From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 8724EAD49 for ; Wed, 4 Jan 2023 16:17:24 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9C9D9C433D2; Wed, 4 Jan 2023 16:17:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1672849044; bh=28ckKiyj9m0vg3THgDlgJYCvyX5Xu6g7B6dQBS8gd2Q=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=aTnfd8rTB0nkbSXvABRkWGFn4gPolfFhGtW15d5FvL4f/+nqVKI4LZMPoasTyZK5q 1/UxMkvM7uIBsq3O4A8m8qYaNniymab8W22mdaOEQNULv+7dU5yZC0EHx13dYTOMoF SnC0oObVuguPNX57tvnGdEh5CrqqZk/0rua9lBF8= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, kernel test robot , Richard Weinberger , Anton Ivanov , Johannes Berg , "Michael S. Tsirkin" , Al Viro , Xiu Jianfeng , Vincent Whitchurch , linux-um@lists.infradead.org, Kees Cook Subject: [PATCH 6.1 124/207] um: virt-pci: Avoid GCC non-NULL warning Date: Wed, 4 Jan 2023 17:06:22 +0100 Message-Id: <20230104160515.842647496@linuxfoundation.org> X-Mailer: git-send-email 2.39.0 In-Reply-To: <20230104160511.905925875@linuxfoundation.org> References: <20230104160511.905925875@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Kees Cook commit bdc77507fecd00ddad2f502f86a48a9ec38f0f84 upstream. GCC gets confused about the return value of get_cpu_var() possibly being NULL, so explicitly test for it before calls to memcpy() and memset(). Avoids warnings like this: arch/um/drivers/virt-pci.c: In function 'um_pci_send_cmd': include/linux/fortify-string.h:48:33: warning: argument 1 null where non-null expected [-Wnonnull] 48 | #define __underlying_memcpy __builtin_memcpy | ^ include/linux/fortify-string.h:438:9: note: in expansion of macro '__underlying_memcpy' 438 | __underlying_##op(p, q, __fortify_size); \ | ^~~~~~~~~~~~~ include/linux/fortify-string.h:483:26: note: in expansion of macro '__fortify_memcpy_chk' 483 | #define memcpy(p, q, s) __fortify_memcpy_chk(p, q, s, \ | ^~~~~~~~~~~~~~~~~~~~ arch/um/drivers/virt-pci.c:100:9: note: in expansion of macro 'memcpy' 100 | memcpy(buf, cmd, cmd_size); | ^~~~~~ While at it, avoid literal "8" and use stored sizeof(buf->data) in memset() and um_pci_send_cmd(). Reported-by: kernel test robot Link: https://lore.kernel.org/lkml/202211271212.SUZSC9f9-lkp@intel.com Fixes: ba38961a069b ("um: Enable FORTIFY_SOURCE") Cc: Richard Weinberger Cc: Anton Ivanov Cc: Johannes Berg Cc: "Michael S. Tsirkin" Cc: Al Viro Cc: Xiu Jianfeng Cc: Vincent Whitchurch Cc: linux-um@lists.infradead.org Cc: stable@vger.kernel.org Signed-off-by: Kees Cook Signed-off-by: Greg Kroah-Hartman --- arch/um/drivers/virt-pci.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) --- a/arch/um/drivers/virt-pci.c +++ b/arch/um/drivers/virt-pci.c @@ -97,7 +97,8 @@ static int um_pci_send_cmd(struct um_pci } buf = get_cpu_var(um_pci_msg_bufs); - memcpy(buf, cmd, cmd_size); + if (buf) + memcpy(buf, cmd, cmd_size); if (posted) { u8 *ncmd = kmalloc(cmd_size + extra_size, GFP_ATOMIC); @@ -182,6 +183,7 @@ static unsigned long um_pci_cfgspace_rea struct um_pci_message_buffer *buf; u8 *data; unsigned long ret = ULONG_MAX; + size_t bytes = sizeof(buf->data); if (!dev) return ULONG_MAX; @@ -189,7 +191,8 @@ static unsigned long um_pci_cfgspace_rea buf = get_cpu_var(um_pci_msg_bufs); data = buf->data; - memset(buf->data, 0xff, sizeof(buf->data)); + if (buf) + memset(data, 0xff, bytes); switch (size) { case 1: @@ -204,7 +207,7 @@ static unsigned long um_pci_cfgspace_rea goto out; } - if (um_pci_send_cmd(dev, &hdr, sizeof(hdr), NULL, 0, data, 8)) + if (um_pci_send_cmd(dev, &hdr, sizeof(hdr), NULL, 0, data, bytes)) goto out; switch (size) {