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-rw-r--r--security/apparmor/file.c457
-rw-r--r--security/apparmor/include/file.h217
2 files changed, 674 insertions, 0 deletions
diff --git a/security/apparmor/file.c b/security/apparmor/file.c
new file mode 100644
index 000000000000..7312db741219
--- /dev/null
+++ b/security/apparmor/file.c
@@ -0,0 +1,457 @@
+/*
+ * AppArmor security module
+ *
+ * This file contains AppArmor mediation of files
+ *
+ * Copyright (C) 1998-2008 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 "include/apparmor.h"
+#include "include/audit.h"
+#include "include/file.h"
+#include "include/match.h"
+#include "include/path.h"
+#include "include/policy.h"
+
+struct file_perms nullperms;
+
+
+/**
+ * audit_file_mask - convert mask to permission string
+ * @buffer: buffer to write string to (NOT NULL)
+ * @mask: permission mask to convert
+ */
+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';
+
+ audit_log_string(ab, str);
+}
+
+/**
+ * file_audit_cb - call back for file specific audit fields
+ * @ab: audit_buffer (NOT NULL)
+ * @va: audit struct to audit values of (NOT NULL)
+ */
+static void file_audit_cb(struct audit_buffer *ab, void *va)
+{
+ struct common_audit_data *sa = va;
+ uid_t fsuid = current_fsuid();
+
+ if (sa->aad.fs.request & AA_AUDIT_FILE_MASK) {
+ audit_log_format(ab, " requested_mask=");
+ audit_file_mask(ab, sa->aad.fs.request);
+ }
+ if (sa->aad.fs.denied & AA_AUDIT_FILE_MASK) {
+ audit_log_format(ab, " denied_mask=");
+ audit_file_mask(ab, sa->aad.fs.denied);
+ }
+ if (sa->aad.fs.request & AA_AUDIT_FILE_MASK) {
+ audit_log_format(ab, " fsuid=%d", fsuid);
+ audit_log_format(ab, " ouid=%d", sa->aad.fs.ouid);
+ }
+
+ if (sa->aad.fs.target) {
+ audit_log_format(ab, " target=");
+ audit_log_untrustedstring(ab, sa->aad.fs.target);
+ }
+}
+
+/**
+ * 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)
+ * @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,
+ gfp_t gfp, int op, u32 request, const char *name,
+ const char *target, uid_t ouid, const char *info, int error)
+{
+ int type = AUDIT_APPARMOR_AUTO;
+ struct common_audit_data sa;
+ COMMON_AUDIT_DATA_INIT(&sa, NONE);
+ sa.aad.op = op,
+ sa.aad.fs.request = request;
+ sa.aad.name = name;
+ sa.aad.fs.target = target;
+ sa.aad.fs.ouid = ouid;
+ sa.aad.info = info;
+ sa.aad.error = error;
+
+ if (likely(!sa.aad.error)) {
+ u32 mask = perms->audit;
+
+ if (unlikely(AUDIT_MODE(profile) == AUDIT_ALL))
+ mask = 0xffff;
+
+ /* mask off perms that are not being force audited */
+ sa.aad.fs.request &= mask;
+
+ if (likely(!sa.aad.fs.request))
+ return 0;
+ type = AUDIT_APPARMOR_AUDIT;
+ } else {
+ /* only report permissions that were denied */
+ sa.aad.fs.request = sa.aad.fs.request & ~perms->allow;
+
+ if (sa.aad.fs.request & perms->kill)
+ type = AUDIT_APPARMOR_KILL;
+
+ /* quiet known rejects, assumes quiet and kill do not overlap */
+ if ((sa.aad.fs.request & perms->quiet) &&
+ AUDIT_MODE(profile) != AUDIT_NOQUIET &&
+ AUDIT_MODE(profile) != AUDIT_ALL)
+ sa.aad.fs.request &= ~perms->quiet;
+
+ if (!sa.aad.fs.request)
+ return COMPLAIN_MODE(profile) ? 0 : sa.aad.error;
+ }
+
+ sa.aad.fs.denied = sa.aad.fs.request & ~perms->allow;
+ return aa_audit(type, profile, gfp, &sa, file_audit_cb);
+}
+
+/**
+ * map_old_perms - map old file perms layout to the new layout
+ * @old: permission set in old mapping
+ *
+ * Returns: new permission mapping
+ */
+static u32 map_old_perms(u32 old)
+{
+ u32 new = old & 0xf;
+ if (old & MAY_READ)
+ new |= AA_MAY_META_READ;
+ if (old & MAY_WRITE)
+ new |= AA_MAY_META_WRITE | AA_MAY_CREATE | AA_MAY_DELETE |
+ AA_MAY_CHMOD | AA_MAY_CHOWN;
+ if (old & 0x10)
+ new |= AA_MAY_LINK;
+ /* the old mapping lock and link_subset flags where overlaid
+ * and use was determined by part of a pair that they were in
+ */
+ if (old & 0x20)
+ new |= AA_MAY_LOCK | AA_LINK_SUBSET;
+ if (old & 0x40) /* AA_EXEC_MMAP */
+ new |= AA_EXEC_MMAP;
+
+ new |= AA_MAY_META_READ;
+
+ return new;
+}
+
+/**
+ * compute_perms - 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)
+ *
+ * TODO: convert from dfa + state to permission entry, do computation conversion
+ * at load time.
