From 74c8a6af692a552e67462f98da5bcee1a0f0a925 Mon Sep 17 00:00:00 2001 From: Rustam Kovhaev Date: Wed, 24 Feb 2021 12:00:30 -0800 Subject: [PATCH] ntfs: check for valid standard information attribute commit 4dfe6bd94959222e18d512bdf15f6bf9edb9c27c 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=c584225dabdea2f71969 Signed-off-by: Rustam Kovhaev Reported-by: syzbot+c584225dabdea2f71969@syzkaller.appspotmail.com Tested-by: syzbot+c584225dabdea2f71969@syzkaller.appspotmail.com Acked-by: Anton Altaparmakov Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- fs/ntfs/inode.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/fs/ntfs/inode.c b/fs/ntfs/inode.c index 84933a0af49b..672feb96e250 100644 --- a/fs/ntfs/inode.c +++ b/fs/ntfs/inode.c @@ -628,6 +628,12 @@ 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));