6.18-stable review patch. If anyone has any objections, please let me know.
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From: Raphael Pinsonneault-Thibeault rpthibeault@gmail.com
[ Upstream commit 73e6b9dacf72a1e7a4265eacca46f8f33e0997d6 ]
Fix a KMSAN un-init bug found by syzkaller.
ntfs_get_bh() expects a buffer from sb_getblk(), that buffer may not be uptodate. We do not bring the buffer uptodate before setting it as uptodate. If the buffer were to not be uptodate, it could mean adding a buffer with un-init data to the mi record. Attempting to load that record will trigger KMSAN.
Avoid this by setting the buffer as uptodate, if it’s not already, by overwriting it.
Reported-by: syzbot+7a2ba6b7b66340cff225@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=7a2ba6b7b66340cff225 Tested-by: syzbot+7a2ba6b7b66340cff225@syzkaller.appspotmail.com Fixes: 4342306f0f0d5 ("fs/ntfs3: Add file operations and implementation") Signed-off-by: Raphael Pinsonneault-Thibeault rpthibeault@gmail.com Signed-off-by: Konstantin Komarov almaz.alexandrovich@paragon-software.com Signed-off-by: Sasha Levin sashal@kernel.org --- fs/ntfs3/fsntfs.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/fs/ntfs3/fsntfs.c b/fs/ntfs3/fsntfs.c index c7a2f191254da..5ae910e9ecbda 100644 --- a/fs/ntfs3/fsntfs.c +++ b/fs/ntfs3/fsntfs.c @@ -1349,7 +1349,14 @@ int ntfs_get_bh(struct ntfs_sb_info *sbi, const struct runs_tree *run, u64 vbo, } if (buffer_locked(bh)) __wait_on_buffer(bh); - set_buffer_uptodate(bh); + + lock_buffer(bh); + if (!buffer_uptodate(bh)) + { + memset(bh->b_data, 0, blocksize); + set_buffer_uptodate(bh); + } + unlock_buffer(bh); } else { bh = ntfs_bread(sb, block); if (!bh) {