1 files changed, 370 insertions, 147 deletions

diff --git a/security/apparmor/file.c b/security/apparmor/file.c
index 750564c3ab71..3382518b87fa 100644
--- a/security/apparmor/file.c
+++ b/security/apparmor/file.c
@@ -12,15 +12,30 @@
  * License.
  */
 
+#include <linux/tty.h>
+#include <linux/fdtable.h>
+#include <linux/file.h>
+
 #include "include/apparmor.h"
 #include "include/audit.h"
+#include "include/context.h"
 #include "include/file.h"
 #include "include/match.h"
 #include "include/path.h"
 #include "include/policy.h"
+#include "include/label.h"
 
-struct file_perms nullperms;
+static u32 map_mask_to_chr_mask(u32 mask)
+{
+	u32 m = mask & PERMS_CHRS_MASK;
 
+	if (mask & AA_MAY_GETATTR)
+		m |= MAY_READ;
+	if (mask & (AA_MAY_SETATTR | AA_MAY_CHMOD | AA_MAY_CHOWN))
+		m |= MAY_WRITE;
+
+	return m;
+}
 
 /**
  * audit_file_mask - convert mask to permission string
@@ -31,29 +46,7 @@ static void audit_file_mask(struct audit_buffer *ab, u32 mask)
 {
 	char str[10];
 
-	char *m = str;
-
-	if (mask & AA_EXEC_MMAP)
-		*m++ = 'm';
-	if (mask & (MAY_READ | AA_MAY_META_READ))
-		*m++ = 'r';
-	if (mask & (MAY_WRITE | AA_MAY_META_WRITE | AA_MAY_CHMOD |
-		    AA_MAY_CHOWN))
-		*m++ = 'w';
-	else if (mask & MAY_APPEND)
-		*m++ = 'a';
-	if (mask & AA_MAY_CREATE)
-		*m++ = 'c';
-	if (mask & AA_MAY_DELETE)
-		*m++ = 'd';
-	if (mask & AA_MAY_LINK)
-		*m++ = 'l';
-	if (mask & AA_MAY_LOCK)
-		*m++ = 'k';
-	if (mask & MAY_EXEC)
-		*m++ = 'x';
-	*m = '\0';
-
+	aa_perm_mask_to_str(str, aa_file_perm_chrs, map_mask_to_chr_mask(mask));
 	audit_log_string(ab, str);
 }
 
@@ -67,22 +60,26 @@ static void file_audit_cb(struct audit_buffer *ab, void *va)
 	struct common_audit_data *sa = va;
 	kuid_t fsuid = current_fsuid();
 
-	if (aad(sa)->fs.request & AA_AUDIT_FILE_MASK) {
+	if (aad(sa)->request & AA_AUDIT_FILE_MASK) {
 		audit_log_format(ab, " requested_mask=");
-		audit_file_mask(ab, aad(sa)->fs.request);
+		audit_file_mask(ab, aad(sa)->request);
 	}
-	if (aad(sa)->fs.denied & AA_AUDIT_FILE_MASK) {
+	if (aad(sa)->denied & AA_AUDIT_FILE_MASK) {
 		audit_log_format(ab, " denied_mask=");
-		audit_file_mask(ab, aad(sa)->fs.denied);
+		audit_file_mask(ab, aad(sa)->denied);
 	}
-	if (aad(sa)->fs.request & AA_AUDIT_FILE_MASK) {
+	if (aad(sa)->request & AA_AUDIT_FILE_MASK) {
 		audit_log_format(ab, " fsuid=%d",
 				 from_kuid(&init_user_ns, fsuid));
 		audit_log_format(ab, " ouid=%d",
 				 from_kuid(&init_user_ns, aad(sa)->fs.ouid));
 	}
 
