From 0669fb63cfe5c5f7a06f0f390dbb5dcc511cea2b Mon Sep 17 00:00:00 2001
From: Richard Russon <rich@flatcap.org>
Date: Mon, 29 Apr 2019 14:57:29 +0100
Subject: [PATCH] libmutt: fix charset code for degenerate cases

---
 mutt/charset.c | 29 +++++++++++++++++++++++++----
 1 file changed, 25 insertions(+), 4 deletions(-)

diff --git a/mutt/charset.c b/mutt/charset.c
index 6bbd92755..5065351c5 100644
--- a/mutt/charset.c
+++ b/mutt/charset.c
@@ -269,6 +269,9 @@ static const char *lookup_charset(enum LookupType type, const char *cs)
  */
 int mutt_ch_convert_nonmime_string(char **ps)
 {
+  if (!ps)
+    return -1;
+
   const char *c1 = NULL;
 
   for (const char *c = C_AssumedCharset; c; c = c1 ? c1 + 1 : 0)
@@ -310,6 +313,9 @@ int mutt_ch_convert_nonmime_string(char **ps)
  */
 void mutt_ch_canonical_charset(char *buf, size_t buflen, const char *name)
 {
+  if (!buf || !name)
+    return;
+
   char in[1024], scratch[1024];
 
   mutt_str_strfcpy(in, name, sizeof(in));
@@ -679,6 +685,9 @@ const char *mutt_ch_iconv_lookup(const char *chs)
  */
 int mutt_ch_check(const char *s, size_t slen, const char *from, const char *to)
 {
+  if (!s || !from || !to)
+    return -1;
+
   int rc = 0;
   iconv_t cd = mutt_ch_iconv_open(to, from, 0);
   if (cd == (iconv_t) -1)
@@ -713,10 +722,10 @@ int mutt_ch_check(const char *s, size_t slen, const char *from, const char *to)
  */
 int mutt_ch_convert_string(char **ps, const char *from, const char *to, int flags)
 {
-  iconv_t cd;
-  const char *repls[] = { "\357\277\275", "?", 0 };
+  if (!ps)
+    return -1;
+
   char *s = *ps;
-  int rc = 0;
 
   if (!s || !*s)
     return 0;
@@ -724,7 +733,10 @@ int mutt_ch_convert_string(char **ps, const char *from, const char *to, int flag
   if (!to || !from)
     return -1;
 
-  cd = mutt_ch_iconv_open(to, from, flags);
+  const char *repls[] = { "\357\277\275", "?", 0 };
+  int rc = 0;
+
+  iconv_t cd = mutt_ch_iconv_open(to, from, flags);
   if (cd == (iconv_t) -1)
     return -1;
 
@@ -774,6 +786,9 @@ int mutt_ch_convert_string(char **ps, const char *from, const char *to, int flag
  */
 bool mutt_ch_check_charset(const char *cs, bool strict)
 {
+  if (!cs)
+    return false;
+
   if (mutt_ch_is_utf8(cs))
     return true;
 
@@ -841,6 +856,9 @@ struct FgetConv *mutt_ch_fgetconv_open(FILE *fp, const char *from, const char *t
  */
 void mutt_ch_fgetconv_close(struct FgetConv **fc)
 {
+  if (!fc || !*fc)
+    return;
+
   if ((*fc)->cd != (iconv_t) -1)
     iconv_close((*fc)->cd);
   FREE(fc);
@@ -920,6 +938,9 @@ int mutt_ch_fgetconv(struct FgetConv *fc)
  */
 char *mutt_ch_fgetconvs(char *buf, size_t buflen, struct FgetConv *fc)
 {
+  if (!buf)
+    return NULL;
+
   size_t r;
   for (r = 0; (r + 1) < buflen;)
   {
-- 
2.49.0