output/email: reset custom fields during init

[inashivb]

Redmine ticket: None yet. Need somebody to confirm if the analysis is correct and this is a bug. This purely came from "works on my machine" case of OISF/suricata-verify#1405 after I spent way too much time figuring the difference in behaviors and finally tried to check the code.

I believe (and tested) that the alternate solution for this problem is:

diff --git a/src/output-json-smtp.c b/src/output-json-smtp.c
index cc3003907..f7674687c 100644
--- a/src/output-json-smtp.c
+++ b/src/output-json-smtp.c
@@ -122,7 +122,7 @@ static OutputInitResult OutputSmtpLogInitSub(ConfNode *conf, OutputCtx *parent_c
     OutputInitResult result = { NULL, false };
     OutputJsonCtx *ojc = parent_ctx->data;
 
-    OutputJsonEmailCtx *email_ctx = SCMalloc(sizeof(OutputJsonEmailCtx));
+    OutputJsonEmailCtx *email_ctx = SCCalloc(1, sizeof(OutputJsonEmailCtx));
     if (unlikely(email_ctx == NULL))
         return result;

I'm not sure which one is more ideal.

[codecov]

Codecov Report

Merging #9544 (a3b2743) into master (bb15a8f) will decrease coverage by 0.02%.
The diff coverage is 100.00%.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #9544      +/-   ##
==========================================
- Coverage   82.19%   82.18%   -0.02%     
==========================================
  Files         968      968              
  Lines      274216   274216              
==========================================
- Hits       225405   225374      -31     
- Misses      48811    48842      +31     

Flag	Coverage Δ
fuzzcorpus	64.07% <100.00%> (+<0.01%)	⬆️
suricata-verify	60.90% <100.00%> (-0.03%)	⬇️
unittests	62.88% <0.00%> (-0.01%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

[victorjulien]

When 8 opens we will merge #9388. I think I would prefer the same fix here, as you suggest.

[victorjulien]

To be clear, I would to see a new PR with the SCCalloc approach.