-	if (aad(sa)->fs.target) {
+	if (aad(sa)->peer) {
+		audit_log_format(ab, " target=");
+		aa_label_xaudit(ab, labels_ns(aad(sa)->label), aad(sa)->peer,
+				FLAG_VIEW_SUBNS, GFP_ATOMIC);
+	} else if (aad(sa)->fs.target) {
 		audit_log_format(ab, " target=");
 		audit_log_untrustedstring(ab, aad(sa)->fs.target);
 	}
@@ -92,28 +89,30 @@ static void file_audit_cb(struct audit_buffer *ab, void *va)
  * aa_audit_file - handle the auditing of file operations
  * @profile: the profile being enforced  (NOT NULL)
  * @perms: the permissions computed for the request (NOT NULL)
- * @gfp: allocation flags
  * @op: operation being mediated
  * @request: permissions requested
  * @name: name of object being mediated (MAYBE NULL)
  * @target: name of target (MAYBE NULL)
+ * @tlabel: target label (MAY BE NULL)
  * @ouid: object uid
  * @info: extra information message (MAYBE NULL)
  * @error: 0 if operation allowed else failure error code
  *
  * Returns: %0 or error on failure
  */
-int aa_audit_file(struct aa_profile *profile, struct file_perms *perms,
+int aa_audit_file(struct aa_profile *profile, struct aa_perms *perms,
 		  const char *op, u32 request, const char *name,
-		  const char *target, kuid_t ouid, const char *info, int error)
+		  const char *target, struct aa_label *tlabel,
+		  kuid_t ouid, const char *info, int error)
 {
 	int type = AUDIT_APPARMOR_AUTO;
 	DEFINE_AUDIT_DATA(sa, LSM_AUDIT_DATA_TASK, op);
 
 	sa.u.tsk = NULL;
-	aad(&sa)->fs.request = request;
+	aad(&sa)->request = request;
 	aad(&sa)->name = name;
 	aad(&sa)->fs.target = target;
+	aad(&sa)->peer = tlabel;
 	aad(&sa)->fs.ouid = ouid;
 	aad(&sa)->info = info;
 	aad(&sa)->error = error;
@@ -126,34 +125,67 @@ int aa_audit_file(struct aa_profile *profile, struct file_perms *perms,
 			mask = 0xffff;
 
 		/* mask off perms that are not being force audited */
-		aad(&sa)->fs.request &= mask;
+		aad(&sa)->request &= mask;
 
-		if (likely(!aad(&sa)->fs.request))
+		if (likely(!aad(&sa)->request))
 			return 0;
 		type = AUDIT_APPARMOR_AUDIT;
 	} else {
 		/* only report permissions that were denied */
-		aad(&sa)->fs.request = aad(&sa)->fs.request & ~perms->allow;
-		AA_BUG(!aad(&sa)->fs.request);
+		aad(&sa)->request = aad(&sa)->request & ~perms->allow;
+		AA_BUG(!aad(&sa)->request);
 
-		if (aad(&sa)->fs.request & perms->kill)
+		if (aad(&sa)->request & perms->kill)
 			type = AUDIT_APPARMOR_KILL;
 
 		/* quiet known rejects, assumes quiet and kill do not overlap */
-		if ((aad(&sa)->fs.request & perms->quiet) &&
+		if ((aad(&sa)->request & perms->quiet) &&
 		    AUDIT_MODE(profile) != AUDIT_NOQUIET &&
 		    AUDIT_MODE(profile) != AUDIT_ALL)
-			aad(&sa)->fs.request &= ~perms->quiet;
+			aad(&sa)->request &= ~perms->quiet;
 
-		if (!aad(&sa)->fs.request)
-			return COMPLAIN_MODE(profile) ? 0 : aad(&sa)->error;
+		if (!aad(&sa)->request)
+			return aad(&sa)->error;
 	}
 
-	aad(&sa)->fs.denied = aad(&sa)->fs.request & ~perms->allow;
+	aad(&sa)->denied = aad(&sa)->request & ~perms->allow;
 	return aa_audit(type, profile, &sa, file_audit_cb);
 }
 
