From dc22d0df73a7ecb036d73cfa1814ddf998ff131b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Nikola=20Forr=C3=B3?= <nforro@redhat.com>
Date: Tue, 17 Jan 2017 14:03:00 +0100
Subject: [PATCH] Fix SIGSEGV crash in smtp_auth_var()
Add warning message for empty from variable

---
 sendout.c | 13 +++++++++++++
 smtp.c    |  5 ++++-
 2 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/sendout.c b/sendout.c
index c52f15d..f83952a 100644
--- a/sendout.c
+++ b/sendout.c
@@ -966,6 +966,19 @@ mail1(struct header *hp, int printheaders, struct message *quote,
 		return STOP;
 	}
 #endif
+
+	/*
+	 * Variable "from" is set but empty, let user know
+	 * that something is wrong.
+	 */
+	if ((cp = value("from")) != NULL && !*cp) {
+		fprintf(stderr, "From address is empty. ");
+		fprintf(stderr, "Check your mail config ");
+		fprintf(stderr, "file for typos. E.g. no ");
+		fprintf(stderr, "whitespace after set from=");
+		fprintf(stderr, "\n");
+	}
+
 	if ((cp = value("autocc")) != NULL && *cp)
 		hp->h_cc = cat(hp->h_cc, checkaddrs(sextract(cp, GCC|GFULL)));
 	if ((cp = value("autobcc")) != NULL && *cp)
diff --git a/smtp.c b/smtp.c
index b4561e3..baab5d1 100644
--- a/smtp.c
+++ b/smtp.c
@@ -135,7 +135,7 @@ myaddrs(struct header *hp)
 		if (hp->h_from->n_name)
 			return savestr(hp->h_from->n_name);
 	}
-	if ((cp = value("from")) != NULL)
+	if ((cp = value("from")) != NULL && *cp)
 		return cp;
 	/*
 	 * When invoking sendmail directly, it's its task
@@ -177,6 +177,9 @@ smtp_auth_var(const char *type, const char *addr)
 	char	*var, *cp;
 	int	len;
 
+	if (type == NULL || addr == NULL)
+		return NULL;
+
 	var = ac_alloc(len = strlen(type) + strlen(addr) + 7);
 	snprintf(var, len, "smtp-auth%s-%s", type, addr);
 	if ((cp = value(var)) != NULL)
-- 
2.7.4