From: Theodore Ts'o Date: Sat, 16 Jun 2018 19:40:48 +0000 (-0400) Subject: ext4: never move the system.data xattr out of the inode body X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=8cdb5240ec5928b20490a2bb34cb87e9a5f40226;p=linux.git ext4: never move the system.data xattr out of the inode body 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 Cc: stable@kernel.org --- diff --git a/fs/ext4/xattr.c b/fs/ext4/xattr.c index 0263692979ec4..72377b77fbd7d 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(