diff options
| -rw-r--r-- | Documentation/ABI/testing/ima_policy | 6 | ||||
| -rw-r--r-- | security/integrity/ima/ima_policy.c | 74 |
2 files changed, 75 insertions, 5 deletions
diff --git a/Documentation/ABI/testing/ima_policy b/Documentation/ABI/testing/ima_policy index 070779e8d836..b0e3d278e799 100644 --- a/Documentation/ABI/testing/ima_policy +++ b/Documentation/ABI/testing/ima_policy @@ -27,7 +27,7 @@ Description: lsm: [[subj_user=] [subj_role=] [subj_type=] [obj_user=] [obj_role=] [obj_type=]] option: [[appraise_type=]] [template=] [permit_directio] - [appraise_flag=] [keyrings=] + [appraise_flag=] [appraise_algos=] [keyrings=] base: func:= [BPRM_CHECK][MMAP_CHECK][CREDS_CHECK][FILE_CHECK][MODULE_CHECK] [FIRMWARE_CHECK] @@ -55,6 +55,10 @@ Description: label:= [selinux]|[kernel_info]|[data_label] data_label:= a unique string used for grouping and limiting critical data. For example, "selinux" to measure critical data for SELinux. + appraise_algos:= comma-separated list of hash algorithms + For example, "sha256,sha512" to only accept to appraise + files where the security.ima xattr was hashed with one + of these two algorithms. default policy: # PROC_SUPER_MAGIC diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c index 1536e6f5eb22..cb86da0e562b 100644 --- a/security/integrity/ima/ima_policy.c +++ b/security/integrity/ima/ima_policy.c @@ -960,7 +960,7 @@ enum { Opt_fsuuid, Opt_uid_eq, Opt_euid_eq, Opt_fowner_eq, 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_appraise_type, Opt_appraise_flag, Opt_appraise_algos, Opt_permit_directio, Opt_pcr, Opt_template, Opt_keyrings, Opt_label, Opt_err }; @@ -995,6 +995,7 @@ static const match_table_t policy_tokens = { {Opt_fowner_lt, "fowner<%s"}, {Opt_appraise_type, "appraise_type=%s"}, {Opt_appraise_flag, "appraise_flag=%s"}, + {Opt_appraise_algos, "appraise_algos=%s"}, {Opt_permit_directio, "permit_directio"}, {Opt_pcr, "pcr=%s"}, {Opt_template, "template=%s"}, @@ -1095,7 +1096,8 @@ static bool ima_validate_rule(struct ima_rule_entry *entry) return false; if (entry->action != APPRAISE && - entry->flags & (IMA_DIGSIG_REQUIRED | IMA_MODSIG_ALLOWED | IMA_CHECK_BLACKLIST)) + entry->flags & (IMA_DIGSIG_REQUIRED | IMA_MODSIG_ALLOWED | + IMA_CHECK_BLACKLIST | IMA_VALIDATE_ALGOS)) return false; /* @@ -1125,7 +1127,7 @@ static bool ima_validate_rule(struct ima_rule_entry *entry) IMA_UID | IMA_FOWNER | IMA_FSUUID | IMA_INMASK | IMA_EUID | IMA_PCR | IMA_FSNAME | IMA_DIGSIG_REQUIRED | - IMA_PERMIT_DIRECTIO)) + IMA_PERMIT_DIRECTIO | IMA_VALIDATE_ALGOS)) return false; break; @@ -1137,7 +1139,7 @@ static bool ima_validate_rule(struct ima_rule_entry *entry) IMA_INMASK | IMA_EUID | IMA_PCR | IMA_FSNAME | IMA_DIGSIG_REQUIRED | IMA_PERMIT_DIRECTIO | IMA_MODSIG_ALLOWED | - IMA_CHECK_BLACKLIST)) + IMA_CHECK_BLACKLIST | IMA_VALIDATE_ALGOS)) return false; break; @@ -1187,6 +1189,28 @@ static bool ima_validate_rule(struct ima_rule_entry *entry) return true; } +static unsigned int ima_parse_appraise_algos(char *arg) +{ + unsigned int res = 0; + int idx; + char *token; + + while ((token = strsep(&arg, ",")) != NULL) { + idx = match_string(hash_algo_name, HASH_ALGO__LAST, token); + + if (idx < 0) { + pr_err("unknown hash algorithm \"%s\"", + token); + return 0; + } + + /* Add the hash algorithm to the 'allowed' bitfield */ + res |= (1U << idx); + } + + return res; +} + static int ima_parse_rule(char *rule, struct ima_rule_entry *entry) { struct audit_buffer *ab; @@ -1522,6 +1546,25 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry) else result = -EINVAL; break; + case Opt_appraise_algos: + ima_log_string(ab, "appraise_algos", args[0].from); + + if (entry->allowed_algos) { + result = -EINVAL; + break; + } + + entry->allowed_algos = + ima_parse_appraise_algos(args[0].from); + /* invalid or empty list of algorithms */ + if (!entry->allowed_algos) { + result = -EINVAL; + break; + } + + entry->flags |= IMA_VALIDATE_ALGOS; + + break; case Opt_permit_directio: entry->flags |= IMA_PERMIT_DIRECTIO; break; @@ -1714,6 +1757,23 @@ static void ima_show_rule_opt_list(struct seq_file *m, seq_printf(m, "%s%s", i ? "|" : "", opt_list->items[i]); } +static void ima_policy_show_appraise_algos(struct seq_file *m, + unsigned int allowed_hashes) +{ + int idx, list_size = 0; + + for (idx = 0; idx < HASH_ALGO__LAST; idx++) { + if (!(allowed_hashes & (1U << idx))) + continue; + + /* only add commas if the list contains multiple entries */ + if (list_size++) + seq_puts(m, ","); + + seq_puts(m, hash_algo_name[idx]); + } +} + int ima_policy_show(struct seq_file *m, void *v) { struct ima_rule_entry *entry = v; @@ -1825,6 +1885,12 @@ int ima_policy_show(struct seq_file *m, void *v) seq_puts(m, " "); } + if (entry->flags & IMA_VALIDATE_ALGOS) { + seq_puts(m, "appraise_algos="); + ima_policy_show_appraise_algos(m, entry->allowed_algos); + seq_puts(m, " "); + } + for (i = 0; i < MAX_LSM_RULES; i++) { if (entry->lsm[i].rule) { switch (i) { |