Re: [Qemu-devel] [PATCH 2/2] qemu-io: better input validation for vector-based commands

[Kevin Wolf <kwolf@redhat.com>]

Christoph Hellwig schrieb:
> Fix up a couple of issues with validating the input of the various
> length arguments for the vectored I/O commands:
> 
>  - do the alignment check on each length instead the always 0 count
>    argument
>  - use a long long varibale for the cvtnum return value so that we
>    can check wether it wasn't a number
>  - check for a too large argument instead of truncating it
> 
> Also refactor it into a common helper for all four calers and avoid
> parsing the numbers twice.
> 
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> 
> Index: qemu/qemu-io.c
> ===================================================================
> --- qemu.orig/qemu-io.c	2009-07-01 11:15:39.429264493 +0200
> +++ qemu/qemu-io.c	2009-07-01 11:24:14.463366645 +0200
> @@ -98,6 +98,56 @@ print_report(const char *op, struct time
>  	}
>  }
>  
> +/*
> + * Parse multiple length statements for vectored I/O.
> + */
> +static void *
> +parse_multiple_len(QEMUIOVector *qiov, char **argv, int nr_iov, int pattern)

Hey, a function with a comment! :-)

Now what about using this comment to describe what the function is
actually doing? I mean it doesn't only parse the lengths but prepares a
buffer and an IO vector. It even returns the buffer (before looking at
the code I wondered what void* a pure parsing function might return...)

Otherwise the patch looks good to me.

Kevin