diff options
Diffstat (limited to 'security/integrity/ima/ima_kexec.c')
| -rw-r--r-- | security/integrity/ima/ima_kexec.c | 117 |
1 files changed, 117 insertions, 0 deletions
diff --git a/security/integrity/ima/ima_kexec.c b/security/integrity/ima/ima_kexec.c index 36afd0fe9747..2c4824ac1ce1 100644 --- a/security/integrity/ima/ima_kexec.c +++ b/security/integrity/ima/ima_kexec.c @@ -10,8 +10,125 @@ * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. */ +#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 = { + .version = 1, .buffer_size = 0, .count = 0}; + 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 */ + + 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; + 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"); + 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; + } + + 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. */ |