From: Yu Watanabe <watanabe.yu+github@gmail.com>
Date: Sun, 25 Aug 2024 21:33:42 +0000 (+0900)
Subject: sd-device: refuse earlier when too long ifname is passed to sd_device_new_from_ifname()
X-Git-Tag: v257-rc1~612^2~4
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=55e35a4d59bea8653a428f544490b1d80b848d64;p=thirdparty%2Fsystemd.git

sd-device: refuse earlier when too long ifname is passed to sd_device_new_from_ifname()

Otherwise, alloca() called in strjoina() may trigger assertion.

This partially reverts 3652891c3904992e21739e9bfb004073841db63c.
The commit mistakenly dropped the check.
---

diff --git a/src/libsystemd/sd-device/sd-device.c b/src/libsystemd/sd-device/sd-device.c
index dafda626f07..3d683fb2802 100644
--- a/src/libsystemd/sd-device/sd-device.c
+++ b/src/libsystemd/sd-device/sd-device.c
@@ -345,9 +345,11 @@ _public_ int sd_device_new_from_ifname(sd_device **ret, const char *ifname) {
         assert_return(ret, -EINVAL);
         assert_return(ifname, -EINVAL);
 
-        r = device_new_from_main_ifname(ret, ifname);
-        if (r >= 0)
-                return r;
+        if (ifname_valid(ifname)) {
+                r = device_new_from_main_ifname(ret, ifname);
+                if (r >= 0)
+                        return r;
+        }
 
         r = rtnl_resolve_ifname_full(NULL, RESOLVE_IFNAME_ALTERNATIVE | RESOLVE_IFNAME_NUMERIC, ifname, &main_name, NULL);
         if (r < 0)