+ *
+ * Returns: computed permission set
+ */
+static struct file_perms compute_perms(struct aa_dfa *dfa, unsigned int state,
+ struct path_cond *cond)
+{
+ struct file_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;
+
+ if (current_fsuid() == cond->uid) {
+ perms.allow = map_old_perms(dfa_user_allow(dfa, state));
+ perms.audit = map_old_perms(dfa_user_audit(dfa, state));
+ perms.quiet = map_old_perms(dfa_user_quiet(dfa, state));
+ perms.xindex = dfa_user_xindex(dfa, state);
+ } else {
+ perms.allow = map_old_perms(dfa_other_allow(dfa, state));
+ perms.audit = map_old_perms(dfa_other_audit(dfa, state));
+ perms.quiet = map_old_perms(dfa_other_quiet(dfa, state));
+ perms.xindex = dfa_other_xindex(dfa, state);
+ }
+
+ /* change_profile wasn't determined by ownership in old mapping */
+ if (ACCEPT_TABLE(dfa)[state] & 0x80000000)
+ perms.allow |= AA_MAY_CHANGE_PROFILE;
+
+ return perms;
+}
+
+/**
+ * aa_str_perms - find permission that match @name
+ * @dfa: to match against (MAYBE NULL)
+ * @state: state to start matching in
+ * @name: string to match against dfa (NOT NULL)
+ * @cond: conditions to consider for permission set computation (NOT NULL)
+ * @perms: Returns - the permissions found when matching @name
+ *
+ * Returns: the final state in @dfa when beginning @start and walking @name
+ */
+unsigned int aa_str_perms(struct aa_dfa *dfa, unsigned int start,
+ const char *name, struct path_cond *cond,
+ struct file_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);
+
+ 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)
+{
+ if (d_unlinked(dentry) && dentry->d_inode->i_nlink == 0)
+ return 1;
+ return 0;
+}
+
+/**
+ * aa_path_perm - do permissions check & audit for @path
+ * @op: operation being checked
+ * @profile: 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
+ * @cond: conditional info for this request (NOT NULL)
+ *
+ * Returns: %0 else error if access denied or other error
+ */
+int aa_path_perm(int op, struct aa_profile *profile, struct path *path,
+ int flags, u32 request, struct path_cond *cond)
+{
+ 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_get_name(path, flags, &buffer, &name);
+ if (error) {
+ if (error == -ENOENT && is_deleted(path->dentry)) {
+ /* Access to open files that are deleted are
+ * give a pass (implicit delegation)
+ */
+ error = 0;
+ perms.allow = request;
+ } else if (error == -ENOENT)
+ info = "Failed name lookup - deleted entry";
+ else if (error == -ESTALE)
+ info = "Failed name lookup - disconnected path";
+ else if (error == -ENAMETOOLONG)
+ info = "Failed name lookup - name too long";
+ else
+ info = "Failed name lookup";
+ } 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, GFP_KERNEL, op, request, name,
+ NULL, cond->uid, info, error);
+ kfree(buffer);
+
+ return error;
+}
+
+/**
+ * xindex_is_subset - helper for aa_path_link
+ * @link: link permission set
+ * @target: target permission set
+ *
+ * test target x permissions are equal OR a subset of link x permissions
+ * this is done as part of the subset test, where a hardlink must have
+ * a subset of permissions that the target has.
