From patchwork Tue Apr 5 00:16:11 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ben Hutchings X-Patchwork-Id: 8746001 Return-Path: X-Original-To: patchwork-linux-modules@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 12018C0553 for ; Tue, 5 Apr 2016 00:16:49 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 31E9E2028D for ; Tue, 5 Apr 2016 00:16:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3E38920263 for ; Tue, 5 Apr 2016 00:16:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751595AbcDEAQq (ORCPT ); Mon, 4 Apr 2016 20:16:46 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:44040 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751264AbcDEAQN (ORCPT ); Mon, 4 Apr 2016 20:16:13 -0400 Received: from ben by shadbolt.decadent.org.uk with local (Exim 4.84_2) (envelope-from ) id 1anEfD-0003wO-UG; Tue, 05 Apr 2016 01:16:12 +0100 Date: Tue, 5 Apr 2016 01:16:11 +0100 From: Ben Hutchings To: linux-modules@vger.kernel.org Cc: 820010@bugs.debian.org Message-ID: <20160405001611.GJ21187@decadent.org.uk> MIME-Version: 1.0 Content-Disposition: inline User-Agent: Mutt/1.5.23 (2014-03-12) X-SA-Exim-Connect-IP: X-SA-Exim-Mail-From: ben@decadent.org.uk X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, T_TVD_MIME_EPI, UNPARSEABLE_RELAY autolearn=ham version=3.3.1 Subject: [PATCH] libkmod: Add support for detached module signatures X-SA-Exim-Version: 4.2.1 (built Mon, 26 Dec 2011 16:24:06 +0000) X-SA-Exim-Scanned: Yes (on shadbolt.decadent.org.uk) Sender: owner-linux-modules@vger.kernel.org Precedence: bulk List-ID: X-Virus-Scanned: ClamAV using ClamSMTP Debian will not sign modules during the kernel package build, as this conflicts with the goal of reproducible builds. Instead, we will generate detached signatures offline and include them in a second package. We could attach the signatures when building this second package or at installation time, but that leads to duplication of all modules, either in the archive or on users' systems. To avoid this, add support to libkmod for concatenating modules with detached signatures (files with the '.sig' extension) at load time. Signed-off-by: Ben Hutchings --- I should note that I have *not* tested this with gzip or xz compressed modules. Ben. libkmod/libkmod-file.c | 110 +++++++++++++++++++++++++++++++++++++++++++++---- 1 file changed, 103 insertions(+), 7 deletions(-) diff --git a/libkmod/libkmod-file.c b/libkmod/libkmod-file.c index 5eeba6a912a2..c30a9b92a3ac 100644 --- a/libkmod/libkmod-file.c +++ b/libkmod/libkmod-file.c @@ -52,6 +52,7 @@ struct kmod_file { gzFile gzf; #endif int fd; + int sig_fd; bool direct; off_t size; void *memory; @@ -60,6 +61,37 @@ struct kmod_file { struct kmod_elf *elf; }; +static int append_detached_sig(struct kmod_file *file, size_t buf_size) +{ + struct stat st; + ssize_t read_size; + + if (file->sig_fd < 0) + return 0; + + if (fstat(file->sig_fd, &st) < 0) + return -errno; + + /* Grow the buffer if necessary */ + if ((size_t)st.st_size > buf_size - file->size) { + void *tmp = realloc(file->memory, file->size + st.st_size); + if (tmp == NULL) + return -errno; + file->memory = tmp; + } + + read_size = read(file->sig_fd, (char *)file->memory + file->size, + st.st_size); + if (read_size < 0) + return -errno; + if (read_size != st.st_size) + return -EINVAL; + + file->size += read_size; + + return 0; +} + #ifdef ENABLE_XZ static void