From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 6049FC47DD9 for ; Wed, 27 Mar 2024 21:11:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:Cc:To:From:Subject:Message-ID: Mime-Version:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To: References:List-Owner; bh=00sQBgbZH8W8m3jW4sLCR4MltrrLRH4jghVrOP5QDRI=; b=h/B TzPt6VrsMu63vYr+iNqHT6nr7byD6/oR9G04Vdo/qYTPcpclmDnXORobQI8DzXMV9dHRDf2KfAA+Y 3vEMzjofE/5AG+2TkLfCaDr7GCCq/z/Hm5rnVOi3WnCA554fujxGwJOW/Bs9H8GpFfbzcO/R+PGKG Dzk+3kedbPX8Vy4EnzwsA3hK/XbMUxa2PVAytheIbPRqSsl4Geu8HLUjQ1y2v822cdVr+Tp1BCzYP R5Hoy9DY9xk1rOki8xVso5HmteO/A0OPkQJBEoeY3pEQbMwwKJkg4+z91eVaN4967s6CidSU+rZZt WDe/aWK1k5ROim7Op63XUYZEolxsW+w==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1rpaY1-0000000BACK-3ju5; Wed, 27 Mar 2024 21:11:02 +0000 Received: from mail-yb1-xb4a.google.com ([2607:f8b0:4864:20::b4a]) by bombadil.infradead.org with esmtps (Exim 4.97.1 #2 (Red Hat Linux)) id 1rpaXy-0000000BABV-1U7D for kexec@lists.infradead.org; Wed, 27 Mar 2024 21:10:59 +0000 Received: by mail-yb1-xb4a.google.com with SMTP id 3f1490d57ef6-dcd1779adbeso403207276.3 for ; Wed, 27 Mar 2024 14:10:55 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1711573854; x=1712178654; darn=lists.infradead.org; h=cc:to:from:subject:message-id:mime-version:date:from:to:cc:subject :date:message-id:reply-to; bh=+lkMVelOezh/ZlXJ0pLzE+PWawOJ1uDpRCeivCwpFfI=; b=t/jO55yu5VpzRh+sTYyAvBzayQYg7qHjgE1YcCHV6ThIrCbckaF6bODjxJg9I5LLCq m0a6lVm1thHefLZS1QxMNyg+jugyQeDJkQIanG5834ZeKqOzLMc4qeaPbzgdEXU3k/sn oQNFeNGyyGUgxke62A0A7SaZRQGqQ1X8MCoHPuU/SaDhUecJREAqv8bhy5p++5O2FSfr aysqz5VwLB77zFzK0dhEWTW2eL0/cM8PIQy5pk5Szl8Bd5CZGBrEMzMsqlghpGZAWTq/ klFWeTXFxdR4vrLNAdWofo/YUFoqUfYo7YbN4qU6YMA7MIKfRAhyRpbS62SS9xq6SZrq 1IRw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1711573854; x=1712178654; h=cc:to:from:subject:message-id:mime-version:date:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=+lkMVelOezh/ZlXJ0pLzE+PWawOJ1uDpRCeivCwpFfI=; b=p5uuf86a3V2UDEWBq1wmjLkAXWKcvatY23NvIGkferwNtIhtv6wGZYPuoS+9l9oYqT WBUpKfi0flhp9OJBfmdkB5XJHJdiMjNcU2d7+RuamKG+oJJqdJ5TfZLNqoqwuDBFWcOm rSR2/nesb9fQmycSEEpzZUZVTabeczdmBGIko7TPchUsr8yMIslh70R09d8thmJ3ZIiI +JoL4eCcEOwrq/qTStTIfmSrzqwVF9XSb6uR4uXajIZZQqax6eXbVaCyiv5D1Xe45QzG 93KCTZGXA3mBDAiYVL6hd9cvRs4TYEBir/Skmj1EfM0TYfd3gGB3qT95lp1zTlBEgZz1 eHXw== X-Gm-Message-State: AOJu0YxlcyH8jzeESDB4sHvg/5ssKKnnpBpegabhky/P7IkpA0j70tt7 fyiI4ckpcYjzDb54hvOiZOyaPu/H4mz1zaigz4ohy6hdY7w4h3ejoIHaH03Q8dcQ5Tvi7rIpaTh GL3l+37w3dV5Vea4esIsuuA== X-Google-Smtp-Source: AGHT+IF2W4CfyY1W2KI8dpvyaTKLJ22XNKhwxs5DcbfYiSRg/rNYQ2xBm+UlXjsQKvrjcxKStDc5WbID/PhFU2jObA== X-Received: from jstitt-linux1.c.googlers.com ([fda3:e722:ac3:cc00:2b:ff92:c0a8:23b5]) (user=justinstitt job=sendgmr) by 2002:a05:6902:1009:b0:dc6:ff2b:7e1b with SMTP id w9-20020a056902100900b00dc6ff2b7e1bmr325202ybt.4.1711573854514; Wed, 27 Mar 2024 14:10:54 -0700 (PDT) Date: Wed, 27 Mar 2024 21:10:52 +0000 Mime-Version: 1.0 X-B4-Tracking: v=1; b=H4sIAFuLBGYC/x3MwQqDMAyA4VeRnA3YTqb4KuLBxXTLYW1JpCjiu 6/s+B3+/wJjFTaYmguUi5ikWOHaBuizxjejbNXgO993Dz+g7RopnxgMsybC8qWkjIQvN27D0wV eOUDNs3KQ47+el/v+AZI+IAhqAAAA X-Developer-Key: i=justinstitt@google.com; a=ed25519; pk=tC3hNkJQTpNX/gLKxTNQKDmiQl6QjBNCGKJINqAdJsE= X-Developer-Signature: v=1; a=ed25519-sha256; t=1711573853; l=2631; i=justinstitt@google.com; s=20230717; h=from:subject:message-id; bh=c05JlIhAAX9+Wj5KD5xjyuKpqsfoj6wU7p1hNY3Smz4=; b=dvoo077PNzidPJkbn13FOfdETuWck8T+nbUCWDn79wP+pUbOIiqdMGPeDBqCc5kqKPcrChbca T5lNI9lENkhAMdr88HffzjhBqJSvVobkKfzQHKHkcprOU1eF+49l098 X-Mailer: b4 0.12.3 Message-ID: <20240327-strncpy-fs-proc-vmcore-c-v1-1-e025ed08b1b0@google.com> Subject: [PATCH] vmcore: replace strncpy with strtomem From: Justin Stitt To: Baoquan He , Vivek Goyal , Dave Young Cc: kexec@lists.infradead.