output/email: use SCCalloc for OutputJsonEmailCtx

email_ctx->fields only gets populated when smtp.custom setting is on.
The fn EveEmailLogJSONCustom is called when either
1. smtp.extended setting is on or,
2. email_ctx->fields is populated which means smtp.custom setting is on

In case neither of these are set in suricata.yaml, no call should
ideally be made to the fn EveEmailLogJSONCustom.
However, it turns out that email_ctx->fields is unset and then set only
after the smtp config was found. This leads to email_ctx->fields
sometimes contain value even when no config was given to the smtp
section and can lead to unexpected output.

Fix this by using SCCalloc while initializing OutputJsonEmailCtx struct
instead of SCMalloc.

Bug 6380

(cherry picked from commit 7406ac0fa595658c70ed3f13cf79656f2b0d290a)

diff --git a/src/output-json-smtp.c b/src/output-json-smtp.c
index e331b01023abbab5eda11b1062f0803afaf071af..2b57f2ebed37af9e7858923c3a8001555c31b51a 100644 (file)
--- a/src/output-json-smtp.c
+++ b/src/output-json-smtp.c
@@ -126,7 +126,7 @@ 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;