Adding upstream version 4.19.249.upstream/4.19.249upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 173 insertions, 0 deletions

diff --git a/security/integrity/ima/ima_kexec.c b/security/integrity/ima/ima_kexec.c
new file mode 100644
index 000000000..6a10d4d8b
--- /dev/null
+++ b/security/integrity/ima/ima_kexec.c
@@ -0,0 +1,173 @@
+/*
+ * Copyright (C) 2016 IBM Corporation
+ *
+ * Authors:
+ * Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>
+ * Mimi Zohar <zohar@linux.vnet.ibm.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/seq_file.h>
+#include <linux/vmalloc.h>
+#include <linux/kexec.h>
+#include "ima.h"
+
+#ifdef CONFIG_IMA_KEXEC
+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;
+
+	/* segment size can't change between kexec load and execute */
+	file.buf = vmalloc(segment_size);
+	if (!file.buf) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	file.size = segment_size;
+	file.read_pos = 0;
+	file.count = sizeof(khdr);	/* reserved space */
+
+	memset(&khdr, 0, sizeof(khdr));
+	khdr.version = 1;
+	list_for_each_entry_rcu(qe, &ima_measurements, later) {
+		if (file.count < file.size) {
+			khdr.count++;
+			ima_measurements_show(&file, qe);
+		} else {
+			ret = -EINVAL;
+			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;
+	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));
+
+	print_hex_dump(KERN_DEBUG, "ima dump: ", DUMP_PREFIX_NONE,
+			16, 1, file.buf,
+			file.count < 100 ? file.count : 100, true);
+
+	*buffer_size = file.count;
+	*buffer = file.buf;
+out:
+	if (ret == -EINVAL)
+		vfree(file.buf);
+	return ret;
+}
+
+/*
+ * Called during kexec_file_load so that IMA can add a segment to the kexec
+ * image for the measurement list for the next kernel.
+ *
+ * This function assumes that kexec_mutex is held.
+ */
+void ima_add_kexec_buffer(struct kimage *image)
+{
+	struct kexec_buf kbuf = { .image = image, .buf_align = PAGE_SIZE,
+				  .buf_min = 0, .buf_max = ULONG_MAX,
+				  .top_down = true };
+	unsigned long binary_runtime_size;
+
+	/* use more understandable variable names than defined in kbuf */
+	void *kexec_buffer = NULL;
+	size_t kexec_buffer_size;
+	size_t kexec_segment_size;
+	int ret;
+
+	/*
+	 * Reserve an extra half page of memory for additional measurements
+	 * added during the kexec load.
+	 */
+	binary_runtime_size = ima_get_binary_runtime_size();
+	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);
+	if ((kexec_segment_size == ULONG_MAX) ||
+	    ((kexec_segment_size >> PAGE_SHIFT) > totalram_pages / 2)) {
+		pr_err("Binary measurement list too large.\n");
+		return;
+	}
+
+	ima_dump_measurement_list(&kexec_buffer_size, &kexec_buffer,
+				  kexec_segment_size);
+	if (!kexec_buffer) {
+		pr_err("Not enough memory for the kexec measurement buffer.\n");
+		return;
+	}
+
+	kbuf.buffer = kexec_buffer;
+	kbuf.bufsz = kexec_buffer_size;
+	kbuf.memsz = kexec_segment_size;
+	ret = kexec_add_buffer(&kbuf);
+	if (ret) {
+		pr_err("Error passing over kexec measurement buffer.\n");
+		vfree(kexec_buffer);
+		return;
+	}
+
+	ret = arch_ima_add_kexec_buffer(image, kbuf.mem, kexec_segment_size);
+	if (ret) {
+		pr_err("Error passing over kexec measurement buffer.\n");
+		return;
+	}
+
+	image->ima_buffer = kexec_buffer;
+
+	pr_debug("kexec measurement buffer for the loaded kernel at 0x%lx.\n",
+		 kbuf.mem);
+}
+#endif /* IMA_KEXEC */
+
+/*
+ * Restore the measurement list from the previous kernel.
+ */
+void ima_load_kexec_buffer(void)
+{
+	void *kexec_buffer = NULL;
+	size_t kexec_buffer_size = 0;
+	int rc;
+
+	rc = ima_get_kexec_buffer(&kexec_buffer, &kexec_buffer_size);
+	switch (rc) {
+	case 0:
+		rc = ima_restore_measurement_list(kexec_buffer_size,
+						  kexec_buffer);
+		if (rc != 0)
+			pr_err("Failed to restore the measurement list: %d\n",
+				rc);
+
+		ima_free_kexec_buffer();
+		break;
+	case -ENOTSUPP:
+		pr_debug("Restoring the measurement list not supported\n");
+		break;
+	case -ENOENT:
+		pr_debug("No measurement list to restore\n");
+		break;
+	default:
+		pr_debug("Error restoring the measurement list: %d\n", rc);
+	}
+}