From 139069eff7388407f19794384c42a534d618ccd7 Mon Sep 17 00:00:00 2001 From: Mimi Zohar Date: Wed, 5 Nov 2014 07:48:36 -0500 Subject: [PATCH] ima: add support for new "euid" policy condition The new "euid" policy condition measures files with the specified effective uid (euid). In addition, for CAP_SETUID files it measures files with the specified uid or suid. Changelog: - fixed checkpatch.pl warnings - fixed avc denied {setuid} messages - based on Roberto's feedback Signed-off-by: Mimi Zohar Signed-off-by: Dr. Greg Wettstein Cc: stable@vger.kernel.org --- Documentation/ABI/testing/ima_policy | 3 ++- security/integrity/ima/ima_policy.c | 27 +++++++++++++++++++++++---- 2 files changed, 25 insertions(+), 5 deletions(-) diff --git a/Documentation/ABI/testing/ima_policy b/Documentation/ABI/testing/ima_policy index 8ae3f57090d4..4a571fa10f96 100644 --- a/Documentation/ABI/testing/ima_policy +++ b/Documentation/ABI/testing/ima_policy @@ -20,7 +20,7 @@ Description: action: measure | dont_measure | appraise | dont_appraise | audit condition:= base | lsm [option] base: [[func=] [mask=] [fsmagic=] [fsuuid=] [uid=] - [fowner]] + [euid=] [fowner=]] lsm: [[subj_user=] [subj_role=] [subj_type=] [obj_user=] [obj_role=] [obj_type=]] option: [[appraise_type=]] [permit_directio] @@ -31,6 +31,7 @@ Description: fsmagic:= hex value fsuuid:= file system UUID (e.g 8bcbe394-4f13-4144-be8e-5aa9ea2ce2f6) uid:= decimal value + euid:= decimal value fowner:=decimal value lsm: are LSM specific option: appraise_type:= [imasig] diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c index f2421f7fa3c8..525301cf7d90 100644 --- a/security/integrity/ima/ima_policy.c +++ b/security/integrity/ima/ima_policy.c @@ -27,6 +27,7 @@ #define IMA_UID 0x0008 #define IMA_FOWNER 0x0010 #define IMA_FSUUID 0x0020 +#define IMA_EUID 0x0080 #define UNKNOWN 0 #define MEASURE 0x0001 /* same as IMA_MEASURE */ @@ -194,6 +195,16 @@ static bool ima_match_rules(struct ima_rule_entry *rule, return false; if ((rule->flags & IMA_UID) && !uid_eq(rule->uid, cred->uid)) return false; + if (rule->flags & IMA_EUID) { + if (has_capability_noaudit(current, CAP_SETUID)) { + if (!uid_eq(rule->uid, cred->euid) + && !uid_eq(rule->uid, cred->suid) + && !uid_eq(rule->uid, cred->uid)) + return false; + } else if (!uid_eq(rule->uid, cred->euid)) + return false; + } + if ((rule->flags & IMA_FOWNER) && !uid_eq(rule->fowner, inode->i_uid)) return false; for (i = 0; i < MAX_LSM_RULES; i++) { @@ -373,7 +384,8 @@ 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_euid, Opt_fowner, Opt_appraise_type, Opt_fsuuid, Opt_permit_directio }; @@ -394,6 +406,7 @@ static match_table_t policy_tokens = { {Opt_fsmagic, "fsmagic=%s"}, {Opt_fsuuid, "fsuuid=%s"}, {Opt_uid, "uid=%s"}, + {Opt_euid, "euid=%s"}, {Opt_fowner, "fowner=%s"}, {Opt_appraise_type, "appraise_type=%s"}, {Opt_permit_directio, "permit_directio"}, @@ -566,6 +579,9 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry) break; case Opt_uid: ima_log_string(ab, "uid", args[0].from); + case Opt_euid: + if (token == Opt_euid) + ima_log_string(ab, "euid", args[0].from); if (uid_valid(entry->uid)) { result = -EINVAL; @@ -574,11 +590,14 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry) result = kstrtoul(args[0].from, 10, &lnum); if (!result) { - entry->uid = make_kuid(current_user_ns(), (uid_t)lnum); - if (!uid_valid(entry->uid) || (((uid_t)lnum) != lnum)) + entry->uid = make_kuid(current_user_ns(), + (uid_t) lnum); + if (!uid_valid(entry->uid) || + (uid_t)lnum != lnum) result = -EINVAL; else - entry->flags |= IMA_UID; + entry->flags |= (token == Opt_uid) + ? IMA_UID : IMA_EUID; } break; case Opt_fowner: