From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-171.mta0.migadu.com (out-171.mta0.migadu.com [91.218.175.171]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D2AF435F612 for ; Mon, 16 Mar 2026 21:39:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.171 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773697187; cv=none; b=QY9Sl8cAelgXkggYSpHdrpCCUCXYBiyyOHpUc88PYhBt/LnKdarDxqsyWEWqcX7K+ZRu9Cv287xtv+VRrHMCobjMAB3GpfBK+Z4dcd5oMYb0/CZyJRSTOeQ8iuOsW4oC4WTLoKik3gAIsuax3fjxVlGwMl61hyT+B03m7if+e3U= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773697187; c=relaxed/simple; bh=y3ZOzIY4/QEDnjGKIWgAVDt4UY6Uk0rSVlWAUMgnY/Y=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=i6ROXNPl6mdOJZs1XFWi1TgA9B7Dp8tdLvzAaf9BL/+1uhXUNRfn6tfHKSYnjaZ4xMHi4+r0rUbBNhni8B6HKAZRYC6Dq1zl/4IX2d+ak7KjVI3xjRBk4Xjo1PTDvtYkbBhEay+ZTXdoGmfC1eKV/nItikZt2bFK4FDoxlJnSao= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=fTdTWkVO; arc=none smtp.client-ip=91.218.175.171 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="fTdTWkVO" X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1773697172; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=g5IGTONtY0VHhTPLe2jQ75NVMwEU+nkYgpelgwNPAVQ=; b=fTdTWkVO3ob+8tbcwAhrvnXrSfCq73/g/ndUEHqEh48nzAj6R4DnMmp7ABHpvVde4YjOnX /cAO45/s3cvkqsn2Ysr1yu9Uy2Sc7OnJFllqN2AoTNv8eK5749RJdkLkrHOfebAXeHGXMA OGpyqBpBEOAoXEBpJXHPMYw56fgH9DU= From: Thorsten Blum To: "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Simon Horman , Amir Goldstein , Christian Brauner , Tim Bird Cc: Thorsten Blum , netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH net-next] net/dns_resolver: clean up and simplify dns_query() Date: Mon, 16 Mar 2026 22:38:45 +0100 Message-ID: <20260316213846.1049655-3-thorsten.blum@linux.dev> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=1917; i=thorsten.blum@linux.dev; h=from:subject; bh=y3ZOzIY4/QEDnjGKIWgAVDt4UY6Uk0rSVlWAUMgnY/Y=; b=owGbwMvMwCUWt7pQ4caZUj3G02pJDJk7KtIrJtrF1CbNeHPugoJnw/IwLq4mWyGh0zN8l34Rq syfu2dbRykLgxgXg6yYIsuDWT9m+JbWVG4yidgJM4eVCWQIAxenAEwklpOR4emPB4fvzl4QOud4 TAq7mErYmT0bra0Pdc5e/uDu0wi9iFOMDBN9l3PoXaheJ336YGpurae8w7pne3ZkFoW3JjtNneA 2iQEA X-Developer-Key: i=thorsten.blum@linux.dev; a=openpgp; fpr=1D60735E8AEF3BE473B69D84733678FD8DFEEAD4 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT Fold the name length checks into a single early check, and use kmemdup_nul() for name-only descriptions and snprintf() for ":" descriptions to simplify dns_query(). Signed-off-by: Thorsten Blum --- Compile-tested only. --- net/dns_resolver/dns_query.c | 40 ++++++++++++++---------------------- 1 file changed, 15 insertions(+), 25 deletions(-) diff --git a/net/dns_resolver/dns_query.c b/net/dns_resolver/dns_query.c index 53da62984447..3bdea41a2367 100644 --- a/net/dns_resolver/dns_query.c +++ b/net/dns_resolver/dns_query.c @@ -78,43 +78,33 @@ int dns_query(struct net *net, { struct key *rkey; struct user_key_payload *upayload; - size_t typelen, desclen; - char *desc, *cp; + char *desc; int ret, len; 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 "[:]" */ - typelen = 0; - desclen = 0; - if (type) { - typelen = strlen(type); - if (typelen < 1) + if (!type) { + desc = kmemdup_nul(name, namelen, GFP_KERNEL); + if (!desc) + return -ENOMEM; + } else { + size_t desclen = strlen(type); + + if (desclen == 0) return -EINVAL; - desclen += typelen + 1; - } - - if (namelen < 3 || namelen > 255) - return -EINVAL; - desclen += namelen + 1; - desc = kmalloc(desclen, GFP_KERNEL); - if (!desc) - return -ENOMEM; + desclen += 1 + namelen + 1; + desc = kmalloc(desclen, GFP_KERNEL); + if (!desc) + return -ENOMEM; - cp = desc; - if (type) { - memcpy(cp, type, typelen); - cp += typelen; - *cp++ = ':'; + snprintf(desc, desclen, "%s:%.*s", type, (int)namelen, name); } - memcpy(cp, name, namelen); - cp += namelen; - *cp = '\0'; if (!options) options = "";