From 0e5a247cb37a97d843ef76d09d5f80deb7893ba3 Mon Sep 17 00:00:00 2001 From: Dmitry Kasatkin Date: Fri, 8 Jun 2012 13:58:49 +0300 Subject: [PATCH] ima: added policy support for 'security.ima' type The 'security.ima' extended attribute may contain either the file data's hash or a digital signature. This patch adds support for requiring a specific extended attribute type. It extends the IMA policy with a new keyword 'appraise_type=imasig'. (Default is hash.) Changelog v2: - Fixed Documentation/ABI/testing/ima_policy option syntax Changelog v1: - Differentiate between 'required' vs. 'actual' extended attribute Signed-off-by: Dmitry Kasatkin Signed-off-by: Mimi Zohar --- Documentation/ABI/testing/ima_policy | 4 +++- security/integrity/ima/ima_appraise.c | 5 +++++ security/integrity/ima/ima_main.c | 1 + security/integrity/ima/ima_policy.c | 18 +++++++++++++++++- security/integrity/integrity.h | 2 ++ 5 files changed, 28 insertions(+), 2 deletions(-) diff --git a/Documentation/ABI/testing/ima_policy b/Documentation/ABI/testing/ima_policy index 6a0fc808fb6d..de16de3f148d 100644 --- a/Documentation/ABI/testing/ima_policy +++ b/Documentation/ABI/testing/ima_policy @@ -18,10 +18,11 @@ Description: rule format: action [condition ...] action: measure | dont_measure | appraise | dont_appraise | audit - condition:= base | lsm + condition:= base | lsm [option] base: [[func=] [mask=] [fsmagic=] [uid=] [fowner]] lsm: [[subj_user=] [subj_role=] [subj_type=] [obj_user=] [obj_role=] [obj_type=]] + option: [[appraise_type=]] base: func:= [BPRM_CHECK][MMAP_CHECK][FILE_CHECK][MODULE_CHECK] mask:= [MAY_READ] [MAY_WRITE] [MAY_APPEND] [MAY_EXEC] @@ -29,6 +30,7 @@ Description: uid:= decimal value fowner:=decimal value lsm: are LSM specific + option: appraise_type:= [imasig] default policy: # PROC_SUPER_MAGIC diff --git a/security/integrity/ima/ima_appraise.c b/security/integrity/ima/ima_appraise.c index fa675c907e0f..8004332ccb8f 100644 --- a/security/integrity/ima/ima_appraise.c +++ b/security/integrity/ima/ima_appraise.c @@ -102,6 +102,11 @@ int ima_appraise_measurement(struct integrity_iint_cache *iint, switch (xattr_value->type) { case IMA_XATTR_DIGEST: + if (iint->flags & IMA_DIGSIG_REQUIRED) { + cause = "IMA signature required"; + status = INTEGRITY_FAIL; + break; + } rc = memcmp(xattr_value->digest, iint->ima_xattr.digest, IMA_DIGEST_SIZE); if (rc) { diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c index cd00ba39e8e0..3cdd78768c29 100644 --- a/security/integrity/ima/ima_main.c +++ b/security/integrity/ima/ima_main.c @@ -169,6 +169,7 @@ static int process_measurement(struct file *file, const char *filename, * (IMA_MEASURE, IMA_MEASURED, IMA_APPRAISE, IMA_APPRAISED, * IMA_AUDIT, IMA_AUDITED) */ iint->flags |= action; + action &= IMA_DO_MASK; action &= ~((iint->flags & IMA_DONE_MASK) >> 1); /* Nothing to do, just return existing appraised status */ diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c index 95194539d75e..1a2543a8ee53 100644 --- a/security/integrity/ima/ima_policy.c +++ b/security/integrity/ima/ima_policy.c @@ -245,6 +245,8 @@ int ima_match_policy(struct inode *inode, enum ima_hooks func, int mask, if (!ima_match_rules(entry, inode, func, mask)) continue; + action |= entry->flags & IMA_ACTION_FLAGS; + action |= entry->action & IMA_DO_MASK; if (entry->action & IMA_DO_MASK) actmask &= ~(entry->action | entry->action << 1); @@ -318,7 +320,8 @@ enum { Opt_audit, Opt_obj_user, Opt_obj_role, Opt_obj_type, Opt_subj_user, Opt_subj_role, Opt_subj_type, - Opt_func, Opt_mask, Opt_fsmagic, Opt_uid, Opt_fowner + Opt_func, Opt_mask, Opt_fsmagic, Opt_uid, Opt_fowner, + Opt_appraise_type }; static match_table_t policy_tokens = { @@ -338,6 +341,7 @@ static match_table_t policy_tokens = { {Opt_fsmagic, "fsmagic=%s"}, {Opt_uid, "uid=%s"}, {Opt_fowner, "fowner=%s"}, + {Opt_appraise_type, "appraise_type=%s"}, {Opt_err, NULL} }; @@ -560,6 +564,18 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry) LSM_SUBJ_TYPE, AUDIT_SUBJ_TYPE); break; + case Opt_appraise_type: + if (entry->action != APPRAISE) { + result = -EINVAL; + break; + } + + ima_log_string(ab, "appraise_type", args[0].from); + if ((strcmp(args[0].from, "imasig")) == 0) + entry->flags |= IMA_DIGSIG_REQUIRED; + else + result = -EINVAL; + break; case Opt_err: ima_log_string(ab, "UNKNOWN", p); result = -EINVAL; diff --git a/security/integrity/integrity.h b/security/integrity/integrity.h index 0a298def5036..9334691b2b75 100644 --- a/security/integrity/integrity.h +++ b/security/integrity/integrity.h @@ -26,7 +26,9 @@ #define IMA_AUDITED 0x0080 /* iint cache flags */ +#define IMA_ACTION_FLAGS 0xff00 #define IMA_DIGSIG 0x0100 +#define IMA_DIGSIG_REQUIRED 0x0200 #define IMA_DO_MASK (IMA_MEASURE | IMA_APPRAISE | IMA_AUDIT) #define IMA_DONE_MASK (IMA_MEASURED | IMA_APPRAISED | IMA_AUDITED \