From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-183.mta1.migadu.com (out-183.mta1.migadu.com [95.215.58.183]) (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 3EF1D2459FE for ; Sun, 21 Jun 2026 13:18:47 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.183 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782047930; cv=none; b=rNF0O1Boo2sNqkd8k5I574XhTJU3z4sIdng51vdNxhyLy8vg6Ot8EF1/aGsZgu3Qv3+rLCNmWXklESa/Dj/2yGBZswi5hVLzWMceZvQyuwqcHdDMhGTjzorGhk59Tq8St9g+Ikn8mXDtdXIiI6fevio9Au0uhx0w7A+LNLdBFN8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782047930; c=relaxed/simple; bh=AyPxKl5oBQalTzhyidZ2I8buKQepo27B+cbRvOvJGyE=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=Zn9GrysV4MZae6A9bsMag9S0//we3hSldFTYzf9va0RQTFVcQ7RVUhoEIbVgQZDE8E5WQ26HLewPIn6SPy/1n3Lp4bnoJydpD1K01dRYrwvOyFSPzRtb0MMv0CyVdUX/g/lbUnCHB3Xa4HieCwKOGhAvdKIjADLcYd+64DvD1VI= 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=p0Z2Zwc4; arc=none smtp.client-ip=95.215.58.183 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="p0Z2Zwc4" 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=1782047926; 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=Uk1iymDuJIMBegf3LSsRMQr90HS3BQmdoLuXkwIxLLw=; b=p0Z2Zwc4IL/Ix0gByyuB8+CYFp2XOGMH8gkS79PPSKp6ccrosc9wD4cE2z0f3etFSbNQFz nHLs3UI/nVdpwDD+jzCIV6PtcfFOWEF2KedmQwtt+CSLseDgKs6rQnhyYsmkyIJ/fo3zod 2ju+B0izJRro/jBObgvSiWhn+2Xln3A= From: Thorsten Blum To: Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , Chao Fan Cc: Thorsten Blum , stable@vger.kernel.org, Borislav Petkov , linux-kernel@vger.kernel.org Subject: [PATCH v2] x86/boot: Reject overlong acpi_rsdp= values Date: Sun, 21 Jun 2026 15:18:36 +0200 Message-ID: <20260621131836.175468-2-thorsten.blum@linux.dev> 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=1428; i=thorsten.blum@linux.dev; h=from:subject; bh=AyPxKl5oBQalTzhyidZ2I8buKQepo27B+cbRvOvJGyE=; b=owGbwMvMwCUWt7pQ4caZUj3G02pJDFnmT9ak3e1/d5d5h+jvhxU5zkpfBa9v3tHYb7/8qdiFi plvQ1Umd5SyMIhxMciKKbI8mPVjhm9pTeUmk4idMHNYmUCGMHBxCsBFljH8L570YIKWlnehr6fn 0r/hwlsFJY+vrtpoWXy+nX1Kvlx7IcM/u2MJ0e2LZnnWH6sz1rItY7VqmpU8KVPRn2n2OlOjm84 sAA== X-Developer-Key: i=thorsten.blum@linux.dev; a=openpgp; fpr=1D60735E8AEF3BE473B69D84733678FD8DFEEAD4 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT cmdline_find_option() returns the full length of the acpi_rsdp= value even if it is truncated. However, get_cmdline_acpi_rsdp() only checks whether acpi_rsdp= is present and does not reject overlong values that do not fit in the buffer. Reject overlong values and warn to prevent boot_kstrtoul() from parsing a truncated value and thus from silently using the wrong RSDP address. Fixes: 3c98e71b42a7 ("x86/boot: Add "acpi_rsdp=" early parsing") Cc: stable@vger.kernel.org Signed-off-by: Thorsten Blum --- Changes in v2: - Warn on overlong acpi_rsdp= values (Boris) - v1: https://lore.kernel.org/r/20260617130417.36651-4-thorsten.blum@linux.dev/ --- arch/x86/boot/compressed/acpi.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/arch/x86/boot/compressed/acpi.c b/arch/x86/boot/compressed/acpi.c index f196b1d1ddf8..baaad01d2074 100644 --- a/arch/x86/boot/compressed/acpi.c +++ b/arch/x86/boot/compressed/acpi.c @@ -184,10 +184,15 @@ static unsigned long get_cmdline_acpi_rsdp(void) 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\n"); + return 0; + } + if (boot_kstrtoul(val, 16, &addr)) return 0; #endif