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authorAnirudh Rayabharam <mail@anirudhrb.com>2021-05-07 00:26:54 +0530
committerTheodore Ts'o <tytso@mit.edu>2021-06-17 10:53:19 -0400
commitce3aba43599f0b50adbebff133df8d08a3d5fffe (patch)
treebe466ea324adc1db0512031e2282c6551a2f7850 /fs/ext4
parent618f003199c6188e01472b03cdbba227f1dc5f24 (diff)
ext4: fix kernel infoleak via ext4_extent_header
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>
Diffstat (limited to 'fs/ext4')
-rw-r--r--fs/ext4/extents.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index cbf37b2cf871..1293de50c8d4 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);