From patchwork Tue Mar 4 19:03:45 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: steven chen X-Patchwork-Id: 14001294 Received: from linux.microsoft.com (linux.microsoft.com [13.77.154.182]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 46C35255249; Tue, 4 Mar 2025 19:04:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=13.77.154.182 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741115046; cv=none; b=pOcLNX/N2IcZizdzk8cWcK78FgUgYR0BNwJEJNKACpBzEByFsQ/sZMUrw6fbSCrYQiaaaJddTHUF7NdtXzzOti9/UHwNGhZEZwTqXXfSq+X+d5/t2yCP4bkEe5rvH9RYiyZdgwDK+QNDg5HvCX36XiWFstkncWF9F5GWd70pk1c= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741115046; c=relaxed/simple; bh=PR11GixKwgbHqjBG3Xwe6yAkygzEPHe7rYyxz0V03GU=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=Mm4U0m4G0NXwGPmNgwBIxfiKU5m3B4NRC0M8tX8dhfH6s5E3O50MOMfrrVAMHUS47hoYg/TxrVQp4L9CKu4uxTHOkySDjrVhm2awq0PM7M3Iig/ElsY+DqA19VxlTWGIs1B2Z786J0xgMr7PJcU71PXtxf3AQU5MLZTMUmrs7VE= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.microsoft.com; spf=pass smtp.mailfrom=linux.microsoft.com; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b=msKS1WHY; arc=none smtp.client-ip=13.77.154.182 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.microsoft.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.microsoft.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b="msKS1WHY" Received: from localhost.localdomain (unknown [167.220.59.4]) by linux.microsoft.com (Postfix) with ESMTPSA id AA199210EAF4; Tue, 4 Mar 2025 11:03:57 -0800 (PST) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com AA199210EAF4 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1741115037; bh=TySiPt+k7LZohgWdCfqZ715ev4lvAar3YqlGLSd+xws=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=msKS1WHYbLBXvch0PyZ5wemL3/orZT030frA1wWmttxZvG8/HTnLZnqhnO14h2OV6 BjqkjFpuQlucGQZhAh6NTm5Nu8xrNB2SeGmlUU9HA+4uDexqgmU56cPzA11PXkZdSU 0flMUp1kSjhVVRBpDrRD4b0cprjS0QVRe/KSxiNU= From: steven chen To: zohar@linux.ibm.com, stefanb@linux.ibm.com, roberto.sassu@huaweicloud.com, roberto.sassu@huawei.com, eric.snowberg@oracle.com, ebiederm@xmission.com, paul@paul-moore.com, code@tyhicks.com, bauermann@kolabnow.com, linux-integrity@vger.kernel.org, kexec@lists.infradead.org, linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org Cc: madvenka@linux.microsoft.com, nramas@linux.microsoft.com, James.Bottomley@HansenPartnership.com, bhe@redhat.com, vgoyal@redhat.com, dyoung@redhat.com Subject: [PATCH v9 1/7] ima: copy only complete measurement records across kexec Date: Tue, 4 Mar 2025 11:03:45 -0800 Message-Id: <20250304190351.96975-2-chenste@linux.microsoft.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20250304190351.96975-1-chenste@linux.microsoft.com> References: <20250304190351.96975-1-chenste@linux.microsoft.com> Precedence: bulk X-Mailing-List: linux-security-module@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Carrying the IMA measurement list across kexec requires allocating a buffer and copying the measurement records. Separate allocating the buffer and copying the measurement records into separate functions in order to allocate the buffer at kexec 'load' and copy the measurements at kexec 'execute'. This patch includes the following changes: - Refactor ima_dump_measurement_list() to move the memory allocation to a separate function ima_alloc_kexec_file_buf() which allocates buffer of size 'kexec_segment_size' at kexec 'load'. - Make the local variable ima_kexec_file in ima_dump_measurement_list() a local static to the file, so that it can be accessed from ima_alloc_kexec_file_buf(). Compare actual memory required to ensure there is enough memory for the entire measurement record. - Copy only complete measurement records. - Make necessary changes to the function ima_add_kexec_buffer() to call the above two functions. - Compared the memory size allocated with memory size of the entire measurement record. Copy only complete measurement records if there is enough memory. If there is not enough memory, it will not copy any IMA measurement records, and this situation will result in a failure of remote attestation. Suggested-by: Mimi Zohar Signed-off-by: Tushar Sugandhi Signed-off-by: steven chen --- security/integrity/ima/ima.h | 1 + security/integrity/ima/ima_kexec.c | 105 ++++++++++++++++++++++------- security/integrity/ima/ima_queue.c | 4 +- 3 files changed, 83 insertions(+), 27 deletions(-) diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h index 24d09ea91b87..4428fcf42167 100644 --- a/security/integrity/ima/ima.h +++ b/security/integrity/ima/ima.h @@ -274,6 +274,7 @@ bool ima_template_has_modsig(const struct ima_template_desc *ima_template); int ima_restore_measurement_entry(struct ima_template_entry *entry); int ima_restore_measurement_list(loff_t bufsize, void *buf); int ima_measurements_show(struct seq_file *m, void *v); +int ima_get_binary_runtime_entry_size(struct ima_template_entry *entry); unsigned long ima_get_binary_runtime_size(void); int ima_init_template(void); void ima_init_template_list(void); diff --git a/security/integrity/ima/ima_kexec.c b/security/integrity/ima/ima_kexec.c index 9d45f4d26f73..6195df128482 100644 --- a/security/integrity/ima/ima_kexec.c +++ b/security/integrity/ima/ima_kexec.c @@ -15,63 +15,106 @@ #include "ima.h" #ifdef CONFIG_IMA_KEXEC +static struct seq_file ima_kexec_file; + +static void ima_reset_kexec_file(struct seq_file *sf) +{ + sf->buf = NULL; + sf->size = 0; + sf->read_pos = 0; + sf->count = 0; +} + +static void ima_free_kexec_file_buf(struct seq_file *sf) +{ + vfree(sf->buf); + ima_reset_kexec_file(sf); +} + +static int ima_alloc_kexec_file_buf(size_t segment_size) +{ + /* + * kexec 'load' may be called multiple times. + * Free and realloc the buffer only if the segment_size is + * changed from the previous kexec 'load' call. + */ + if (ima_kexec_file.buf && ima_kexec_file.size == segment_size) + goto out; + + ima_free_kexec_file_buf(&ima_kexec_file); + + /* segment size can't change between kexec load and execute */ + ima_kexec_file.buf = vmalloc(segment_size); + if (!ima_kexec_file.buf) + return -ENOMEM; + + ima_kexec_file.size = segment_size; + +out: + ima_kexec_file.read_pos = 0; + ima_kexec_file.count = sizeof(struct ima_kexec_hdr); /* reserved space */ + + return 0; +} + +/* + * Copy the measurement list to the allocated memory + * compare the size of IMA measurement list with the size of the allocated memory + * if the size of the allocated memory is not less than the size of IMA measurement list + * copy the measurement list to the allocated memory. + * else return error + */ static int ima_dump_measurement_list(unsigned long *buffer_size, void **buffer, unsigned long segment_size) { struct ima_queue_entry *qe; - struct seq_file file; struct ima_kexec_hdr khdr; int ret = 0; + size_t entry_size = 0; - /* segment size can't change between kexec load and execute */ - file.buf = vmalloc(segment_size); - if (!file.buf) { - ret = -ENOMEM; - goto out; + if (!ima_kexec_file.buf) { + pr_err("Kexec file buf not allocated\n"); + return -EINVAL; } - file.file = NULL; - file.size = segment_size; - file.read_pos = 0; - file.count = sizeof(khdr); /* reserved space */ - memset(&khdr, 0, sizeof(khdr)); khdr.version = 1; /* This is an append-only list, no need to hold the RCU read lock */ list_for_each_entry_rcu(qe, &ima_measurements, later, true) { - if (file.count < file.size) { + entry_size += ima_get_binary_runtime_entry_size(qe->entry); + if (entry_size <= segment_size) { khdr.count++; - ima_measurements_show(&file, qe); + ima_measurements_show(&ima_kexec_file, qe); } else { ret = -EINVAL; + pr_err("IMA log file is too big for Kexec buf\n"); break; } } if (ret < 0) goto out; - /* * fill in reserved space with some buffer details * (eg. version, buffer size, number of measurements) */ - khdr.buffer_size = file.count; + khdr.buffer_size = ima_kexec_file.count; if (ima_canonical_fmt) { khdr.version = cpu_to_le16(khdr.version); khdr.count = cpu_to_le64(khdr.count); khdr.buffer_size = cpu_to_le64(khdr.buffer_size); } - memcpy(file.buf, &khdr, sizeof(khdr)); + memcpy(ima_kexec_file.buf, &khdr, sizeof(khdr)); print_hex_dump_debug("ima dump: ", DUMP_PREFIX_NONE, 16, 1, - file.buf, file.count < 100 ? file.count : 100, + ima_kexec_file.buf, ima_kexec_file.count < 100 ? + ima_kexec_file.count : 100, true); - *buffer_size = file.count; - *buffer = file.buf; + *buffer_size = ima_kexec_file.count; + *buffer = ima_kexec_file.buf; + out: - if (ret == -EINVAL) - vfree(file.buf); return ret; } @@ -90,7 +133,7 @@ void ima_add_kexec_buffer(struct kimage *image) /* use more understandable variable names than defined in kbuf */ void *kexec_buffer = NULL; - size_t kexec_buffer_size; + size_t kexec_buffer_size = 0; size_t kexec_segment_size; int ret; @@ -110,13 +153,19 @@ void ima_add_kexec_buffer(struct kimage *image) return; } - ima_dump_measurement_list(&kexec_buffer_size, &kexec_buffer, - kexec_segment_size); - if (!kexec_buffer) { + ret = ima_alloc_kexec_file_buf(kexec_segment_size); + if (ret < 0) { pr_err("Not enough memory for the kexec measurement buffer.\n"); return; } + ret = ima_dump_measurement_list(&kexec_buffer_size, &kexec_buffer, + kexec_segment_size); + if (ret < 0) { + pr_err("Failed to dump IMA measurements. Error:%d.\n", ret); + return; + } + kbuf.buffer = kexec_buffer; kbuf.bufsz = kexec_buffer_size; kbuf.memsz = kexec_segment_size; @@ -131,6 +180,12 @@ void ima_add_kexec_buffer(struct kimage *image) image->ima_buffer_size = kexec_segment_size; image->ima_buffer = kexec_buffer; + /* + * kexec owns kexec_buffer after kexec_add_buffer() is called + * and it will vfree() that buffer. + */ + ima_reset_kexec_file(&ima_kexec_file); + kexec_dprintk("kexec measurement buffer for the loaded kernel at 0x%lx.\n", kbuf.mem); } diff --git a/security/integrity/ima/ima_queue.c b/security/integrity/ima/ima_queue.c index 83d53824aa98..3dfd178d4292 100644 --- a/security/integrity/ima/ima_queue.c +++ b/security/integrity/ima/ima_queue.c @@ -78,7 +78,7 @@ static struct ima_queue_entry *ima_lookup_digest_entry(u8 *digest_value, * binary_runtime_measurement list entry, which contains a * couple of variable length fields (e.g template name and data). */ -static int get_binary_runtime_size(struct ima_template_entry *entry) +int ima_get_binary_runtime_entry_size(struct ima_template_entry *entry) { int size = 0; @@ -122,7 +122,7 @@ static int ima_add_digest_entry(struct ima_template_entry *entry, if (binary_runtime_size != ULONG_MAX) { int size; - size = get_binary_runtime_size(entry); + size = ima_get_binary_runtime_entry_size(entry); binary_runtime_size = (binary_runtime_size < ULONG_MAX - size) ? binary_runtime_size + size : ULONG_MAX; } From patchwork Tue Mar 4 19:03:46 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: steven chen X-Patchwork-Id: 14001293 Received: from linux.microsoft.com (linux.microsoft.com [13.77.154.182]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 46AF7253F2A; Tue, 4 Mar 2025 19:04:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=13.77.154.182 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741115046; cv=none; b=pcq3sf6ysanylsJAUGnrjqR0Wh2MTtDMERQp2zLl9rqQPPkutp+DgIwsMi7nNMCBZTd3xlm2lzbo44ksqrEw4X6gzwBMFjrs/E8n0ZA6g/injaPkcI5oC+uwwrkqnnRrkavoQ+HtrWzQkGAW7etuPVMihgA4wyzdw4lS4iYPzc4= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741115046; c=relaxed/simple; bh=pD1H3asyMZ0VZ1iTcZ+E7bEPXPmDb0ZznjbNPV9kD0U=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=r5m6wSfpPqXzX6RzThvE2b4ur38cIYQQHX19943YBUUdbpcwMJ27RpvEKGwbcNLkyby+X2vx7Tzvp1jCncdMSozeyCtiUMPiu8ceRNasWOgsxfYmU+RiiN1U8+l/erhBydexSqqBqqFV7njqoqT0/4Bw6qx1s2t+Woj0So58HKI= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.microsoft.com; spf=pass smtp.mailfrom=linux.microsoft.com; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b=qQVKvgY1; arc=none smtp.client-ip=13.77.154.182 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.microsoft.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.microsoft.