xfs: Validate the length of on-disk ACLs
In xfs_acl_from_disk, instead of trusting that xfs_acl.acl_cnt is correct,
make sure that the length of the attributes is correct as well. Also, turn
the aclp parameter into a const pointer.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
diff --git a/fs/xfs/libxfs/xfs_format.h b/fs/xfs/libxfs/xfs_format.h
index 9590a06..0e62682 100644
--- a/fs/xfs/libxfs/xfs_format.h
+++ b/fs/xfs/libxfs/xfs_format.h
@@ -1487,9 +1487,13 @@
sizeof(struct xfs_acl_entry) \
: 25)
-#define XFS_ACL_MAX_SIZE(mp) \
+#define XFS_ACL_SIZE(cnt) \
(sizeof(struct xfs_acl) + \
- sizeof(struct xfs_acl_entry) * XFS_ACL_MAX_ENTRIES((mp)))
+ sizeof(struct xfs_acl_entry) * cnt)
+
+#define XFS_ACL_MAX_SIZE(mp) \
+ XFS_ACL_SIZE(XFS_ACL_MAX_ENTRIES((mp)))
+
/* On-disk XFS extended attribute names */
#define SGI_ACL_FILE "SGI_ACL_FILE"
diff --git a/fs/xfs/xfs_acl.c b/fs/xfs/xfs_acl.c
index 4b641676..763e365 100644
--- a/fs/xfs/xfs_acl.c
+++ b/fs/xfs/xfs_acl.c
@@ -37,16 +37,19 @@
STATIC struct posix_acl *
xfs_acl_from_disk(
- struct xfs_acl *aclp,
- int max_entries)
+ const struct xfs_acl *aclp,
+ int len,
+ int max_entries)
{
struct posix_acl_entry *acl_e;
struct posix_acl *acl;
- struct xfs_acl_entry *ace;
+ const struct xfs_acl_entry *ace;
unsigned int count, i;
+ if (len < sizeof(*aclp))
+ return ERR_PTR(-EFSCORRUPTED);
count = be32_to_cpu(aclp->acl_cnt);
- if (count > max_entries)
+ if (count > max_entries || XFS_ACL_SIZE(count) != len)
return ERR_PTR(-EFSCORRUPTED);
acl = posix_acl_alloc(count, GFP_KERNEL);
@@ -163,7 +166,7 @@
goto out;
}
- acl = xfs_acl_from_disk(xfs_acl, XFS_ACL_MAX_ENTRIES(ip->i_mount));
+ acl = xfs_acl_from_disk(xfs_acl, len, XFS_ACL_MAX_ENTRIES(ip->i_mount));
if (IS_ERR(acl))
goto out;
