apparmor: Improve debug print infrastructure

Make it so apparmor debug output can be controlled by class flags
as well as the debug flag on labels. This provides much finer
control at what is being output so apparmor doesn't flood the
logs with information that is not needed, making it hard to find
what is important.

Signed-off-by: John Johansen <john.johansen@canonical.com>

security/apparmor/domain.c

@@ -652,7 +652,7 @@ static struct aa_label *profile_transition(const struct cred *subj_cred,
 	if (error) {
 		if (profile_unconfined(profile) ||
 		    (profile->label.flags & FLAG_IX_ON_NAME_ERROR)) {
-			AA_DEBUG("name lookup ix on error");
+			AA_DEBUG(DEBUG_DOMAIN, "name lookup ix on error");
 			error = 0;
 			new = aa_get_newest_label(&profile->label);
 		}
@@ -664,10 +664,10 @@ static struct aa_label *profile_transition(const struct cred *subj_cred,
 		new = find_attach(bprm, profile->ns,
 				  &profile->ns->base.profiles, name, &info);
 		if (new) {
-			AA_DEBUG("unconfined attached to new label");
+			AA_DEBUG(DEBUG_DOMAIN, "unconfined attached to new label");
 			return new;
 		}
-		AA_DEBUG("unconfined exec no attachment");
+		AA_DEBUG(DEBUG_DOMAIN, "unconfined exec no attachment");
 		return aa_get_newest_label(&profile->label);
 	}
 
@@ -766,7 +766,7 @@ static int profile_onexec(const struct cred *subj_cred,
 	if (error) {
 		if (profile_unconfined(profile) ||
 		    (profile->label.flags & FLAG_IX_ON_NAME_ERROR)) {
-			AA_DEBUG("name lookup ix on error");
+			AA_DEBUG(DEBUG_DOMAIN, "name lookup ix on error");
 			error = 0;
 		}
 		xname = bprm->filename;
@@ -1216,7 +1216,8 @@ int aa_change_hat(const char *hats[], int count, u64 token, int flags)
 		if (task_no_new_privs(current) && !unconfined(label) &&
 		    !aa_label_is_unconfined_subset(new, ctx->nnp)) {
 			/* not an apparmor denial per se, so don't log it */
-			AA_DEBUG("no_new_privs - change_hat denied");
+			AA_DEBUG(DEBUG_DOMAIN,
+				 "no_new_privs - change_hat denied");
 			error = -EPERM;
 			goto out;
 		}
@@ -1237,7 +1238,8 @@ int aa_change_hat(const char *hats[], int count, u64 token, int flags)
 		if (task_no_new_privs(current) && !unconfined(label) &&
 		    !aa_label_is_unconfined_subset(previous, ctx->nnp)) {
 			/* not an apparmor denial per se, so don't log it */
-			AA_DEBUG("no_new_privs - change_hat denied");
+			AA_DEBUG(DEBUG_DOMAIN,
+				 "no_new_privs - change_hat denied");
 			error = -EPERM;
 			goto out;
 		}
@@ -1343,7 +1345,7 @@ int aa_change_profile(const char *fqname, int flags)
 
 	if (!fqname || !*fqname) {
 		aa_put_label(label);
-		AA_DEBUG("no profile name");
+		AA_DEBUG(DEBUG_DOMAIN, "no profile name");
 		return -EINVAL;
 	}
 
@@ -1462,7 +1464,8 @@ check:
 		if (task_no_new_privs(current) && !unconfined(label) &&
 		    !aa_label_is_unconfined_subset(new, ctx->nnp)) {
 			/* not an apparmor denial per se, so don't log it */
-			AA_DEBUG("no_new_privs - change_hat denied");
+			AA_DEBUG(DEBUG_DOMAIN,
+				 "no_new_privs - change_hat denied");
 			error = -EPERM;
 			goto out;
 		}

security/apparmor/include/apparmor.h

@@ -43,7 +43,7 @@
 /* Control parameters settable through module/boot flags */
 extern enum audit_mode aa_g_audit;
 extern bool aa_g_audit_header;
-extern bool aa_g_debug;
+extern int aa_g_debug;
 extern bool aa_g_hash_policy;
 extern bool aa_g_export_binary;
 extern int aa_g_rawdata_compression_level;

security/apparmor/include/lib.h

@@ -18,23 +18,35 @@
 
 extern struct aa_dfa *stacksplitdfa;
 
