From patchwork Tue Jun 23 17:55:33 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kevin Wolf X-Patchwork-Id: 11621297 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 069FA618 for ; Tue, 23 Jun 2020 17:57:14 +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 91A9720774 for ; Tue, 23 Jun 2020 17:57:13 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="eKGT/Jye" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 91A9720774 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]:34198 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jnnAW-0001GL-Ey for patchwork-qemu-devel@patchwork.kernel.org; Tue, 23 Jun 2020 13:57:12 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:50746) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jnn9T-00082d-9p for qemu-devel@nongnu.org; Tue, 23 Jun 2020 13:56:07 -0400 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:55653 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 1jnn9Q-0007cI-Ut for qemu-devel@nongnu.org; Tue, 23 Jun 2020 13:56:06 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1592934963; 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=Is2tIf/0DtLHm8mVWWn82hWvvU03LrDXNghp6ja0Zdw=; b=eKGT/JyePkgOWR7pTGpOQIBrnu4/CJkFq62JpsSVVJvSpBvwr+QLs8w2R7IPTE/GohP2MF 9E+UhdvcIgYeveqQWg2lUsfAAYTs4AgwBnkNkKw8b/pA2VpZ7s8rQLBbt8/3kGb7rW60Ee 6BGEWjKMKal8ZqA6OJHkjYWjSRhlzVw= 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-375-wODfEqFEMdiC6HtJeFfl9g-1; Tue, 23 Jun 2020 13:55:59 -0400 X-MC-Unique: wODfEqFEMdiC6HtJeFfl9g-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 47222100A61E; Tue, 23 Jun 2020 17:55:57 +0000 (UTC) Received: from linux.fritz.box.com (ovpn-115-78.ams2.redhat.com [10.36.115.78]) by smtp.corp.redhat.com (Postfix) with ESMTP id 2161C71688; Tue, 23 Jun 2020 17:55:55 +0000 (UTC) From: Kevin Wolf To: qemu-block@nongnu.org Subject: [PATCH 1/2] vvfat: Check that updated filenames are valid Date: Tue, 23 Jun 2020 19:55:33 +0200 Message-Id: <20200623175534.38286-2-kwolf@redhat.com> In-Reply-To: <20200623175534.38286-1-kwolf@redhat.com> References: <20200623175534.38286-1-kwolf@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Received-SPF: pass client-ip=207.211.31.120; envelope-from=kwolf@redhat.com; helo=us-smtp-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/06/23 02:55:19 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, nhuck15@gmail.com, qemu-devel@nongnu.org, ppandit@redhat.com 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 Reviewed-by: Eric Blake --- block/vvfat.c | 23 +++++++++++++++++++++++ 1 file changed, 23 insertions(+) diff --git a/block/vvfat.c b/block/vvfat.c index c65a98e3ee..2fab371258 100644 --- a/block/vvfat.c +++ b/block/vvfat.c @@ -520,6 +520,25 @@ 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) != 0)) + { + return false; + } + } + return true; +} + static uint8_t to_valid_short_char(gunichar c) { c = g_unichar_toupper(c); @@ -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;