From 4351c294b8c1028077280f761e158d167b592974 Mon Sep 17 00:00:00 2001 From: Mimi Zohar Date: Wed, 5 Nov 2014 07:53:55 -0500 Subject: [PATCH] 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(-) diff --git a/Documentation/ABI/testing/ima_policy b/Documentation/ABI/testing/ima_policy index 4a571fa..0a378a8 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 525301c..b3a2038 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); -- 2.7.4