out: return -EPERM; } -int security_validate_transition(u32 oldsid, u32 newsid, u32 tasksid, - u16 orig_tclass) +static int security_compute_validatetrans(u32 oldsid, u32 newsid, u32 tasksid, + u16 orig_tclass, bool user) { struct context *ocontext; struct context *ncontext; @@ -794,11 +794,12 @@ int security_validate_transition(u32 oldsid, u32 newsid, u32 tasksid, read_lock(&policy_rwlock); - tclass = unmap_class(orig_tclass); + if (!user) + tclass = unmap_class(orig_tclass); + else + tclass = orig_tclass; if (!tclass || tclass > policydb.p_classes.nprim) { - printk(KERN_ERR "SELinux: %s: unrecognized class %d\n", - __func__, tclass); rc = -EINVAL; goto out; } @@ -832,8 +833,13 @@ int security_validate_transition(u32 oldsid, u32 newsid, u32 tasksid, while (constraint) { if (!constraint_expr_eval(ocontext, ncontext, tcontext, constraint->expr)) { - rc = security_validtrans_handle_fail(ocontext, ncontext, - tcontext, tclass); + if (user) + rc = -EPERM; + else + rc = security_validtrans_handle_fail(ocontext, + ncontext, + tcontext, + tclass); goto out; } constraint = constraint->next; @@ -844,6 +850,20 @@ out: return rc; } +int security_validate_transition_user(u32 oldsid, u32 newsid, u32 tasksid, + u16 tclass) +{ + return security_compute_validatetrans(oldsid, newsid, tasksid, + tclass, true); +} + +int security_validate_transition(u32 oldsid, u32 newsid, u32 tasksid, + u16 orig_tclass) +{ + return security_compute_validatetrans(oldsid, newsid, tasksid, + orig_tclass, false); +} + /* * security_bounded_transition - check whether the given * transition is directed to bounded, or not. -- cgit