 /**
+ * is_deleted - test if a file has been completely unlinked
+ * @dentry: dentry of file to test for deletion  (NOT NULL)
+ *
+ * Returns: %1 if deleted else %0
+ */
+static inline bool is_deleted(struct dentry *dentry)
+{
+	if (d_unlinked(dentry) && d_backing_inode(dentry)->i_nlink == 0)
+		return 1;
+	return 0;
+}
+
+static int path_name(const char *op, struct aa_label *label,
+		     const struct path *path, int flags, char *buffer,
+		     const char **name, struct path_cond *cond, u32 request)
+{
+	struct aa_profile *profile;
+	const char *info = NULL;
+	int error;
+
+	error = aa_path_name(path, flags, buffer, name, &info,
+			     labels_profile(label)->disconnected);
+	if (error) {
+		fn_for_each_confined(label, profile,
+			aa_audit_file(profile, &nullperms, op, request, *name,
+				      NULL, NULL, cond->uid, info, error));
+		return error;
+	}
+
+	return 0;
+}
+
+/**
  * map_old_perms - map old file perms layout to the new layout
  * @old: permission set in old mapping
  *
@@ -163,10 +195,10 @@ static u32 map_old_perms(u32 old)
 {
 	u32 new = old & 0xf;
 	if (old & MAY_READ)
-		new |= AA_MAY_META_READ;
+		new |= AA_MAY_GETATTR | AA_MAY_OPEN;
 	if (old & MAY_WRITE)
-		new |= AA_MAY_META_WRITE | AA_MAY_CREATE | AA_MAY_DELETE |
-			AA_MAY_CHMOD | AA_MAY_CHOWN;
+		new |= AA_MAY_SETATTR | AA_MAY_CREATE | AA_MAY_DELETE |
+		       AA_MAY_CHMOD | AA_MAY_CHOWN | AA_MAY_OPEN;
 	if (old & 0x10)
 		new |= AA_MAY_LINK;
 	/* the old mapping lock and link_subset flags where overlaid
@@ -181,7 +213,7 @@ static u32 map_old_perms(u32 old)
 }
 
 /**
- * compute_perms - convert dfa compressed perms to internal perms
+ * aa_compute_fperms - convert dfa compressed perms to internal perms
  * @dfa: dfa to compute perms for   (NOT NULL)
  * @state: state in dfa
  * @cond:  conditions to consider  (NOT NULL)
@@ -191,17 +223,21 @@ static u32 map_old_perms(u32 old)
  *
  * Returns: computed permission set
  */
-static struct file_perms compute_perms(struct aa_dfa *dfa, unsigned int state,
-				       struct path_cond *cond)
+struct aa_perms aa_compute_fperms(struct aa_dfa *dfa, unsigned int state,
+				  struct path_cond *cond)
 {
-	struct file_perms perms;
+	struct aa_perms perms;
 
 	/* FIXME: change over to new dfa format
 	 * currently file perms are encoded in the dfa, new format
 	 * splits the permissions from the dfa.  This mapping can be
 	 * done at profile load
 	 */
-	perms.kill = 0;
+	perms.deny = 0;
+	perms.kill = perms.stop = 0;
+	perms.complain = perms.cond = 0;
+	perms.hide = 0;
+	perms.prompt = 0;
 
 	if (uid_eq(current_fsuid(), cond->uid)) {
 		perms.allow = map_old_perms(dfa_user_allow(dfa, state));
@@ -214,7 +250,7 @@ static struct file_perms compute_perms(struct aa_dfa *dfa, unsigned int state,
 		perms.quiet = map_old_perms(dfa_other_quiet(dfa, state));
 		perms.xindex = dfa_other_xindex(dfa, state);
 	}
-	perms.allow |= AA_MAY_META_READ;
+	perms.allow |= AA_MAY_GETATTR;
 
 	/* change_profile wasn't determined by ownership in old mapping */
 	if (ACCEPT_TABLE(dfa)[state] & 0x80000000)
@@ -237,37 +273,55 @@ static struct file_perms compute_perms(struct aa_dfa *dfa, unsigned int state,
  */
 unsigned int aa_str_perms(struct aa_dfa *dfa, unsigned int start,
 			  const char *name, struct path_cond *cond,
-			  struct file_perms *perms)
+			  struct aa_perms *perms)
 {
 	unsigned int state;
-	if (!dfa) {
-		*perms = nullperms;
-		return DFA_NOMATCH;
-	}
-
 	state = aa_dfa_match(dfa, start, name);
-	*perms = compute_perms(dfa, state, cond);
+	*perms = aa_compute_fperms(dfa, state, cond);
 
