Merge tag 'selinux-pr-20220110' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux

Pull selinux updates from Paul Moore:
 "Nothing too significant, but five SELinux patches for v5.17 that do
  the following:

   - Harden the code through additional use of the struct_size() macro

   - Plug some memory leaks

   - Clean up the code via removal of the security_add_mnt_opt() LSM
     hook and minor tweaks to selinux_add_opt()

   - Rename security_task_getsecid_subj() to better reflect its actual
     behavior/use - now called security_current_getsecid_subj()"

* tag 'selinux-pr-20220110' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux:
  selinux: minor tweaks to selinux_add_opt()
  selinux: fix potential memleak in selinux_add_opt()
  security,selinux: remove security_add_mnt_opt()
  selinux: Use struct_size() helper in kmalloc()
  lsm: security_task_getsecid_subj() -> security_current_getsecid_subj()

9 files changed, 49 insertions, 109 deletions

diff --git a/security/apparmor/lsm.c b/security/apparmor/lsm.c
index 0d6585056f3d..4f0eecb67dde 100644
--- a/security/apparmor/lsm.c
+++ b/security/apparmor/lsm.c
@@ -728,7 +728,14 @@ static void apparmor_bprm_committed_creds(struct linux_binprm *bprm)
 	return;
 }
 
-static void apparmor_task_getsecid(struct task_struct *p, u32 *secid)
+static void apparmor_current_getsecid_subj(u32 *secid)
+{
+	struct aa_label *label = aa_get_current_label();
+	*secid = label->secid;
+	aa_put_label(label);
+}
+
+static void apparmor_task_getsecid_obj(struct task_struct *p, u32 *secid)
 {
 	struct aa_label *label = aa_get_task_label(p);
 	*secid = label->secid;
@@ -1252,8 +1259,8 @@ static struct security_hook_list apparmor_hooks[] __lsm_ro_after_init = {
 
 	LSM_HOOK_INIT(task_free, apparmor_task_free),
 	LSM_HOOK_INIT(task_alloc, apparmor_task_alloc),
-	LSM_HOOK_INIT(task_getsecid_subj, apparmor_task_getsecid),
-	LSM_HOOK_INIT(task_getsecid_obj, apparmor_task_getsecid),
+	LSM_HOOK_INIT(current_getsecid_subj, apparmor_current_getsecid_subj),
+	LSM_HOOK_INIT(task_getsecid_obj, apparmor_task_getsecid_obj),
 	LSM_HOOK_INIT(task_setrlimit, apparmor_task_setrlimit),
 	LSM_HOOK_INIT(task_kill, apparmor_task_kill),
 
diff --git a/security/integrity/ima/ima_appraise.c b/security/integrity/ima/ima_appraise.c
index dbba51583e7c..17232bbfb9f9 100644
--- a/security/integrity/ima/ima_appraise.c
+++ b/security/integrity/ima/ima_appraise.c
@@ -76,7 +76,7 @@ int ima_must_appraise(struct user_namespace *mnt_userns, struct inode *inode,
 	if (!ima_appraise)
 		return 0;
 
-	security_task_getsecid_subj(current, &secid);
+	security_current_getsecid_subj(&secid);
 	return ima_match_policy(mnt_userns, inode, current_cred(), secid,
 				func, mask, IMA_APPRAISE | IMA_HASH, NULL,
 				NULL, NULL, NULL);
diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
index 465865412100..8c6e4514d494 100644
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c
@@ -408,7 +408,7 @@ int ima_file_mmap(struct file *file, unsigned long prot)
 	u32 secid;
 
 	if (file && (prot & PROT_EXEC)) {
-		security_task_getsecid_subj(current, &secid);
+		security_current_getsecid_subj(&secid);
 		return process_measurement(file, current_cred(), secid, NULL,
 					   0, MAY_EXEC, MMAP_CHECK);
 	}
@@ -446,7 +446,7 @@ int ima_file_mprotect(struct vm_area_struct *vma, unsigned long prot)
 	    !(prot & PROT_EXEC) || (vma->vm_flags & VM_EXEC))
 		return 0;
 
-	security_task_getsecid_subj(current, &secid);
+	security_current_getsecid_subj(&secid);
 	inode = file_inode(vma->vm_file);
 	action = ima_get_action(file_mnt_user_ns(vma->vm_file), inode,
 				current_cred(), secid, MAY_EXEC, MMAP_CHECK,
@@ -487,7 +487,7 @@ int ima_bprm_check(struct linux_binprm *bprm)
 	int ret;
 	u32 secid;
 
-	security_task_getsecid_subj(current, &secid);
+	security_current_getsecid_subj(&secid);
 	ret = process_measurement(bprm->file, current_cred(), secid, NULL, 0,
 				  MAY_EXEC, BPRM_CHECK);
 	if (ret)
@@ -512,7 +512,7 @@ int ima_file_check(struct file *file, int mask)
 {
 	u32 secid;
 