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b="qQVKvgY1" Received: from localhost.localdomain (unknown [167.220.59.4]) by linux.microsoft.com (Postfix) with ESMTPSA id DD945210EAF5; Tue, 4 Mar 2025 11:03:57 -0800 (PST) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com DD945210EAF5 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1741115038; bh=GjiBuoKXsGyAWW6cnySvQv4nQ9sBfDgvkq6VWxqqivo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=qQVKvgY1FlgcHfMKgMiLN33jbU7Np8CgnNa/lOH0rXsuul3op0pQkknnhFbUb7B/V 9dCdk2v9eCAnhvMB7lkk/mwGgdfP4JfUcgJJHE9lFWM7TVaOK7VhsdtB9evmSvIrmH 5UZa3Dr5US/BQsqycrB4i5xmrf10q1QnFAQcHeZw= From: steven chen To: zohar@linux.ibm.com, stefanb@linux.ibm.com, roberto.sassu@huaweicloud.com, roberto.sassu@huawei.com, eric.snowberg@oracle.com, ebiederm@xmission.com, paul@paul-moore.com, code@tyhicks.com, bauermann@kolabnow.com, linux-integrity@vger.kernel.org, kexec@lists.infradead.org, linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org Cc: madvenka@linux.microsoft.com, nramas@linux.microsoft.com, James.Bottomley@HansenPartnership.com, bhe@redhat.com, vgoyal@redhat.com, dyoung@redhat.com Subject: [PATCH v9 2/7] kexec: define functions to map and unmap segments Date: Tue, 4 Mar 2025 11:03:46 -0800 Message-Id: <20250304190351.96975-3-chenste@linux.microsoft.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20250304190351.96975-1-chenste@linux.microsoft.com> References: <20250304190351.96975-1-chenste@linux.microsoft.com> Precedence: bulk X-Mailing-List: linux-security-module@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 The content of memory segments carried over to the new kernel during the kexec systemcall can be changed at kexec 'execute' stage, but the size of the memory segments cannot be changed at kexec 'execute' stage. To copy IMA measurement logs during the kexec operation, IMA needs to allocate memory at the kexec 'load' stage and map the segments to the kimage structure. The mapped address will then be used to copy IMA measurements during the kexec 'execute' stage. Currently, the mechanism to map and unmap segments to the kimage structure is not available to subsystems outside of kexec. Implement kimage_map_segment() to enable IMA to map measurement log list to the kimage structure during kexec 'load' stage. This function takes a kimage pointer, a memory address, and a size, then gathers the source pages within the specified address range, creates an array of page pointers, and maps these to a contiguous virtual address range. The function returns the start virtual address of this range if successful, or NULL on failure. Implement kimage_unmap_segment() for unmapping segments using vunmap(). From: Tushar Sugandhi Signed-off-by: Tushar Sugandhi Cc: Eric Biederman Cc: Baoquan He Cc: Vivek Goyal Cc: Dave Young Signed-off-by: steven chen --- include/linux/kexec.h | 6 +++++ kernel/kexec_core.c | 54 +++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 60 insertions(+) diff --git a/include/linux/kexec.h b/include/linux/kexec.h index f0e9f8eda7a3..7d6b12f8b8d0 100644 --- a/include/linux/kexec.h +++ b/include/linux/kexec.h @@ -467,13 +467,19 @@ extern bool kexec_file_dbg_print; #define kexec_dprintk(fmt, arg...) \ do { if (kexec_file_dbg_print) pr_info(fmt, ##arg); } while (0) +extern void *kimage_map_segment(struct kimage *image, unsigned long addr, unsigned long size); +extern void kimage_unmap_segment(void *buffer); #else /* !CONFIG_KEXEC_CORE */ struct pt_regs; struct task_struct; +struct kimage; static inline void __crash_kexec(struct pt_regs *regs) { } static inline void crash_kexec(struct pt_regs *regs) { } static inline int kexec_should_crash(struct task_struct *p) { return 0; } static inline int kexec_crash_loaded(void) { return 0; } +static inline void *kimage_map_segment(struct kimage *image, unsigned long addr, unsigned long size) +{ return NULL; } +static inline void kimage_unmap_segment(void *buffer) { } #define kexec_in_progress false #endif /* CONFIG_KEXEC_CORE */ diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c index c0bdc1686154..63e4d16b6023 100644 --- a/kernel/kexec_core.c +++ b/kernel/kexec_core.c @@ -867,6 +867,60 @@ int kimage_load_segment(struct kimage *image, return result; } +void *kimage_map_segment(struct kimage *image, + unsigned long addr, unsigned long size) +{ + unsigned long eaddr = addr + size; + unsigned long src_page_addr, dest_page_addr; + unsigned int npages; + struct page **src_pages; + int i; + kimage_entry_t *ptr, entry; + void *vaddr = NULL; + + /* + * Collect the source pages and map them in a contiguous VA range. + */ + npages = PFN_UP(eaddr) - PFN_DOWN(addr); + src_pages = kmalloc_array(npages, sizeof(*src_pages), GFP_KERNEL); + if (!src_pages) { + pr_err("Could not allocate ima pages array.\n"); + return NULL; + } + + i = 0; + for_each_kimage_entry(image, ptr, entry) { + if (entry & IND_DESTINATION) { + dest_page_addr = entry & PAGE_MASK; + } else if (entry & IND_SOURCE) { + if (dest_page_addr >= addr && dest_page_addr < eaddr) { + src_page_addr = entry & PAGE_MASK; + src_pages[i++] = + virt_to_page(__va(src_page_addr)); + if (i == npages) + break; + dest_page_addr += PAGE_SIZE; + } + } + } + + /* Sanity check. */ + WARN_ON(i < npages); + + vaddr = vmap(src_pages, npages, VM_MAP, PAGE_KERNEL); + kfree(src_pages); + + if (!vaddr) + pr_err("Could not map ima buffer.\n"); + + return vaddr; +} + +void kimage_unmap_segment(void *segment_buffer) +{ + vunmap(segment_buffer); +} + struct kexec_load_limit { /* Mutex protects the limit count. */ struct mutex mutex; From patchwork Tue Mar 4 19:03:47 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: steven chen X-Patchwork-Id: 14001292 Received: from linux.microsoft.com (linux.microsoft.com [13.77.154.182]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 46C98259C8D; 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arc=none smtp.client-ip=13.77.154.182 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.microsoft.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.microsoft.