TOMOYO: Allow controlling generation of access granted logs for per an entry basis.

Add per-entry flag which controls generation of grant logs because Xen and KVM
issues ioctl requests so frequently. For example,

  file ioctl /dev/null 0x5401 grant_log=no

will suppress /sys/kernel/security/tomoyo/audit even if preference says
grant_log=yes .

Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: James Morris <jmorris@namei.org>

5 files changed, 38 insertions, 1 deletions

diff --git a/security/tomoyo/audit.c b/security/tomoyo/audit.c
index 5dbb1f7617c..075c3a6d164 100644
--- a/security/tomoyo/audit.c
+++ b/security/tomoyo/audit.c
@@ -313,6 +313,7 @@ static unsigned int tomoyo_log_count;
  */
 static bool tomoyo_get_audit(const struct tomoyo_policy_namespace *ns,
                              const u8 profile, const u8 index,
+                             const struct tomoyo_acl_info *matched_acl,
                              const bool is_granted)
 {
         u8 mode;
@@ -324,6 +325,9 @@ static bool tomoyo_get_audit(const struct tomoyo_policy_namespace *ns,
         p = tomoyo_profile(ns, profile);
         if (tomoyo_log_count >= p->pref[TOMOYO_PREF_MAX_AUDIT_LOG])
                 return false;
+        if (is_granted && matched_acl && matched_acl->cond &&
+            matched_acl->cond->grant_log != TOMOYO_GRANTLOG_AUTO)
+                return matched_acl->cond->grant_log == TOMOYO_GRANTLOG_YES;
         mode = p->config[index];
         if (mode == TOMOYO_CONFIG_USE_DEFAULT)
                 mode = p->config[category];
@@ -350,7 +354,8 @@ void tomoyo_write_log2(struct tomoyo_request_info *r, int len, const char *fmt,
         char *buf;
         struct tomoyo_log *entry;
         bool quota_exceeded = false;
-        if (!tomoyo_get_audit(r->domain->ns, r->profile, r->type, r->granted))
+        if (!tomoyo_get_audit(r->domain->ns, r->profile, r->type,
+                              r->matched_acl, r->granted))
                 goto out;
         buf = tomoyo_init_log(r, len, fmt, args);
         if (!buf)
diff --git a/security/tomoyo/common.c b/security/tomoyo/common.c
index 85d915587a7..2704c384bf1 100644
--- a/security/tomoyo/common.c
+++ b/security/tomoyo/common.c
@@ -1272,6 +1272,10 @@ static bool tomoyo_print_condition(struct tomoyo_io_buffer *head,
                 head->r.cond_step++;
                 /* fall through */
         case 3:
+                if (cond->grant_log != TOMOYO_GRANTLOG_AUTO)
+                        tomoyo_io_printf(head, " grant_log=%s",
+                                         tomoyo_yesno(cond->grant_log ==
+                                                      TOMOYO_GRANTLOG_YES));
                 tomoyo_set_lf(head);
                 return true;
         }
diff --git a/security/tomoyo/common.h b/security/tomoyo/common.h
index d1c758e7f92..435b3d869fc 100644
--- a/security/tomoyo/common.h
+++ b/security/tomoyo/common.h
@@ -179,6 +179,16 @@ enum tomoyo_domain_info_flags_index {
         TOMOYO_MAX_DOMAIN_INFO_FLAGS
 };
 
+/* Index numbers for audit type. */
+enum tomoyo_grant_log {
+        /* Follow profile's configuration. */
+        TOMOYO_GRANTLOG_AUTO,
+        /* Do not generate grant log. */
+        TOMOYO_GRANTLOG_NO,
+        /* Generate grant_log. */
+        TOMOYO_GRANTLOG_YES,
+};
+
 /* Index numbers for group entries. */
 enum tomoyo_group_id {
         TOMOYO_PATH_GROUP,
@@ -471,6 +481,7 @@ struct tomoyo_request_info {
                         int need_dev;
                 } mount;
         } param;
+        struct tomoyo_acl_info *matched_acl;
         u8 param_type;
         bool granted;
         u8 retry;
@@ -635,6 +646,7 @@ struct tomoyo_condition {
         u16 names_count; /* Number of "struct tomoyo_name_union names". */
         u16 argc; /* Number of "struct tomoyo_argv". */
         u16 envc; /* Number of "struct tomoyo_envp". */
+        u8 grant_log; /* One of values in "enum tomoyo_grant_log". */
         /*
          * struct tomoyo_condition_element condition[condc];
          * struct tomoyo_number_union values[numbers_count];
diff --git a/security/tomoyo/condition.c b/security/tomoyo/condition.c
index 8a05f71eaf6..3a05eb3e2a6 100644
--- a/security/tomoyo/condition.c
+++ b/security/tomoyo/condition.c
@@ -348,6 +348,7 @@ static inline bool tomoyo_same_condition(const struct tomoyo_condition *a,
                 a->numbers_count == b->numbers_count &&
                 a->names_count == b->names_count &&
                 a->argc == b->argc && a->envc == b->envc &&
+                a->grant_log == b->grant_log &&
                 !memcmp(a + 1, b + 1, a->size - sizeof(*a));
 }
 
@@ -486,6 +487,20 @@ rerun:
                         goto out;
                 dprintk(KERN_WARNING "%u: <%s>%s=<%s>\n", __LINE__, left_word,
                         is_not ? "!" : "", right_word);
+                if (!strcmp(left_word, "grant_log")) {
+                        if (entry) {
+                                if (is_not ||
+                                    entry->grant_log != TOMOYO_GRANTLOG_AUTO)
+                                        goto out;
+                                else if (!strcmp(right_word, "yes"))
+                                        entry->grant_log = TOMOYO_GRANTLOG_YES;
+                                else if (!strcmp(right_word, "no"))
+                                        entry->grant_log = TOMOYO_GRANTLOG_NO;
+                                else
+                                        goto out;
+                        }
+                        continue;
+                }
                 if (!strncmp(left_word, "exec.argv[", 10)) {
                         if (!argv) {
                                 e.argc++;
diff --git a/security/tomoyo/domain.c b/security/tomoyo/domain.c
index 5931fb1c04d..498fea732f4 100644
--- a/security/tomoyo/domain.c
+++ b/security/tomoyo/domain.c
@@ -157,6 +157,7 @@ retry:
                         continue;
                 if (!tomoyo_condition(r, ptr->cond))
                         continue;
+                r->matched_acl = ptr;
                 r->granted = true;
                 return;
         }