From patchwork Fri Jul 3 09:21:40 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kevin Wolf X-Patchwork-Id: 11641537 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 50BC014B7 for ; Fri, 3 Jul 2020 09:26:03 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 27E9220723 for ; Fri, 3 Jul 2020 09:26:03 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="DUEYBj63" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 27E9220723 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Received: from localhost ([::1]:34458 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jrHxK-0002dZ-AT for patchwork-qemu-devel@patchwork.kernel.org; Fri, 03 Jul 2020 05:26:02 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:36074) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jrHtZ-0002sX-Ua for qemu-devel@nongnu.org; Fri, 03 Jul 2020 05:22:09 -0400 Received: from us-smtp-delivery-1.mimecast.com ([205.139.110.120]:21826 helo=us-smtp-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1jrHtU-0000yP-5V for qemu-devel@nongnu.org; Fri, 03 Jul 2020 05:22:09 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1593768121; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=EXHYq9VZV/tJ7a6JAX6lA4GzjQ3hJSx7GfnbUr6wp1I=; b=DUEYBj63Di2wvA9cESGBI5owq2JL+R06+C9wSoCfjmfeDcgI50/saUL0QBJiTb9hEHUsop h9RT4vfyb2hZh4CL91QzTI5efnmFc+DFWJ7jLKMmuqx0mn9lguKiI7u+4mPhzbPsO2/GWo 7FKChyWYQwSlxIMWqV9gBbholuQnW/A= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-38-IlAGgAVWOnK8Hd-FZ5w2NA-1; Fri, 03 Jul 2020 05:21:57 -0400 X-MC-Unique: IlAGgAVWOnK8Hd-FZ5w2NA-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 65CF6107ACCD; Fri, 3 Jul 2020 09:21:56 +0000 (UTC) Received: from linux.fritz.box.com (ovpn-114-90.ams2.redhat.com [10.36.114.90]) by smtp.corp.redhat.com (Postfix) with ESMTP id 732967AC71; Fri, 3 Jul 2020 09:21:55 +0000 (UTC) From: Kevin Wolf To: qemu-block@nongnu.org Subject: [PULL 4/7] vvfat: Check that updated filenames are valid Date: Fri, 3 Jul 2020 11:21:40 +0200 Message-Id: <20200703092143.165594-5-kwolf@redhat.com> In-Reply-To: <20200703092143.165594-1-kwolf@redhat.com> References: <20200703092143.165594-1-kwolf@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=kwolf@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Received-SPF: pass client-ip=205.139.110.120; envelope-from=kwolf@redhat.com; helo=us-smtp-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/07/03 03:38:32 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -30 X-Spam_score: -3.1 X-Spam_bar: --- X-Spam_report: (-3.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-1, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H3=-0.01, RCVD_IN_MSPIKE_WL=-0.01, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=_AUTOLEARN X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: kwolf@redhat.com, peter.maydell@linaro.org, qemu-devel@nongnu.org Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" FAT allows only a restricted set of characters in file names, and for some of the illegal characters, it's actually important that we catch them: If filenames can contain '/', the guest can construct filenames containing "../" and escape from the assigned vvfat directory. The same problem could arise if ".." was ever accepted as a literal filename. Fix this by adding a check that all filenames are valid in check_directory_consistency(). Reported-by: Nathan Huckleberry Signed-off-by: Kevin Wolf Message-Id: <20200623175534.38286-2-kwolf@redhat.com> Reviewed-by: Eric Blake Signed-off-by: Kevin Wolf --- block/vvfat.c | 25 ++++++++++++++++++++++++- 1 file changed, 24 insertions(+), 1 deletion(-) diff --git a/block/vvfat.c b/block/vvfat.c index c65a98e3ee..62230542e5 100644 --- a/block/vvfat.c +++ b/block/vvfat.c @@ -520,12 +520,31 @@ static void set_begin_of_direntry(direntry_t* direntry, uint32_t begin) direntry->begin_hi = cpu_to_le16((begin >> 16) & 0xffff); } +static bool valid_filename(const unsigned char *name) +{ + unsigned char c; + if (!strcmp((const char*)name, ".") || !strcmp((const char*)name, "..")) { + return false; + } + for (; (c = *name); name++) { + if (!((c >= '0' && c <= '9') || + (c >= 'A' && c <= 'Z') || + (c >= 'a' && c <= 'z') || + c > 127 || + strchr("$%'-_@~`!(){}^#&.+,;=[]", c) != NULL)) + { + return false; + } + } + return true; +} + static uint8_t to_valid_short_char(gunichar c) { c = g_unichar_toupper(c); if ((c >= '0' && c <= '9') || (c >= 'A' && c <= 'Z') || - strchr("$%'-_@~`!(){}^#&", c) != 0) { + strchr("$%'-_@~`!(){}^#&", c) != NULL) { return c; } else { return 0; @@ -2098,6 +2117,10 @@ DLOG(fprintf(stderr, "check direntry %d:\n", i); print_direntry(direntries + i)) } lfn.checksum = 0x100; /* cannot use long name twice */ + if (!valid_filename(lfn.name)) { + fprintf(stderr, "Invalid file name\n"); + goto fail; + } if (path_len + 1 + lfn.len >= PATH_MAX) { fprintf(stderr, "Name too long: %s/%s\n", path, lfn.name); goto fail;