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b="aPWmRBFI" Received: from localhost.localdomain (unknown [167.220.59.4]) by linux.microsoft.com (Postfix) with ESMTPSA id 1C963210EAF6; Tue, 4 Mar 2025 11:03:58 -0800 (PST) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 1C963210EAF6 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1741115038; bh=rDwLyG8x98JlAJ3JT4WjH9zB21oyx+c9LLRVfLQwzE8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=aPWmRBFITjcXbcl1gxET8+qChdsH2s0kFGBJeKYeVmBoRPlaVQotLjfreDCfmaF1z TkqFOSKhzqAfL8HX55bOr/DT0mQSUeO9BakMo3MWOT0/FEdUPLCETOPP7mNsbVjbtB NeRCBIfpPry6C7Q2qQlegjT0MrB+9RnSyRnj33v4= From: steven chen To: zohar@linux.ibm.com, stefanb@linux.ibm.com, roberto.sassu@huaweicloud.com, roberto.sassu@huawei.com, eric.snowberg@oracle.com, ebiederm@xmission.com, paul@paul-moore.com, code@tyhicks.com, bauermann@kolabnow.com, linux-integrity@vger.kernel.org, kexec@lists.infradead.org, linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org Cc: madvenka@linux.microsoft.com, nramas@linux.microsoft.com, James.Bottomley@HansenPartnership.com, bhe@redhat.com, vgoyal@redhat.com, dyoung@redhat.com Subject: [PATCH v9 3/7] ima: kexec: skip IMA segment validation after kexec soft reboot Date: Tue, 4 Mar 2025 11:03:47 -0800 Message-Id: <20250304190351.96975-4-chenste@linux.microsoft.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20250304190351.96975-1-chenste@linux.microsoft.com> References: <20250304190351.96975-1-chenste@linux.microsoft.com> Precedence: bulk X-Mailing-List: linux-security-module@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 The kexec_calculate_store_digests() function calculates and stores the digest of the segment during the kexec_file_load syscall, where the IMA segment is also allocated. With this series, the IMA segment will be updated with the measurement log at the kexec execute stage when a soft reboot is initiated. Therefore, the digests should be updated for the IMA segment in the normal case. The content of memory segments carried over to the new kernel during the kexec systemcall can be changed at kexec 'execute' stage, but the size and the location of the memory segments cannot be changed at kexec 'execute' stage. However, during the kexec execute stage, if kexec_calculate_store_digests() API is call to update the digest, it does not reuse the same memory segment allocated during the kexec 'load' stage and the new memory segment required cannot be transferred/mapped to the new kernel. As a result, digest verification will fail in verify_sha256_digest() after a kexec soft reboot into the new kernel. Therefore, the digest calculation/verification of the IMA segment needs to be skipped. To address this, skip the calculation and storage of the digest for the IMA segment in kexec_calculate_store_digests() so that it is not added to the purgatory_sha_regions. Since verify_sha256_digest() only verifies 'purgatory_sha_regions', no change is needed in verify_sha256_digest() in this context. With this change, the IMA segment is not included in the digest calculation, storage, and verification. Signed-off-by: Tushar Sugandhi Cc: Eric Biederman Cc: Baoquan He Cc: Vivek Goyal Cc: Dave Young Signed-off-by: steven chen Reviewed-by: Stefan Berger Reviewed-by: Mimi Zohar --- include/linux/kexec.h | 3 +++ kernel/kexec_file.c | 22 ++++++++++++++++++++++ security/integrity/ima/ima_kexec.c | 3 +++ 3 files changed, 28 insertions(+) diff --git a/include/linux/kexec.h b/include/linux/kexec.h index 7d6b12f8b8d0..107e726f2ef3 100644 --- a/include/linux/kexec.h +++ b/include/linux/kexec.h @@ -362,6 +362,9 @@ struct kimage { phys_addr_t ima_buffer_addr; size_t ima_buffer_size; + + unsigned long ima_segment_index; + bool is_ima_segment_index_set; #endif /* Core ELF header buffer */ diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c index 3eedb8c226ad..606132253c79 100644 --- a/kernel/kexec_file.c +++ b/kernel/kexec_file.c @@ -38,6 +38,21 @@ void set_kexec_sig_enforced(void) } #endif +#ifdef CONFIG_IMA_KEXEC +static bool check_ima_segment_index(struct kimage *image, int i) +{ + if (image->is_ima_segment_index_set && i == image->ima_segment_index) + return true; + else + return false; +} +#else +static bool check_ima_segment_index(struct kimage *image, int i) +{ + return false; +} +#endif + static int kexec_calculate_store_digests(struct kimage *image); /* Maximum size in bytes for kernel/initrd files. */ @@ -764,6 +779,13 @@ static int kexec_calculate_store_digests(struct kimage *image) if (ksegment->kbuf == pi->purgatory_buf) continue; + /* + * Skip the segment if ima_segment_index is set and matches + * the current index + */ + if (check_ima_segment_index(image, i)) + continue; + ret = crypto_shash_update(desc, ksegment->kbuf, ksegment->bufsz); if (ret) diff --git a/security/integrity/ima/ima_kexec.c b/security/integrity/ima/ima_kexec.c index 6195df128482..0465beca8867 100644 --- a/security/integrity/ima/ima_kexec.c +++ b/security/integrity/ima/ima_kexec.c @@ -169,6 +169,7 @@ void ima_add_kexec_buffer(struct kimage *image) kbuf.buffer = kexec_buffer; kbuf.bufsz = kexec_buffer_size; kbuf.memsz = kexec_segment_size; + image->is_ima_segment_index_set = false; ret = kexec_add_buffer(&kbuf); if (ret) { pr_err("Error passing over kexec measurement buffer.\n"); @@ -179,6 +180,8 @@ void ima_add_kexec_buffer(struct kimage *image) image->ima_buffer_addr = kbuf.mem; image->ima_buffer_size = kexec_segment_size; image->ima_buffer = kexec_buffer; + image->ima_segment_index = image->nr_segments - 1; + image->is_ima_segment_index_set = true; /* * kexec owns kexec_buffer after kexec_add_buffer() is called From patchwork Tue Mar 4 19:03:48 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: steven chen X-Patchwork-Id: 14001295 Received: from linux.microsoft.com (linux.microsoft.com [13.77.154.182]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 46BCF254844; Tue, 4 Mar 2025 19:04:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=13.77.154.182 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741115047; cv=none; b=Nh/dY0RuQYECyVoyaErLHlcN8N6BZDp6grpkjxnUaQuR3U0AwQ/eHMx9WxYexxVrgC7BRcxklRhGuY4upWs8klutKBEVX7ir2cFxpqifQ+sDuncAgwqn1RqFr+0rY5h0tbEfaOkAH0Hgk1d2FODsEJzc86jOV9l+xWEg3qetdek= ARC-Message-Signature: i=1; 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Tue, 4 Mar 2025 11:03:58 -0800 (PST) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 51A4E210EAF7 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1741115038; bh=55oilYOb/o5X5igsf+VHhahT6DeIeNK9q6z0NvNx3Vo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=hzOJfNKRXf9WZr29HaD8vqFuq7rMgkOe+gPGHmUnDR/hLsN/en6QpzoJyRAPbGVl5 Nwyi2Z3d7L11aCGnY5lhypWw0chrQc8JY9uY3V88yL3pV5ZL4HaqJ2yd/sgZqNQ9oH Q7xCtw+7geDx10RmqdmsKkhRTNxrGSNJ8QpNIlvA= From: steven chen To: zohar@linux.ibm.com, stefanb@linux.ibm.com, roberto.sassu@huaweicloud.com, roberto.sassu@huawei.com, eric.snowberg@oracle.com, ebiederm@xmission.com, paul@paul-moore.com, code@tyhicks.com, bauermann@kolabnow.com, linux-integrity@vger.kernel.org, kexec@lists.infradead.org, linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org Cc: madvenka@linux.microsoft.com, nramas@linux.microsoft.com, James.Bottomley@HansenPartnership.com, bhe@redhat.com, vgoyal@redhat.com, dyoung@redhat.com Subject: [PATCH v9 4/7] ima: kexec: define functions to copy IMA log at soft boot Date: Tue, 4 Mar 2025 11:03:48 -0800 Message-Id: <20250304190351.96975-5-chenste@linux.microsoft.