[libvirt] [PATCH 3/3] nss: Don't leak memory on parse error

Michal Privoznik posted 3 patches 6 years, 6 months ago
[libvirt] [PATCH 3/3] nss: Don't leak memory on parse error
Posted by Michal Privoznik 6 years, 6 months ago
If yajl_parse() fails, we try to print an error message. For
that, yajl_get_error() is used. However, its documentation say
that caller is also responsible for freeing the memory it
allocates by using yajl_free_error().

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
---
 tools/nss/libvirt_nss_leases.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/tools/nss/libvirt_nss_leases.c b/tools/nss/libvirt_nss_leases.c
index 577b5a2fd1..977e3415f7 100644
--- a/tools/nss/libvirt_nss_leases.c
+++ b/tools/nss/libvirt_nss_leases.c
@@ -399,9 +399,10 @@ findLeases(const char *file,
 
         if (yajl_parse(parser, (const unsigned char *)line, rv)  !=
             yajl_status_ok) {
-            ERROR("Parse failed %s",
-                  yajl_get_error(parser, 1,
-                                 (const unsigned char*)line, rv));
+            unsigned char *err = yajl_get_error(parser, 1,
+                                                (const unsigned char*)line, rv);
+            ERROR("Parse failed %s", (const char *) err);
+            yajl_free_error(parser, err);
             goto cleanup;
         }
     }
-- 
2.21.0

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Re: [libvirt] [PATCH 3/3] nss: Don't leak memory on parse error
Posted by Daniel P. Berrangé 6 years, 6 months ago
On Fri, Aug 09, 2019 at 10:49:11AM +0200, Michal Privoznik wrote:
> If yajl_parse() fails, we try to print an error message. For
> that, yajl_get_error() is used. However, its documentation say
> that caller is also responsible for freeing the memory it
> allocates by using yajl_free_error().
> 
> Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
> ---
>  tools/nss/libvirt_nss_leases.c | 7 ++++---
>  1 file changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/tools/nss/libvirt_nss_leases.c b/tools/nss/libvirt_nss_leases.c
> index 577b5a2fd1..977e3415f7 100644
> --- a/tools/nss/libvirt_nss_leases.c
> +++ b/tools/nss/libvirt_nss_leases.c
> @@ -399,9 +399,10 @@ findLeases(const char *file,
>  
>          if (yajl_parse(parser, (const unsigned char *)line, rv)  !=
>              yajl_status_ok) {
> -            ERROR("Parse failed %s",
> -                  yajl_get_error(parser, 1,
> -                                 (const unsigned char*)line, rv));
> +            unsigned char *err = yajl_get_error(parser, 1,
> +                                                (const unsigned char*)line, rv);
> +            ERROR("Parse failed %s", (const char *) err);
> +            yajl_free_error(parser, err);
>              goto cleanup;
>          }
>      }

Same fix needed in libvirt_nss_macs.c too

Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>


Regards,
Daniel
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Re: [libvirt] [PATCH 3/3] nss: Don't leak memory on parse error
Posted by Michal Privoznik 6 years, 6 months ago
On 8/9/19 11:04 AM, Daniel P. Berrangé wrote:
> On Fri, Aug 09, 2019 at 10:49:11AM +0200, Michal Privoznik wrote:
>> If yajl_parse() fails, we try to print an error message. For
>> that, yajl_get_error() is used. However, its documentation say
>> that caller is also responsible for freeing the memory it
>> allocates by using yajl_free_error().
>>
>> Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
>> ---
>>   tools/nss/libvirt_nss_leases.c | 7 ++++---
>>   1 file changed, 4 insertions(+), 3 deletions(-)
>>
>> diff --git a/tools/nss/libvirt_nss_leases.c b/tools/nss/libvirt_nss_leases.c
>> index 577b5a2fd1..977e3415f7 100644
>> --- a/tools/nss/libvirt_nss_leases.c
>> +++ b/tools/nss/libvirt_nss_leases.c
>> @@ -399,9 +399,10 @@ findLeases(const char *file,
>>   
>>           if (yajl_parse(parser, (const unsigned char *)line, rv)  !=
>>               yajl_status_ok) {
>> -            ERROR("Parse failed %s",
>> -                  yajl_get_error(parser, 1,
>> -                                 (const unsigned char*)line, rv));
>> +            unsigned char *err = yajl_get_error(parser, 1,
>> +                                                (const unsigned char*)line, rv);
>> +            ERROR("Parse failed %s", (const char *) err);
>> +            yajl_free_error(parser, err);
>>               goto cleanup;
>>           }
>>       }
> 
> Same fix needed in libvirt_nss_macs.c too

Ah, good point. I completely forgot about libvirt_nss_macs.c; The 
problem I'm fixing in 1/3 applies there too. I'm squashing in the 
obvious fix (even though macs JSON doesn't have any unexpected keys yet).

Thanks,
Michal

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