lsm: cleanup the debug and console output in lsm_init.c

Move away from an init specific init_debug() macro to a more general
lsm_pr()/lsm_pr_cont()/lsm_pr_dbg() set of macros that are available
both before and after init.  In the process we do a number of minor
changes to improve the LSM initialization output and cleanup the code
somewhat.

Reviewed-by: Casey Schaufler <casey@schaufler-ca.com>
Reviewed-by: John Johansen <john.johhansen@canonical.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>

Author: pcmoore

security/lsm.h

@@ -6,9 +6,20 @@
 #ifndef _LSM_H_
 #define _LSM_H_
 
+#include <linux/printk.h>
 #include <linux/lsm_hooks.h>
 #include <linux/lsm_count.h>
 
+/* LSM debugging */
+extern bool lsm_debug;
+#define lsm_pr(...)		pr_info(__VA_ARGS__)
+#define lsm_pr_cont(...)	pr_cont(__VA_ARGS__)
+#define lsm_pr_dbg(...)							\
+	do {								\
+		if (lsm_debug)						\
+			pr_info(__VA_ARGS__);				\
+	} while (0)
+
 /* List of configured LSMs */
 extern unsigned int lsm_active_cnt;
 extern const struct lsm_id *lsm_idlist[];

security/lsm_init.c

@@ -30,13 +30,6 @@ static __initdata const char *lsm_order_legacy;
 static __initdata struct lsm_info *lsm_order[MAX_LSM_COUNT + 1];
 static __initdata struct lsm_info *lsm_exclusive;
 
-static __initdata bool debug;
-#define init_debug(...)							\
-	do {								\
-		if (debug)						\
-			pr_info(__VA_ARGS__);				\
-	} while (0)
-
 #define lsm_order_for_each(iter)					\
 	for ((iter) = lsm_order; *(iter); (iter)++)
 #define lsm_for_each_raw(iter)						\
@@ -77,7 +70,7 @@ __setup("lsm=", lsm_choose_lsm);
  */
 static int __init lsm_debug_enable(char *str)
 {
-	debug = true;
+	lsm_debug = true;
 	return 1;
 }
 __setup("lsm.debug", lsm_debug_enable);
@@ -143,22 +136,28 @@ static void __init lsm_order_append(struct lsm_info *lsm, const char *src)
 		return;
 
 	/* Skip explicitly disabled LSMs. */
-	if (lsm->enabled && !lsm_is_enabled(lsm))
-		goto out;
+	if (lsm->enabled && !lsm_is_enabled(lsm)) {
+		lsm_pr_dbg("skip previously disabled LSM %s:%s\n",
+			   src, lsm->id->name);
+		return;
+	}
 
-	if (WARN(lsm_active_cnt == MAX_LSM_COUNT,
-		 "%s: out of LSM static calls!?\n", src)) {
+	if (lsm_active_cnt == MAX_LSM_COUNT) {
+		pr_warn("exceeded maximum LSM count on %s:%s\n",
+			src, lsm->id->name);
 		lsm_enabled_set(lsm, false);
-		goto out;
+		return;
 	}
 
 	if (lsm->flags & LSM_FLAG_EXCLUSIVE) {
 		if (lsm_exclusive) {
-			init_debug("exclusive disabled: %s\n", lsm->id->name);
+			lsm_pr_dbg("skip exclusive LSM conflict %s:%s\n",
+				   src, lsm->id->name);
 			lsm_enabled_set(lsm, false);
-			goto out;
+			return;
 		} else {
-			init_debug("exclusive chosen:   %s\n", lsm->id->name);
+			lsm_pr_dbg("select exclusive LSM %s:%s\n",
+				   src, lsm->id->name);
 			lsm_exclusive = lsm;
 		}
 	}
@@ -167,9 +166,7 @@ static void __init lsm_order_append(struct lsm_info *lsm, const char *src)
 	lsm_order[lsm_active_cnt] = lsm;
 	lsm_idlist[lsm_active_cnt++] = lsm->id;
 
-out:
-	init_debug("%s ordered: %s (%s)\n", src, lsm->id->name,
-		   lsm_is_enabled(lsm) ? "enabled" : "disabled");
+	lsm_pr_dbg("enabling LSM %s:%s\n", src, lsm->id->name);
 }
 
 /**
@@ -239,7 +236,7 @@ static void __init lsm_init_single(struct lsm_info *lsm)
 	if (!lsm_is_enabled(lsm))
 		return;
 