-/*
- * DEBUG remains global (no per profile flag) since it is mostly used in sysctl
- * which is not related to profile accesses.
- */
-
-#define DEBUG_ON (aa_g_debug)
 /*
  * split individual debug cases out in preparation for finer grained
  * debug controls in the future.
  */
-#define AA_DEBUG_LABEL DEBUG_ON
 #define dbg_printk(__fmt, __args...) pr_debug(__fmt, ##__args)
-#define AA_DEBUG(fmt, args...)						\
+
+#define DEBUG_NONE 0
+#define DEBUG_LABEL_ABS_ROOT 1
+#define DEBUG_LABEL 2
+#define DEBUG_DOMAIN 4
+#define DEBUG_POLICY 8
+#define DEBUG_INTERFACE 0x10
+
+#define DEBUG_ALL 0x1f		/* update if new DEBUG_X added */
+#define DEBUG_PARSE_ERROR (-1)
+
+#define DEBUG_ON (aa_g_debug != DEBUG_NONE)
+#define DEBUG_ABS_ROOT (aa_g_debug & DEBUG_LABEL_ABS_ROOT)
+
+#define AA_DEBUG(opt, fmt, args...)					\
 	do {								\
-		if (DEBUG_ON)						\
-			pr_debug_ratelimited("AppArmor: " fmt, ##args);	\
+		if (aa_g_debug & opt)					\
+			pr_warn_ratelimited("%s: " fmt, __func__, ##args); \
 	} while (0)
+#define AA_DEBUG_LABEL(LAB, X, fmt, args)				\
+do {									\
+	if ((LAB)->flags & FLAG_DEBUG1)					\
+		AA_DEBUG(X, fmt, args);					\
+} while (0)
 
 #define AA_WARN(X) WARN((X), "APPARMOR WARN %s: %s\n", __func__, #X)
 
@@ -51,6 +63,9 @@ extern struct aa_dfa *stacksplitdfa;
 #define AA_BUG_FMT(X, fmt, args...) no_printk(fmt, ##args)
 #endif
 
+int aa_parse_debug_params(const char *str);
+int aa_print_debug_params(char *buffer);
+
 #define AA_ERROR(fmt, args...)						\
 	pr_err_ratelimited("AppArmor: " fmt, ##args)
 
@@ -281,7 +296,7 @@ __do_cleanup:								\
 	}								\
 __done:									\
 	if (!__new_)							\
-		AA_DEBUG("label build failed\n");			\
+		AA_DEBUG(DEBUG_LABEL, "label build failed\n");		\
 	(__new_);							\
 })
 

security/apparmor/label.c

@@ -431,7 +431,7 @@ struct aa_label *aa_label_alloc(int size, struct aa_proxy *proxy, gfp_t gfp)
 
 	/*  + 1 for null terminator entry on vec */
 	new = kzalloc(struct_size(new, vec, size + 1), gfp);
-	AA_DEBUG("%s (%p)\n", __func__, new);
+	AA_DEBUG(DEBUG_LABEL, "%s (%p)\n", __func__, new);
 	if (!new)
 		goto fail;
 
@@ -1617,7 +1617,7 @@ int aa_label_snxprint(char *str, size_t size, struct aa_ns *ns,
 	AA_BUG(!str && size != 0);
 	AA_BUG(!label);
 
-	if (AA_DEBUG_LABEL && (flags & FLAG_ABS_ROOT)) {
+	if (DEBUG_ABS_ROOT && (flags & FLAG_ABS_ROOT)) {
 		ns = root_ns;
 		len = snprintf(str, size, "_");
 		update_for_len(total, len, size, str);
@@ -1731,7 +1731,7 @@ void aa_label_xaudit(struct audit_buffer *ab, struct aa_ns *ns,
 	    display_mode(ns, label, flags)) {
 		len  = aa_label_asxprint(&name, ns, label, flags, gfp);
 		if (len < 0) {
-			AA_DEBUG("label print error");
+			AA_DEBUG(DEBUG_LABEL, "label print error");
 			return;
 		}
 		str = name;
@@ -1759,7 +1759,7 @@ void aa_label_seq_xprint(struct seq_file *f, struct aa_ns *ns,
 
 		len = aa_label_asxprint(&str, ns, label, flags, gfp);
 		if (len < 0) {
-			AA_DEBUG("label print error");
+			AA_DEBUG(DEBUG_LABEL, "label print error");
 			return;
 		}
 		seq_puts(f, str);
@@ -1782,7 +1782,7 @@ void aa_label_xprintk(struct aa_ns *ns, struct aa_label *label, int flags,
 