+ *
+ * Returns: %1 if subset else %0
+ */
+static inline bool xindex_is_subset(u32 link, u32 target)
+{
+ if (((link & ~AA_X_UNSAFE) != (target & ~AA_X_UNSAFE)) ||
+ ((link & AA_X_UNSAFE) && !(target & AA_X_UNSAFE)))
+ return 0;
+
+ 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,
+ struct path *new_dir, struct dentry *new_dentry)
+{
+ struct path link = { new_dir->mnt, new_dentry };
+ struct path target = { new_dir->mnt, old_dentry };
+ struct path_cond cond = {
+ old_dentry->d_inode->i_uid,
+ old_dentry->d_inode->i_mode
+ };
+ char *buffer = NULL, *buffer2 = NULL;
+ const char *lname, *tname = NULL, *info = NULL;
+ struct file_perms lperms, perms;
+ u32 request = AA_MAY_LINK;
+ unsigned int state;
+ int error;
+
+ lperms = nullperms;
+
+ /* buffer freed below, lname is pointer in buffer */
+ error = aa_get_name(&link, profile->path_flags, &buffer, &lname);
+ if (error)
+ goto audit;
+
+ /* buffer2 freed below, tname is pointer in buffer2 */
+ error = aa_get_name(&target, profile->path_flags, &buffer2, &tname);
+ 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);
+
+ 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);
+
+ /* force audit/quiet masks for link are stored in the second entry
+ * in the link pair.
+ */
+ lperms.audit = perms.audit;
+ lperms.quiet = perms.quiet;
+ lperms.kill = perms.kill;
+
+ if (!(perms.allow & AA_MAY_LINK)) {
+ info = "target restricted";
+ goto audit;
+ }
+
+ /* done if link subset test is not required */
+ 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.
+ */
+ aa_str_perms(profile->file.dfa, profile->file.start, tname, &cond,
+ &perms);
+
+ /* AA_MAY_LINK is not considered in the subset test */
+ request = lperms.allow & ~AA_MAY_LINK;
+ lperms.allow &= perms.allow | AA_MAY_LINK;
+
+ request |= AA_AUDIT_FILE_MASK & (lperms.allow & ~perms.allow);
+ if (request & ~lperms.allow) {
+ goto audit;
+ } else if ((lperms.allow & MAY_EXEC) &&
+ !xindex_is_subset(lperms.xindex, perms.xindex)) {
+ lperms.allow &= ~MAY_EXEC;
+ request |= MAY_EXEC;
+ info = "link not subset of target";
+ goto audit;
+ }
+
+done_tests:
+ error = 0;
+
+audit:
+ error = aa_audit_file(profile, &lperms, GFP_KERNEL, OP_LINK, request,
+ lname, tname, cond.uid, info, error);
+ kfree(buffer);
+ kfree(buffer2);
+
+ return error;
+}
+
+/**
+ * aa_file_perm - do permission revalidation check & audit for @file
+ * @op: operation being checked
+ * @profile: profile 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(int op, struct aa_profile *profile, struct file *file,
+ u32 request)
+{
+ struct path_cond cond = {
+ .uid = file->f_path.dentry->d_inode->i_uid,
+ .mode = file->f_path.dentry->d_inode->i_mode
+ };
+
+ return aa_path_perm(op, profile, &file->f_path, PATH_DELEGATE_DELETED,
+ request, &cond);
+}
diff --git a/security/apparmor/include/file.h b/security/apparmor/include/file.h
new file mode 100644
index 000000000000..be36feabb16a
--- /dev/null
+++ b/security/apparmor/include/file.h
@@ -0,0 +1,217 @@
+/*
+ * AppArmor security module
+ *
+ * This file contains AppArmor file mediation function definitions.
+ *
+ * Copyright (C) 1998-2008 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.
