From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: passt.top; dmarc=none (p=none dis=none) header.from=gibson.dropbear.id.au Authentication-Results: passt.top; dkim=pass (2048-bit key; secure) header.d=gibson.dropbear.id.au header.i=@gibson.dropbear.id.au header.a=rsa-sha256 header.s=202502 header.b=DFrTniAR; dkim-atps=neutral Received: from mail.ozlabs.org (gandalf.ozlabs.org [150.107.74.76]) by passt.top (Postfix) with ESMTPS id C391D5A061F for ; Wed, 19 Feb 2025 04:14:47 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gibson.dropbear.id.au; s=202502; t=1739934871; bh=qYz/ZgL5nBkE+Rt00RaNBxWcJkI9Z4o9F+MjWaAJkUI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=DFrTniARYlv7joeoOsO29xFTdhGVrEpFvVwYXscR0q/tYn3RPWJtBQTjJ7wL+HoPB QaeYl/lX3UX9sslx5IfYQ4MVNYclDZVGbqJV02lgdJ8nXgfgBdVZhu5e7fmwAScx8x gJKUiuc4e0fdT2ijCdf7+pMmP3e7ivORv1oPCOwlqfVHSOgKw3WFqtnXw6ALKgbzFK OiiGnCXtcvivE172k5RfxMw+Jfe3cATy2/qkdl8RGcOjJPCCmQiWFr/HCjmtuXTO7D WYUTMIG+VzSVWCq3tXdSkDVf0ASX82QDD6o2LbR3xemB1/N92faQmGbRptN/R9PWyC VknSRWKSame6Q== Received: by gandalf.ozlabs.org (Postfix, from userid 1007) id 4YyM1z26Y2z4wyk; Wed, 19 Feb 2025 14:14:31 +1100 (AEDT) From: David Gibson To: Stefano Brivio , passt-dev@passt.top Subject: [PATCH 1/3] conf: More thorough error checking when parsing --mtu option Date: Wed, 19 Feb 2025 14:14:27 +1100 Message-ID: <20250219031429.3708026-2-david@gibson.dropbear.id.au> X-Mailer: git-send-email 2.48.1 In-Reply-To: <20250219031429.3708026-1-david@gibson.dropbear.id.au> References: <20250219031429.3708026-1-david@gibson.dropbear.id.au> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Message-ID-Hash: XLOWSDVUGY2MJJCV5NORSVNT2Y4F4S6W X-Message-ID-Hash: XLOWSDVUGY2MJJCV5NORSVNT2Y4F4S6W X-MailFrom: dgibson@gandalf.ozlabs.org X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; emergency; loop; banned-address; member-moderation; nonmember-moderation; administrivia; implicit-dest; max-recipients; max-size; news-moderation; no-subject; digests; suspicious-header CC: David Gibson X-Mailman-Version: 3.3.8 Precedence: list List-Id: Development discussion and patches for passt Archived-At: Archived-At: List-Archive: List-Archive: List-Help: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: We're a bit sloppy with parsing MTU which can lead to some surprising, though fairly harmless, results: * Passing a non-number like '-m xyz' will not give an error and act like -m 0 * Junk after a number (e.g. '-m 1500pqr') will be ignored rather than giving an error * We parse the MTU as a long, then immediately assign to an int, so on some platforms certain ludicrously out of bounds values will be silently truncated, rather than giving an error Be a bit more thorough with the error checking to avoid that. Signed-off-by: David Gibson --- conf.c | 21 +++++++++++++++------ 1 file changed, 15 insertions(+), 6 deletions(-) diff --git a/conf.c b/conf.c index 18017f51..335f37c9 100644 --- a/conf.c +++ b/conf.c @@ -1652,20 +1652,29 @@ void conf(struct ctx *c, int argc, char **argv) die("Invalid PID file: %s", optarg); break; - case 'm': + case 'm': { + unsigned long mtu; + char *e; + errno = 0; - c->mtu = strtol(optarg, NULL, 0); + mtu = strtoul(optarg, &e, 0); + + if (errno || *e) + die("Invalid MTU: %s", optarg); - if (!c->mtu) { + if (!mtu) { c->mtu = -1; break; } - if (c->mtu < ETH_MIN_MTU || c->mtu > (int)ETH_MAX_MTU || - errno) - die("Invalid MTU: %s", optarg); + if (mtu < ETH_MIN_MTU || mtu > ETH_MAX_MTU) { + die("MTU %lu out of range (%u..%u)", mtu, + ETH_MIN_MTU, ETH_MAX_MTU); + } + c->mtu = mtu; break; + } case 'a': if (inet_pton(AF_INET6, optarg, &c->ip6.addr) && !IN6_IS_ADDR_UNSPECIFIED(&c->ip6.addr) && -- 2.48.1