 	return state;
 }
 
-/**
- * is_deleted - test if a file has been completely unlinked
- * @dentry: dentry of file to test for deletion  (NOT NULL)
- *
- * Returns: %1 if deleted else %0
- */
-static inline bool is_deleted(struct dentry *dentry)
+int __aa_path_perm(const char *op, struct aa_profile *profile, const char *name,
+		   u32 request, struct path_cond *cond, int flags,
+		   struct aa_perms *perms)
 {
-	if (d_unlinked(dentry) && d_backing_inode(dentry)->i_nlink == 0)
-		return 1;
-	return 0;
+	int e = 0;
+
+	if (profile_unconfined(profile))
+		return 0;
+	aa_str_perms(profile->file.dfa, profile->file.start, name, cond, perms);
+	if (request & ~perms->allow)
+		e = -EACCES;
+	return aa_audit_file(profile, perms, op, request, name, NULL, NULL,
+			     cond->uid, NULL, e);
+}
+
+
+static int profile_path_perm(const char *op, struct aa_profile *profile,
+			     const struct path *path, char *buffer, u32 request,
+			     struct path_cond *cond, int flags,
+			     struct aa_perms *perms)
+{
+	const char *name;
+	int error;
+
+	if (profile_unconfined(profile))
+		return 0;
+
+	error = path_name(op, &profile->label, path,
+			  flags | profile->path_flags, buffer, &name, cond,
+			  request);
+	if (error)
+		return error;
+	return __aa_path_perm(op, profile, name, request, cond, flags,
+			      perms);
 }
 
 /**
  * aa_path_perm - do permissions check & audit for @path
  * @op: operation being checked
- * @profile: profile being enforced  (NOT NULL)
+ * @label: profile being enforced  (NOT NULL)
  * @path: path to check permissions of  (NOT NULL)
  * @flags: any additional path flags beyond what the profile specifies
  * @request: requested permissions
@@ -275,35 +329,23 @@ static inline bool is_deleted(struct dentry *dentry)
  *
  * Returns: %0 else error if access denied or other error
  */
-int aa_path_perm(const char *op, struct aa_profile *profile,
+int aa_path_perm(const char *op, struct aa_label *label,
 		 const struct path *path, int flags, u32 request,
 		 struct path_cond *cond)
 {
+	struct aa_perms perms = {};
+	struct aa_profile *profile;
 	char *buffer = NULL;
-	struct file_perms perms = {};
-	const char *name, *info = NULL;
 	int error;
 
-	flags |= profile->path_flags | (S_ISDIR(cond->mode) ? PATH_IS_DIR : 0);
-	error = aa_path_name(path, flags, &buffer, &name, &info);
-	if (error) {
-		if (error == -ENOENT && is_deleted(path->dentry)) {
-			/* Access to open files that are deleted are
-			 * give a pass (implicit delegation)
-			 */
-			error = 0;
-			info = NULL;
-			perms.allow = request;
-		}
-	} else {
-		aa_str_perms(profile->file.dfa, profile->file.start, name, cond,
-			     &perms);
-		if (request & ~perms.allow)
-			error = -EACCES;
-	}
-	error = aa_audit_file(profile, &perms, op, request, name, NULL,
-			      cond->uid, info, error);
-	kfree(buffer);
+	flags |= PATH_DELEGATE_DELETED | (S_ISDIR(cond->mode) ? PATH_IS_DIR :
+								0);
+	get_buffers(buffer);
+	error = fn_for_each_confined(label, profile,
+			profile_path_perm(op, profile, path, buffer, request,
+					  cond, flags, &perms));
+
+	put_buffers(buffer);
 
 	return error;
 }
@@ -328,65 +370,40 @@ static inline bool xindex_is_subset(u32 link, u32 target)
 	return 1;
 }
 
