From: Thorsten Blum <thorsten.blum@linux.dev>
Date: Mon, 25 May 2026 09:54:01 +0000 (+0200)
Subject: net/dns_resolver: consolidate namelen checks in dns_query
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=f289c0664f64578355d10a85a6e0108fd182043c;p=thirdparty%2Flinux.git

net/dns_resolver: consolidate namelen checks in dns_query

Consolidate the namelen checks and return -EINVAL early if needed. Drop
the namelen == 0 check since it is covered by namelen < 3.

Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20260525095400.821912-3-thorsten.blum@linux.dev
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---

diff --git a/net/dns_resolver/dns_query.c b/net/dns_resolver/dns_query.c
index e1c09d7b82007..c250d82cad965 100644
--- a/net/dns_resolver/dns_query.c
+++ b/net/dns_resolver/dns_query.c
@@ -73,7 +73,7 @@ int dns_query(struct net *net,
 	kenter("%s,%*.*s,%zu,%s",
 	       type, (int)namelen, (int)namelen, name, namelen, options);
 
-	if (!name || namelen == 0)
+	if (!name || namelen < 3 || namelen > 255)
 		return -EINVAL;
 
 	/* construct the query key description as "[<type>:]<name>" */
@@ -86,8 +86,6 @@ int dns_query(struct net *net,
 		desclen += typelen + 1;
 	}
 
-	if (namelen < 3 || namelen > 255)
-		return -EINVAL;
 	desclen += namelen + 1;
 
 	desc = kmalloc(desclen, GFP_KERNEL);