Merge pull request #10 from a3f/fix-buffer-underflow

jonrebm · web-flow · commit db25c6566d98 · 2026-01-15T10:16:32.000+01:00
Fix buffer underflow when serial peer spews garbage
diff --git a/mux.c b/mux.c
@@ -29,7 +29,7 @@ char *answerback;
 
 static void write_receive_buf(const unsigned char *buf, int len)
 {
-	if (!len)
+	if (len <= 0)
 		return;
 
 	write(STDOUT_FILENO, buf, len);
@@ -41,7 +41,7 @@ static int handle_receive_buf(struct ios_ops *ios, unsigned char *buf, int len)
 {
 	unsigned char *sendbuf = buf;
 
-	while (len) {
+	while (len > 0) {
 		switch (*buf) {
 		case 5:
 			write_receive_buf(sendbuf, buf - sendbuf);

Original file line number	Diff line number	Diff line change
`@@ -29,7 +29,7 @@ char *answerback;`
`29`	`29`
`30`	`30`	`static void write_receive_buf(const unsigned char *buf, int len)`
`31`	`31`	`{`
`32`		`- if (!len)`
	`32`	`+ if (len <= 0)`
`33`	`33`	`return;`
`34`	`34`
`35`	`35`	`write(STDOUT_FILENO, buf, len);`
`@@ -41,7 +41,7 @@ static int handle_receive_buf(struct ios_ops ios, unsigned char buf, int len)`
`41`	`41`	`{`
`42`	`42`	`unsigned char *sendbuf = buf;`
`43`	`43`
`44`		`- while (len) {`
	`44`	`+ while (len > 0) {`
`45`	`45`	`switch (*buf) {`
`46`	`46`	`case 5:`
`47`	`47`	`write_receive_buf(sendbuf, buf - sendbuf);`