-	init_debug("initializing %s\n", lsm->id->name);
+	lsm_pr_dbg("initializing %s\n", lsm->id->name);
 	ret = lsm->init();
 	WARN(ret, "%s failed to initialize: %d\n", lsm->id->name, ret);
 }
@@ -266,8 +263,8 @@ static void __init lsm_order_parse(const char *list, const char *src)
 			if ((lsm->flags & LSM_FLAG_LEGACY_MAJOR) &&
 			     strcmp(lsm->id->name, lsm_order_legacy)) {
 				lsm_enabled_set(lsm, false);
-				init_debug("security=%s disabled: %s (only one legacy major LSM)\n",
-					   lsm_order_legacy, lsm->id->name);
+				lsm_pr_dbg("skip legacy LSM conflict %s:%s\n",
+					   src, lsm->id->name);
 			}
 		}
 	}
@@ -310,16 +307,15 @@ static void __init lsm_order_parse(const char *list, const char *src)
 		if (lsm_order_exists(lsm))
 			continue;
 		lsm_enabled_set(lsm, false);
-		init_debug("%s skipped: %s (not in requested order)\n",
-			   src, lsm->id->name);
+		lsm_pr_dbg("skip disabled LSM %s:%s\n", src, lsm->id->name);
 	}
 }
 
 /**
  * lsm_static_call_init - Initialize a LSM's static calls
  * @hl: LSM hook list
  */
-static void __init lsm_static_call_init(struct security_hook_list *hl)
+static int __init lsm_static_call_init(struct security_hook_list *hl)
 {
 	struct lsm_static_call *scall = hl->scalls;
 	int i;
@@ -331,11 +327,12 @@ static void __init lsm_static_call_init(struct security_hook_list *hl)
 					     hl->hook.lsm_func_addr);
 			scall->hl = hl;
 			static_branch_enable(scall->active);
-			return;
+			return 0;
 		}
 		scall++;
 	}
-	panic("%s - Ran out of static slots.\n", __func__);
+
+	return -ENOSPC;
 }
 
 /**
@@ -353,7 +350,9 @@ void __init security_add_hooks(struct security_hook_list *hooks, int count,
 
 	for (i = 0; i < count; i++) {
 		hooks[i].lsmid = lsmid;
-		lsm_static_call_init(&hooks[i]);
+		if (lsm_static_call_init(&hooks[i]))
+			panic("exhausted LSM callback slots with LSM %s\n",
+			      lsmid->name);
 	}
 }
 
@@ -384,58 +383,42 @@ int __init security_init(void)
 {
 	unsigned int cnt;
 	struct lsm_info **lsm;
-	struct lsm_info *early;
-	unsigned int first = 0;
 
-	init_debug("legacy security=%s\n", lsm_order_legacy ? : " *unspecified*");
-	init_debug("  CONFIG_LSM=%s\n", lsm_order_builtin);
-	init_debug("boot arg lsm=%s\n", lsm_order_cmdline ? : " *unspecified*");
+	if (lsm_debug) {
+		lsm_pr("built-in LSM list: %s\n", lsm_order_builtin);
+		lsm_pr("legacy LSM parameter: %s\n", lsm_order_legacy);
+		lsm_pr("boot LSM parameter: %s\n", lsm_order_cmdline);
+	}
 
 	if (lsm_order_cmdline) {
-		if (lsm_order_legacy) {
-			pr_warn("security=%s is ignored because it is superseded by lsm=%s\n",
-				lsm_order_legacy, lsm_order_cmdline);
+		if (lsm_order_legacy)
 			lsm_order_legacy = NULL;
-		}
 		lsm_order_parse(lsm_order_cmdline, "cmdline");
 	} else
 		lsm_order_parse(lsm_order_builtin, "builtin");
 
 	lsm_order_for_each(lsm)
 		lsm_prepare(*lsm);
 
