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authorTheodore Ts'o <tytso@mit.edu>2018-06-16 15:40:48 -0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-07-11 16:31:30 +0200
commit1f18321d31d0971a5e9a02a9e67a6d94b638fca3 (patch)
parent0abaed0c74f4dbd3f5a9dcb9fb6b472735874b5e (diff)
ext4: never move the system.data xattr out of the inode body
commit 8cdb5240ec5928b20490a2bb34cb87e9a5f40226 upstream. When expanding the extra isize space, we must never move the system.data xattr out of the inode body. For performance reasons, it doesn't make any sense, and the inline data implementation assumes that system.data xattr is never in the external xattr block. This addresses CVE-2018-10880 https://bugzilla.kernel.org/show_bug.cgi?id=200005 Signed-off-by: Theodore Ts'o <tytso@mit.edu> Cc: stable@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
1 files changed, 5 insertions, 0 deletions
diff --git a/fs/ext4/xattr.c b/fs/ext4/xattr.c
index 0263692979ec..72377b77fbd7 100644
--- a/fs/ext4/xattr.c
+++ b/fs/ext4/xattr.c
@@ -2657,6 +2657,11 @@ static int ext4_xattr_make_inode_space(handle_t *handle, struct inode *inode,
last = IFIRST(header);
/* Find the entry best suited to be pushed into EA block */
for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
+ /* never move system.data out of the inode */
+ if ((last->e_name_len == 4) &&
+ (last->e_name_index == EXT4_XATTR_INDEX_SYSTEM) &&
+ !memcmp(last->e_name, "data", 4))
+ continue;
total_size = EXT4_XATTR_LEN(last->e_name_len);
if (!last->e_value_inum)
total_size += EXT4_XATTR_SIZE(