From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AG47ELvKJqpVGa+l0n5uc+uG3wptWGGh+0sUAgfXcXCL6tZOXHvmrCoKW3GcriQRixDxy7nFL8+W ARC-Seal: i=1; a=rsa-sha256; t=1520828876; cv=none; d=google.com; s=arc-20160816; b=cWn+9qjKr431xqO9LM2ToiA6l+VGUiIs7mwJueI6N/hROjwqRIoZxBG+4jDi5lCJy4 DdXBwjgtMXshimvFjF94MTvFmCnSv7KhG1h5Y3PNOhCx/9sx2erXsAT20V4et84wdtc2 A9NO9WdvBoflqN6obWdusnDgnq4iYt67FIHU+w5E903Od2C/CPmBP4mGaiAUhVCMVBHB DtQn846p/ZGUTsGyb8wk6NmabfrGA/3k2yv11UgN/JsxIcNl43zTXDvm5UG9t1JvRsLa Q82ZyeVWnCoQ/A+hcrirIt26YFBR9LOjNHXFnJkNX2RG5PyM/mqzhb4ZX+EHoANVAyUE 4axw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=message-id:date:subject:cc:to:from:dkim-signature:dkim-signature :delivered-to:list-id:list-subscribe:list-unsubscribe:list-help :list-post:precedence:mailing-list:arc-authentication-results; bh=VpjFo8u6KOeUvTmN6GDsZxaVQ85RQKupAr0HUwUmvXo=; b=H5q6bgoUJJduX6z93Pfa96uSl9YQXoybr3ctwjAqpazIKwKCTQZ11ITQTwX2NiwRKG sHHG95mqXG3xz3l8miWzk3s0o4aR/LpJwlePBV+/anlCX/C4IGbNf6hX3AvfwaLiSuaj fQCpfhxhHLm38EpVA7kx/YOeX9CR+G0VyzcImY04ZbZQkuD0tEJNOmC0uhXJqO9bk19Z LX+0Z66grtX8EhS5Bqgr7j/EMVEEcKj8qzcg3ZyebOrfqMGeBZIko6hGRjCsgpIE+ZDu 49AZh2g8gMw340F4bvnGT9lriZYTzJKhWR/MnUH7mekmNTtQu8/UN6CDXIdf3D/KISHw mKfw== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@tobin.cc header.s=fm2 header.b=WJ1t/ou7; dkim=pass header.i=@messagingengine.com header.s=fm2 header.b=fKwuEN/e; spf=pass (google.com: domain of kernel-hardening-return-12408-gregkh=linuxfoundation.org@lists.openwall.com designates 195.42.179.200 as permitted sender) smtp.mailfrom=kernel-hardening-return-12408-gregkh=linuxfoundation.org@lists.openwall.com Authentication-Results: mx.google.com; dkim=pass header.i=@tobin.cc header.s=fm2 header.b=WJ1t/ou7; dkim=pass header.i=@messagingengine.com header.s=fm2 header.b=fKwuEN/e; spf=pass (google.com: domain of kernel-hardening-return-12408-gregkh=linuxfoundation.org@lists.openwall.com designates 195.42.179.200 as permitted sender) smtp.mailfrom=kernel-hardening-return-12408-gregkh=linuxfoundation.org@lists.openwall.com Mailing-List: contact kernel-hardening-help@lists.openwall.com; run by ezmlm List-Post: List-Help: List-Unsubscribe: List-Subscribe: X-ME-Sender: From: "Tobin C. Harding" To: Rob Herring , Frank Rowand Cc: "Tobin C. Harding" , devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, kernel-hardening@lists.openwall.com, Tycho Andersen , Kees Cook Subject: [PATCH] of: unittest: Remove VLA stack usage Date: Mon, 12 Mar 2018 15:27:23 +1100 Message-Id: <1520828843-22289-1-git-send-email-me@tobin.cc> X-Mailer: git-send-email 2.7.4 X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: =?utf-8?q?1594704660258031955?= X-GMAIL-MSGID: =?utf-8?q?1594704660258031955?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: The kernel would like to have all stack VLA usage removed[1]. This is a test function so the execution speed is not critical. We can allocate memory for this buffer instead of using a VLA. If kmalloc() fails just return. Allocate buffer with kmalloc(). [1]: https://lkml.org/lkml/2018/3/7/621 Signed-off-by: Tobin C. Harding --- Kees is this annoying you, CC'ing you an all my VLA patches? drivers/of/unittest.c | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-) diff --git a/drivers/of/unittest.c b/drivers/of/unittest.c index 1991fe4319f5..38cbc343b7da 100644 --- a/drivers/of/unittest.c +++ b/drivers/of/unittest.c @@ -254,12 +254,18 @@ static void __init of_unittest_check_tree_linkage(void) static void __init of_unittest_printf_one(struct device_node *np, const char *fmt, const char *expected) { - unsigned char buf[strlen(expected)+10]; + unsigned char *buf; + int buf_size; int size, i; + buf_size = strlen(expected) + 10; + buf = kmalloc(buf_size, GFP_KERNEL); + if (!buf) + return; + /* Baseline; check conversion with a large size limit */ - memset(buf, 0xff, sizeof(buf)); - size = snprintf(buf, sizeof(buf) - 2, fmt, np); + memset(buf, 0xff, buf_size); + size = snprintf(buf, buf_size - 2, fmt, np); /* use strcmp() instead of strncmp() here to be absolutely sure strings match */ unittest((strcmp(buf, expected) == 0) && (buf[size+1] == 0xff), @@ -270,12 +276,13 @@ static void __init of_unittest_printf_one(struct device_node *np, const char *fm size++; for (i = 0; i < 2; i++, size--) { /* Clear the buffer, and make sure it works correctly still */ - memset(buf, 0xff, sizeof(buf)); + memset(buf, 0xff, buf_size); snprintf(buf, size+1, fmt, np); unittest(strncmp(buf, expected, size) == 0 && (buf[size+1] == 0xff), "snprintf failed; size=%i fmt='%s' expected='%s' rslt='%s'\n", size, fmt, expected, buf); } + kfree(buf); } static void __init of_unittest_printf(void) -- 2.7.4