 		len = aa_label_asxprint(&str, ns, label, flags, gfp);
 		if (len < 0) {
-			AA_DEBUG("label print error");
+			AA_DEBUG(DEBUG_LABEL, "label print error");
 			return;
 		}
 		pr_info("%s", str);
@@ -1865,7 +1865,7 @@ struct aa_label *aa_label_strn_parse(struct aa_label *base, const char *str,
 	AA_BUG(!str);
 
 	str = skipn_spaces(str, n);
-	if (str == NULL || (AA_DEBUG_LABEL && *str == '_' &&
+	if (str == NULL || (DEBUG_ABS_ROOT && *str == '_' &&
 			    base != &root_ns->unconfined->label))
 		return ERR_PTR(-EINVAL);
 

security/apparmor/lib.c

@@ -25,6 +25,97 @@ struct aa_perms allperms = { .allow = ALL_PERMS_MASK,
 			     .quiet = ALL_PERMS_MASK,
 			     .hide = ALL_PERMS_MASK };
 
+struct val_table_ent {
+	const char *str;
+	int value;
+};
+
+struct val_table_ent debug_values_table[] = {
+	{ "N", DEBUG_NONE },
+	{ "none", DEBUG_NONE },
+	{ "n", DEBUG_NONE },
+	{ "0", DEBUG_NONE },
+	{ "all", DEBUG_ALL },
+	{ "Y", DEBUG_ALL },
+	{ "y", DEBUG_ALL },
+	{ "1", DEBUG_ALL },
+	{ "abs_root", DEBUG_LABEL_ABS_ROOT },
+	{ "label", DEBUG_LABEL },
+	{ "domain", DEBUG_DOMAIN },
+	{ "policy", DEBUG_POLICY },
+	{ "interface", DEBUG_INTERFACE },
+	{ NULL, 0 }
+};
+
+static struct val_table_ent *val_table_find_ent(struct val_table_ent *table,
+						const char *name, size_t len)
+{
+	struct val_table_ent *entry;
+
+	for (entry = table; entry->str != NULL; entry++) {
+		if (strncmp(entry->str, name, len) == 0 &&
+		    strlen(entry->str) == len)
+			return entry;
+	}
+	return NULL;
+}
+
+int aa_parse_debug_params(const char *str)
+{
+	struct val_table_ent *ent;
+	const char *next;
+	int val = 0;
+
+	do {
+		size_t n = strcspn(str, "\r\n,");
+
+		next = str + n;
+		ent = val_table_find_ent(debug_values_table, str, next - str);
+		if (ent)
+			val |= ent->value;
+		else
+			AA_DEBUG(DEBUG_INTERFACE, "unknown debug type '%.*s'",
+				 (int)(next - str), str);
+		str = next + 1;
+	} while (*next != 0);
+	return val;
+}
+
+/**
+ * aa_mask_to_str - convert a perm mask to its short string
+ * @str: character buffer to store string in (at least 10 characters)
+ * @str_size: size of the @str buffer
+ * @chrs: NUL-terminated character buffer of permission characters
+ * @mask: permission mask to convert
+ */
+static int val_mask_to_str(char *str, size_t size,
+			   const struct val_table_ent *table, u32 mask)
+{
+	const struct val_table_ent *ent;
+	int total = 0;
+
+	for (ent = table; ent->str; ent++) {
+		if (ent->value && (ent->value & mask) == ent->value) {
+			int len = scnprintf(str, size, "%s%s", total ? "," : "",
+					    ent->str);
+			size -= len;
+			str += len;
+			total += len;
+			mask &= ~ent->value;
+		}
+	}
+
+	return total;
+}
+
+int aa_print_debug_params(char *buffer)
+{
+	if (!aa_g_debug)
+		return sprintf(buffer, "N");
+	return val_mask_to_str(buffer, PAGE_SIZE, debug_values_table,
+			       aa_g_debug);
+}
+
 /**
  * aa_free_str_table - free entries str table
  * @t: the string table to free  (MAYBE NULL)

security/apparmor/lsm.c

@@ -1571,6 +1571,9 @@ static const struct kernel_param_ops param_ops_aalockpolicy = {
 	.get = param_get_aalockpolicy
 };
 
+static int param_set_debug(const char *val, const struct kernel_param *kp);
+static int param_get_debug(char *buffer, const struct kernel_param *kp);
+
 static int param_set_audit(const char *val, const struct kernel_param *kp);
 static int param_get_audit(char *buffer, const struct kernel_param *kp);
 
