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authorRustam Kovhaev <rkovhaev@gmail.com>2020-10-14 01:48:17 +0200
committerLinus Torvalds <torvalds@linux-foundation.org>2020-10-14 03:38:27 +0200
commit4f8c94022f0bc3babd0a124c0a7dcdd7547bd94e (patch)
treef220f6ea642d54e435f5351fe64a3634d56fb7e0
parentscripts/decodecode: add the capability to supply the program counter (diff)
downloadlinux-4f8c94022f0bc3babd0a124c0a7dcdd7547bd94e.tar.xz
linux-4f8c94022f0bc3babd0a124c0a7dcdd7547bd94e.zip
ntfs: add check for mft record size in superblock
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>
-rw-r--r--fs/ntfs/inode.c6
1 files changed, 6 insertions, 0 deletions
diff --git a/fs/ntfs/inode.c b/fs/ntfs/inode.c
index 9bb9f0952b18..caf563981532 100644
--- a/fs/ntfs/inode.c
+++ b/fs/ntfs/inode.c
@@ -1810,6 +1810,12 @@ 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. */