diff options
| -rw-r--r-- | Documentation/ABI/testing/ima_policy | 16 | ||||
| -rw-r--r-- | include/linux/ima.h | 14 | ||||
| -rw-r--r-- | security/integrity/ima/Makefile | 1 | ||||
| -rw-r--r-- | security/integrity/ima/ima.h | 9 | ||||
| -rw-r--r-- | security/integrity/ima/ima_api.c | 8 | ||||
| -rw-r--r-- | security/integrity/ima/ima_appraise.c | 4 | ||||
| -rw-r--r-- | security/integrity/ima/ima_asymmetric_keys.c | 58 | ||||
| -rw-r--r-- | security/integrity/ima/ima_main.c | 12 | ||||
| -rw-r--r-- | security/integrity/ima/ima_policy.c | 95 | ||||
| -rw-r--r-- | security/keys/key.c | 10 |
10 files changed, 207 insertions, 20 deletions
diff --git a/Documentation/ABI/testing/ima_policy b/Documentation/ABI/testing/ima_policy index 29aaedf33246..cd572912c593 100644 --- a/Documentation/ABI/testing/ima_policy +++ b/Documentation/ABI/testing/ima_policy @@ -25,11 +25,11 @@ Description: lsm: [[subj_user=] [subj_role=] [subj_type=] [obj_user=] [obj_role=] [obj_type=]] option: [[appraise_type=]] [template=] [permit_directio] - [appraise_flag=] + [appraise_flag=] [keyrings=] base: func:= [BPRM_CHECK][MMAP_CHECK][CREDS_CHECK][FILE_CHECK][MODULE_CHECK] [FIRMWARE_CHECK] [KEXEC_KERNEL_CHECK] [KEXEC_INITRAMFS_CHECK] - [KEXEC_CMDLINE] + [KEXEC_CMDLINE] [KEY_CHECK] mask:= [[^]MAY_READ] [[^]MAY_WRITE] [[^]MAY_APPEND] [[^]MAY_EXEC] fsmagic:= hex value @@ -42,6 +42,9 @@ Description: appraise_flag:= [check_blacklist] Currently, blacklist check is only for files signed with appended signature. + keyrings:= list of keyrings + (eg, .builtin_trusted_keys|.ima). Only valid + when action is "measure" and func is KEY_CHECK. template:= name of a defined IMA template type (eg, ima-ng). Only valid when action is "measure". pcr:= decimal value @@ -113,3 +116,12 @@ Description: Example of appraise rule allowing modsig appended signatures: appraise func=KEXEC_KERNEL_CHECK appraise_type=imasig|modsig + + Example of measure rule using KEY_CHECK to measure all keys: + + measure func=KEY_CHECK + + Example of measure rule using KEY_CHECK to only measure + keys added to .builtin_trusted_keys or .ima keyring: + + measure func=KEY_CHECK keyrings=.builtin_trusted_keys|.ima diff --git a/include/linux/ima.h b/include/linux/ima.h index 6d904754d858..3b89136bc218 100644 --- a/include/linux/ima.h +++ b/include/linux/ima.h @@ -101,6 +101,20 @@ static inline void ima_add_kexec_buffer(struct kimage *image) {} #endif +#if defined(CONFIG_IMA) && defined(CONFIG_ASYMMETRIC_PUBLIC_KEY_SUBTYPE) +extern void ima_post_key_create_or_update(struct key *keyring, + struct key *key, + const void *payload, size_t plen, + unsigned long flags, bool create); +#else +static inline void ima_post_key_create_or_update(struct key *keyring, + struct key *key, + const void *payload, + size_t plen, + unsigned long flags, + bool create) {} +#endif /* CONFIG_IMA && CONFIG_ASYMMETRIC_PUBLIC_KEY_SUBTYPE */ + #ifdef CONFIG_IMA_APPRAISE extern bool is_ima_appraise_enabled(void); extern void ima_inode_post_setattr(struct dentry *dentry); diff --git a/security/integrity/ima/Makefile b/security/integrity/ima/Makefile index 31d57cdf2421..207a0a9eb72c 100644 --- a/security/integrity/ima/Makefile +++ b/security/integrity/ima/Makefile @@ -12,3 +12,4 @@ ima-$(CONFIG_IMA_APPRAISE) += ima_appraise.o ima-$(CONFIG_IMA_APPRAISE_MODSIG) += ima_modsig.o ima-$(CONFIG_HAVE_IMA_KEXEC) += ima_kexec.o obj-$(CONFIG_IMA_BLACKLIST_KEYRING) += ima_mok.o +obj-$(CONFIG_ASYMMETRIC_PUBLIC_KEY_SUBTYPE) += ima_asymmetric_keys.o diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h index df4ca482fb53..f06238e41a7c 100644 --- a/security/integrity/ima/ima.h +++ b/security/integrity/ima/ima.h @@ -193,6 +193,7 @@ static inline unsigned long ima_hash_key(u8 *digest) hook(KEXEC_INITRAMFS_CHECK) \ hook(POLICY_CHECK) \ hook(KEXEC_CMDLINE) \ + hook(KEY_CHECK) \ hook(MAX_CHECK) #define __ima_hook_enumify(ENUM) ENUM, @@ -207,7 +208,8 @@ struct modsig; /* LIM API function definitions */ int ima_get_action(struct inode *inode, const struct cred *cred, u32 secid, int mask, enum ima_hooks func, int *pcr, - struct ima_template_desc **template_desc); + struct ima_template_desc **template_desc, + const char *keyring); int ima_must_measure(struct inode *inode, int mask, enum ima_hooks func); int ima_collect_measurement(struct integrity_iint_cache *iint, struct file *file, void *buf, loff_t size, @@ -219,7 +221,7 @@ void ima_store_measurement(struct integrity_iint_cache *iint, struct file *file, struct ima_template_desc *template_desc); void process_buffer_measurement(const void *buf, int size, const char *eventname, enum ima_hooks func, - int pcr); + int pcr, const char *keyring); void ima_audit_measurement(struct integrity_iint_cache *iint, const unsigned char *filename); int ima_alloc_init_template(struct ima_event_data *event_data, @@ -234,7 +236,8 @@ const char *ima_d_path(const struct path *path, char **pathbuf, char *filename); /* IMA policy related functions */ int ima_match_policy(struct inode *inode, const struct cred *cred, u32 secid, enum ima_hooks func, int mask, int flags, int *pcr, - struct ima_template_desc **template_desc); + struct ima_template_desc **template_desc, + const char *keyring); void ima_init_policy(void); void ima_update_policy(void); void ima_update_policy_flag(void); diff --git a/security/integrity/ima/ima_api.c b/security/integrity/ima/ima_api.c index 610759fe63b8..f6bc00914aa5 100644 --- a/security/integrity/ima/ima_api.c +++ b/security/integrity/ima/ima_api.c @@ -169,12 +169,13 @@ err_out: * @func: caller identifier * @pcr: pointer filled in if matched measure policy sets pcr= * @template_desc: pointer filled in if matched measure policy sets template= + * @keyring: keyring name used to determine the action * * The policy is defined in terms of keypairs: * subj=, obj=, type=, func=, mask=, fsmagic= * subj,obj, and type: are LSM specific. * func: FILE_CHECK | BPRM_CHECK | CREDS_CHECK | MMAP_CHECK | MODULE_CHECK - * | KEXEC_CMDLINE + * | KEXEC_CMDLINE | KEY_CHECK * mask: contains the permission mask * fsmagic: hex value * @@ -183,14 +184,15 @@ err_out: */ int ima_get_action(struct inode *inode, const struct cred *cred, u32 secid, int mask, enum ima_hooks func, int *pcr, - struct ima_template_desc **template_desc) + struct ima_template_desc **template_desc, + const char *keyring) { int flags = IMA_MEASURE | IMA_AUDIT | IMA_APPRAISE | IMA_HASH; flags &= ima_policy_flag; return ima_match_policy(inode, cred, secid, func, mask, flags, pcr, - template_desc); + template_desc, keyring); } /* diff --git a/security/integrity/ima/ima_appraise.c b/security/integrity/ima/ima_appraise.c index 300c8d2943c5..a9649b04b9f1 100644 --- a/security/integrity/ima/ima_appraise.c +++ b/security/integrity/ima/ima_appraise.c @@ -55,7 +55,7 @@ int ima_must_appraise(struct inode *inode, int mask, enum ima_hooks func) security_task_getsecid(current, &secid); return ima_match_policy(inode, current_cred(), secid, func, mask, - IMA_APPRAISE | IMA_HASH, NULL, NULL); + IMA_APPRAISE | IMA_HASH, NULL, NULL, NULL); } static int ima_fix_xattr(struct dentry *dentry, @@ -330,7 +330,7 @@ int ima_check_blacklist(struct integrity_iint_cache *iint, if ((rc == -EPERM) && (iint->flags & IMA_MEASURE)) process_buffer_measurement(digest, digestsize, "blacklisted-hash", NONE, - pcr); + pcr, NULL); } return rc; diff --git a/security/integrity/ima/ima_asymmetric_keys.c b/security/integrity/ima/ima_asymmetric_keys.c new file mode 100644 index 000000000000..fea2e7dd3b09 --- /dev/null +++ b/security/integrity/ima/ima_asymmetric_keys.c @@ -0,0 +1,58 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * Copyright (C) 2019 Microsoft Corporation + * + * Author: Lakshmi Ramasubramanian (nramas@linux.microsoft.com) + * + * File: ima_asymmetric_keys.c + * Defines an IMA hook to measure asymmetric keys on key + * create or update. + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include <keys/asymmetric-type.h> +#include "ima.h" + +/** + * ima_post_key_create_or_update - measure asymmetric keys + * @keyring: keyring to which the key is linked to + * @key: created or updated key + * @payload: The data used to instantiate or update the key. + * @payload_len: The length of @payload. + * @flags: key flags + * @create: flag indicating whether the key was created or updated + * + * Keys can only be measured, not appraised. + * The payload data used to instantiate or update the key is measured. + */ +void ima_post_key_create_or_update(struct key *keyring, struct key *key, + const void *payload, size_t payload_len, + unsigned long flags, bool create) +{ + /* Only asymmetric keys are handled by this hook. */ + if (key->type != &key_type_asymmetric) + return; + + if (!payload || (payload_len == 0)) + return; + + /* + * keyring->description points to the name of the keyring + * (such as ".builtin_trusted_keys", ".ima", etc.) to + * which the given key is linked to. + * + * The name of the keyring is passed in the "eventname" + * parameter to process_buffer_measurement() and is set + * in the "eventname" field in ima_event_data for + * the key measurement IMA event. + * + * The name of the keyring is also passed in the "keyring" + * parameter to process_buffer_measurement() to check + * if the IMA policy is configured to measure a key linked + * to the given keyring. + */ + process_buffer_measurement(payload, payload_len, + keyring->description, KEY_CHECK, 0, + keyring->description); +} diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c index d7e987baf127..2272c3255c7d 100644 --- a/security/integrity/ima/ima_main.c +++ b/security/integrity/ima/ima_main.c @@ -215,7 +215,7 @@ static int process_measurement(struct file *file, const struct cred *cred, * Included is the appraise submask. */ action = ima_get_action(inode, cred, secid, mask, func, &pcr, - &template_desc); + &template_desc, NULL); violation_check = ((func == FILE_CHECK || func == MMAP_CHECK) && (ima_policy_flag & IMA_MEASURE)); if (!action && !violation_check) @@ -632,12 +632,13 @@ int ima_load_data(enum kernel_load_data_id id) * @eventname: event name to be used for the buffer entry. * @func: IMA hook * @pcr: pcr to extend the measurement + * @keyring: keyring name to determine the action to be performed * * Based on policy, the buffer is measured into the ima log. */ void process_buffer_measurement(const void *buf, int size, const char *eventname, enum ima_hooks func, - int pcr) + int pcr, const char *keyring) { int ret = 0; struct ima_template_entry *entry = NULL; @@ -655,6 +656,9 @@ void process_buffer_measurement(const void *buf, int size, int action = 0; u32 secid; + if (!ima_policy_flag) + return; + /* * Both LSM hooks and auxilary based buffer measurements are * based on policy. To avoid code duplication, differentiate @@ -665,7 +669,7 @@ void process_buffer_measurement(const void *buf, int size, if (func) { security_task_getsecid(current, &secid); action = ima_get_action(NULL, current_cred(), secid, 0, func, - &pcr, &template); + &pcr, &template, keyring); if (!