-	security_task_getsecid_subj(current, &secid);
+	security_current_getsecid_subj(&secid);
 	return process_measurement(file, current_cred(), secid, NULL, 0,
 				   mask & (MAY_READ | MAY_WRITE | MAY_EXEC |
 					   MAY_APPEND), FILE_CHECK);
@@ -709,7 +709,7 @@ int ima_read_file(struct file *file, enum kernel_read_file_id read_id,
 
 	/* Read entire file for all partial reads. */
 	func = read_idmap[read_id] ?: FILE_CHECK;
-	security_task_getsecid_subj(current, &secid);
+	security_current_getsecid_subj(&secid);
 	return process_measurement(file, current_cred(), secid, NULL,
 				   0, MAY_READ, func);
 }
@@ -752,7 +752,7 @@ int ima_post_read_file(struct file *file, void *buf, loff_t size,
 	}
 
 	func = read_idmap[read_id] ?: FILE_CHECK;
-	security_task_getsecid_subj(current, &secid);
+	security_current_getsecid_subj(&secid);
 	return process_measurement(file, current_cred(), secid, buf, size,
 				   MAY_READ, func);
 }
@@ -905,7 +905,7 @@ int process_buffer_measurement(struct user_namespace *mnt_userns,
 	 * buffer measurements.
 	 */
 	if (func) {
-		security_task_getsecid_subj(current, &secid);
+		security_current_getsecid_subj(&secid);
 		action = ima_get_action(mnt_userns, inode, current_cred(),
 					secid, 0, func, &pcr, &template,
 					func_data, NULL);
diff --git a/security/security.c b/security/security.c
index c88167a414b4..3d4eb474f35b 100644
--- a/security/security.c
+++ b/security/security.c
@@ -994,14 +994,6 @@ int security_sb_clone_mnt_opts(const struct super_block *oldsb,
 }
 EXPORT_SYMBOL(security_sb_clone_mnt_opts);
 
-int security_add_mnt_opt(const char *option, const char *val, int len,
-			 void **mnt_opts)
-{
-	return call_int_hook(sb_add_mnt_opt, -EINVAL,
-					option, val, len, mnt_opts);
-}
-EXPORT_SYMBOL(security_add_mnt_opt);
-
 int security_move_mount(const struct path *from_path, const struct path *to_path)
 {
 	return call_int_hook(move_mount, 0, from_path, to_path);
@@ -1808,12 +1800,12 @@ int security_task_getsid(struct task_struct *p)
 	return call_int_hook(task_getsid, 0, p);
 }
 
-void security_task_getsecid_subj(struct task_struct *p, u32 *secid)
+void security_current_getsecid_subj(u32 *secid)
 {
 	*secid = 0;
-	call_void_hook(task_getsecid_subj, p, secid);
+	call_void_hook(current_getsecid_subj, secid);
 }
-EXPORT_SYMBOL(security_task_getsecid_subj);
+EXPORT_SYMBOL(security_current_getsecid_subj);
 
 void security_task_getsecid_obj(struct task_struct *p, u32 *secid)
 {
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index dde4ecc0cd18..5b6895e4fc29 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -230,19 +230,6 @@ static inline u32 cred_sid(const struct cred *cred)
 }
 
 /*
- * get the subjective security ID of a task
- */
-static inline u32 task_sid_subj(const struct task_struct *task)
-{
-	u32 sid;
-
-	rcu_read_lock();
-	sid = cred_sid(rcu_dereference(task->cred));
-	rcu_read_unlock();
-	return sid;
-}
-
-/*
  * get the objective security ID of a task
  */
 static inline u32 task_sid_obj(const struct task_struct *task)
@@ -988,82 +975,54 @@ out:
 static int selinux_add_opt(int token, const char *s, void **mnt_opts)
 {
 	struct selinux_mnt_opts *opts = *mnt_opts;
+	bool is_alloc_opts = false;
 