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-hardening@vger.kernel.org, Justin Stitt X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240327_141058_471280_B73B0589 X-CRM114-Status: GOOD ( 13.93 ) X-BeenThere: kexec@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "kexec" Errors-To: kexec-bounces+kexec=archiver.kernel.org@lists.infradead.org strncpy() is in the process of being replaced as it is deprecated in some situations [1]. While the specific use of strncpy that this patch targets is not exactly deprecated, the real mission is to rid the kernel of all its uses. Looking at vmcoredd_header's definition: | struct vmcoredd_header { | __u32 n_namesz; /* Name size */ | __u32 n_descsz; /* Content size */ | __u32 n_type; /* NT_VMCOREDD */ | __u8 name[8]; /* LINUX\0\0\0 */ | __u8 dump_name[VMCOREDD_MAX_NAME_BYTES]; /* Device dump's name */ | }; ... we can see that both `name` and `dump_name` are u8s. It seems `name` wants to be NUL-padded (based on the comment above), but for the sake of symmetry lets NUL-pad both of these. Mark these buffers as __nonstring and use strtomem_pad. Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings [1] Link: https://github.com/KSPP/linux/issues/90 Cc: linux-hardening@vger.kernel.org Signed-off-by: Justin Stitt --- Note: build-tested only. Found with: $ rg "strncpy\(" --- fs/proc/vmcore.c | 5 ++--- include/uapi/linux/vmcore.h | 4 ++-- 2 files changed, 4 insertions(+), 5 deletions(-) diff --git a/fs/proc/vmcore.c b/fs/proc/vmcore.c index 1fb213f379a5..5d7ecf3b75e8 100644 --- a/fs/proc/vmcore.c +++ b/fs/proc/vmcore.c @@ -1370,9 +1370,8 @@ static void vmcoredd_write_header(void *buf, struct vmcoredd_data *data, vdd_hdr->n_descsz = size + sizeof(vdd_hdr->dump_name); vdd_hdr->n_type = NT_VMCOREDD; - strncpy((char *)vdd_hdr->name, VMCOREDD_NOTE_NAME, - sizeof(vdd_hdr->name)); - memcpy(vdd_hdr->dump_name, data->dump_name, sizeof(vdd_hdr->dump_name)); + strtomem_pad(vdd_hdr->name, VMCOREDD_NOTE_NAME, 0); + strtomem_pad(vdd_hdr->dump_name, data->dump_name, 0); } /** diff --git a/include/uapi/linux/vmcore.h b/include/uapi/linux/vmcore.h index 3e9da91866ff..7053e2b62fa0 100644 --- a/include/uapi/linux/vmcore.h +++ b/include/uapi/linux/vmcore.h @@ -11,8 +11,8 @@ struct vmcoredd_header { __u32 n_namesz; /* Name size */ __u32 n_descsz; /* Content size */ __u32 n_type; /* NT_VMCOREDD */ - __u8 name[8]; /* LINUX\0\0\0 */ - __u8 dump_name[VMCOREDD_MAX_NAME_BYTES]; /* Device dump's name */ + __u8 name[8] __nonstring; /* LINUX\0\0\0 */ + __u8 dump_name[VMCOREDD_MAX_NAME_BYTES] __nonstring; /* Device dump's name */ }; #endif /* _UAPI_VMCORE_H */ --- base-commit: 928a87efa42302a23bb9554be081a28058495f22 change-id: 20240327-strncpy-fs-proc-vmcore-c-b18d761feaef Best regards, -- Justin Stitt _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec