Re: [libvirt] [PATCH] virsh: Null terminated the string memcpy from buffer explicitly
On 2012年06月14日 19:16, Eric Blake wrote:
On 06/14/2012 05:09 AM, Osier Yang wrote:
> ---
> tools/virsh.c | 6 ++++--
> 1 files changed, 4 insertions(+), 2 deletions(-)
A bit light on the commit message. Does this solve an actual crash, or
does it just silence an overactive static code analyzer?
It's detected by valgrind:
# valgrind -v virsh change-media 3 hdc /var/lib/libvirt/images/foo2.img
==16217== 1 errors in context 1 of 12:
==16217== Invalid read of size 1
==16217== at 0x4A07804: __GI_strlen (mc_replace_strmem.c:284)
==16217== by 0x3019F167F6: xdr_string (in /lib64/libc-2.12.so)
==16217== by 0x3033709E8D: xdr_remote_nonnull_string
(remote_protocol.c:31)
==16217== by 0x303370E5CB: xdr_remote_domain_update_device_flags_args
(remote_protocol.c:2028)
==16217== by 0x30337197D1: virNetMessageEncodePayload
(virnetmessage.c:341)
==16217== by 0x30337135E1: virNetClientProgramCall
(virnetclientprogram.c:327)
==16217== by 0x30336F1EFD: callWithFD (remote_driver.c:4586)
==16217== by 0x30336F1F7B: call (remote_driver.c:4607)
==16217== by 0x30336F42F2: remoteDomainUpdateDeviceFlags
(remote_client_bodies.h:2865)
==16217== by 0x30336D46E5: virDomainUpdateDeviceFlags (libvirt.c:9457)
==16217== by 0x41AEE8: cmdChangeMedia (virsh.c:15249)
==16217== by 0x413CB4: vshCommandRun (virsh.c:18669)
==16217== Address 0x4ec5e25 is 0 bytes after a block of size 293 alloc'd
==16217== at 0x4A04A28: calloc (vg_replace_malloc.c:467)
==16217== by 0x303364F1DB: virAllocN (memory.c:129)
==16217== by 0x41A844: vshPrepareDiskXML (virsh.c:15043)
==16217== by 0x41AECC: cmdChangeMedia (virsh.c:15246)
==16217== by 0x413CB4: vshCommandRun (virsh.c:18669)
==16217== by 0x423973: main (virsh.c:20261)
>
> diff --git a/tools/virsh.c b/tools/virsh.c
> index 98305c0..4509020 100644
> --- a/tools/virsh.c
> +++ b/tools/virsh.c
> @@ -15069,11 +15069,13 @@ cleanup:
> VIR_FREE(device_type);
> VIR_FREE(disk_type);
> if (xml_buf) {
> - if (VIR_ALLOC_N(ret, xmlBufferLength(xml_buf))< 0) {
> + int len = xmlBufferLength(xml_buf);
> + if (VIR_ALLOC_N(ret, len + 1)< 0) {
> virReportOOMError();
> return NULL;
> }
> - memcpy(ret, (char *)xmlBufferContent(xml_buf), xmlBufferLength(xml_buf));
> + memcpy(ret, (char *)xmlBufferContent(xml_buf), len);
> + ret[len] = '\0';
At any rate, the conversion makes sense. ACK, if you'll improve the
commit message.
Thanks, pushed with commit messege improved.
Osier