[libvirt] [PATCH] network: Avoid memory leaks on networkBuildDnsmasqArgv

[Osier Yang]

On 2012年01月06日 13:14, ajia at redhat.com wrote:
> From: Alex Jia<ajia at redhat.com>
>
> Detected by valgrind. Leaks introduced in commit 973af236.
>
> * src/network/bridge_driver.c: fix memory leaks on failure and successful path.
>
> * How to reproduce?
> % cd tests&&  valgrind -v --leak-check=full ./networkxml2argvtest
>
> * Actual result:
>
> ==2226== 3 bytes in 1 blocks are definitely lost in loss record 1 of 24
> ==2226==    at 0x4A05FDE: malloc (vg_replace_malloc.c:236)
> ==2226==    by 0x39CF0FEDE7: __vasprintf_chk (in /lib64/libc-2.12.so)
> ==2226==    by 0x41DFF7: virVasprintf (stdio2.h:199)
> ==2226==    by 0x41E0B7: virAsprintf (util.c:1695)
> ==2226==    by 0x41A2D9: networkBuildDhcpDaemonCommandLine (bridge_driver.c:545)
> ==2226==    by 0x4145C8: testCompareXMLToArgvHelper (networkxml2argvtest.c:47)
> ==2226==    by 0x4156A1: virtTestRun (testutils.c:141)
> ==2226==    by 0x414332: mymain (networkxml2argvtest.c:123)
> ==2226==    by 0x414D97: virtTestMain (testutils.c:696)
> ==2226==    by 0x39CF01ECDC: (below main) (in /lib64/libc-2.12.so)
> ==2226==
> ==2226== 3 bytes in 1 blocks are definitely lost in loss record 2 of 24
> ==2226==    at 0x4A05FDE: malloc (vg_replace_malloc.c:236)
> ==2226==    by 0x39CF0FEDE7: __vasprintf_chk (in /lib64/libc-2.12.so)
> ==2226==    by 0x41DFF7: virVasprintf (stdio2.h:199)
> ==2226==    by 0x41E0B7: virAsprintf (util.c:1695)
> ==2226==    by 0x41A307: networkBuildDhcpDaemonCommandLine (bridge_driver.c:551)
> ==2226==    by 0x4145C8: testCompareXMLToArgvHelper (networkxml2argvtest.c:47)
> ==2226==    by 0x4156A1: virtTestRun (testutils.c:141)
> ==2226==    by 0x414332: mymain (networkxml2argvtest.c:123)
> ==2226==    by 0x414D97: virtTestMain (testutils.c:696)
> ==2226==    by 0x39CF01ECDC: (below main) (in /lib64/libc-2.12.so)
> ==2226==
> ==2226== 5 bytes in 1 blocks are definitely lost in loss record 4 of 24
> ==2226==    at 0x4A05FDE: malloc (vg_replace_malloc.c:236)
> ==2226==    by 0x39CF0FEDE7: __vasprintf_chk (in /lib64/libc-2.12.so)
> ==2226==    by 0x41DFF7: virVasprintf (stdio2.h:199)
> ==2226==    by 0x41E0B7: virAsprintf (util.c:1695)
> ==2226==    by 0x41A2AB: networkBuildDhcpDaemonCommandLine (bridge_driver.c:539)
> ==2226==    by 0x4145C8: testCompareXMLToArgvHelper (networkxml2argvtest.c:47)
> ==2226==    by 0x4156A1: virtTestRun (testutils.c:141)
> ==2226==    by 0x414332: mymain (networkxml2argvtest.c:123)
> ==2226==    by 0x414D97: virtTestMain (testutils.c:696)
> ==2226==    by 0x39CF01ECDC: (below main) (in /lib64/libc-2.12.so)
> ==2226==
> ==2226== LEAK SUMMARY:
> ==2226==    definitely lost: 11 bytes in 3 blocks
>
> Signed-off-by: Alex Jia<ajia at redhat.com>
> ---
>   src/network/bridge_driver.c |    6 ++++++
>   1 files changed, 6 insertions(+), 0 deletions(-)
>
> diff --git a/src/network/bridge_driver.c b/src/network/bridge_driver.c
> index 9afada7..63a28a6 100644
> --- a/src/network/bridge_driver.c
> +++ b/src/network/bridge_driver.c
> @@ -544,12 +544,15 @@ networkBuildDnsmasqArgv(virNetworkObjPtr network,
>                   if (dns->srvrecords[i].priority) {
>                       if (virAsprintf(&recordPriority, "%d", dns->srvrecords[i].priority)<  0) {
>                           virReportOOMError();
> +                        VIR_FREE(recordPort);
>                           goto cleanup;
>                       }
>                   }
>                   if (dns->srvrecords[i].weight) {
>                       if (virAsprintf(&recordWeight, "%d", dns->srvrecords[i].weight)<  0) {
>                           virReportOOMError();
> +                        VIR_FREE(recordPort);
> +                        VIR_FREE(recordPriority);
>                           goto cleanup;
>                       }
>                   }
> @@ -567,6 +570,9 @@ networkBuildDnsmasqArgv(virNetworkObjPtr network,
>                   }
>
>                   virCommandAddArgPair(cmd, "--srv-host", record);
> +                VIR_FREE(recordPort);
> +                VIR_FREE(recordPriority);
> +                VIR_FREE(recordWeight);
>                   VIR_FREE(record);
>               }
>           }


These fixes are right, but you might also want to free() "recordPort",
"recordPriority", and "recordWeight" before "goto cleanup" in following
branch:

                 if (virAsprintf(&record, "%s.%s.%s,%s,%s,%s,%s",
                                 dns->srvrecords[i].service,
                                 dns->srvrecords[i].protocol,
                                 dns->srvrecords[i].domain   ? 
dns->srvrecords[i].domain : "",
                                 dns->srvrecords[i].target   ? 
dns->srvrecords[i].target : "",
                                 recordPort                  ? 
recordPort                : "",
                                 recordPriority              ? 
recordPriority            : "",
                                 recordWeight                ? 
recordWeight              : "") < 0) {


And personally I'd use "goto", too much duplicate VIR_FREE use.

Regards,
Osier