diff options
Diffstat (limited to 'security/integrity')
| -rw-r--r-- | security/integrity/evm/evm_crypto.c | 2 | ||||
| -rw-r--r-- | security/integrity/evm/evm_main.c | 2 | ||||
| -rw-r--r-- | security/integrity/ima/Kconfig | 11 | ||||
| -rw-r--r-- | security/integrity/ima/ima.h | 12 | ||||
| -rw-r--r-- | security/integrity/ima/ima_kexec.c | 196 | ||||
| -rw-r--r-- | security/integrity/ima/ima_main.c | 35 | ||||
| -rw-r--r-- | security/integrity/ima/ima_queue.c | 5 |
7 files changed, 216 insertions, 47 deletions
diff --git a/security/integrity/evm/evm_crypto.c b/security/integrity/evm/evm_crypto.c index 7c06ffd633d2..a5e730ffda57 100644 --- a/security/integrity/evm/evm_crypto.c +++ b/security/integrity/evm/evm_crypto.c @@ -180,7 +180,7 @@ static void hmac_add_misc(struct shash_desc *desc, struct inode *inode, } /* - * Dump large security xattr values as a continuous ascii hexademical string. + * Dump large security xattr values as a continuous ascii hexadecimal string. * (pr_debug is limited to 64 bytes.) */ static void dump_security_xattr_l(const char *prefix, const void *src, diff --git a/security/integrity/evm/evm_main.c b/security/integrity/evm/evm_main.c index 377e57e9084f..0add782e73ba 100644 --- a/security/integrity/evm/evm_main.c +++ b/security/integrity/evm/evm_main.c @@ -169,7 +169,7 @@ static int is_unsupported_hmac_fs(struct dentry *dentry) * and compare it against the stored security.evm xattr. * * For performance: - * - use the previoulsy retrieved xattr value and length to calculate the + * - use the previously retrieved xattr value and length to calculate the * HMAC.) * - cache the verification result in the iint, when available. * diff --git a/security/integrity/ima/Kconfig b/security/integrity/ima/Kconfig index 475c32615006..976e75f9b9ba 100644 --- a/security/integrity/ima/Kconfig +++ b/security/integrity/ima/Kconfig @@ -321,4 +321,15 @@ 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" + range 0 40 + 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.h b/security/integrity/ima/ima.h index 24d09ea91b87..e3d71d8d56e3 100644 --- a/security/integrity/ima/ima.h +++ b/security/integrity/ima/ima.h @@ -149,6 +149,9 @@ struct ima_kexec_hdr { #define IMA_CHECK_BLACKLIST 0x40000000 #define IMA_VERITY_REQUIRED 0x80000000 +/* Exclude non-action flags which are not rule-specific. */ +#define IMA_NONACTION_RULE_FLAGS (IMA_NONACTION_FLAGS & ~IMA_NEW_FILE) + #define IMA_DO_MASK (IMA_MEASURE | IMA_APPRAISE | IMA_AUDIT | \ IMA_HASH | IMA_APPRAISE_SUBMASK) #define IMA_DONE_MASK (IMA_MEASURED | IMA_APPRAISED | IMA_AUDITED | \ @@ -178,7 +181,8 @@ struct ima_kexec_hdr { #define IMA_UPDATE_XATTR 1 #define IMA_CHANGE_ATTR 2 #define IMA_DIGSIG 3 -#define IMA_MUST_MEASURE 4 +#define IMA_MAY_EMIT_TOMTOU 4 +#define IMA_EMITTED_OPENWRITERS 5 /* IMA integrity metadata associated with an inode */ struct ima_iint_cache { @@ -240,6 +244,12 @@ 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 9d45f4d26f73..7362f68f2d8b 100644 --- a/security/integrity/ima/ima_kexec.c +++ b/security/integrity/ima/ima_kexec.c @@ -12,66 +12,118 @@ #include <linux/kexec.h> #include <linux/of.h> #include <linux/ima.h> +#include <linux/reboot.h> +#include <asm/page.h> #include "ima.h" #ifdef CONFIG_IMA_KEXEC +#define IMA_KEXEC_EVENT_LEN 256 + +static bool ima_kexec_update_registered; +static struct seq_file ima_kexec_file; +static size_t kexec_segment_size; +static void *ima_kexec_buffer; + +static void ima_free_kexec_file_buf(struct seq_file *sf) +{ + vfree(sf->buf); + sf->buf = NULL; + sf->size = 0; + sf->read_pos = 0; + sf->count = 0; +} + +void ima_measure_kexec_event(const char *event_name) +{ + char ima_kexec_event[IMA_KEXEC_EVENT_LEN]; + size_t buf_size = 0; + long len; + int n; + + buf_size = ima_get_binary_runtime_size(); + len = atomic_long_read(&ima_htable.len); + + 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) +{ + /* + * 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 */ + ima_measure_kexec_event("kexec_load"); + + return 0; +} + 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; + 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) { + if (ima_kexec_file.count < ima_kexec_file.size) { khdr.count++; - ima_measurements_show(&file, qe); + ima_measurements_show(&ima_kexec_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; + 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; -out: - if (ret == -EINVAL) - vfree(file.buf); + *buffer_size = ima_kexec_file.count; + *buffer = ima_kexec_file.buf; + return ret; } @@ -87,32 +139,39 @@ 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 */ + size_t kexec_buffer_size = 0; void *kexec_buffer = NULL; - size_t kexec_buffer_size; - size_t kexec_segment_size; int ret; + if (image->type == KEXEC_TYPE_CRASH) + return; + /* - * 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"); 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; } @@ -120,6 +179,7 @@ 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"); @@ -130,10 +190,80 @@ 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_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) +{ + size_t buf_size = 0; + int ret = NOTIFY_OK; + void *buf = NULL; + + 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; +} + +static struct notifier_block update_buffer_nb = { + .notifier_call = ima_update_kexec_buffer, + .priority = INT_MIN +}; + +/* + * 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 */ /* diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c index 9f9897a7c217..f99ab1a3b0f0 100644 --- a/security/integrity/ima/ima_main.c +++ b/security/integrity/ima/ima_main.c @@ -129,16 +129,22 @@ static void ima_rdwr_violation_check(struct file *file, if (atomic_read(&inode->i_readcount) && IS_IMA(inode)) { if (!iint) iint = ima_iint_find(inode); + /* IMA_MEASURE is set from reader side */ - if (iint && test_bit(IMA_MUST_MEASURE, - &iint->atomic_flags)) + if (iint && test_and_clear_bit(IMA_MAY_EMIT_TOMTOU, + &iint->atomic_flags)) send_tomtou = true; } } else { if (must_measure) - set_bit(IMA_MUST_MEASURE, &iint->atomic_flags); - if (inode_is_open_for_write(inode) && must_measure) - send_writers = true; + set_bit(IMA_MAY_EMIT_TOMTOU, &iint->atomic_flags); + + /* Limit number of open_writers violations */ + if (inode_is_open_for_write(inode) && must_measure) { + if (!test_and_set_bit(IMA_EMITTED_OPENWRITERS, + &iint->atomic_flags)) + send_writers = true; + } } if (!send_tomtou && !send_writers) @@ -167,6 +173,8 @@ static void ima_check_last_writer(struct ima_iint_cache *iint, if (atomic_read(&inode->i_writecount) == 1) { struct kstat stat; + clear_bit(IMA_EMITTED_OPENWRITERS, &iint->atomic_flags); + update = test_and_clear_bit(IMA_UPDATE_XATTR, &iint->atomic_flags); if ((iint->flags & IMA_NEW_FILE) || @@ -237,7 +245,9 @@ static int process_measurement(struct file *file, const struct cred *cred, &allowed_algos); violation_check = ((func == FILE_CHECK || func == MMAP_CHECK || func == MMAP_CHECK_REQPROT) && - (ima_policy_flag & IMA_MEASURE)); + (ima_policy_flag & IMA_MEASURE) && + ((action & IMA_MEASURE) || + (file->f_mode & FMODE_WRITE))); if (!action && !violation_check) return 0; @@ -269,10 +279,13 @@ static int process_measurement(struct file *file, const struct cred *cred, mutex_lock(&iint->mutex); if (test_and_clear_bit(IMA_CHANGE_ATTR, &iint->atomic_flags)) - /* reset appraisal flags if ima_inode_post_setattr was called */ + /* + * Reset appraisal flags (action and non-action rule-specific) + * if ima_inode_post_setattr was called. + */ iint->flags &= ~(IMA_APPRAISE | IMA_APPRAISED | IMA_APPRAISE_SUBMASK | IMA_APPRAISED_SUBMASK | - IMA_NONACTION_FLAGS); + IMA_NONACTION_RULE_FLAGS); /* * Re-evaulate the file if either the xattr has changed or the @@ -1011,9 +1024,9 @@ int process_buffer_measurement(struct mnt_idmap *idmap, } /* - * Both LSM hooks and auxilary based buffer measurements are - * based on policy. To avoid code duplication, differentiate - * between the LSM hooks and auxilary buffer measurements, + * Both LSM hooks and auxiliary based buffer measurements are + * based on policy. To avoid code duplication, differentiate + * between the LSM hooks and auxiliary buffer measurements, * retrieving the policy rule information only for the LSM hook * buffer measurements. */ diff --git a/security/integrity/ima/ima_queue.c b/security/integrity/ima/ima_queue.c index 83d53824aa98..590637e81ad1 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; |