From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 F0B8E23645D for ; Wed, 26 Aug 2026 10:09:17 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787738959; cv=none; b=BykLLESAQnNK0rQx3UgfWcNDzyPokfdYoyS/ztXwHW/1u/oZd5/vuH9o6R1+DpnJW1MjhCqzdoMwGA0tiryniDL9k6v9K5ynGevhE0HomScQQrwtEkrBeaZrPZG33wMlpEd3q7QSFfm2F1MXmrqrLuNiN2/Tg38ma18ikqG4GvQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787738959; c=relaxed/simple; bh=WfVeRD8Iz4hWkP+/YTAqhOU0ZJWXSyiFfi3U0lmlfho=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=q5+0whzMYf3PGoUbmy1/5Plo9SsZbXH9+pPZv9m68SfpZ4aDMs5zs+ThN0f7k5GuLfmxcVk/2fmzAEGPxhX7+fxtmJ8O3KooQxjeQvb4Wjy+lazxy22W+3l9RKTDl7XZbCQleyk14H4z+/dcBMjuWEak++tAH/3Hg6m/bfWVOj8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=jWZyF62P; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="jWZyF62P" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6A27E1F000E9; Wed, 26 Aug 2026 10:09:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1787738957; bh=SA8TDdzZ2BIWprpXuHdPsGZuSpSBsJ/ccvlKf1HV23Y=; h=From:To:Cc:Subject:Date; b=jWZyF62PQUfsap4qAn/NF47mxj59/MD8QBrmouWOOfMp+VjEOOBJYYyK4nZTLCCk3 dA4UpxakQXtYEl5aFlXjp7AbRnFKXYPQFvGis3WHifsJ3OhMOtDoO2DhGB9A/u/j2k HpyLl7KQr88PruJ5EwM3eDLwXYZdgLxSmCZrVJeNYNO55JTehz7qr66+f1cp+WdjXB +ukuyUzYksZyE3XxpqQNxGdyTbYQ+V8sqom6QCvKcO3paI5azZslcUXVikG3J/Ad0Y J4PKZf5yzlSvtT9tF4M7fdHqwKyrbYvxTj2zjFS06/YQyLwl8FhKjeMEikieGo/HWv XBhMjV0FNMqsQ== From: Thorsten Blum To: Andrew Morton , Dan Moulding Cc: Thorsten Blum , linux-kernel@vger.kernel.org Subject: [PATCH] init: Fix early boot crash with bare hostname parameter Date: Wed, 26 Aug 2026 12:09:03 +0200 Message-ID: <20260826100904.296151-2-blum@kernel.org> X-Mailer: git-send-email 2.55.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=962; i=blum@kernel.org; h=from:subject; bh=WfVeRD8Iz4hWkP+/YTAqhOU0ZJWXSyiFfi3U0lmlfho=; b=owGbwMvMwCUWt7pQ4caZUj3G02pJDFl9ux0S1O9f15XNXlbCsWWZf/89jfDb+5j+nbWRjrRlD mnmOeLWUcrCIMbFICumyPJg1o8ZvqU1lZtMInbCzGFlAhnCwMUpABMJ0mP4n1kbz/BZaIIL953q T3LJnE1/++97iBd22/+e2WH16rcUL8N/F7vusjLm5KTG+4rxHdW6vRPP7TvFy9w57ch9DXaXR8Y MAA== X-Developer-Key: i=blum@kernel.org; a=openpgp; fpr=1D60735E8AEF3BE473B69D84733678FD8DFEEAD4 Content-Transfer-Encoding: 8bit When a bare hostname parameter is specified on the kernel command line without the '=' separator, early parameter parsing passes NULL to early_hostname(), which dereferences it in strscpy() and can crash the system during early boot. Reject NULL values in early_hostname() and return -EINVAL instead. Fixes: 5a704629f2c1 ("init: add "hostname" kernel parameter") Cc: stable@vger.kernel.org Signed-off-by: Thorsten Blum --- init/version.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/init/version.c b/init/version.c index 94c96f6fbfe6..0bd5c45aabc4 100644 --- a/init/version.c +++ b/init/version.c @@ -23,6 +23,9 @@ static int __init early_hostname(char *arg) size_t maxlen = bufsize - 1; ssize_t arglen; + if (!arg) + return -EINVAL; + arglen = strscpy(init_uts_ns.name.nodename, arg, bufsize); if (arglen < 0) { pr_warn("hostname parameter exceeds %zd characters and will be truncated",