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Re: [Qemu-devel] [PATCH 2/2] pci: rewrite devaddr parsing
From: |
Michael S. Tsirkin |
Subject: |
Re: [Qemu-devel] [PATCH 2/2] pci: rewrite devaddr parsing |
Date: |
Fri, 17 Feb 2012 12:08:10 +0200 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
On Thu, Feb 16, 2012 at 01:39:02PM -0700, Eric Blake wrote:
> On 02/16/2012 12:23 PM, malc wrote:
> > On Thu, 16 Feb 2012, Michael S. Tsirkin wrote:
> >
> >> Use scanf instead of manual string scanning.
> >>
> >> +
> >> + /* Parse [[<domain>:]<bus>:]<slot> */
> >> + sscanf(addr, "%x:%x:%x%n", &dom, &bus, &slot, &n);
> >
> > sscanf can fail.
>
> Worse, the *scanf family has undefined behavior on integer overflow. If
> addr contains "100000000000000:0:0", there's no telling whether it will
> be diagnosed as a parse error, or silently accepted and truncated, in
> which case, there's no telling what dom will contain.
>
> I cringe any time I see someone using scanf to parse numbers from
> arbitrary user input; I barely tolerate it for parsing things generated
> by the kernel, but even there, I won't ever use scanf myself.
> Same goes
> for atoi. _Only_ strtol and friends can robustly parse arbitrary input
> into integers.
Seems easy to fix: I'll just set maximum field width of 8.
Any other issues?
> --
> Eric Blake address@hidden +1-919-301-3266
> Libvirt virtualization library http://libvirt.org
>
- [Qemu-devel] [PATCH 0/2] pci devaddr parsing cleanups, Michael S. Tsirkin, 2012/02/16
- [Qemu-devel] [PATCH 1/2] pci: don't export an internal function, Michael S. Tsirkin, 2012/02/16
- [Qemu-devel] [PATCH 2/2] pci: rewrite devaddr parsing, Michael S. Tsirkin, 2012/02/16
- Re: [Qemu-devel] [PATCH 2/2] pci: rewrite devaddr parsing, malc, 2012/02/16
- Re: [Qemu-devel] [PATCH 2/2] pci: rewrite devaddr parsing, Eric Blake, 2012/02/16
- Re: [Qemu-devel] [PATCH 2/2] pci: rewrite devaddr parsing, malc, 2012/02/16
- Re: [Qemu-devel] [PATCH 2/2] pci: rewrite devaddr parsing,
Michael S. Tsirkin <=
- Re: [Qemu-devel] [PATCH 2/2] pci: rewrite devaddr parsing, Markus Armbruster, 2012/02/17
- Re: [Qemu-devel] [PATCH 2/2] pci: rewrite devaddr parsing, Michael S. Tsirkin, 2012/02/19
- Re: [Qemu-devel] [PATCH 2/2] pci: rewrite devaddr parsing, Michael S. Tsirkin, 2012/02/19
- Re: [Qemu-devel] [PATCH 2/2] pci: rewrite devaddr parsing, Michael S. Tsirkin, 2012/02/17
- Re: [Qemu-devel] [PATCH 2/2] pci: rewrite devaddr parsing, malc, 2012/02/17
- Re: [Qemu-devel] [PATCH 2/2] pci: rewrite devaddr parsing, Michael S. Tsirkin, 2012/02/17