From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793210692; b=nvfiJbuyjU9ppeUAL7atkXhMyc2B75C2xJZmiKM6tzTv0qKAEkM5kIHl4jl4mpxcdso6 2rEPueC14hW8FP5zJOKci+2MSd83mxDk73Tv2svGtEugNPYwigR0z10K3GzZLRZ1czbXV m2A4F6zOpxKSrKVcojF7nzBGM5D4HF3mF3uwvW8JLz/1w9vJHIGbEGaVCg89glPC4QJEs 3bhHzblNbRmiOLKnO+cRrJPUw8P4YPXuUfI54R7+lUSWSa5vIyTXBStBXlF/NzMrleG5u qkN6TUcaBXuK9FFpdnV7CVA2x4wKtzbwN2e7Jd8sgaio5M3Uyd770I/fnRKr0k67F6Q== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793210692; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:User-Agent:X-stable:X-Patchwork-Hint: MIME-Version:Content-Transfer-Encoding; bh=3doC8WoHzA8cCFbVwbJ0q+atiCExHVc80PXjEnQSADQ=; b=dvF55N9+Go++Yh4SUCARA9tJvpYl4LKQTPMEkKO7Hu7+uhDyHWvqJFjnHi/RTSbg7A6t 2aQhl9upg1mjfv0zOmmdZwhghkMs8V7l+DHJXumnmDed3I54JwqpfL+5sJX0J4SBbZ2qx PakBRrUoClmst2Ksg0BsTZFmgbYcCpNBWftGkf1VoDECVbsMQslZm8dQi1sVq1Crl+qXE +O7nrHaMDGdYJwiAi3Gz42q03Ar6SbvnVdObGzTfu21/2LsoD6ikilodPD6y/NVCWU1QQ HTFUJ8zFLQDn5EiWO2YivVi6jTMw5jbT5Q4RsewSd7PmY3uCR/NOhSGcP7sx1RlJ8GQ== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=Or5NwrYH; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 38052606A31A; Wed, 28 Oct 2026 18:04:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=Or5NwrYH Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8ABE51F01825; Wed, 28 Oct 2026 18:04:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1793210692; bh=3doC8WoHzA8cCFbVwbJ0q+atiCExHVc80PXjEnQSADQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=Or5NwrYH8qntPrTPnr6tBq9szOc2Bb2FJWy79PKCBf1JiPgb09UjTliFlKqMmibaA aDOP9w+nqThCebMa16IC1tFeukZTlgsCv1FZLtf5Gj3BOKAISsOybPpW1Houmo76nd HLR90Mu2yWdqualLiurdmG0GG+lW7hkQ/6Tl5Wus= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Vega , Yuqi Xu , Ren Wei , Simon Horman , Paolo Abeni , Sasha Levin Subject: [PATCH 5.15 114/571] net: ipconfig: bound DHCP option construction Date: Wed, 28 Oct 2026 17:54:21 +0100 Message-ID: <20261028170010.725593424@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261028170008.009143722@linuxfoundation.org> References: <20261028170008.009143722@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: patches@lists.linux.dev List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Yuqi Xu [ Upstream commit e47a1958e12abc3a17b5231a4f21c8f1bf662e08 ] ic_dhcp_init_options() appends the hostname (option 12), vendor-class (option 60) and client-ID (option 61) options into the fixed 312-byte bootp_pkt.exten[] buffer. Only the client-ID branch checked the remaining space; the hostname and vendor-class writes were unbounded. A 64-byte hostname together with the maximum 252-byte dhcpclass= identifier needs 18 + (2 + 64) + (2 + 252) = 338 of the 312 available bytes even before the terminating END marker, so the vendor-class memcpy runs past the end of exten[]. With CONFIG_FORTIFY_SOURCE this is reported as a field-spanning write and, when the kernel is booted with panic_on_warn=1, aborts boot with a panic. Route the optional options through a common helper that makes sure the option, its 2-byte header and the END marker all fit and drops an option that would not. Configurations with short options keep sending exactly the same bytes as before. Fixes: 130c0f47fdf9 ("ipconfig: send host-name in DHCP requests") Cc: stable@vger.kernel.org Reported-by: Vega Assisted-by: LLM Signed-off-by: Yuqi Xu Reviewed-by: Ren Wei Reviewed-by: Simon Horman Link: https://patch.msgid.link/7808dfbfa2162dfd0b19f59aff5742d6e0db2abb.1789798023.git.xuyuqiabc@gmail.com Signed-off-by: Paolo Abeni Signed-off-by: Sasha Levin --- net/ipv4/ipconfig.c | 45 ++++++++++++++++++++++++++------------------- 1 file changed, 26 insertions(+), 19 deletions(-) diff --git a/net/ipv4/ipconfig.c b/net/ipv4/ipconfig.c index 083782a4e010d..eae75cd120858 100644 --- a/net/ipv4/ipconfig.c +++ b/net/ipv4/ipconfig.c @@ -665,6 +665,24 @@ static const u8 ic_bootp_cookie[4] = { 99, 130, 83, 99 }; #ifdef IPCONFIG_DHCP +static bool __init +ic_dhcp_add_option(u8 **options, const u8 *end, u8 type, const void *value, + int len) +{ + u8 *e = *options; + + /* leave room for the option header and the END marker */ + if (len > U8_MAX || end - e < len + 3) + return false; + + *e++ = type; + *e++ = len; + memcpy(e, value, len); + *options = e + len; + + return true; +} + static void __init ic_dhcp_init_options(u8 *options, struct ic_device *d) { @@ -680,6 +698,7 @@ ic_dhcp_init_options(u8 *options, struct ic_device *d) 42, /* NTP servers */ }; u8 mt = (ic_servaddr == NONE) ? DHCPDISCOVER : DHCPREQUEST; + u8 *end = options + sizeof(((struct bootp_pkt *)0)->exten); u8 *e = options; int len; @@ -710,31 +729,19 @@ ic_dhcp_init_options(u8 *options, struct ic_device *d) e += sizeof(ic_req_params); if (ic_host_name_set) { - *e++ = 12; /* host-name */ len = strlen(utsname()->nodename); - *e++ = len; - memcpy(e, utsname()->nodename, len); - e += len; + ic_dhcp_add_option(&e, end, 12, utsname()->nodename, len); } if (*vendor_class_identifier) { - pr_info("DHCP: sending class identifier \"%s\"\n", - vendor_class_identifier); - *e++ = 60; /* Class-identifier */ len = strlen(vendor_class_identifier); - *e++ = len; - memcpy(e, vendor_class_identifier, len); - e += len; + if (ic_dhcp_add_option(&e, end, 60, vendor_class_identifier, len)) + pr_info("DHCP: sending class identifier \"%s\"\n", + vendor_class_identifier); } len = strlen(dhcp_client_identifier + 1); - /* the minimum length of identifier is 2, include 1 byte type, - * and can not be larger than the length of options - */ - if (len >= 1 && len < 312 - (e - options) - 1) { - *e++ = 61; - *e++ = len + 1; - memcpy(e, dhcp_client_identifier, len + 1); - e += len + 1; - } + /* the minimum length of identifier is 2, include 1 byte type */ + if (len >= 1) + ic_dhcp_add_option(&e, end, 61, dhcp_client_identifier, len + 1); *e++ = 255; /* End of the list */ } -- 2.53.0