[PATCH] Fix audispd crash on ARM 32-Bits

[Tia, Javier]

Hi Steve,

Thank you for your prompt response and for pointing to a solution.

Yes, this patch it's applied to audit v2.4.3. It's an embedded device, 
and at the moment, we're unable to upgrade the audit to a higher audit 
version.

If audit v2.4.y were still maintainable, would you accept this patch for 
audit v2.4.y?

-Javier

On 12/12/20 1:45 PM, Steve Grubb wrote:
> Hello,
> 
> Thanks for the patch. But if its true that this is against audit-2.4.3, then
> there is a good chance this is fixed by 2.8.5. There were a number of fixes in
> this area that fixed various issues with plugins.
> 
> Best Regards,
> -Steve
> 
> On Friday, December 11, 2020 9:10:50 PM EST Javier Tiá wrote:
>> On ARM 32-Bits, audispd is crashing. Backtrace:
>>
>> (gdb) bt
>> 0  0xb6e20958 in __GI_raise (sig=sig at entry=6)
>>     at /usr/src/debug/glibc/2.23-r0/git/sysdeps/unix/sysv/linux/raise.c:54
>> 1  0xb6e21e58 in __GI_abort ()
>>     at /usr/src/debug/glibc/2.23-r0/git/stdlib/abort.c:118
>> 2  0xb6e59d64 in __libc_message (do_abort=do_abort at entry=2,
>>     fmt=0xb6f1119c "*** Error in `%s': %s: 0x%s ***\n")
>>     at /usr/src/debug/glibc/2.23-r0/git/sysdeps/posix/libc_fatal.c:175
>> 3  0xb6e60108 in malloc_printerr (action=<optimized out>,
>>     str=0xb6f11354 "double free or corruption (fasttop)", ptr=<optimized
>> out>, ar_ptr=<optimized out>)
>>     at /usr/src/debug/glibc/2.23-r0/git/malloc/malloc.c:5007
>> 4  0xb6e60a98 in _int_free (av=0xb6f2d79c <main_arena>, p=<optimized out>,
>>     have_lock=<optimized out>)
>>     at /usr/src/debug/glibc/2.23-r0/git/malloc/malloc.c:3868
>> 5  0x004234b8 in free_pconfig (config=0x43b398)
>>     at
>> /usr/src/debug/audit/2.4.3-r8/audit-2.4.3/audisp/audispd-pconfig.c:513 6
>> 0x00421244 in main (argc=<optimized out>, argv=<optimized out>) at
>> /usr/src/debug/audit/2.4.3-r8/audit-2.4.3/audisp/audispd.c:464
>>
>> (gdb) f 5
>> (gdb) p config->path
>> $2 = 0x43b5f0 ""
>> (gdb) p config->name
>> $3 = 0x43b370 "h\264C
>>
>> Be paranoid and overwrite config->path with zero bytes before doing the
>> free().
>> ---
>>   audisp/audispd-pconfig.c | 4 ++++
>>   1 file changed, 4 insertions(+)
>>
>> diff --git a/audisp/audispd-pconfig.c b/audisp/audispd-pconfig.c
>> index a8b7878..a13f681 100644
>> --- a/audisp/audispd-pconfig.c
>> +++ b/audisp/audispd-pconfig.c
>> @@ -510,7 +510,11 @@ void free_pconfig(plugin_conf_t *config)
>>   		close(config->plug_pipe[0]);
>>   	if (config->plug_pipe[1] >= 0)
>>   		close(config->plug_pipe[1]);
>> +	/* Be paranoid and overwrite config->path with zero bytes before doing
>> the +	 * free() */
>> +	memset(config->path, 0, strlen(config->path));
>>   	free((void *)config->path);
>> +	config->path = NULL;
>>   	free((void *)config->name);
>>   }
> 
> 
> 
>