Avoid null pointer dereference in reencode().

Returning "*txt" if "txt" is a null pointer is a bad thing. Spotted with
clang-analyzer.

Signed-off-by: Lukas Fleischer <cgit@cryptocrack.de>
Signed-off-by: Lars Hjemli <hjemli@gmail.com>

1 files changed, 4 insertions, 1 deletions

diff --git a/parsing.c b/parsing.c
index c9e4350..151c0fe 100644
--- a/parsing.c
+++ b/parsing.c
@@ -42,129 +42,132 @@ void cgit_parse_url(const char *url)
 		ctx.qry.repo = ctx.repo->url;
 		p = strchr(cmd + 1, '/');
 		if (p) {
 			p[0] = '\0';
 			if (p[1])
 				ctx.qry.path = trim_end(p + 1, '/');
 		}
 		if (cmd[1])
 			ctx.qry.page = xstrdup(cmd + 1);
 		return;
 	}
 }
 
 char *substr(const char *head, const char *tail)
 {
 	char *buf;
 
 	buf = xmalloc(tail - head + 1);
 	strncpy(buf, head, tail - head);
 	buf[tail - head] = '\0';
 	return buf;
 }
 
 char *parse_user(char *t, char **name, char **email, unsigned long *date)
 {
 	char *p = t;
 	int mode = 1;
 
 	while (p && *p) {
 		if (mode == 1 && *p == '<') {
 			*name = substr(t, p - 1);
 			t = p;
 			mode++;
 		} else if (mode == 1 && *p == '\n') {
 			*name = substr(t, p);
 			p++;
 			break;
 		} else if (mode == 2 && *p == '>') {
 			*email = substr(t, p + 1);
 			t = p;
 			mode++;
 		} else if (mode == 2 && *p == '\n') {
 			*email = substr(t, p);
 			p++;
 			break;
 		} else if (mode == 3 && isdigit(*p)) {
 			*date = atol(p);
 			mode++;
 		} else if (*p == '\n') {
 			p++;
 			break;
 		}
 		p++;
 	}
 	return p;
 }
 
 #ifdef NO_ICONV
 #define reencode(a, b, c)
 #else
 const char *reencode(char **txt, const char *src_enc, const char *dst_enc)
 {
 	char *tmp;
 
-	if (!txt || !*txt || !src_enc || !dst_enc)
+	if (!txt)
+		return NULL;
+
+	if (!*txt || !src_enc || !dst_enc)
 		return *txt;
 
 	/* no encoding needed if src_enc equals dst_enc */
 	if(!strcasecmp(src_enc, dst_enc))
 		return *txt;
 
 	tmp = reencode_string(*txt, dst_enc, src_enc);
 	if (tmp) {
 		free(*txt);
 		*txt = tmp;
 	}
 	return *txt;
 }
 #endif
 
 struct commitinfo *cgit_parse_commit(struct commit *commit)
 {
 	struct commitinfo *ret;
 	char *p = commit->buffer, *t = commit->buffer;
 
 	ret = xmalloc(sizeof(*ret));
 	ret->commit = commit;
 	ret->author = NULL;
 	ret->author_email = NULL;
 	ret->committer = NULL;
 	ret->committer_email = NULL;
 	ret->subject = NULL;
 	ret->msg = NULL;
 	ret->msg_encoding = NULL;
 
 	if (p == NULL)
 		return ret;
 
 	if (strncmp(p, "tree ", 5))
 		die("Bad commit: %s", sha1_to_hex(commit->object.sha1));
 	else
 		p += 46; // "tree " + hex[40] + "\n"
 
 	while (!strncmp(p, "parent ", 7))
 		p += 48; // "parent " + hex[40] + "\n"
 
 	if (p && !strncmp(p, "author ", 7)) {
 		p = parse_user(p + 7, &ret->author, &ret->author_email,
 			&ret->author_date);
 	}
 
 	if (p && !strncmp(p, "committer ", 9)) {
 		p = parse_user(p + 9, &ret->committer, &ret->committer_email,
 			&ret->committer_date);
 	}
 
 	if (p && !strncmp(p, "encoding ", 9)) {
 		p += 9;
 		t = strchr(p, '\n');
 		if (t) {
 			ret->msg_encoding = substr(p, t + 1);
 			p = t + 1;
 		}
 	}
 
 	/* if no special encoding is found, assume UTF-8 */
 	if(!ret->msg_encoding)
 		ret->msg_encoding = xstrdup("UTF-8");