(action & IMA_MEASURE)) return; } @@ -718,7 +722,7 @@ void ima_kexec_cmdline(const void *buf, int size) { if (buf && size != 0) process_buffer_measurement(buf, size, "kexec-cmdline", - KEXEC_CMDLINE, 0); + KEXEC_CMDLINE, 0, NULL); } static int __init init_ima(void) diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c index f19a895ad7cd..a4dde9d575b2 100644 --- a/security/integrity/ima/ima_policy.c +++ b/security/integrity/ima/ima_policy.c @@ -34,6 +34,7 @@ #define IMA_EUID 0x0080 #define IMA_PCR 0x0100 #define IMA_FSNAME 0x0200 +#define IMA_KEYRINGS 0x0400 #define UNKNOWN 0 #define MEASURE 0x0001 /* same as IMA_MEASURE */ @@ -79,6 +80,7 @@ struct ima_rule_entry { int type; /* audit type */ } lsm[MAX_LSM_RULES]; char *fsname; + char *keyrings; /* Measure keys added to these keyrings */ struct ima_template_desc *template; }; @@ -357,6 +359,50 @@ int ima_lsm_policy_change(struct notifier_block *nb, unsigned long event, } /** + * ima_match_keyring - determine whether the keyring matches the measure rule + * @rule: a pointer to a rule + * @keyring: name of the keyring to match against the measure rule + * @cred: a pointer to a credentials structure for user validation + * + * Returns true if keyring matches one in the rule, false otherwise. + */ +static bool ima_match_keyring(struct ima_rule_entry *rule, + const char *keyring, const struct cred *cred) +{ + char *keyrings, *next_keyring, *keyrings_ptr; + bool matched = false; + + if ((rule->flags & IMA_UID) && !rule->uid_op(cred->uid, rule->uid)) + return false; + + if (!rule->keyrings) + return true; + + if (!keyring) + return false; + + keyrings = kstrdup(rule->keyrings, GFP_KERNEL); + if (!keyrings) + return false; + + /* + * "keyrings=" is specified in the policy in the format below: + * keyrings=.builtin_trusted_keys|.ima|.evm + */ + keyrings_ptr = keyrings; + while ((next_keyring = strsep(&keyrings_ptr, "|")) != NULL) { + if (!strcmp(next_keyring, keyring)) { + matched = true; + break; + } + } + + kfree(keyrings); + + return matched; +} + +/** * ima_match_rules - determine whether an inode matches the measure rule. * @rule: a pointer to a rule * @inode: a pointer to an inode @@ -364,18 +410,23 @@ int ima_lsm_policy_change(struct notifier_block *nb, unsigned long event, * @secid: the secid of the task to be validated * @func: LIM hook identifier * @mask: requested action (MAY_READ | MAY_WRITE | MAY_APPEND | MAY_EXEC) + * @keyring: keyring name to check in policy for KEY_CHECK func * * Returns true on rule match, false on failure. */ static bool ima_match_rules(struct ima_rule_entry *rule, struct inode *inode, const struct cred *cred, u32 secid, - enum ima_hooks func, int mask) + enum ima_hooks func, int mask, + const char *keyring) { int i; - if (func == KEXEC_CMDLINE) { - if ((rule->flags & IMA_FUNC) && (rule->func == func)) + if ((func == KEXEC_CMDLINE) || (func == KEY_CHECK)) { + if ((rule->flags & IMA_FUNC) && (rule->func == func)) { + if (func == KEY_CHECK) + return ima_match_keyring(rule, keyring, cred); return true; + } return false; } if ((rule->flags & IMA_FUNC) && @@ -479,6 +530,8 @@ static int get_subaction(struct ima_rule_entry *rule, enum ima_hooks func) * @mask: requested action (MAY_READ | MAY_WRITE | MAY_APPEND | MAY_EXEC) * @pcr: set the pcr to extend * @template_desc: the template that should