-/**
- * aa_path_link - Handle hard link permission check
- * @profile: the profile being enforced  (NOT NULL)
- * @old_dentry: the target dentry  (NOT NULL)
- * @new_dir: directory the new link will be created in  (NOT NULL)
- * @new_dentry: the link being created  (NOT NULL)
- *
- * Handle the permission test for a link & target pair.  Permission
- * is encoded as a pair where the link permission is determined
- * first, and if allowed, the target is tested.  The target test
- * is done from the point of the link match (not start of DFA)
- * making the target permission dependent on the link permission match.
- *
- * The subset test if required forces that permissions granted
- * on link are a subset of the permission granted to target.
- *
- * Returns: %0 if allowed else error
- */
-int aa_path_link(struct aa_profile *profile, struct dentry *old_dentry,
-		 const struct path *new_dir, struct dentry *new_dentry)
+static int profile_path_link(struct aa_profile *profile,
+			     const struct path *link, char *buffer,
+			     const struct path *target, char *buffer2,
+			     struct path_cond *cond)
 {
-	struct path link = { .mnt = new_dir->mnt, .dentry = new_dentry };
-	struct path target = { .mnt = new_dir->mnt, .dentry = old_dentry };
-	struct path_cond cond = {
-		d_backing_inode(old_dentry)->i_uid,
-		d_backing_inode(old_dentry)->i_mode
-	};
-	char *buffer = NULL, *buffer2 = NULL;
-	const char *lname, *tname = NULL, *info = NULL;
-	struct file_perms lperms, perms;
+	const char *lname, *tname = NULL;
+	struct aa_perms lperms = {}, perms;
+	const char *info = NULL;
 	u32 request = AA_MAY_LINK;
 	unsigned int state;
 	int error;
 
-	lperms = nullperms;
-
-	/* buffer freed below, lname is pointer in buffer */
-	error = aa_path_name(&link, profile->path_flags, &buffer, &lname,
-			     &info);
+	error = path_name(OP_LINK, &profile->label, link, profile->path_flags,
+			  buffer, &lname, cond, AA_MAY_LINK);
 	if (error)
 		goto audit;
 
 	/* buffer2 freed below, tname is pointer in buffer2 */
-	error = aa_path_name(&target, profile->path_flags, &buffer2, &tname,
-			     &info);
+	error = path_name(OP_LINK, &profile->label, target, profile->path_flags,
+			  buffer2, &tname, cond, AA_MAY_LINK);
 	if (error)
 		goto audit;
 
 	error = -EACCES;
 	/* aa_str_perms - handles the case of the dfa being NULL */
 	state = aa_str_perms(profile->file.dfa, profile->file.start, lname,
-			     &cond, &lperms);
+			     cond, &lperms);
 
 	if (!(lperms.allow & AA_MAY_LINK))
 		goto audit;
 
 	/* test to see if target can be paired with link */
 	state = aa_dfa_null_transition(profile->file.dfa, state);
-	aa_str_perms(profile->file.dfa, state, tname, &cond, &perms);
+	aa_str_perms(profile->file.dfa, state, tname, cond, &perms);
 
 	/* force audit/quiet masks for link are stored in the second entry
 	 * in the link pair.
@@ -397,6 +414,7 @@ int aa_path_link(struct aa_profile *profile, struct dentry *old_dentry,
 
 	if (!(perms.allow & AA_MAY_LINK)) {
 		info = "target restricted";
+		lperms = perms;
 		goto audit;
 	}
 
@@ -404,10 +422,10 @@ int aa_path_link(struct aa_profile *profile, struct dentry *old_dentry,
 	if (!(perms.allow & AA_LINK_SUBSET))
 		goto done_tests;
 
-	/* Do link perm subset test requiring allowed permission on link are a
-	 * subset of the allowed permissions on target.
+	/* Do link perm subset test requiring allowed permission on link are
+	 * a subset of the allowed permissions on target.
 	 */
-	aa_str_perms(profile->file.dfa, profile->file.start, tname, &cond,
+	aa_str_perms(profile->file.dfa, profile->file.start, tname, cond,
 		     &perms);
 
