From: Yann Sionneau <redacted>
Date: Sun, 16 Mar 2025 14:11:42 +0000 (+0100)
Subject: input/protocoldata: Check if lookup_protocol_name is valid
X-Git-Url: https://sigrok.org/gitaction?a=commitdiff_plain;h=afc8ba47b1900045fd2d15d30712be4c167c95c8;p=libsigrok.git

input/protocoldata: Check if lookup_protocol_name is valid

As of today, the code does not crash because all protocols have names.
But the name of the first element is not checked to be non-NULL
before calling strcmp(). This can result in a future crash if the
code logic changes.

This is mostly a change to robustify the lookup_protocol_name() function.

Also, this commit simplifies the indexing logic of the protocols array.
---

diff --git a/src/input/protocoldata.c b/src/input/protocoldata.c
index 905e33e4..22454b3b 100644
--- a/src/input/protocoldata.c
+++ b/src/input/protocoldata.c
@@ -408,7 +408,8 @@ struct context {
 		enum textinput_t textinput;
 		enum proto_type_t {
 			PROTO_TYPE_NONE,
-			PROTO_TYPE_UART,
+			PROTO_TYPE_FIRST,
+			PROTO_TYPE_UART = PROTO_TYPE_FIRST,
 			PROTO_TYPE_SPI,
 			PROTO_TYPE_I2C,
 			PROTO_TYPE_COUNT,
@@ -2520,13 +2521,13 @@ static int lookup_protocol_name(struct context *inc)
 	name = inc->curr_opts.proto_name;
 	if (!name || !*name) {
 		/* Fallback to first item after NONE slot. */
-		handler = &protocols[PROTO_TYPE_NONE + 1];
+		handler = &protocols[PROTO_TYPE_FIRST];
 		name = handler->name;
+		if (!name)
+			return SR_ERR_ARG;
 	}
 
-	for (idx = 0; idx < ARRAY_SIZE(protocols); idx++) {
-		if (idx == PROTO_TYPE_NONE)
-			continue;
+	for (idx = PROTO_TYPE_FIRST; idx < ARRAY_SIZE(protocols); idx++) {
 		handler = &protocols[idx];
 		if (!handler->name || !*handler->name)
 			continue;