On 01/27/2012 11:34 AM, Cole Robinson wrote:
> On my f16 box at least, this tries to free p unconditionally which isn't
> always okay, 'p' is freeable only under a limited scope.
You must not have yajl-devel installed. No wonder I didn't see that I
had introduced a regression.
> ---
> src/qemu/qemu_capabilities.c | 3 +--
> 1 files changed, 1 insertions(+), 2 deletions(-)
>
> diff --git a/src/qemu/qemu_capabilities.c b/src/qemu/qemu_capabilities.c
> index 6dee9d8..5487ecd 100644
> --- a/src/qemu/qemu_capabilities.c
> +++ b/src/qemu/qemu_capabilities.c
> @@ -1336,10 +1336,9 @@ fail:
> qemuReportError(VIR_ERR_INTERNAL_ERROR,
> _("cannot parse %s version number in '%s'"),
> qemu, p ? p : help);
> -
> -cleanup:
> VIR_FREE(p);
>
> +cleanup:
Yuck. Why are we even calling strndup in the first place, just to
produce a nicer error message? I'm pushing this instead.
From ab6f1c9814f88e0547a5567176282f501fb138e2 Mon Sep 17 00:00:00 2001
From: Eric Blake <eblake@xxxxxxxxxx>
Date: Fri, 27 Jan 2012 13:53:11 -0700
Subject: [PATCH] qemu: avoid double free of qemu help output
If yajl was not compiled in, we end up freeing an incoming
parameter, which leads to a bogus free later on. Regression
introduced in commit 6e769eb.
* src/qemu/qemu_capabilities.c (qemuCapsParseHelpStr): Avoid alloc
on failure path, which in turn fixes bogus free.
Reported by Cole Robinson.
---
src/qemu/qemu_capabilities.c | 10 ++++------
1 files changed, 4 insertions(+), 6 deletions(-)
diff --git a/src/qemu/qemu_capabilities.c b/src/qemu/qemu_capabilities.c
index 6dee9d8..426637c 100644
--- a/src/qemu/qemu_capabilities.c
+++ b/src/qemu/qemu_capabilities.c
@@ -1330,16 +1330,14 @@ int qemuCapsParseHelpStr(const char *qemu,
fail:
p = strchr(help, '\n');
- if (p)
- p = strndup(help, p - help);
+ if (!p)
+ p = strchr(help, '\0');
qemuReportError(VIR_ERR_INTERNAL_ERROR,
- _("cannot parse %s version number in '%s'"),
- qemu, p ? p : help);
+ _("cannot parse %s version number in '%.*s'"),
+ qemu, (int) (p - help), help);
cleanup:
- VIR_FREE(p);
-
return -1;
}
--
1.7.7.6
--
Eric Blake eblake@xxxxxxxxxx +1-919-301-3266
Libvirt virtualization library http://libvirt.org
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