xz_uncompress_belch(struct kmod_file *file, lzma_ret ret) { @@ -144,6 +176,7 @@ static int load_xz(struct kmod_file *file) { lzma_stream strm = LZMA_STREAM_INIT; lzma_ret lzret; + size_t buf_size; int ret; lzret = lzma_stream_decoder(&strm, UINT64_MAX, LZMA_CONCATENATED); @@ -155,7 +188,14 @@ static int load_xz(struct kmod_file *file) return -EINVAL; } ret = xz_uncompress(&strm, file); + buf_size = file->size + strm->avail_out; lzma_end(&strm); + + if (!ret) { + ret = append_detached_sig(file, buf_size); + if (ret) + free(file->memory); + } return ret; } @@ -214,6 +254,11 @@ static int load_zlib(struct kmod_file *file) file->memory = p; file->size = did; + + err = append_detached_sig(file, total); + if (err) + goto error; + p = NULL; return 0; @@ -254,18 +299,50 @@ static int load_reg(struct kmod_file *file) if (fstat(file->fd, &st) < 0) return -errno; - file->size = st.st_size; - file->memory = mmap(NULL, file->size, PROT_READ, MAP_PRIVATE, - file->fd, 0); - if (file->memory == MAP_FAILED) - return -errno; - file->direct = true; + if (file->sig_fd < 0) { + file->size = st.st_size; + file->memory = mmap(NULL, file->size, PROT_READ, MAP_PRIVATE, + file->fd, 0); + if (file->memory == MAP_FAILED) + return -errno; + file->direct = true; + } else { + size_t plain_size = st.st_size, sig_size; + _cleanup_free_ unsigned char *p = NULL; + ssize_t ret; + + if (fstat(file->sig_fd, &st) < 0) + return -errno; + sig_size = st.st_size; + + p = malloc(plain_size + sig_size); + if (!p) + return -errno; + + ret = read(file->fd, p, plain_size); + if (ret < 0) + return -errno; + if ((size_t)ret != plain_size) + return -EINVAL; + file->memory = p; + file->size = plain_size; + + ret = append_detached_sig(file, plain_size + sig_size); + if (ret) + return ret; + + p = NULL; + } + return 0; } static void unload_reg(struct kmod_file *file) { - munmap(file->memory, file->size); + if (file->direct) + munmap(file->memory, file->size); + else + free(file->memory); } static const struct file_ops reg_ops = { @@ -285,6 +362,7 @@ struct kmod_file *kmod_file_open(const struct kmod_ctx *ctx, const char *filename) { struct kmod_file *file = calloc(1, sizeof(struct kmod_file)); + char *sig_filename = NULL; const struct comp_type *itr; size_t magic_size_max = 0; int err; @@ -292,12 +370,25 @@ struct kmod_file *kmod_file_open(const struct kmod_ctx *ctx, if (file == NULL) return NULL; + file->sig_fd = -1; + file->fd = open(filename, O_RDONLY|O_CLOEXEC); if (file->fd < 0) { err = -errno; goto error; } + /* Try to open a detached signature. If it's missing, that's OK. */ + if (asprintf(&sig_filename, "%s.sig", filename) < 0) { + err = -errno; + goto error; + } + file->sig_fd = open(sig_filename, O_RDONLY|O_CLOEXEC); + if (file->sig_fd < 0 && errno != ENOENT) { + err = -errno; + goto error; + } + for (itr = comp_types; itr->ops.load != NULL; itr++) { if (magic_size_max < itr->magic_size) magic_size_max = itr->magic_size; @@ -336,7 +427,10 @@ struct kmod_file *kmod_file_open(const struct kmod_ctx *ctx, err = file->ops->load(file); file->ctx = ctx; error: + free(sig_filename); if (err < 0) { + if (file->sig_fd >= 0) + close(file->sig_fd); if (file->fd >= 0) close(file->fd); free(file); @@ -373,6 +467,8 @@ void kmod_file_unref(struct kmod_file *file) kmod_elf_unref(file->elf); file->ops->unload(file); + if (file->sig_fd >= 0) + close(file->sig_fd); if (file->fd >= 0) close(file->fd); free(file);