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20250304190351.96975-1-chenste@linux.microsoft.com> References: <20250304190351.96975-1-chenste@linux.microsoft.com> Precedence: bulk X-Mailing-List: linux-security-module@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 The IMA log is currently copied to the new kernel during kexec 'load' using ima_dump_measurement_list(). However, the log copied at kexec 'load' may result in loss of IMA measurements that only occurred after kexec "load'. Therefore, the log needs to be copied during kexec 'execute'. Setup the needed infrastructure to move the IMA log copy from kexec 'load' to 'execute'. Define a new IMA hook ima_update_kexec_buffer() as a stub function. It will be used to call ima_dump_measurement_list() during kexec 'execute'. Implement ima_kexec_post_load() function to be invoked after the new Kernel image has been loaded for kexec. ima_kexec_post_load() maps the IMA buffer to a segment in the newly loaded Kernel. It also registers the reboot notifier_block to trigger ima_update_kexec_buffer() at kexec 'execute'. Signed-off-by: Tushar Sugandhi Cc: Eric Biederman Cc: Baoquan He Cc: Vivek Goyal Cc: Dave Young Signed-off-by: steven chen Reviewed-by: Stefan Berger --- include/linux/ima.h | 3 ++ security/integrity/ima/ima_kexec.c | 47 ++++++++++++++++++++++++++++++ 2 files changed, 50 insertions(+) diff --git a/include/linux/ima.h b/include/linux/ima.h index 0bae61a15b60..8e29cb4e6a01 100644 --- a/include/linux/ima.h +++ b/include/linux/ima.h @@ -32,6 +32,9 @@ static inline void ima_appraise_parse_cmdline(void) {} #ifdef CONFIG_IMA_KEXEC extern void ima_add_kexec_buffer(struct kimage *image); +extern void ima_kexec_post_load(struct kimage *image); +#else +static inline void ima_kexec_post_load(struct kimage *image) {} #endif #else diff --git a/security/integrity/ima/ima_kexec.c b/security/integrity/ima/ima_kexec.c index 0465beca8867..074848dcd30f 100644 --- a/security/integrity/ima/ima_kexec.c +++ b/security/integrity/ima/ima_kexec.c @@ -12,10 +12,14 @@ #include #include #include +#include +#include #include "ima.h" #ifdef CONFIG_IMA_KEXEC static struct seq_file ima_kexec_file; +static void *ima_kexec_buffer; +static bool ima_kexec_update_registered; static void ima_reset_kexec_file(struct seq_file *sf) { @@ -192,6 +196,49 @@ void ima_add_kexec_buffer(struct kimage *image) kexec_dprintk("kexec measurement buffer for the loaded kernel at 0x%lx.\n", kbuf.mem); } + +/* + * Called during kexec execute so that IMA can update the measurement list. + */ +static int ima_update_kexec_buffer(struct notifier_block *self, + unsigned long action, void *data) +{ + return NOTIFY_OK; +} + +struct notifier_block update_buffer_nb = { + .notifier_call = ima_update_kexec_buffer, + .priority = 1, +}; + +/* + * Create a mapping for the source pages that contain the IMA buffer + * so we can update it later. + */ +void ima_kexec_post_load(struct kimage *image) +{ + if (ima_kexec_buffer) { + kimage_unmap_segment(ima_kexec_buffer); + ima_kexec_buffer = NULL; + } + + if (!image->ima_buffer_addr) + return; + + ima_kexec_buffer = kimage_map_segment(image, + image->ima_buffer_addr, + image->ima_buffer_size); + if (!ima_kexec_buffer) { + pr_err("Could not map measurements buffer.\n"); + return; + } + + if (!ima_kexec_update_registered) { + register_reboot_notifier(&update_buffer_nb); + ima_kexec_update_registered = true; + } +} + #endif /* IMA_KEXEC */ /* From patchwork Tue Mar 4 19:03:49 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: steven chen X-Patchwork-Id: 14001298 Received: from linux.microsoft.com (linux.microsoft.com [13.77.154.182]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 3EA60259CA4; Tue, 4 Mar 2025 19:04:06 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=13.77.154.182 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741115048; cv=none; b=pKzyhx/l8AsQt1EVofZQCmWSql+v9PcbxqseWQFdz1ihmj5vBsk7qg9AaZp/9r5/FgelkabsHlGUaFhnzegHMKEbvEEDOcj72QEIA2BBlir/lXO4mrF+PedjZeiPqb171SHfxa7W3guW0COwXLCdsT7wZngYWHVhtn5tCJhpymE= ARC-Message-Signature: i=1; a=rsa-sha256; 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Tue, 4 Mar 2025 11:03:58 -0800 (PST) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 84CC9210EAF8 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1741115038; bh=7qnmbvahwvU7VlIgXZzoWEJ45XsjExtxy1rAtdhREgo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=NZdJcJQv061fMY1A2AoQnRr9v4JAZL+k9i9U6aJ7rqyRioRPGGSMdNItmzNghhFyB kuERyFP1JLcZggQDeg/J6CMAcw5XXC5eJ201jIZ8giFUdfvo7QUTb9ykpojEdlCV+D QLqa0vElJsT+kS3S7sZNJ8n8GQ7ikTz7UBjAcBbo= From: steven chen To: zohar@linux.ibm.com, stefanb@linux.ibm.com, roberto.sassu@huaweicloud.com, roberto.sassu@huawei.com, eric.snowberg@oracle.com, ebiederm@xmission.com, paul@paul-moore.com, code@tyhicks.com, bauermann@kolabnow.com, linux-integrity@vger.kernel.org, kexec@lists.infradead.org, linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org Cc: madvenka@linux.microsoft.com, nramas@linux.microsoft.com, James.Bottomley@HansenPartnership.com, bhe@redhat.com, vgoyal@redhat.com, dyoung@redhat.com Subject: [PATCH v9 5/7] ima: kexec: move IMA log copy from kexec load to execute Date: Tue, 4 Mar 2025 11:03:49 -0800 Message-Id: <20250304190351.96975-6-chenste@linux.microsoft.