From patchwork Thu Dec 9 20:26:42 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Wielaard X-Patchwork-Id: 48724 Return-Path: X-Original-To: patchwork@sourceware.org Delivered-To: patchwork@sourceware.org Received: from server2.sourceware.org (localhost [IPv6:::1]) by sourceware.org (Postfix) with ESMTP id 540CD385801A for ; Thu, 9 Dec 2021 20:27:14 +0000 (GMT) X-Original-To: elfutils-devel@sourceware.org Delivered-To: elfutils-devel@sourceware.org Received: from gnu.wildebeest.org (gnu.wildebeest.org [45.83.234.184]) by sourceware.org (Postfix) with ESMTPS id 967F63858C27 for ; Thu, 9 Dec 2021 20:27:08 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 967F63858C27 Authentication-Results: sourceware.org; dmarc=none (p=none dis=none) header.from=klomp.org Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=klomp.org Received: from reform (deer0x0f.wildebeest.org [172.31.17.145]) (using TLSv1.2 with cipher ADH-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by gnu.wildebeest.org (Postfix) with ESMTPSA id 3EAA33000ED0; Thu, 9 Dec 2021 21:27:07 +0100 (CET) Received: by reform (Postfix, from userid 1000) id DCBF32E83733; Thu, 9 Dec 2021 21:26:50 +0100 (CET) From: Mark Wielaard To: elfutils-devel@sourceware.org Subject: [PATCH] libdwfl: Don't try to convert too many dyns in dwfl_link_map_report Date: Thu, 9 Dec 2021 21:26:42 +0100 Message-Id: <20211209202642.514141-1-mark@klomp.org> X-Mailer: git-send-email 2.30.2 MIME-Version: 1.0 X-Spam-Status: No, score=-10.0 required=5.0 tests=BAYES_00, GIT_PATCH_0, KAM_DMARC_STATUS, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.4 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on server2.sourceware.org X-BeenThere: elfutils-devel@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Elfutils-devel mailing list List-Unsubscribe: , List-Archive: List-Help: List-Subscribe: , Cc: Mark Wielaard Errors-To: elfutils-devel-bounces+patchwork=sourceware.org@sourceware.org Sender: "Elfutils-devel" When trying to read (corrupt) dynamic entries from a core file we only want to read and convert the entries we could read. Also make sure we don't try to allocate too bug a buffer. Signed-off-by: Mark Wielaard --- libdwfl/ChangeLog | 6 ++++++ libdwfl/link_map.c | 14 +++++++++++++- 2 files changed, 19 insertions(+), 1 deletion(-) diff --git a/libdwfl/ChangeLog b/libdwfl/ChangeLog index 1f593ac9..856bd335 100644 --- a/libdwfl/ChangeLog +++ b/libdwfl/ChangeLog @@ -1,3 +1,9 @@ +2021-12-09 Mark Wielaard + + * link_map.c (dwfl_link_map_report): Limit dyn_filesz malloc size + to max possible. When converting make sure we don't exceed the number + of bytes available in either in.d_buf or out.d_buf. + 2021-12-08 Mark Wielaard * dwfl_segment_report_module.c (dwfl_segment_report_module): Check diff --git a/libdwfl/link_map.c b/libdwfl/link_map.c index 623b3062..ad93501e 100644 --- a/libdwfl/link_map.c +++ b/libdwfl/link_map.c @@ -994,6 +994,17 @@ dwfl_link_map_report (Dwfl *dwfl, const void *auxv, size_t auxv_size, if ((*memory_callback) (dwfl, dyn_segndx, &in.d_buf, &in.d_size, dyn_vaddr, dyn_filesz, memory_callback_arg)) { + size_t entsize = (elfclass == ELFCLASS32 + ? sizeof (Elf32_Dyn) : sizeof (Elf64_Dyn)); + if (unlikely (dyn_filesz > SIZE_MAX / entsize)) + { + __libdwfl_seterrno (DWFL_E_NOMEM); + return false; + } + /* We can only process as many bytes as there are in + in.d_size. The data might have been truncated. */ + if (dyn_filesz > in.d_size) + dyn_filesz = in.d_size; void *buf = malloc (dyn_filesz); Elf32_Dyn (*d32)[dyn_filesz / sizeof (Elf32_Dyn)] = buf; Elf64_Dyn (*d64)[dyn_filesz / sizeof (Elf64_Dyn)] = buf; @@ -1009,7 +1020,8 @@ dwfl_link_map_report (Dwfl *dwfl, const void *auxv, size_t auxv_size, .d_size = dyn_filesz, .d_buf = buf }; - in.d_size = out.d_size; + if (in.d_size > out.d_size) + in.d_size = out.d_size; if (likely ((elfclass == ELFCLASS32 ? elf32_xlatetom : elf64_xlatetom) (&out, &in, elfdata) != NULL))