From: Rustam Kovhaev rkovhaev@gmail.com Subject: ntfs: check for valid standard information attribute

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 rkovhaev@gmail.com Reported-by: syzbot+c584225dabdea2f71969@syzkaller.appspotmail.com Tested-by: syzbot+c584225dabdea2f71969@syzkaller.appspotmail.com Acked-by: Anton Altaparmakov anton@tuxera.com Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org ---

fs/ntfs/inode.c | 6 ++++++ 1 file changed, 6 insertions(+)

--- a/fs/ntfs/inode.c~ntfs-check-for-valid-standard-information-attribute +++ a/fs/ntfs/inode.c @@ -629,6 +629,12 @@ static int ntfs_read_locked_inode(struct } 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));

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