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ntfs: add check for mft record size in superblock

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[ Upstream commit 4f8c94022f0bc3babd0a124c0a7dcdd7547bd94e ]

Number of bytes allocated for mft record should be equal to the mft record
size stored in ntfs superblock as reported by syzbot, userspace might
trigger out-of-bounds read by dereferencing ctx->attr in ntfs_attr_find()

Reported-by: syzbot+aed06913f36eff9b544e@syzkaller.appspotmail.com
Signed-off-by: Rustam Kovhaev <rkovhaev@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Tested-by: syzbot+aed06913f36eff9b544e@syzkaller.appspotmail.com
Acked-by: Anton Altaparmakov <anton@tuxera.com>
Link: https://syzkaller.appspot.com/bug?extid=aed06913f36eff9b544e
Link: https://lkml.kernel.org/r/20200824022804.226242-1-rkovhaev@gmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Rustam Kovhaev 2020-10-13 16:48:17 -07:00 committed by Greg Kroah-Hartman
parent 4b799668be
commit dff5d77411
1 changed files with 6 additions and 0 deletions
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6
fs/ntfs/inode.c
View file

@ -1835,6 +1835,12 @@ int ntfs_read_inode_mount(struct inode *vi)
brelse(bh);
}
if (le32_to_cpu(m->bytes_allocated) != vol->mft_record_size) {
ntfs_error(sb, "Incorrect mft record size %u in superblock, should be %u.",
le32_to_cpu(m->bytes_allocated), vol->mft_record_size);
goto err_out;
}
/* Apply the mst fixups. */
if (post_read_mst_fixup((NTFS_RECORD*)m, vol->mft_record_size)) {
/* FIXME: Try to use the $MFTMirr now. */