+ */
+
+#ifndef __AA_FILE_H
+#define __AA_FILE_H
+
+#include <linux/path.h>
+
+#include "domain.h"
+#include "match.h"
+
+struct aa_profile;
+
+/*
+ * We use MAY_EXEC, MAY_WRITE, MAY_READ, MAY_APPEND and the following flags
+ * for profile permissions
+ */
+#define AA_MAY_CREATE 0x0010
+#define AA_MAY_DELETE 0x0020
+#define AA_MAY_META_WRITE 0x0040
+#define AA_MAY_META_READ 0x0080
+
+#define AA_MAY_CHMOD 0x0100
+#define AA_MAY_CHOWN 0x0200
+#define AA_MAY_LOCK 0x0400
+#define AA_EXEC_MMAP 0x0800
+
+#define AA_MAY_LINK 0x1000
+#define AA_LINK_SUBSET AA_MAY_LOCK /* overlaid */
+#define AA_MAY_ONEXEC 0x40000000 /* exec allows onexec */
+#define AA_MAY_CHANGE_PROFILE 0x80000000
+#define AA_MAY_CHANGEHAT 0x80000000 /* ctrl auditing only */
+
+#define AA_AUDIT_FILE_MASK (MAY_READ | MAY_WRITE | MAY_EXEC | MAY_APPEND |\
+ AA_MAY_CREATE | AA_MAY_DELETE | \
+ AA_MAY_META_READ | AA_MAY_META_WRITE | \
+ AA_MAY_CHMOD | AA_MAY_CHOWN | AA_MAY_LOCK | \
+ AA_EXEC_MMAP | AA_MAY_LINK)
+
+/*
+ * The xindex is broken into 3 parts
+ * - index - an index into either the exec name table or the variable table
+ * - exec type - which determines how the executable name and index are used
+ * - flags - which modify how the destination name is applied
+ */
+#define AA_X_INDEX_MASK 0x03ff
+
+#define AA_X_TYPE_MASK 0x0c00
+#define AA_X_TYPE_SHIFT 10
+#define AA_X_NONE 0x0000
+#define AA_X_NAME 0x0400 /* use executable name px */
+#define AA_X_TABLE 0x0800 /* use a specified name ->n# */
+
+#define AA_X_UNSAFE 0x1000
+#define AA_X_CHILD 0x2000 /* make >AA_X_NONE apply to children */
+#define AA_X_INHERIT 0x4000
+#define AA_X_UNCONFINED 0x8000
+
+/* AA_SECURE_X_NEEDED - is passed in the bprm->unsafe field */
+#define AA_SECURE_X_NEEDED 0x8000
+
+/* need to make conditional which ones are being set */
+struct path_cond {
+ uid_t uid;
+ umode_t mode;
+};
+
+/* struct file_perms - file permission
+ * @allow: mask of permissions that are allowed
+ * @audit: mask of permissions to force an audit message for
+ * @quiet: mask of permissions to quiet audit messages for
+ * @kill: mask of permissions that when matched will kill the task
+ * @xindex: exec transition index if @allow contains MAY_EXEC
+ *
+ * The @audit and @queit mask should be mutually exclusive.
+ */
+struct file_perms {
+ u32 allow;
+ u32 audit;
+ u32 quiet;
+ u32 kill;
+ u16 xindex;
+};
+
+extern struct file_perms nullperms;
+
+#define COMBINED_PERM_MASK(X) ((X).allow | (X).audit | (X).quiet | (X).kill)
+
+/* FIXME: split perms from dfa and match this to description
+ * also add delegation info.
