libxl: Resolve possible resource leak in dom0 maximum memory setting

[libvirt] [PATCH] libxl: Resolve possible resource leak in dom0 maximum memory setting

Posted by John Ferlan 7 years, 2 months ago

If either the "if (STRPREFIX(mem_tokens[j], "max:"))" is never entered
or the "if (virStrToLong_ull(mem_tokens[j] + 4, &p, 10, maxmem) < 0)" break
is hit, control goes back to the outer loop processing 'cmd_tokens' and
it's possible that the 'mem_tokens' would be overwritten.

Found by Coverity

Signed-off-by: John Ferlan <jferlan@redhat.com>
---

 Of course this is what led me down the path of the recently sent virusbmock
patch...

 src/libxl/libxl_conf.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/libxl/libxl_conf.c b/src/libxl/libxl_conf.c
index 6ce2e0a..f5b788b 100644
--- a/src/libxl/libxl_conf.c
+++ b/src/libxl/libxl_conf.c
@@ -1622,6 +1622,7 @@ libxlDriverGetDom0MaxmemConf(libxlDriverConfigPtr cfg,
                 goto cleanup;
             }
         }
+        virStringListFree(mem_tokens);
     }
 
  physmem:
-- 
2.7.4

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Re: [libvirt] [PATCH] libxl: Resolve possible resource leak in dom0 maximum memory setting

Posted by Michal Privoznik 7 years, 2 months ago

On 02/10/2017 02:06 PM, John Ferlan wrote:
> If either the "if (STRPREFIX(mem_tokens[j], "max:"))" is never entered
> or the "if (virStrToLong_ull(mem_tokens[j] + 4, &p, 10, maxmem) < 0)" break
> is hit, control goes back to the outer loop processing 'cmd_tokens' and
> it's possible that the 'mem_tokens' would be overwritten.
> 
> Found by Coverity
> 
> Signed-off-by: John Ferlan <jferlan@redhat.com>
> ---
> 
>  Of course this is what led me down the path of the recently sent virusbmock
> patch...
> 
>  src/libxl/libxl_conf.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/src/libxl/libxl_conf.c b/src/libxl/libxl_conf.c
> index 6ce2e0a..f5b788b 100644
> --- a/src/libxl/libxl_conf.c
> +++ b/src/libxl/libxl_conf.c
> @@ -1622,6 +1622,7 @@ libxlDriverGetDom0MaxmemConf(libxlDriverConfigPtr cfg,
>                  goto cleanup;
>              }
>          }
> +        virStringListFree(mem_tokens);
>      }
>  
>   physmem:
> 

This will work. The other possible location is just before:

if (!(mem_tokens = virStringSplit(cmd_tokens[i], ",", 0)))

line.

ACK

Michal

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