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20250304190351.96975-1-chenste@linux.microsoft.com> References: <20250304190351.96975-1-chenste@linux.microsoft.com> Precedence: bulk X-Mailing-List: linux-security-module@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 ima_dump_measurement_list() is called during kexec 'load', which may result in loss of IMA measurements during kexec soft reboot. Due to missed measurements that only occurred after kexec 'load', this function needs to be called during kexec 'execute'. This patch includes the following changes: - Implement kimage_file_post_load() function to be invoked after the new kernel image has been loaded for kexec. - Call kimage_file_post_load() from kexec_file_load() syscall only for kexec soft reboot scenarios and not for KEXEC_FILE_ON_CRASH. It will map the IMA segment, and register reboot notifier for the function ima_update_kexec_buffer() which would copy the IMA log at kexec soft reboot. - Make kexec_segment_size variable local static to the file so that it becomes accessible both during kexec 'load' and 'execute'. - Move ima_dump_measurement_list() call from ima_add_kexec_buffer() to ima_update_kexec_buffer(). - Copy the measurement list as much as possible. - Remove ima_reset_kexec_file() call from ima_add_kexec_buffer(), now that the buffer is being copied at kexec 'execute', and resetting the file at kexec 'load' would corrupt the buffer. Signed-off-by: Tushar Sugandhi Cc: Eric Biederman Cc: Baoquan He Cc: Vivek Goyal Cc: Dave Young Signed-off-by: steven chen Reviewed-by: Stefan Berger --- kernel/kexec_file.c | 10 +++++++ security/integrity/ima/ima_kexec.c | 48 ++++++++++++++++++------------ 2 files changed, 39 insertions(+), 19 deletions(-) diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c index 606132253c79..ab449b43aaee 100644 --- a/kernel/kexec_file.c +++ b/kernel/kexec_file.c @@ -201,6 +201,13 @@ kimage_validate_signature(struct kimage *image) } #endif +static void kimage_file_post_load(struct kimage *image) +{ +#ifdef CONFIG_IMA_KEXEC + ima_kexec_post_load(image); +#endif +} + /* * In file mode list of segments is prepared by kernel. Copy relevant * data from user space, do error checking, prepare segment list @@ -428,6 +435,9 @@ SYSCALL_DEFINE5(kexec_file_load, int, kernel_fd, int, initrd_fd, kimage_terminate(image); + if (!(flags & KEXEC_FILE_ON_CRASH)) + kimage_file_post_load(image); + ret = machine_kexec_post_load(image); if (ret) goto out; diff --git a/security/integrity/ima/ima_kexec.c b/security/integrity/ima/ima_kexec.c index 074848dcd30f..dd49658153ca 100644 --- a/security/integrity/ima/ima_kexec.c +++ b/security/integrity/ima/ima_kexec.c @@ -19,6 +19,7 @@ #ifdef CONFIG_IMA_KEXEC static struct seq_file ima_kexec_file; static void *ima_kexec_buffer; +static size_t kexec_segment_size; static bool ima_kexec_update_registered; static void ima_reset_kexec_file(struct seq_file *sf) @@ -66,7 +67,8 @@ static int ima_alloc_kexec_file_buf(size_t segment_size) * compare the size of IMA measurement list with the size of the allocated memory * if the size of the allocated memory is not less than the size of IMA measurement list * copy the measurement list to the allocated memory. - * else return error + * else + * copy the measurement list as much as possible. */ static int ima_dump_measurement_list(unsigned long *buffer_size, void **buffer, unsigned long segment_size) @@ -96,8 +98,6 @@ static int ima_dump_measurement_list(unsigned long *buffer_size, void **buffer, } } - if (ret < 0) - goto out; /* * fill in reserved space with some buffer details * (eg. version, buffer size, number of measurements) @@ -118,7 +118,6 @@ static int ima_dump_measurement_list(unsigned long *buffer_size, void **buffer, *buffer_size = ima_kexec_file.count; *buffer = ima_kexec_file.buf; -out: return ret; } @@ -138,7 +137,6 @@ void ima_add_kexec_buffer(struct kimage *image) /* use more understandable variable names than defined in kbuf */ void *kexec_buffer = NULL; size_t kexec_buffer_size = 0; - size_t kexec_segment_size; int ret; /* @@ -163,13 +161,6 @@ void ima_add_kexec_buffer(struct kimage *image) return; } - ret = ima_dump_measurement_list(&kexec_buffer_size, &kexec_buffer, - kexec_segment_size); - if (ret < 0) { - pr_err("Failed to dump IMA measurements. Error:%d.\n", ret); - return; - } - kbuf.buffer = kexec_buffer; kbuf.bufsz = kexec_buffer_size; kbuf.memsz = kexec_segment_size; @@ -187,12 +178,6 @@ void ima_add_kexec_buffer(struct kimage *image) image->ima_segment_index = image->nr_segments - 1; image->is_ima_segment_index_set = true; - /* - * kexec owns kexec_buffer after kexec_add_buffer() is called - * and it will vfree() that buffer. - */ - ima_reset_kexec_file(&ima_kexec_file); - kexec_dprintk("kexec measurement buffer for the loaded kernel at 0x%lx.\n", kbuf.mem); } @@ -203,7 +188,32 @@ void ima_add_kexec_buffer(struct kimage *image) static int ima_update_kexec_buffer(struct notifier_block *self, unsigned long action, void *data) { - return NOTIFY_OK; + void *buf = NULL; + size_t buf_size = 0; + int ret = NOTIFY_OK; + + if (!kexec_in_progress) { + pr_info("No kexec in progress.\n"); + return ret; + } + + if (!ima_kexec_buffer) { + pr_err("Kexec buffer not set.\n"); + return ret; + } + + ret = ima_dump_measurement_list(&buf_size, &buf, kexec_segment_size); + + if (ret) + pr_err("Dump measurements failed. Error:%d\n", ret); + + if (buf_size != 0) + memcpy(ima_kexec_buffer, buf, buf_size); + + kimage_unmap_segment(ima_kexec_buffer); + ima_kexec_buffer = NULL; + + return ret; } struct notifier_block update_buffer_nb = { From patchwork Tue Mar 4 19:03:50 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: steven chen X-Patchwork-Id: 14001297 Received: from linux.microsoft.com (linux.microsoft.com [13.77.154.182]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 3E9F7259CA3; Tue, 4 Mar 2025 19:04:06 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=13.77.154.182 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741115047; cv=none; b=KhpnJwkQ3dGcmcjG+dC8i2OEEGlNWaWPG93kiZWOd8suDxYIDgWkvtMdEAb+W1n/U7Qvz5KF8gjrI1l9sShkoaRjvAu59UbzwvJsu6GnAnPudoA5l5zBg/v0cAgcLPSXM/B20soO2SLoA5xTMmD2hCsOl4phIyfkWio1ZUOB+O4= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741115047; c=relaxed/simple; bh=OsxKZ3uF2aRWtW8U5Q0hBt5QMQGFxad/c4GW7JdlzRc=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=gkGMyiTH1YON0gIpOOQqAlnCLYST41y4CV6AN13ob+7Uzi3Oqcaniw++Bc+U+2EErGgZLJxVXgRxBfAGX9RjICqMMTOvrmWRFeOV0TRZhV8jOuFi0y+x/qrkZ42fKW83j40tzSKskkwlhFTdq4vK6Jl4ipJWy5tBsK/Yk+wQwkY= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.microsoft.com; spf=pass smtp.mailfrom=linux.microsoft.com; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b=casVGVZg; arc=none smtp.client-ip=13.77.154.182 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.microsoft.