-	pr_info("initializing lsm=");
-	lsm_early_for_each_raw(early) {
-		if (lsm_is_enabled(early))
-			pr_cont("%s%s",
-				first++ == 0 ? "" : ",", early->id->name);
-	}
-	lsm_order_for_each(lsm) {
-		if (lsm_is_enabled(*lsm))
-			pr_cont("%s%s",
-				first++ == 0 ? "" : ",", (*lsm)->id->name);
+	if (lsm_debug) {
+		lsm_pr("blob(cred) size %d\n", blob_sizes.lbs_cred);
+		lsm_pr("blob(file) size %d\n", blob_sizes.lbs_file);
+		lsm_pr("blob(ib) size %d\n", blob_sizes.lbs_ib);
+		lsm_pr("blob(inode) size %d\n", blob_sizes.lbs_inode);
+		lsm_pr("blob(ipc) size %d\n", blob_sizes.lbs_ipc);
+		lsm_pr("blob(key) size %d\n", blob_sizes.lbs_key);
+		lsm_pr("blob(msg_msg)_size %d\n", blob_sizes.lbs_msg_msg);
+		lsm_pr("blob(sock) size %d\n", blob_sizes.lbs_sock);
+		lsm_pr("blob(superblock) size %d\n", blob_sizes.lbs_superblock);
+		lsm_pr("blob(perf_event) size %d\n", blob_sizes.lbs_perf_event);
+		lsm_pr("blob(task) size %d\n", blob_sizes.lbs_task);
+		lsm_pr("blob(tun_dev) size %d\n", blob_sizes.lbs_tun_dev);
+		lsm_pr("blob(xattr) count %d\n", blob_sizes.lbs_xattr_count);
+		lsm_pr("blob(bdev) size %d\n", blob_sizes.lbs_bdev);
+		lsm_pr("blob(bpf_map) size %d\n", blob_sizes.lbs_bpf_map);
+		lsm_pr("blob(bpf_prog) size %d\n", blob_sizes.lbs_bpf_prog);
+		lsm_pr("blob(bpf_token) size %d\n", blob_sizes.lbs_bpf_token);
 	}
-	pr_cont("\n");
-
-	init_debug("cred blob size       = %d\n", blob_sizes.lbs_cred);
-	init_debug("file blob size       = %d\n", blob_sizes.lbs_file);
-	init_debug("ib blob size         = %d\n", blob_sizes.lbs_ib);
-	init_debug("inode blob size      = %d\n", blob_sizes.lbs_inode);
-	init_debug("ipc blob size        = %d\n", blob_sizes.lbs_ipc);
-#ifdef CONFIG_KEYS
-	init_debug("key blob size        = %d\n", blob_sizes.lbs_key);
-#endif /* CONFIG_KEYS */
-	init_debug("msg_msg blob size    = %d\n", blob_sizes.lbs_msg_msg);
-	init_debug("sock blob size       = %d\n", blob_sizes.lbs_sock);
-	init_debug("superblock blob size = %d\n", blob_sizes.lbs_superblock);
-	init_debug("perf event blob size = %d\n", blob_sizes.lbs_perf_event);
-	init_debug("task blob size       = %d\n", blob_sizes.lbs_task);
-	init_debug("tun device blob size = %d\n", blob_sizes.lbs_tun_dev);
-	init_debug("xattr slots          = %d\n", blob_sizes.lbs_xattr_count);
-	init_debug("bdev blob size       = %d\n", blob_sizes.lbs_bdev);
-	init_debug("bpf map blob size    = %d\n", blob_sizes.lbs_bpf_map);
-	init_debug("bpf prog blob size   = %d\n", blob_sizes.lbs_bpf_prog);
-	init_debug("bpf token blob size  = %d\n", blob_sizes.lbs_bpf_token);
 
 	if (blob_sizes.lbs_file)
 		lsm_file_cache = kmem_cache_create("lsm_file_cache",
@@ -447,9 +430,9 @@ int __init security_init(void)
 						    SLAB_PANIC, NULL);
 
 	if (lsm_cred_alloc((struct cred __rcu *)current->cred, GFP_KERNEL))
-		panic("%s: early cred alloc failed.\n", __func__);
+		panic("early LSM cred alloc failed\n");
 	if (lsm_task_alloc(current))
-		panic("%s: early task alloc failed.\n", __func__);
+		panic("early LSM task alloc failed\n");
 
 	cnt = 0;
 	lsm_order_for_each(lsm) {

security/security.c

@@ -73,6 +73,8 @@ const char *const lockdown_reasons[LOCKDOWN_CONFIDENTIALITY_MAX + 1] = {
 	[LOCKDOWN_CONFIDENTIALITY_MAX] = "confidentiality",
 };
 
+bool lsm_debug __ro_after_init;
+
 unsigned int lsm_active_cnt __ro_after_init;
 const struct lsm_id *lsm_idlist[MAX_LSM_COUNT];