diff --git a/include/linux/ima.h b/include/linux/ima.h index 0eb7c2e7f0d633..96528d00713998 100644 --- a/include/linux/ima.h +++ b/include/linux/ima.h @@ -11,6 +11,7 @@ #define _LINUX_IMA_H #include +#include struct linux_binprm; #ifdef CONFIG_IMA @@ -23,6 +24,10 @@ extern int ima_post_read_file(struct file *file, void *buf, loff_t size, enum kernel_read_file_id id); extern void ima_post_path_mknod(struct dentry *dentry); +#ifdef CONFIG_KEXEC_FILE +extern void ima_add_kexec_buffer(struct kimage *image); +#endif + #else static inline int ima_bprm_check(struct linux_binprm *bprm) { @@ -60,6 +65,12 @@ static inline void ima_post_path_mknod(struct dentry *dentry) return; } +#ifdef CONFIG_KEXEC_FILE +static inline void ima_add_kexec_buffer(struct kimage *image) +{ +} +#endif + #endif /* CONFIG_IMA */ #ifdef CONFIG_IMA_APPRAISE diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c index 0e90d1446cb0a8..75c1b8d67a728d 100644 --- a/kernel/kexec_file.c +++ b/kernel/kexec_file.c @@ -19,6 +19,7 @@ #include #include #include +#include #include #include #include @@ -248,6 +249,9 @@ kimage_file_prepare_segments(struct kimage *image, int kernel_fd, int initrd_fd, } } + /* IMA needs to pass the measurement list to the next kernel. */ + ima_add_kexec_buffer(image); + /* Call arch image load handlers */ ldata = arch_kexec_kernel_image_load(image); diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h index db25f54a04fe5b..0334001055d742 100644 --- a/security/integrity/ima/ima.h +++ b/security/integrity/ima/ima.h @@ -102,6 +102,11 @@ struct ima_queue_entry { }; extern struct list_head ima_measurements; /* list of all measurements */ +#ifdef CONFIG_KEXEC_FILE +extern void *kexec_buffer; +extern size_t kexec_buffer_size; +#endif + /* Internal IMA function definitions */ int ima_init(void); int ima_fs_init(void); diff --git a/security/integrity/ima/ima_init.c b/security/integrity/ima/ima_init.c index 32912bd54eadda..a1924d0f3b2b3c 100644 --- a/security/integrity/ima/ima_init.c +++ b/security/integrity/ima/ima_init.c @@ -21,6 +21,7 @@ #include #include #include +#include #include "ima.h" @@ -104,6 +105,29 @@ void __init ima_load_x509(void) } #endif +#ifdef CONFIG_KEXEC_FILE +static void ima_load_kexec_buffer(void) +{ + int rc; + + /* Fetch the buffer from the previous kernel, if any. */ + rc = kexec_get_handover_buffer(&kexec_buffer, &kexec_buffer_size); + if (rc == 0) { + /* Demonstrate that buffer handover works. */ + pr_err("kexec buffer contents: %s\n", (char *) kexec_buffer); + pr_err("kexec buffer contents after update: %s\n", + (char *) kexec_buffer + 4 * PAGE_SIZE + 10); + + kexec_free_handover_buffer(); + } else if (rc == -ENOENT) + pr_debug("No kexec buffer from the previous kernel.\n"); + else + pr_debug("Error restoring kexec buffer: %d\n", rc); +} +#else +static void ima_load_kexec_buffer(void) { } +#endif + int __init ima_init(void) { u8 pcr_i[TPM_DIGEST_SIZE]; @@ -134,5 +158,7 @@ int __init ima_init(void) ima_init_policy(); + ima_load_kexec_buffer(); + return ima_fs_init(); } diff --git a/security/integrity/ima/ima_template.c b/security/integrity/ima/ima_template.c index febd12ed9b55ab..6dd3f902567d71 100644 --- a/security/integrity/ima/ima_template.c +++ b/security/integrity/ima/ima_template.c @@ -15,6 +15,8 @@ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt +#include +#include #include "ima.h" #include "ima_template_lib.h" @@ -182,6 +184,89 @@ static int template_desc_init_fields(const char *template_fmt, return 0; } +#ifdef CONFIG_KEXEC_FILE +void *kexec_buffer = NULL; +size_t kexec_buffer_size = 0; + +/* Physical address of the measurement buffer in the next kernel. */ +unsigned long kexec_buffer_load_addr = 0; + +/* + * Called during reboot. IMA can add here new events that were generated after + * the kexec image was loaded. + */ +static int ima_update_kexec_buffer(struct notifier_block *self, + unsigned long action, void *data) +{ + int ret; + + if (!kexec_in_progress) + return NOTIFY_OK; + + /* + * Add content deep in the buffer to show that we can update + * all of it. + */ + strcpy(kexec_buffer + 4 * PAGE_SIZE + 10, + "Updated kexec buffer contents."); + + ret = kexec_update_segment(kexec_buffer, kexec_buffer_size, + kexec_buffer_load_addr, kexec_buffer_size); + if (ret) + pr_err("Error updating kexec buffer: %d\n", ret); + + return NOTIFY_OK; +} + +struct notifier_block update_buffer_nb = { + .notifier_call = ima_update_kexec_buffer, +}; + +/* + * Called during kexec_file_load so that IMA can add a segment to the kexec + * image with the measurement event log for the next kernel. + */ +void ima_add_kexec_buffer(struct kimage *image) +{ + /* Ask not to checksum the segment, we may have to update it later. */ + struct kexec_buf kbuf = { .image = image, .buf_align = PAGE_SIZE, + .buf_min = 0, .buf_max = ULONG_MAX, + .top_down = true, .skip_checksum = true }; + bool first_kexec_load = kexec_buffer_load_addr == 0; + int ret; + + if (!kexec_can_hand_over_buffer()) + return; + + if (!first_kexec_load) + kfree(kexec_buffer); + + /* Create a relatively big buffer, for testing. */ + kexec_buffer_size = kbuf.bufsz = kbuf.memsz = 5 * PAGE_SIZE; + kexec_buffer = kbuf.buffer = kzalloc(kexec_buffer_size, GFP_KERNEL); + if (!kexec_buffer) { + pr_err("Not enough memory for the kexec measurement buffer.\n"); + return; + } + + /* Add some content for demonstration purposes. */ + strcpy(kexec_buffer, "Buffer contents at kexec load time."); + + ret = kexec_add_handover_buffer(&kbuf); + if (ret) { + pr_err("Error passing over kexec measurement buffer.\n"); + return; + } + kexec_buffer_load_addr = kbuf.mem; + + if (first_kexec_load) + register_reboot_notifier(&update_buffer_nb); + + pr_debug("kexec measurement buffer for the loaded kernel at 0x%lx.\n", + kexec_buffer_load_addr); +} +#endif /* CONFIG_KEXEC_FILE */ + struct ima_template_desc *ima_template_desc_current(void) { if (!ima_template)