 	/* AA_MAY_LINK is not considered in the subset test */
@@ -429,10 +447,121 @@ done_tests:
 	error = 0;
 
 audit:
-	error = aa_audit_file(profile, &lperms, OP_LINK, request,
-			      lname, tname, cond.uid, info, error);
-	kfree(buffer);
-	kfree(buffer2);
+	return aa_audit_file(profile, &lperms, OP_LINK, request, lname, tname,
+			     NULL, cond->uid, info, error);
+}
+
+/**
+ * aa_path_link - Handle hard link permission check
+ * @label: the label being enforced  (NOT NULL)
+ * @old_dentry: the target dentry  (NOT NULL)
+ * @new_dir: directory the new link will be created in  (NOT NULL)
+ * @new_dentry: the link being created  (NOT NULL)
+ *
+ * Handle the permission test for a link & target pair.  Permission
+ * is encoded as a pair where the link permission is determined
+ * first, and if allowed, the target is tested.  The target test
+ * is done from the point of the link match (not start of DFA)
+ * making the target permission dependent on the link permission match.
+ *
+ * The subset test if required forces that permissions granted
+ * on link are a subset of the permission granted to target.
+ *
+ * Returns: %0 if allowed else error
+ */
+int aa_path_link(struct aa_label *label, struct dentry *old_dentry,
+		 const struct path *new_dir, struct dentry *new_dentry)
+{
+	struct path link = { .mnt = new_dir->mnt, .dentry = new_dentry };
+	struct path target = { .mnt = new_dir->mnt, .dentry = old_dentry };
+	struct path_cond cond = {
+		d_backing_inode(old_dentry)->i_uid,
+		d_backing_inode(old_dentry)->i_mode
+	};
+	char *buffer = NULL, *buffer2 = NULL;
+	struct aa_profile *profile;
+	int error;
+
+	/* buffer freed below, lname is pointer in buffer */
+	get_buffers(buffer, buffer2);
+	error = fn_for_each_confined(label, profile,
+			profile_path_link(profile, &link, buffer, &target,
+					  buffer2, &cond));
+	put_buffers(buffer, buffer2);
+
+	return error;
+}
+
+static void update_file_ctx(struct aa_file_ctx *fctx, struct aa_label *label,
+			    u32 request)
+{
+	struct aa_label *l, *old;
+
+	/* update caching of label on file_ctx */
+	spin_lock(&fctx->lock);
+	old = rcu_dereference_protected(fctx->label,
+					spin_is_locked(&fctx->lock));
+	l = aa_label_merge(old, label, GFP_ATOMIC);
+	if (l) {
+		if (l != old) {
+			rcu_assign_pointer(fctx->label, l);
+			aa_put_label(old);
+		} else
+			aa_put_label(l);
+		fctx->allow |= request;
+	}
+	spin_unlock(&fctx->lock);
+}
+
+static int __file_path_perm(const char *op, struct aa_label *label,
+			    struct aa_label *flabel, struct file *file,
+			    u32 request, u32 denied)
+{
+	struct aa_profile *profile;
+	struct aa_perms perms = {};
+	struct path_cond cond = {
+		.uid = file_inode(file)->i_uid,
+		.mode = file_inode(file)->i_mode
+	};
+	char *buffer;
+	int flags, error;
+
+	/* revalidation due to label out of date. No revocation at this time */
+	if (!denied && aa_label_is_subset(flabel, label))
+		/* TODO: check for revocation on stale profiles */
+		return 0;
+
+	flags = PATH_DELEGATE_DELETED | (S_ISDIR(cond.mode) ? PATH_IS_DIR : 0);
+	get_buffers(buffer);
+
+	/* check every profile in task label not in current cache */
+	error = fn_for_each_not_in_set(flabel, label, profile,
+			profile_path_perm(op, profile, &file->f_path, buffer,
+					  request, &cond, flags, &perms));
+	if (denied && !error) {
+		/*
+		 * check every profile in file label that was not tested
+		 * in the initial check above.
+		 *
+		 * TODO: cache full perms so this only happens because of
+		 * conditionals
+		 * TODO: don't audit here
+		 */
+		if (label == flabel)
+			error = fn_for_each(label, profile,
+				profile_path_perm(op, profile, &file->f_path,
+						  buffer, request, &cond, flags,
+						  &perms));
+		else
+			error = fn_for_each_not_in_set(label, flabel, profile,
+				profile_path_perm(op, profile, &file->f_path,
+						  buffer, request, &cond, flags,
+						  &perms));
+	}
+	if (!error)
+		update_file_ctx(file_ctx(file), label, request);
+
+	put_buffers(buffer);
 