@@ -1604,8 +1607,9 @@ module_param_named(rawdata_compression_level, aa_g_rawdata_compression_level,
 		   aacompressionlevel, 0400);
 
 /* Debug mode */
-bool aa_g_debug = IS_ENABLED(CONFIG_SECURITY_APPARMOR_DEBUG_MESSAGES);
-module_param_named(debug, aa_g_debug, aabool, S_IRUSR | S_IWUSR);
+int aa_g_debug;
+module_param_call(debug, param_set_debug, param_get_debug,
+		  &aa_g_debug, 0600);
 
 /* Audit mode */
 enum audit_mode aa_g_audit;
@@ -1798,6 +1802,34 @@ static int param_get_aacompressionlevel(char *buffer,
 	return param_get_int(buffer, kp);
 }
 
+static int param_get_debug(char *buffer, const struct kernel_param *kp)
+{
+	if (!apparmor_enabled)
+		return -EINVAL;
+	if (apparmor_initialized && !aa_current_policy_view_capable(NULL))
+		return -EPERM;
+	return aa_print_debug_params(buffer);
+}
+
+static int param_set_debug(const char *val, const struct kernel_param *kp)
+{
+	int i;
+
+	if (!apparmor_enabled)
+		return -EINVAL;
+	if (!val)
+		return -EINVAL;
+	if (apparmor_initialized && !aa_current_policy_admin_capable(NULL))
+		return -EPERM;
+
+	i = aa_parse_debug_params(val);
+	if (i == DEBUG_PARSE_ERROR)
+		return -EINVAL;
+
+	aa_g_debug = i;
+	return 0;
+}
+
 static int param_get_audit(char *buffer, const struct kernel_param *kp)
 {
 	if (!apparmor_enabled)

security/apparmor/policy.c

@@ -280,7 +280,7 @@ void aa_free_profile(struct aa_profile *profile)
 	struct aa_ruleset *rule, *tmp;
 	struct rhashtable *rht;
 
-	AA_DEBUG("%s(%p)\n", __func__, profile);
+	AA_DEBUG(DEBUG_POLICY, "%s(%p)\n", __func__, profile);
 
 	if (!profile)
 		return;
@@ -833,8 +833,8 @@ bool aa_policy_admin_capable(const struct cred *subj_cred,
 	bool capable = policy_ns_capable(subj_cred, label, user_ns,
 					 CAP_MAC_ADMIN) == 0;
 
-	AA_DEBUG("cap_mac_admin? %d\n", capable);
-	AA_DEBUG("policy locked? %d\n", aa_g_lock_policy);
+	AA_DEBUG(DEBUG_POLICY, "cap_mac_admin? %d\n", capable);
+	AA_DEBUG(DEBUG_POLICY, "policy locked? %d\n", aa_g_lock_policy);
 
 	return aa_policy_view_capable(subj_cred, label, ns) && capable &&
 		!aa_g_lock_policy;

security/apparmor/policy_ns.c

@@ -107,7 +107,7 @@ static struct aa_ns *alloc_ns(const char *prefix, const char *name)
 	struct aa_ns *ns;
 
 	ns = kzalloc(sizeof(*ns), GFP_KERNEL);
-	AA_DEBUG("%s(%p)\n", __func__, ns);
+	AA_DEBUG(DEBUG_POLICY, "%s(%p)\n", __func__, ns);
 	if (!ns)
 		return NULL;
 	if (!aa_policy_init(&ns->base, prefix, name, GFP_KERNEL))

security/apparmor/procattr.c

@@ -125,12 +125,14 @@ int aa_setprocattr_changehat(char *args, size_t size, int flags)
 		for (count = 0; (hat < end) && count < 16; ++count) {
 			char *next = hat + strlen(hat) + 1;
 			hats[count] = hat;
-			AA_DEBUG("%s: (pid %d) Magic 0x%llx count %d hat '%s'\n"
+			AA_DEBUG(DEBUG_DOMAIN,
+				 "%s: (pid %d) Magic 0x%llx count %d hat '%s'\n"
 				 , __func__, current->pid, token, count, hat);
 			hat = next;
 		}
 	} else
-		AA_DEBUG("%s: (pid %d) Magic 0x%llx count %d Hat '%s'\n",
+		AA_DEBUG(DEBUG_DOMAIN,
+			 "%s: (pid %d) Magic 0x%llx count %d Hat '%s'\n",
 			 __func__, current->pid, token, count, "<NULL>");
 
 	return aa_change_hat(hats, count, token, flags);