be used for this rule + * @keyring: the keyring name, if given, to be used to check in the policy. + * keyring can be NULL if func is anything other than KEY_CHECK. * * Measure decision based on func/mask/fsmagic and LSM(subj/obj/type) * conditions. @@ -489,7 +542,8 @@ static int get_subaction(struct ima_rule_entry *rule, enum ima_hooks func) */ int ima_match_policy(struct inode *inode, const struct cred *cred, u32 secid, enum ima_hooks func, int mask, int flags, int *pcr, - struct ima_template_desc **template_desc) + struct ima_template_desc **template_desc, + const char *keyring) { struct ima_rule_entry *entry; int action = 0, actmask = flags | (flags << 1); @@ -503,7 +557,8 @@ int ima_match_policy(struct inode *inode, const struct cred *cred, u32 secid, if (!(entry->action & actmask)) continue; - if (!ima_match_rules(entry, inode, cred, secid, func, mask)) + if (!ima_match_rules(entry, inode, cred, secid, func, mask, + keyring)) continue; action |= entry->flags & IMA_ACTION_FLAGS; @@ -766,7 +821,8 @@ enum { Opt_uid_gt, Opt_euid_gt, Opt_fowner_gt, Opt_uid_lt, Opt_euid_lt, Opt_fowner_lt, Opt_appraise_type, Opt_appraise_flag, - Opt_permit_directio, Opt_pcr, Opt_template, Opt_err + Opt_permit_directio, Opt_pcr, Opt_template, Opt_keyrings, + Opt_err }; static const match_table_t policy_tokens = { @@ -802,6 +858,7 @@ static const match_table_t policy_tokens = { {Opt_permit_directio, "permit_directio"}, {Opt_pcr, "pcr=%s"}, {Opt_template, "template=%s"}, + {Opt_keyrings, "keyrings=%s"}, {Opt_err, NULL} }; @@ -997,6 +1054,8 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry) entry->func = POLICY_CHECK; else if (strcmp(args[0].from, "KEXEC_CMDLINE") == 0) entry->func = KEXEC_CMDLINE; + else if (strcmp(args[0].from, "KEY_CHECK") == 0) + entry->func = KEY_CHECK; else result = -EINVAL; if (!result) @@ -1049,6 +1108,23 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry) result = 0; entry->flags |= IMA_FSNAME; break; + case Opt_keyrings: + ima_log_string(ab, "keyrings", args[0].from); + + if ((entry->keyrings) || + (entry->action != MEASURE) || + (entry->func != KEY_CHECK)) { + result = -EINVAL; + break; + } + entry->keyrings = kstrdup(args[0].from, GFP_KERNEL); + if (!entry->keyrings) { + result = -ENOMEM; + break; + } + result = 0; + entry->flags |= IMA_KEYRINGS; + break; case Opt_fsuuid: ima_log_string(ab, "fsuuid", args[0].from); @@ -1424,6 +1500,13 @@ int ima_policy_show(struct seq_file *m, void *v) seq_puts(m, " "); } + if (entry->flags & IMA_KEYRINGS) { + if (entry->keyrings != NULL) + snprintf(tbuf, sizeof(tbuf), "%s", entry->keyrings); + seq_printf(m, pt(Opt_keyrings), tbuf); + seq_puts(m, " "); + } + if (entry->flags & IMA_PCR) { snprintf(tbuf, sizeof(tbuf), "%d", entry->pcr); seq_printf(m, pt(Opt_pcr), tbuf); diff --git a/security/keys/key.c b/security/keys/key.c index 764f4c57913e..718bf7217420 100644 --- a/security/keys/key.c +++ b/security/keys/key.c @@ -13,6 +13,7 @@ #include <linux/security.h> #include <linux/workqueue.h> #include <linux/random.h> +#include <linux/ima.h> #include <linux/err.h> #include "internal.h" @@ -936,6 +937,9 @@ key_ref_t key_create_or_update(key_ref_t keyring_ref, goto error_link_end; } + ima_post_key_create_or_update(keyring, key, payload, plen, + flags, true); + key_ref = make_key_ref(key, is_key_possessed(keyring_ref)); error_link_end: @@ -965,6 +969,12 @@ error: } key_ref = __key_update(key_ref, &prep); + + if (!IS_ERR(key_ref)) + ima_post_key_create_or_update(keyring, key, + payload, plen, + flags, false); + goto error_free_prep; } EXPORT_SYMBOL(key_create_or_update); |