Ignore empty ALPN elements in CLI args
@@ -1809,26 +1809,46 @@ unsigned char *next_protos_parse(size_t *outlen, const char *in)
size_t len;
unsigned char *out;
size_t i, start = 0;
+ size_t skipped = 0;
len = strlen(in);
- if (len >= 65535)
+ if (len == 0 || len >= 65535)
return NULL;
- out = app_malloc(strlen(in) + 1, "NPN buffer");
+ out = app_malloc(len + 1, "NPN buffer");
for (i = 0; i <= len; ++i) {
if (i == len || in[i] == ',') {
+ /*
+ * Zero-length ALPN elements are invalid on the wire, we could be
+ * strict and reject the entire string, but just ignoring extra
+ * commas seems harmless and more friendly.
+ *
+ * Every comma we skip in this way puts the input buffer another
+ * byte ahead of the output buffer, so all stores into the output
+ * buffer need to be decremented by the number commas skipped.
+ */
+ if (i == start) {
+ ++start;
+ ++skipped;
+ continue;
+ }
if (i - start > 255) {
OPENSSL_free(out);
return NULL;
}
- out[start] = (unsigned char)(i - start);
+ out[start-skipped] = (unsigned char)(i - start);
start = i + 1;
} else {
- out[i + 1] = in[i];
+ out[i + 1 - skipped] = in[i];
}
}
- *outlen = len + 1;
+ if (len <= skipped) {
+ OPENSSL_free(out);
+ return NULL;
+ }
+
+ *outlen = len + 1 - skipped;
return out;
}
