ntfs: check for valid standard information attribute

stable inclusion
from stable-5.10.19
commit 9f04a05fa1ed725db82993e6075c6b1b60cfc3cb
bugzilla: 50607

--------------------------------

commit 4dfe6bd9 upstream.

Mounting a corrupted filesystem with NTFS resulted in a kernel crash.

We should check for valid STANDARD_INFORMATION attribute offset and length
before trying to access it

Link: https://lkml.kernel.org/r/20210217155930.1506815-1-rkovhaev@gmail.com
Link: https://syzkaller.appspot.com/bug?extid=c584225dabdea2f71969Signed-off-by: NRustam Kovhaev <rkovhaev@gmail.com>
Reported-by: syzbot+c584225dabdea2f71969@syzkaller.appspotmail.com
Tested-by: syzbot+c584225dabdea2f71969@syzkaller.appspotmail.com
Acked-by: NAnton Altaparmakov <anton@tuxera.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>
Acked-by: NXie XiuQi <xiexiuqi@huawei.com>

fs/ntfs/inode.c

@@ -629,6 +629,12 @@ static int ntfs_read_locked_inode(struct inode *vi)
 	}
 	a = ctx->attr;
 	/* Get the standard information attribute value. */
+	if ((u8 *)a + le16_to_cpu(a->data.resident.value_offset)
+			+ le32_to_cpu(a->data.resident.value_length) >
+			(u8 *)ctx->mrec + vol->mft_record_size) {
+		ntfs_error(vi->i_sb, "Corrupt standard information attribute in inode.");
+		goto unm_err_out;
+	}
 	si = (STANDARD_INFORMATION*)((u8*)a +
 			le16_to_cpu(a->data.resident.value_offset));