| From ce3aba43599f0b50adbebff133df8d08a3d5fffe Mon Sep 17 00:00:00 2001 |
| From: Anirudh Rayabharam <mail@anirudhrb.com> |
| Date: Fri, 7 May 2021 00:26:54 +0530 |
| Subject: ext4: fix kernel infoleak via ext4_extent_header |
| |
| From: Anirudh Rayabharam <mail@anirudhrb.com> |
| |
| commit ce3aba43599f0b50adbebff133df8d08a3d5fffe upstream. |
| |
| Initialize eh_generation of struct ext4_extent_header to prevent leaking |
| info to userspace. Fixes KMSAN kernel-infoleak bug reported by syzbot at: |
| http://syzkaller.appspot.com/bug?id=78e9ad0e6952a3ca16e8234724b2fa92d041b9b8 |
| |
| Cc: stable@kernel.org |
| Reported-by: syzbot+2dcfeaf8cb49b05e8f1a@syzkaller.appspotmail.com |
| Fixes: a86c61812637 ("[PATCH] ext3: add extent map support") |
| Signed-off-by: Anirudh Rayabharam <mail@anirudhrb.com> |
| Link: https://lore.kernel.org/r/20210506185655.7118-1-mail@anirudhrb.com |
| Signed-off-by: Theodore Ts'o <tytso@mit.edu> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| fs/ext4/extents.c | 3 +++ |
| 1 file changed, 3 insertions(+) |
| |
| --- a/fs/ext4/extents.c |
| +++ b/fs/ext4/extents.c |
| @@ -825,6 +825,7 @@ void ext4_ext_tree_init(handle_t *handle |
| eh->eh_entries = 0; |
| eh->eh_magic = EXT4_EXT_MAGIC; |
| eh->eh_max = cpu_to_le16(ext4_ext_space_root(inode, 0)); |
| + eh->eh_generation = 0; |
| ext4_mark_inode_dirty(handle, inode); |
| } |
| |
| @@ -1090,6 +1091,7 @@ static int ext4_ext_split(handle_t *hand |
| neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode, 0)); |
| neh->eh_magic = EXT4_EXT_MAGIC; |
| neh->eh_depth = 0; |
| + neh->eh_generation = 0; |
| |
| /* move remainder of path[depth] to the new leaf */ |
| if (unlikely(path[depth].p_hdr->eh_entries != |
| @@ -1167,6 +1169,7 @@ static int ext4_ext_split(handle_t *hand |
| neh->eh_magic = EXT4_EXT_MAGIC; |
| neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode, 0)); |
| neh->eh_depth = cpu_to_le16(depth - i); |
| + neh->eh_generation = 0; |
| fidx = EXT_FIRST_INDEX(neh); |
| fidx->ei_block = border; |
| ext4_idx_store_pblock(fidx, oldblock); |
