Hook the richacl permission checking function into the vfs.
Signed-off-by: Andreas Gruenbacher <agruenba@xxxxxxxxxx>
Cc: Jeff Layton <jlayton@xxxxxxxxxx>
---
fs/namei.c | 70 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++--
fs/richacl.c | 4 ++--
2 files changed, 70 insertions(+), 4 deletions(-)
diff --git a/fs/namei.c b/fs/namei.c
index 4b53754..7ea153b 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -34,6 +34,7 @@
#include <linux/device_cgroup.h>
#include <linux/fs_struct.h>
#include <linux/posix_acl.h>
+#include <linux/richacl.h>
#include <linux/hash.h>
#include <linux/bitops.h>
#include <linux/init_task.h>
@@ -257,7 +258,43 @@ void putname(struct filename *name)
__putname(name);
}
-static int check_acl(struct inode *inode, int mask)
+static int check_richacl(struct inode *inode, int mask)
+{
+#ifdef CONFIG_FS_RICHACL
+ if (mask & MAY_NOT_BLOCK) {
+ struct base_acl *base_acl;
+
+ base_acl = rcu_dereference(inode->i_acl);
+ if (!base_acl)
+ goto no_acl;
+ /* no ->get_richacl() calls in RCU mode... */
+ if (is_uncached_acl(base_acl))
+ return -ECHILD;
+ return richacl_permission(inode, richacl(base_acl),
+ mask & ~MAY_NOT_BLOCK);
+ } else {
+ struct richacl *acl;
+
+ acl = get_richacl(inode);
+ if (IS_ERR(acl))
+ return PTR_ERR(acl);
+ if (acl) {
+ int error = richacl_permission(inode, acl, mask);
+ richacl_put(acl);
+ return error;
+ }
+ }
+no_acl:
+#endif
+ if (mask & (MAY_DELETE_SELF | MAY_TAKE_OWNERSHIP |
+ MAY_CHMOD | MAY_SET_TIMES)) {
+ /* File permission bits cannot grant this. */
+ return -EACCES;
+ }
+ return -EAGAIN;
+}
+
+static int check_posix_acl(struct inode *inode, int mask)
{
#ifdef CONFIG_FS_POSIX_ACL
if (mask & MAY_NOT_BLOCK) {
@@ -295,11 +332,40 @@ static int acl_permission_check(struct inode *inode, int mask)
{
unsigned int mode = inode->i_mode;
+ /*
+ * With POSIX ACLs, the (mode & S_IRWXU) bits exactly match the owner
+ * permissions, and we can skip checking posix acls for the owner.
+ * With richacls, the owner may be granted fewer permissions than the
+ * mode bits seem to suggest (for example, append but not write), and
+ * we always need to check the richacl.
+ */
+
+ if (IS_RICHACL(inode)) {
+ int error;
+
+ /*
+ * The combination of MAY_DELETE_CHILD and MAY_DELETE_SELF
+ * indicates that that we want to check for delete permission
+ * in a directory assuming that we have MAY_DELETE_SELF access
+ * on the victim. We don't require MAY_DELETE_CHILD permission
+ * on the directory, but we do require LSM permission, the
+ * immutability checks, etc.
+ */
+ if ((mask & MAY_DELETE_CHILD) && (mask & MAY_DELETE_SELF)) {
+ mask &= ~(MAY_DELETE_CHILD | MAY_DELETE_SELF);
+ if (!(mask & (MAY_CREATE_FILE | MAY_CREATE_DIR)))
+ mask &= ~MAY_WRITE;
+ }
+
+ error = check_richacl(inode, mask);
+ if (error != -EAGAIN)
+ return error;
+ }
if (likely(uid_eq(current_fsuid(), inode->i_uid)))
mode >>= 6;
else {
if (IS_POSIXACL(inode) && (mode & S_IRWXG)) {
- int error = check_acl(inode, mask);
+ int error = check_posix_acl(inode, mask);
if (error != -EAGAIN)
return error;
}
diff --git a/fs/richacl.c b/fs/richacl.c
index 1945691..416d57c 100644
--- a/fs/richacl.c
+++ b/fs/richacl.c
@@ -293,8 +293,8 @@ richacl_permission(struct inode *inode, const struct richacl *acl,
} else {
/*
* When the acl is not masked, there is no need to determine if
- * the process is in the group class and we can break out
- * earlier of the loop below.
+ * the process is in the group class and we can earlier break
+ * out of the loop below.
*/
in_owner_or_group_class = 1;
}
--
2.7.4
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