git: 40c79e979ea8 - stable/14 - route: avoid overlapping strcpy

The branch stable/14 has been updated by kevans:

URL: https://cgit.FreeBSD.org/src/commit/?id=40c79e979ea8dbbf2262297865754910f8d704c0

commit 40c79e979ea8dbbf2262297865754910f8d704c0
Author:     Kyle Evans <kevans@FreeBSD.org>
AuthorDate: 2024-07-23 20:25:46 +0000
Commit:     Kyle Evans <kevans@FreeBSD.org>
CommitDate: 2024-08-08 19:59:15 +0000

    route: avoid overlapping strcpy
    
    Passing overlapping buffers to strcpy yields an undefined result, so
    let's avoid it. The copy doesn't really need to happen anyways, we can
    just point to the domain part of the hostname.
    
    This was discovered with _FORTIFY_SOURCE.
    
    Sponsored by:   Klara, Inc.
    Sponsored by:   Stormshield
    Reviewed by:    allanjude, emaste, imp, melifaro (all previous version)
    
    (cherry picked from commit 158f319428c10143ce2ffe766416207c75578931)
---
 sbin/route/route.c | 22 ++++++++++++----------
 1 file changed, 12 insertions(+), 10 deletions(-)

diff --git a/sbin/route/route.c b/sbin/route/route.c
index 7cf2bf842559..ad7a906bc142 100644
--- a/sbin/route/route.c
+++ b/sbin/route/route.c
@@ -107,8 +107,8 @@ static u_long  rtm_inits;
 static uid_t	uid;
 static int	defaultfib;
 static int	numfibs;
-static char	domain[MAXHOSTNAMELEN + 1];
-static bool	domain_initialized;
+static char	domain_storage[MAXHOSTNAMELEN + 1];
+static const char	*domain;
 static char	rt_line[NI_MAXHOST];
 static char	net_line[MAXHOSTNAMELEN + 1];
 
@@ -594,14 +594,16 @@ routename(struct sockaddr *sa)
 	const char *cp;
 	int n;
 
-	if (!domain_initialized) {
-		domain_initialized = true;
-		if (gethostname(domain, MAXHOSTNAMELEN) == 0 &&
-		    (cp = strchr(domain, '.'))) {
-			domain[MAXHOSTNAMELEN] = '\0';
-			(void)strcpy(domain, cp + 1);
-		} else
-			domain[0] = '\0';
+	if (domain == NULL) {
+		if (gethostname(domain_storage,
+		    sizeof(domain_storage) - 1) == 0 &&
+		    (cp = strchr(domain_storage, '.')) != NULL) {
+			domain_storage[sizeof(domain_storage) - 1] = '\0';
+			domain = cp + 1;
+		} else {
+			domain_storage[0] = '\0';
+			domain = domain_storage;
+		}
 	}
 
 	/* If the address is zero-filled, use "default". */