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.microsoft.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b="casVGVZg" Received: from localhost.localdomain (unknown [167.220.59.4]) by linux.microsoft.com (Postfix) with ESMTPSA id BA1D6210EAF9; Tue, 4 Mar 2025 11:03:58 -0800 (PST) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com BA1D6210EAF9 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1741115038; bh=C4fpkfAT2qDRSew80giIKdwwL8+StIhxSDKSC7I42as=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=casVGVZgDDZlGFiWiV3hWdWKoyYHaSIQEDZ5oX9eeeCgtOONN/0UQNhCVXntbS03g 9voUHFotE22DmYfcw1/1AfbYJMDF6VmMfarkqJaM1XQw9YLb3C+JWR6o+MSdMBxBEy Ys6JO5etPNGex+zEulwetmCLvpMK80fd+leFg760= From: steven chen To: zohar@linux.ibm.com, stefanb@linux.ibm.com, roberto.sassu@huaweicloud.com, roberto.sassu@huawei.com, eric.snowberg@oracle.com, ebiederm@xmission.com, paul@paul-moore.com, code@tyhicks.com, bauermann@kolabnow.com, linux-integrity@vger.kernel.org, kexec@lists.infradead.org, linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org Cc: madvenka@linux.microsoft.com, nramas@linux.microsoft.com, James.Bottomley@HansenPartnership.com, bhe@redhat.com, vgoyal@redhat.com, dyoung@redhat.com Subject: [PATCH v9 6/7] ima: make the kexec extra memory configurable Date: Tue, 4 Mar 2025 11:03:50 -0800 Message-Id: <20250304190351.96975-7-chenste@linux.microsoft.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20250304190351.96975-1-chenste@linux.microsoft.com> References: <20250304190351.96975-1-chenste@linux.microsoft.com> Precedence: bulk X-Mailing-List: linux-security-module@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 The extra memory allocated for carrying the IMA measurement list across kexec is hard-coded as half a PAGE. Make it configurable. Define a Kconfig option, IMA_KEXEC_EXTRA_MEMORY_KB, to configure the extra memory (in kb) to be allocated for IMA measurements added during kexec soft reboot. Ensure the default value of the option is set such that extra half a page of memory for additional measurements is allocated for the additional measurements. Update ima_add_kexec_buffer() function to allocate memory based on the Kconfig option value, rather than the currently hard-coded one. Suggested-by: Stefan Berger Signed-off-by: Tushar Sugandhi Signed-off-by: steven chen Reviewed-by: Stefan Berger Reviewed-by: Mimi Zohar --- security/integrity/ima/Kconfig | 10 ++++++++++ security/integrity/ima/ima_kexec.c | 16 ++++++++++------ 2 files changed, 20 insertions(+), 6 deletions(-) diff --git a/security/integrity/ima/Kconfig b/security/integrity/ima/Kconfig index 475c32615006..d73c96c3c1c9 100644 --- a/security/integrity/ima/Kconfig +++ b/security/integrity/ima/Kconfig @@ -321,4 +321,14 @@ config IMA_DISABLE_HTABLE help This option disables htable to allow measurement of duplicate records. +config IMA_KEXEC_EXTRA_MEMORY_KB + int "Extra memory for IMA measurements added during kexec soft reboot" + depends on IMA_KEXEC + default 0 + help + IMA_KEXEC_EXTRA_MEMORY_KB determines the extra memory to be + allocated (in kb) for IMA measurements added during kexec soft reboot. + If set to the default value of 0, an extra half page of memory for those + additional measurements will be allocated. + endif diff --git a/security/integrity/ima/ima_kexec.c b/security/integrity/ima/ima_kexec.c index dd49658153ca..9fb1bf5a592a 100644 --- a/security/integrity/ima/ima_kexec.c +++ b/security/integrity/ima/ima_kexec.c @@ -133,22 +133,26 @@ void ima_add_kexec_buffer(struct kimage *image) .buf_min = 0, .buf_max = ULONG_MAX, .top_down = true }; unsigned long binary_runtime_size; - + unsigned long extra_memory; /* use more understandable variable names than defined in kbuf */ void *kexec_buffer = NULL; size_t kexec_buffer_size = 0; int ret; /* - * Reserve an extra half page of memory for additional measurements - * added during the kexec load. + * Reserve extra memory for measurements added during kexec. */ - binary_runtime_size = ima_get_binary_runtime_size(); + if (CONFIG_IMA_KEXEC_EXTRA_MEMORY_KB <= 0) + extra_memory = PAGE_SIZE / 2; + else + extra_memory = CONFIG_IMA_KEXEC_EXTRA_MEMORY_KB * 1024; + binary_runtime_size = ima_get_binary_runtime_size() + extra_memory; + if (binary_runtime_size >= ULONG_MAX - PAGE_SIZE) kexec_segment_size = ULONG_MAX; else - kexec_segment_size = ALIGN(ima_get_binary_runtime_size() + - PAGE_SIZE / 2, PAGE_SIZE); + kexec_segment_size = ALIGN(binary_runtime_size, PAGE_SIZE); + if ((kexec_segment_size == ULONG_MAX) || ((kexec_segment_size >> PAGE_SHIFT) > totalram_pages() / 2)) { pr_err("Binary measurement list too large.\n"); From patchwork Tue Mar 4 19:03:51 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: steven chen X-Patchwork-Id: 14001299 Received: from linux.microsoft.com (linux.microsoft.com [13.77.154.182]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 7BCC225BAC9; Tue, 4 Mar 2025 19:04:06 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=13.77.154.182 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741115048; cv=none; b=WpvpwzYbSse9QFbGb5uZCaWBSwOqB9IhXCCWtdbtS1u9ACmTN1IKn2pHXPiaXcxzjzTW4PXZG/s5irasl0th5NYpgynUxd+X+01OPZVjCmmS7QrztIBZUq8B0RkeX9KHMrNECRRmwwtr8noMEslRbuHRnP8n+KbZLT2ZOrWMcig= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741115048; c=relaxed/simple; bh=ld5Rzt7U3U9kNdPpbYABrBhw8UfYLCmfCpfAmqEgxjw=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=gzRhoKufIcpeoAz4W3nlX+3qJlfwuEFZgd2GnnduVjkyLte1nzBU+EDoRmH0sqfHMy7efOidZgVaSdXJnXF7EtYAKuA6YEcXmTUA1b5mZfNSgVIZ9O+6TtEgViWMVvmN4DAwaZUgzvg9Gacd1lUtgy8Nqv1/48Fh/7kFDfAqre0= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.microsoft.com; spf=pass smtp.mailfrom=linux.microsoft.com; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b=T7HQWhU3; arc=none smtp.client-ip=13.77.154.182 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.microsoft.