html: fix strcpy bug in convert_query_hexchar

The source and destination strings in strcpy() may not overlap.
Instead, use memmove(), which allows overlap.  This fixes test t0104,
where 'url=foo%2bbar/tree' was being parsed improperly.

Signed-off-by: Mark Lodato <lodatom@gmail.com>

1 files changed, 5 insertions, 4 deletions

diff --git a/html.c b/html.c
index 66ba65d..d86b2c1 100644
--- a/html.c
+++ b/html.c
@@ -147,145 +147,146 @@ void html_url_path(char *txt)
 }
 
 void html_url_arg(char *txt)
 {
 	char *t = txt;
 	while(t && *t){
 		int c = *t;
 		if (c=='"' || c=='#' || c=='%' || c=='&' || c=='\'' || c=='+' || c=='?') {
 			write(htmlfd, txt, t - txt);
 			write(htmlfd, fmt("%%%2x", c), 3);
 			txt = t+1;
 		}
 		t++;
 	}
 	if (t!=txt)
 		html(txt);
 }
 
 void html_hidden(char *name, char *value)
 {
 	html("<input type='hidden' name='");
 	html_attr(name);
 	html("' value='");
 	html_attr(value);
 	html("'/>");
 }
 
 void html_option(char *value, char *text, char *selected_value)
 {
 	html("<option value='");
 	html_attr(value);
 	html("'");
 	if (selected_value && !strcmp(selected_value, value))
 		html(" selected='selected'");
 	html(">");
 	html_txt(text);
 	html("</option>\n");
 }
 
 void html_link_open(char *url, char *title, char *class)
 {
 	html("<a href='");
 	html_attr(url);
 	if (title) {
 		html("' title='");
 		html_attr(title);
 	}
 	if (class) {
 		html("' class='");
 		html_attr(class);
 	}
 	html("'>");
 }
 
 void html_link_close(void)
 {
 	html("</a>");
 }
 
 void html_fileperm(unsigned short mode)
 {
 	htmlf("%c%c%c", (mode & 4 ? 'r' : '-'),
 	      (mode & 2 ? 'w' : '-'), (mode & 1 ? 'x' : '-'));
 }
 
 int html_include(const char *filename)
 {
 	FILE *f;
 	char buf[4096];
 	size_t len;
 
 	if (!(f = fopen(filename, "r"))) {
 		fprintf(stderr, "[cgit] Failed to include file %s: %s (%d).\n",
 			filename, strerror(errno), errno);
 		return -1;
 	}
 	while((len = fread(buf, 1, 4096, f)) > 0)
 		write(htmlfd, buf, len);
 	fclose(f);
 	return 0;
 }
 
 int hextoint(char c)
 {
 	if (c >= 'a' && c <= 'f')
 		return 10 + c - 'a';
 	else if (c >= 'A' && c <= 'F')
 		return 10 + c - 'A';
 	else if (c >= '0' && c <= '9')
 		return c - '0';
 	else
 		return -1;
 }
 
 char *convert_query_hexchar(char *txt)
 {
-	int d1, d2;
-	if (strlen(txt) < 3) {
+	int d1, d2, n;
+	n = strlen(txt);
+	if (n < 3) {
 		*txt = '\0';
 		return txt-1;
 	}
 	d1 = hextoint(*(txt+1));
 	d2 = hextoint(*(txt+2));
 	if (d1<0 || d2<0) {
-		strcpy(txt, txt+3);
+		memmove(txt, txt+3, n-3);
 		return txt-1;
 	} else {
 		*txt = d1 * 16 + d2;
-		strcpy(txt+1, txt+3);
+		memmove(txt+1, txt+3, n-2);
 		return txt;
 	}
 }
 
 int http_parse_querystring(char *txt, void (*fn)(const char *name, const char *value))
 {
 	char *t, *value = NULL, c;
 
 	if (!txt)
 		return 0;
 
 	t = txt = strdup(txt);
 	if (t == NULL) {
 		printf("Out of memory\n");
 		exit(1);
 	}
 	while((c=*t) != '\0') {
 		if (c=='=') {
 			*t = '\0';
 			value = t+1;
 		} else if (c=='+') {
 			*t = ' ';
 		} else if (c=='%') {
 			t = convert_query_hexchar(t);
 		} else if (c=='&') {
 			*t = '\0';
 			(*fn)(txt, value);
 			txt = t+1;
 			value = NULL;
 		}
 		t++;
 	}
 	if (t!=txt)
 		(*fn)(txt, value);
 	return 0;
 }