+ */
+static inline u16 dfa_map_xindex(u16 mask)
+{
+ u16 old_index = (mask >> 10) & 0xf;
+ u16 index = 0;
+
+ if (mask & 0x100)
+ index |= AA_X_UNSAFE;
+ if (mask & 0x200)
+ index |= AA_X_INHERIT;
+ if (mask & 0x80)
+ index |= AA_X_UNCONFINED;
+
+ if (old_index == 1) {
+ index |= AA_X_UNCONFINED;
+ } else if (old_index == 2) {
+ index |= AA_X_NAME;
+ } else if (old_index == 3) {
+ index |= AA_X_NAME | AA_X_CHILD;
+ } else {
+ index |= AA_X_TABLE;
+ index |= old_index - 4;
+ }
+
+ return index;
+}
+
+/*
+ * map old dfa inline permissions to new format
+ */
+#define dfa_user_allow(dfa, state) (((ACCEPT_TABLE(dfa)[state]) & 0x7f) | \
+ ((ACCEPT_TABLE(dfa)[state]) & 0x80000000))
+#define dfa_user_audit(dfa, state) ((ACCEPT_TABLE2(dfa)[state]) & 0x7f)
+#define dfa_user_quiet(dfa, state) (((ACCEPT_TABLE2(dfa)[state]) >> 7) & 0x7f)
+#define dfa_user_xindex(dfa, state) \
+ (dfa_map_xindex(ACCEPT_TABLE(dfa)[state] & 0x3fff))
+
+#define dfa_other_allow(dfa, state) ((((ACCEPT_TABLE(dfa)[state]) >> 14) & \
+ 0x7f) | \
+ ((ACCEPT_TABLE(dfa)[state]) & 0x80000000))
+#define dfa_other_audit(dfa, state) (((ACCEPT_TABLE2(dfa)[state]) >> 14) & 0x7f)
+#define dfa_other_quiet(dfa, state) \
+ ((((ACCEPT_TABLE2(dfa)[state]) >> 7) >> 14) & 0x7f)
+#define dfa_other_xindex(dfa, state) \
+ dfa_map_xindex((ACCEPT_TABLE(dfa)[state] >> 14) & 0x3fff)
+
+int aa_audit_file(struct aa_profile *profile, struct file_perms *perms,
+ gfp_t gfp, int op, u32 request, const char *name,
+ const char *target, uid_t ouid, const char *info, int error);
+
+/**
+ * struct aa_file_rules - components used for file rule permissions
+ * @dfa: dfa to match path names and conditionals against
+ * @perms: permission table indexed by the matched state accept entry of @dfa
+ * @trans: transition table for indexed by named x transitions
+ *
+ * File permission are determined by matching a path against @dfa and then
+ * then using the value of the accept entry for the matching state as
+ * an index into @perms. If a named exec transition is required it is
+ * looked up in the transition table.
+ */
+struct aa_file_rules {
+ unsigned int start;
+ struct aa_dfa *dfa;
+ /* struct perms perms; */
+ struct aa_domain trans;
+ /* TODO: add delegate table */
+};
+
+unsigned int aa_str_perms(struct aa_dfa *dfa, unsigned int start,
+ const char *name, struct path_cond *cond,
+ struct file_perms *perms);
+
+int aa_path_perm(int op, struct aa_profile *profile, struct path *path,
+ int flags, u32 request, struct path_cond *cond);
+
+int aa_path_link(struct aa_profile *profile, struct dentry *old_dentry,
+ struct path *new_dir, struct dentry *new_dentry);
+
+int aa_file_perm(int op, struct aa_profile *profile, struct file *file,
+ u32 request);
+
+static inline void aa_free_file_rules(struct aa_file_rules *rules)
+{
+ aa_put_dfa(rules->dfa);
+ aa_free_domain_entries(&rules->trans);
+}
+
+#define ACC_FMODE(x) (("\000\004\002\006"[(x)&O_ACCMODE]) | (((x) << 1) & 0x40))
+
+/* from namei.c */
+#define MAP_OPEN_FLAGS(x) ((((x) + 1) & O_ACCMODE) ? (x) + 1 : (x))
+
+/**
+ * aa_map_file_perms - map file flags to AppArmor permissions
+ * @file: open file to map flags to AppArmor permissions
+ *
+ * Returns: apparmor permission set for the file
+ */
+static inline u32 aa_map_file_to_perms(struct file *file)
+{
+ int flags = MAP_OPEN_FLAGS(file->f_flags);
+ u32 perms = ACC_FMODE(file->f_mode);
+
+ if ((flags & O_APPEND) && (perms & MAY_WRITE))
+ perms = (perms & ~MAY_WRITE) | MAY_APPEND;
+ /* trunc implies write permission */
+ if (flags & O_TRUNC)
+ perms |= MAY_WRITE;
+ if (flags & O_CREAT)
+ perms |= AA_MAY_CREATE;
+
+ return perms;
+}
+
+#endif /* __AA_FILE_H */

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