From: Mike Brady <4265913+mikebrady@users.noreply.github.com>
Date: Tue, 9 Aug 2022 11:34:17 +0000 (+0100)
Subject: Fix get_device_id to work property when using AF_LINK rather than AF_PACKET. Ensure... 
X-Git-Tag: 4.1-rc1~24^2~42^2~5
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=882d6c5b680e68ee35b17e891dc4c11905cf4732;p=thirdparty%2Fshairport-sync.git

Fix get_device_id to work property when using AF_LINK rather than AF_PACKET. Ensure only int_length bytes are copied to the device ID
---

diff --git a/common.c b/common.c
index c4f9ac81..2e582f63 100644
--- a/common.c
+++ b/common.c
@@ -1950,15 +1950,17 @@ int get_device_id(uint8_t *id, int int_length) {
   }
 
   if (getifaddrs(&ifaddr) == -1) {
-    debug(1, "getifaddrs");
     response = -1;
   } else {
     t = id;
-    for (ifa = ifaddr; ifa != NULL; ifa = ifa->ifa_next) {
+    int found = 0;
+    
+    for (ifa = ifaddr; ((ifa != NULL) && (found == 0)); ifa = ifa->ifa_next) {
 #ifdef AF_PACKET
       if ((ifa->ifa_addr) && (ifa->ifa_addr->sa_family == AF_PACKET)) {
         struct sockaddr_ll *s = (struct sockaddr_ll *)ifa->ifa_addr;
-        if ((strcmp(ifa->ifa_name, "lo") != 0) && (found == 0)) {
+        if ((strcmp(ifa->ifa_name, "lo") != 0)) {
+          found = 1;
           for (i = 0; ((i < s->sll_halen) && (i < int_length)); i++) {
             *t++ = s->sll_addr[i];
           }
@@ -1969,15 +1971,16 @@ int get_device_id(uint8_t *id, int int_length) {
       struct sockaddr_dl *sdl = (struct sockaddr_dl *)ifa->ifa_addr;
       if ((sdl) && (sdl->sdl_family == AF_LINK)) {
         if (sdl->sdl_type == IFT_ETHER) {
-          char *s = LLADDR(sdl);
-          for (i = 0; i < sdl->sdl_alen; i++) {
-            debug(1, "char %d: \"%c\".", i, *s);
-            *t++ = (uint8_t)*s++;
+          found = 1;
+          uint8_t *s = (uint8_t *)LLADDR(sdl);
+          for (i = 0; ((i < sdl->sdl_alen) && (i < int_length)); i++) {
+            *t++ = *s++;
           }
         }
       }
 #endif
 #endif
+
     }
     freeifaddrs(ifaddr);
   }