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.microsoft.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b="T7HQWhU3" Received: from localhost.localdomain (unknown [167.220.59.4]) by linux.microsoft.com (Postfix) with ESMTPSA id EE7E9210EAFB; Tue, 4 Mar 2025 11:03:58 -0800 (PST) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com EE7E9210EAFB DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1741115039; bh=7bpzaKJMyV3E8E00HZMPQxpAdeDwOCI+jQV79Yt99/0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=T7HQWhU3oXeIve/XuPEpI9rVt6c4VCA0J5gVMNjF5zkIri2rqUHhNsOqrqPZ6qke+ z5Dagl0YGKTiyXy0EG3B/B7uYI7v1nsQgcgnI5LQSi4TcSWbjqbdlYJChjdzXpNZg7 UD1WWd3Rit7W/1KNg6nq0FoV0buVSnfiH0koAUFw= From: steven chen To: zohar@linux.ibm.com, stefanb@linux.ibm.com, roberto.sassu@huaweicloud.com, roberto.sassu@huawei.com, eric.snowberg@oracle.com, ebiederm@xmission.com, paul@paul-moore.com, code@tyhicks.com, bauermann@kolabnow.com, linux-integrity@vger.kernel.org, kexec@lists.infradead.org, linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org Cc: madvenka@linux.microsoft.com, nramas@linux.microsoft.com, James.Bottomley@HansenPartnership.com, bhe@redhat.com, vgoyal@redhat.com, dyoung@redhat.com Subject: [PATCH v9 7/7] ima: measure kexec load and exec events as critical data Date: Tue, 4 Mar 2025 11:03:51 -0800 Message-Id: <20250304190351.96975-8-chenste@linux.microsoft.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20250304190351.96975-1-chenste@linux.microsoft.com> References: <20250304190351.96975-1-chenste@linux.microsoft.com> Precedence: bulk X-Mailing-List: linux-security-module@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 The amount of memory allocated at kexec load, even with the extra memory allocated, might not be large enough for the entire measurement list. The indeterminate interval between kexec 'load' and 'execute' could exacerbate this problem. Define two new IMA events, 'kexec_load' and 'kexec_execute', to be measured as critical data at kexec 'load' and 'execute' respectively. Report the allocated kexec segment size, IMA binary log size and the runtime measurements count as part of those events. These events, and the values reported through them, serve as markers in the IMA log to verify the IMA events are captured during kexec soft reboot. The presence of a 'kexec_load' event in between the last two 'boot_aggregate' events in the IMA log implies this is a kexec soft reboot, and not a cold-boot. And the absence of 'kexec_execute' event after kexec soft reboot implies missing events in that window which results in inconsistency with TPM PCR quotes, necessitating a cold boot for a successful remote attestation. These critical data events are displayed as hex encoded ascii in the ascii_runtime_measurement_list. Verifying the critical data hash requires calculating the hash of the decoded ascii string. For example, to verify the 'kexec_load' data hash: sudo cat /sys/kernel/security/integrity/ima/ascii_runtime_measurements | grep kexec_load | cut -d' ' -f 6 | xxd -r -p | sha256sum To verify the 'kexec_execute' data hash: sudo cat /sys/kernel/security/integrity/ima/ascii_runtime_measurements | grep kexec_execute | cut -d' ' -f 6 | xxd -r -p | sha256sum Signed-off-by: Tushar Sugandhi Signed-off-by: steven chen Reviewed-by: Stefan Berger --- security/integrity/ima/ima.h | 6 ++++++ security/integrity/ima/ima_kexec.c | 20 ++++++++++++++++++++ security/integrity/ima/ima_queue.c | 5 +++++ 3 files changed, 31 insertions(+) diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h index 4428fcf42167..1452c98242a4 100644 --- a/security/integrity/ima/ima.h +++ b/security/integrity/ima/ima.h @@ -240,6 +240,12 @@ void ima_post_key_create_or_update(struct key *keyring, struct key *key, unsigned long flags, bool create); #endif +#ifdef CONFIG_IMA_KEXEC +void ima_measure_kexec_event(const char *event_name); +#else +static inline void ima_measure_kexec_event(const char *event_name) {} +#endif + /* * The default binary_runtime_measurements list format is defined as the * platform native format. The canonical format is defined as little-endian. diff --git a/security/integrity/ima/ima_kexec.c b/security/integrity/ima/ima_kexec.c index 9fb1bf5a592a..e40c6da4504c 100644 --- a/security/integrity/ima/ima_kexec.c +++ b/security/integrity/ima/ima_kexec.c @@ -17,6 +17,8 @@ #include "ima.h" #ifdef CONFIG_IMA_KEXEC +#define IMA_KEXEC_EVENT_LEN 256 + static struct seq_file ima_kexec_file; static void *ima_kexec_buffer; static size_t kexec_segment_size; @@ -36,6 +38,23 @@ static void ima_free_kexec_file_buf(struct seq_file *sf) ima_reset_kexec_file(sf); } +void ima_measure_kexec_event(const char *event_name) +{ + char ima_kexec_event[IMA_KEXEC_EVENT_LEN]; + size_t buf_size = 0; + long len; + + buf_size = ima_get_binary_runtime_size(); + len = atomic_long_read(&ima_htable.len); + + int n = scnprintf(ima_kexec_event, IMA_KEXEC_EVENT_LEN, + "kexec_segment_size=%lu;ima_binary_runtime_size=%lu;" + "ima_runtime_measurements_count=%ld;", + kexec_segment_size, buf_size, len); + + ima_measure_critical_data("ima_kexec", event_name, ima_kexec_event, n, false, NULL, 0); +} + static int ima_alloc_kexec_file_buf(size_t segment_size) { /* @@ -58,6 +77,7 @@ static int ima_alloc_kexec_file_buf(size_t segment_size) out: ima_kexec_file.read_pos = 0; ima_kexec_file.count = sizeof(struct ima_kexec_hdr); /* reserved space */ + ima_measure_kexec_event("kexec_load"); return 0; } diff --git a/security/integrity/ima/ima_queue.c b/security/integrity/ima/ima_queue.c index 3dfd178d4292..6afb46989cf6 100644 --- a/security/integrity/ima/ima_queue.c +++ b/security/integrity/ima/ima_queue.c @@ -241,6 +241,11 @@ static int ima_reboot_notifier(struct notifier_block *nb, unsigned long action, void *data) { +#ifdef CONFIG_IMA_KEXEC + if (action == SYS_RESTART && data && !strcmp(data, "kexec reboot")) + ima_measure_kexec_event("kexec_execute"); +#endif + ima_measurements_suspend(); return NOTIFY_DONE;