From 6438de9f3fb5180d78a0422695d0b88c687757d3 Mon Sep 17 00:00:00 2001 From: Roberto Sassu Date: Sat, 11 Apr 2015 17:13:06 +0200 Subject: ima: skip measurement of cgroupfs files and update documentation This patch adds a rule in the default measurement policy to skip inodes in the cgroupfs filesystem. Measurements for this filesystem can be avoided, as all the digests collected have the same value of the digest of an empty file. Furthermore, this patch updates the documentation of IMA policies in Documentation/ABI/testing/ima_policy to make it consistent with the policies set in security/integrity/ima/ima_policy.c. Signed-off-by: Roberto Sassu Signed-off-by: Mimi Zohar --- Documentation/ABI/testing/ima_policy | 17 ++++++++++++----- 1 file changed, 12 insertions(+), 5 deletions(-) (limited to 'Documentation/ABI') diff --git a/Documentation/ABI/testing/ima_policy b/Documentation/ABI/testing/ima_policy index d0d0c578324c..232e174aa5de 100644 --- a/Documentation/ABI/testing/ima_policy +++ b/Documentation/ABI/testing/ima_policy @@ -49,11 +49,22 @@ Description: dont_measure fsmagic=0x01021994 dont_appraise fsmagic=0x01021994 # RAMFS_MAGIC - dont_measure fsmagic=0x858458f6 dont_appraise fsmagic=0x858458f6 + # DEVPTS_SUPER_MAGIC + dont_measure fsmagic=0x1cd1 + dont_appraise fsmagic=0x1cd1 + # BINFMTFS_MAGIC + dont_measure fsmagic=0x42494e4d + dont_appraise fsmagic=0x42494e4d # SECURITYFS_MAGIC dont_measure fsmagic=0x73636673 dont_appraise fsmagic=0x73636673 + # SELINUX_MAGIC + dont_measure fsmagic=0xf97cff8c + dont_appraise fsmagic=0xf97cff8c + # CGROUP_SUPER_MAGIC + dont_measure fsmagic=0x27e0eb + dont_appraise fsmagic=0x27e0eb measure func=BPRM_CHECK measure func=FILE_MMAP mask=MAY_EXEC @@ -70,10 +81,6 @@ Description: Examples of LSM specific definitions: SELinux: - # SELINUX_MAGIC - dont_measure fsmagic=0xf97cff8c - dont_appraise fsmagic=0xf97cff8c - dont_measure obj_type=var_log_t dont_appraise obj_type=var_log_t dont_measure obj_type=auditd_log_t -- cgit v1.2.3 From cd025f7f94108995383edddfb61fc8afea6c66a9 Mon Sep 17 00:00:00 2001 From: Mimi Zohar Date: Tue, 21 Apr 2015 16:54:24 -0400 Subject: ima: do not measure or appraise the NSFS filesystem Include don't appraise or measure rules for the NSFS filesystem in the builtin ima_tcb and ima_appraise_tcb policies. Changelog: - Update documentation Signed-off-by: Mimi Zohar Cc: stable@vger.kernel.org # 3.19 --- Documentation/ABI/testing/ima_policy | 3 +++ security/integrity/ima/ima_policy.c | 2 ++ 2 files changed, 5 insertions(+) (limited to 'Documentation/ABI') diff --git a/Documentation/ABI/testing/ima_policy b/Documentation/ABI/testing/ima_policy index 232e174aa5de..8ae3f57090d4 100644 --- a/Documentation/ABI/testing/ima_policy +++ b/Documentation/ABI/testing/ima_policy @@ -65,6 +65,9 @@ Description: # CGROUP_SUPER_MAGIC dont_measure fsmagic=0x27e0eb dont_appraise fsmagic=0x27e0eb + # NSFS_MAGIC + dont_measure fsmagic=0x6e736673 + dont_appraise fsmagic=0x6e736673 measure func=BPRM_CHECK measure func=FILE_MMAP mask=MAY_EXEC diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c index e4244fc43cf1..f2421f7fa3c8 100644 --- a/security/integrity/ima/ima_policy.c +++ b/security/integrity/ima/ima_policy.c @@ -81,6 +81,7 @@ static struct ima_rule_entry default_rules[] = { {.action = DONT_MEASURE, .fsmagic = SELINUX_MAGIC, .flags = IMA_FSMAGIC}, {.action = DONT_MEASURE, .fsmagic = CGROUP_SUPER_MAGIC, .flags = IMA_FSMAGIC}, + {.action = DONT_MEASURE, .fsmagic = NSFS_MAGIC, .flags = IMA_FSMAGIC}, {.action = MEASURE, .func = MMAP_CHECK, .mask = MAY_EXEC, .flags = IMA_FUNC | IMA_MASK}, {.action = MEASURE, .func = BPRM_CHECK, .mask = MAY_EXEC, @@ -101,6 +102,7 @@ static struct ima_rule_entry default_appraise_rules[] = { {.action = DONT_APPRAISE, .fsmagic = BINFMTFS_MAGIC, .flags = IMA_FSMAGIC}, {.action = DONT_APPRAISE, .fsmagic = SECURITYFS_MAGIC, .flags = IMA_FSMAGIC}, {.action = DONT_APPRAISE, .fsmagic = SELINUX_MAGIC, .flags = IMA_FSMAGIC}, + {.action = DONT_APPRAISE, .fsmagic = NSFS_MAGIC, .flags = IMA_FSMAGIC}, {.action = DONT_APPRAISE, .fsmagic = CGROUP_SUPER_MAGIC, .flags = IMA_FSMAGIC}, #ifndef CONFIG_IMA_APPRAISE_SIGNED_INIT {.action = APPRAISE, .fowner = GLOBAL_ROOT_UID, .flags = IMA_FOWNER}, -- cgit v1.2.3 From 139069eff7388407f19794384c42a534d618ccd7 Mon Sep 17 00:00:00 2001 From: Mimi Zohar Date: Wed, 5 Nov 2014 07:48:36 -0500 Subject: 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(-) (limited to 'Documentation/ABI') 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: -- cgit v1.2.3 From 4351c294b8c1028077280f761e158d167b592974 Mon Sep 17 00:00:00 2001 From: Mimi Zohar Date: Wed, 5 Nov 2014 07:53:55 -0500 Subject: ima: extend "mask" policy matching support The current "mask" policy option matches files opened as MAY_READ, MAY_WRITE, MAY_APPEND or MAY_EXEC. This patch extends the "mask" option to match files opened containing one of these modes. For example, "mask=^MAY_READ" would match files opened read-write. 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 | 20 +++++++++++++++----- 2 files changed, 17 insertions(+), 6 deletions(-) (limited to 'Documentation/ABI') diff --git a/Documentation/ABI/testing/ima_policy b/Documentation/ABI/testing/ima_policy index 4a571fa10f96..0a378a88217a 100644 --- a/Documentation/ABI/testing/ima_policy +++ b/Documentation/ABI/testing/ima_policy @@ -27,7 +27,8 @@ Description: base: func:= [BPRM_CHECK][MMAP_CHECK][FILE_CHECK][MODULE_CHECK] [FIRMWARE_CHECK] - mask:= [MAY_READ] [MAY_WRITE] [MAY_APPEND] [MAY_EXEC] + mask:= [[^]MAY_READ] [[^]MAY_WRITE] [[^]MAY_APPEND] + [[^]MAY_EXEC] fsmagic:= hex value fsuuid:= file system UUID (e.g 8bcbe394-4f13-4144-be8e-5aa9ea2ce2f6) uid:= decimal value diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c index 525301cf7d90..b3a2038ed424 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_INMASK 0x0040 #define IMA_EUID 0x0080 #define UNKNOWN 0 @@ -187,6 +188,9 @@ static bool ima_match_rules(struct ima_rule_entry *rule, if ((rule->flags & IMA_MASK) && (rule->mask != mask && func != POST_SETATTR)) return false; + if ((rule->flags & IMA_INMASK) && + (!(rule->mask & mask) && func != POST_SETATTR)) + return false; if ((rule->flags & IMA_FSMAGIC) && rule->fsmagic != inode->i_sb->s_magic) return false; @@ -448,6 +452,7 @@ static void ima_log_string(struct audit_buffer *ab, char *key, char *value) static int ima_parse_rule(char *rule, struct ima_rule_entry *entry) { struct audit_buffer *ab; + char *from; char *p; int result = 0; @@ -538,18 +543,23 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry) if (entry->mask) result = -EINVAL; - if ((strcmp(args[0].from, "MAY_EXEC")) == 0) + from = args[0].from; + if (*from == '^') + from++; + + if ((strcmp(from, "MAY_EXEC")) == 0) entry->mask = MAY_EXEC; - else if (strcmp(args[0].from, "MAY_WRITE") == 0) + else if (strcmp(from, "MAY_WRITE") == 0) entry->mask = MAY_WRITE; - else if (strcmp(args[0].from, "MAY_READ") == 0) + else if (strcmp(from, "MAY_READ") == 0) entry->mask = MAY_READ; - else if (strcmp(args[0].from, "MAY_APPEND") == 0) + else if (strcmp(from, "MAY_APPEND") == 0) entry->mask = MAY_APPEND; else result = -EINVAL; if (!result) - entry->flags |= IMA_MASK; + entry->flags |= (*args[0].from == '^') + ? IMA_INMASK : IMA_MASK; break; case Opt_fsmagic: ima_log_string(ab, "fsmagic", args[0].from); -- cgit v1.2.3