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 E728A43F4CF; Tue, 21 Jul 2026 22:19:40 +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=1784672382; cv=none; b=cZKnk1NnNNJLbjrjKYNx/f9+tPceuRICxEeAt9K/EpkzvV7NMHWktKhywzmn/h+o4TAzxiSQZ8weRMTmJviVyc6vONbM1zo6Jum/Qpi1nFdU3y+kf2TPQbGL7dvyrCYjY9nspfNSHWgg27Q1/nDnKwq5I44lAvXgcRTeC5+sKJg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784672382; c=relaxed/simple; bh=MSPEW5LwTdKeRMPb/ok+iyC9uoha2PBlJcDZR70bwyk=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=uYtfQLqA0RMke6N51dBz2N4KK8MiEQlGz/VmqbW3qkqxNrwOaQ+D0nqHP/UXOQ08D+EpLFhUoXJfHwDkpKqeOc5bz4cKVRUCD+SAgN+bNvbF5fENPKPBfL77n6YPN74/iFgGr0eLDi3yzk13rO9uU9GDSwjJwZ9szfhytacnxSY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=KXb6KwD9; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="KXb6KwD9" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 58F491F000E9; Tue, 21 Jul 2026 22:19:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1784672380; bh=YCqUUjGAXmdjPaX4AD69V7FLQSzSwwjQffTXCwmI+tc=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=KXb6KwD9FmquepMjka+/wl0NXKpvhk6rXKq+YXVm2U7iMPUa0b+OviV4As7mDEAeg f02ZBe0nZpUzZXWgUgq6g8C3oc5fC6j42ZLpYAahv8lboLUj5Y7f2zEJ/ps4/Fog6B xBieVVgxqrQX25yuurdbRemn+fIe1A87ThIVcd7I= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Thorsten Blum , "Borislav Petkov (AMD)" Subject: [PATCH 5.15 586/843] x86/boot: Reject too long acpi_rsdp= values Date: Tue, 21 Jul 2026 17:23:41 +0200 Message-ID: <20260721152419.231913510@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260721152405.946368001@linuxfoundation.org> References: <20260721152405.946368001@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Thorsten Blum commit d130041a7b96f79cd4c7079a6c2431a6db4c9619 upstream. cmdline_find_option() returns the full length of the parsed acpi_rsdp= value. get_cmdline_acpi_rsdp() then silently truncates values which do not fit in the val[] buffer. Prevent boot_kstrtoul() from parsing a truncated value and then the kernel from silently using the wrong RSDP address, see discussion in Link:. Issue a warning so that the user is aware that s/he supplied a malformed value and can get feedback instead of silent crashes. [ bp: Make commit message more precise. ] Fixes: 3c98e71b42a7 ("x86/boot: Add "acpi_rsdp=" early parsing") Signed-off-by: Thorsten Blum Signed-off-by: Borislav Petkov (AMD) Cc: stable@vger.kernel.org Link: https://lore.kernel.org/all/20260617130417.36651-4-thorsten.blum@linux.dev Signed-off-by: Greg Kroah-Hartman --- arch/x86/boot/compressed/acpi.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) --- a/arch/x86/boot/compressed/acpi.c +++ b/arch/x86/boot/compressed/acpi.c @@ -288,10 +288,15 @@ static unsigned long get_cmdline_acpi_rs char val[MAX_ADDR_LEN] = { }; int ret; - ret = cmdline_find_option("acpi_rsdp", val, MAX_ADDR_LEN); + ret = cmdline_find_option("acpi_rsdp", val, sizeof(val)); if (ret < 0) return 0; + if (ret >= sizeof(val)) { + warn("acpi_rsdp= value too long; ignoring"); + return 0; + } + if (boot_kstrtoul(val, 16, &addr)) return 0; #endif