 	return error;
 }
@@ -440,20 +569,114 @@ audit:
 /**
  * aa_file_perm - do permission revalidation check & audit for @file
  * @op: operation being checked
- * @profile: profile being enforced   (NOT NULL)
+ * @label: label being enforced   (NOT NULL)
  * @file: file to revalidate access permissions on  (NOT NULL)
  * @request: requested permissions
  *
  * Returns: %0 if access allowed else error
  */
-int aa_file_perm(const char *op, struct aa_profile *profile, struct file *file,
+int aa_file_perm(const char *op, struct aa_label *label, struct file *file,
 		 u32 request)
 {
-	struct path_cond cond = {
-		.uid = file_inode(file)->i_uid,
-		.mode = file_inode(file)->i_mode
-	};
+	struct aa_file_ctx *fctx;
+	struct aa_label *flabel;
+	u32 denied;
+	int error = 0;
+
+	AA_BUG(!label);
+	AA_BUG(!file);
+
+	fctx = file_ctx(file);
+
+	rcu_read_lock();
+	flabel  = rcu_dereference(fctx->label);
+	AA_BUG(!flabel);
+
+	/* revalidate access, if task is unconfined, or the cached cred
+	 * doesn't match or if the request is for more permissions than
+	 * was granted.
+	 *
+	 * Note: the test for !unconfined(flabel) is to handle file
+	 *       delegation from unconfined tasks
+	 */
+	denied = request & ~fctx->allow;
+	if (unconfined(label) || unconfined(flabel) ||
+	    (!denied && aa_label_is_subset(flabel, label)))
+		goto done;
+
+	/* TODO: label cross check */
+
+	if (file->f_path.mnt && path_mediated_fs(file->f_path.dentry))
+		error = __file_path_perm(op, label, flabel, file, request,
+					 denied);
+
+done:
+	rcu_read_unlock();
+
+	return error;
+}
+
+static void revalidate_tty(struct aa_label *label)
+{
+	struct tty_struct *tty;
+	int drop_tty = 0;
+
+	tty = get_current_tty();
+	if (!tty)
+		return;
+
+	spin_lock(&tty->files_lock);
+	if (!list_empty(&tty->tty_files)) {
+		struct tty_file_private *file_priv;
+		struct file *file;
+		/* TODO: Revalidate access to controlling tty. */
+		file_priv = list_first_entry(&tty->tty_files,
+					     struct tty_file_private, list);
+		file = file_priv->file;
+
+		if (aa_file_perm(OP_INHERIT, label, file, MAY_READ | MAY_WRITE))
+			drop_tty = 1;
+	}
+	spin_unlock(&tty->files_lock);
+	tty_kref_put(tty);
 
-	return aa_path_perm(op, profile, &file->f_path, PATH_DELEGATE_DELETED,
-			    request, &cond);
+	if (drop_tty)
+		no_tty();
+}
+
+static int match_file(const void *p, struct file *file, unsigned int fd)
+{
+	struct aa_label *label = (struct aa_label *)p;
+
+	if (aa_file_perm(OP_INHERIT, label, file, aa_map_file_to_perms(file)))
+		return fd + 1;
+	return 0;
+}
+
+
+/* based on selinux's flush_unauthorized_files */
+void aa_inherit_files(const struct cred *cred, struct files_struct *files)
+{
+	struct aa_label *label = aa_get_newest_cred_label(cred);
+	struct file *devnull = NULL;
+	unsigned int n;
+
+	revalidate_tty(label);
+
+	/* Revalidate access to inherited open files. */
+	n = iterate_fd(files, 0, match_file, label);
+	if (!n) /* none found? */
+		goto out;
+
+	devnull = dentry_open(&aa_null, O_RDWR, cred);
+	if (IS_ERR(devnull))
+		devnull = NULL;
+	/* replace all the matching ones with this */
+	do {
+		replace_fd(n - 1, devnull, 0);
+	} while ((n = iterate_fd(files, n, match_file, label)) != 0);
+	if (devnull)
+		fput(devnull);
+out:
+	aa_put_label(label);
 }