From: Anirudh Rayabharam mail@anirudhrb.com
stable inclusion from stable-5.10.50 commit ea5466f1a77720217a25a859b5a58b618aaba544 bugzilla: 174522 https://gitee.com/openeuler/kernel/issues/I4DNFY
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
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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
Signed-off-by: Chen Jun chenjun102@huawei.com Acked-by: Weilong Chen chenweilong@huawei.com Signed-off-by: Chen Jun chenjun102@huawei.com --- fs/ext4/extents.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c index e6542ba26433..e00a35530a4e 100644 --- a/fs/ext4/extents.c +++ b/fs/ext4/extents.c @@ -825,6 +825,7 @@ void ext4_ext_tree_init(handle_t *handle, struct inode *inode) 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 *handle, struct inode *inode, 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 *handle, struct inode *inode, 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);