res_pjsip: Strip spaces from items parsed from comma-separated lists

Configurations like "aors = a, b, c" were either ignoring everything after "a"
or trying to look up " b".  Same for mailboxes,  ciphers, contacts and a few
others.

To fix, all the strsep(&copy, ",") calls have been wrapped in ast_strip.  To
facilitate this, ast_strip, ast_skip_blanks and ast_skip_nonblanks were
updated to handle null pointers.

In some cases, an ast_strlen_zero() test was added to skip consecutive commas.

There was also an attempt to ast_free an ast_strdupa'd string in
ast_sip_for_each_aor which was causing a SEGV.  I removed it.

Although this issue was reported for realtime, the issue was in the res_pjsip
modules so all config mechanisms were affected.

ASTERISK-25829 #close
Reported-by: Mateusz Kowalski

Change-Id: I0b22a2cf22a7c1c50d4ecacbfa540155bec0e7a2

1 files changed, 12 insertions, 4 deletions

diff --git a/include/asterisk/strings.h b/include/asterisk/strings.h
index af5ae6c55..3701b5305 100644
--- a/include/asterisk/strings.h
+++ b/include/asterisk/strings.h
@@ -145,8 +145,12 @@ static int force_inline attribute_pure ast_ends_with(const char *str, const char
 AST_INLINE_API(
 char * attribute_pure ast_skip_blanks(const char *str),
 {
-	while (*str && ((unsigned char) *str) < 33)
-		str++;
+	if (str) {
+		while (*str && ((unsigned char) *str) < 33) {
+			str++;
+		}
+	}
+
 	return (char *) str;
 }
 )
@@ -184,8 +188,12 @@ char *ast_trim_blanks(char *str),
 AST_INLINE_API(
 char * attribute_pure ast_skip_nonblanks(const char *str),
 {
-	while (*str && ((unsigned char) *str) > 32)
-		str++;
+	if (str) {
+		while (*str && ((unsigned char) *str) > 32) {
+			str++;
+		}
+	}
+
 	return (char *) str;
 }
 )