-	if (token == Opt_seclabel)	/* eaten and completely ignored */
+	if (token == Opt_seclabel)
+		/* eaten and completely ignored */
 		return 0;
+	if (!s)
+		return -ENOMEM;
 
 	if (!opts) {
-		opts = kzalloc(sizeof(struct selinux_mnt_opts), GFP_KERNEL);
+		opts = kzalloc(sizeof(*opts), GFP_KERNEL);
 		if (!opts)
 			return -ENOMEM;
 		*mnt_opts = opts;
+		is_alloc_opts = true;
 	}
-	if (!s)
-		return -ENOMEM;
+
 	switch (token) {
 	case Opt_context:
 		if (opts->context || opts->defcontext)
-			goto Einval;
+			goto err;
 		opts->context = s;
 		break;
 	case Opt_fscontext:
 		if (opts->fscontext)
-			goto Einval;
+			goto err;
 		opts->fscontext = s;
 		break;
 	case Opt_rootcontext:
 		if (opts->rootcontext)
-			goto Einval;
+			goto err;
 		opts->rootcontext = s;
 		break;
 	case Opt_defcontext:
 		if (opts->context || opts->defcontext)
-			goto Einval;
+			goto err;
 		opts->defcontext = s;
 		break;
 	}
-	return 0;
-Einval:
-	pr_warn(SEL_MOUNT_FAIL_MSG);
-	return -EINVAL;
-}
-
-static int selinux_add_mnt_opt(const char *option, const char *val, int len,
-			       void **mnt_opts)
-{
-	int token = Opt_error;
-	int rc, i;
-
-	for (i = 0; i < ARRAY_SIZE(tokens); i++) {
-		if (strcmp(option, tokens[i].name) == 0) {
-			token = tokens[i].opt;
-			break;
-		}
-	}
 
-	if (token == Opt_error)
-		return -EINVAL;
-
-	if (token != Opt_seclabel) {
-		val = kmemdup_nul(val, len, GFP_KERNEL);
-		if (!val) {
-			rc = -ENOMEM;
-			goto free_opt;
-		}
-	}
-	rc = selinux_add_opt(token, val, mnt_opts);
-	if (unlikely(rc)) {
-		kfree(val);
-		goto free_opt;
-	}
-	return rc;
+	return 0;
 
-free_opt:
-	if (*mnt_opts) {
-		selinux_free_mnt_opts(*mnt_opts);
+err:
+	if (is_alloc_opts) {
+		kfree(opts);
 		*mnt_opts = NULL;
 	}
-	return rc;
+	pr_warn(SEL_MOUNT_FAIL_MSG);
+	return -EINVAL;
 }
 
 static int show_sid(struct seq_file *m, u32 sid)
@@ -4210,9 +4169,9 @@ static int selinux_task_getsid(struct task_struct *p)
 			    PROCESS__GETSESSION, NULL);
 }
 
-static void selinux_task_getsecid_subj(struct task_struct *p, u32 *secid)
+static void selinux_current_getsecid_subj(u32 *secid)
 {
-	*secid = task_sid_subj(p);
+	*secid = current_sid();
 }
 
 static void selinux_task_getsecid_obj(struct task_struct *p, u32 *secid)
@@ -7164,7 +7123,7 @@ static struct security_hook_list selinux_hooks[] __lsm_ro_after_init = {
 	LSM_HOOK_INIT(task_setpgid, selinux_task_setpgid),
 	LSM_HOOK_INIT(task_getpgid, selinux_task_getpgid),
 	LSM_HOOK_INIT(task_getsid, selinux_task_getsid),
-	LSM_HOOK_INIT(task_getsecid_subj, selinux_task_getsecid_subj),
+	LSM_HOOK_INIT(current_getsecid_subj, selinux_current_getsecid_subj),
 	LSM_HOOK_INIT(task_getsecid_obj, selinux_task_getsecid_obj),
 	LSM_HOOK_INIT(task_setnice, selinux_task_setnice),
 	LSM_HOOK_INIT(task_setioprio, selinux_task_setioprio),
@@ -7303,7 +7262,6 @@ static struct security_hook_list selinux_hooks[] __lsm_ro_after_init = {
 	LSM_HOOK_INIT(fs_context_dup, selinux_fs_context_dup),
 	LSM_HOOK_INIT(fs_context_parse_param, selinux_fs_context_parse_param),
 	LSM_HOOK_INIT(sb_eat_lsm_opts, selinux_sb_eat_lsm_opts),
-	LSM_HOOK_INIT(sb_add_mnt_opt, selinux_add_mnt_opt),
 #ifdef CONFIG_SECURITY_NETWORK_XFRM
 	LSM_HOOK_INIT(xfrm_policy_clone_security, selinux_xfrm_policy_clone),
 #endif
diff --git a/security/selinux/ss/sidtab.c b/security/selinux/ss/sidtab.c
index 656d50b09f76..293ec048af08 100644
--- a/security/selinux/ss/sidtab.c
+++ b/security/selinux/ss/sidtab.c
@@ -570,7 +570,7 @@ void sidtab_sid2str_put(struct sidtab *s, struct sidtab_entry *entry,
 		goto out_unlock;
 	}
 
-	cache = kmalloc(sizeof(struct sidtab_str_cache) + str_len, GFP_ATOMIC);
+	cache = kmalloc(struct_size(cache, str, str_len), GFP_ATOMIC);
 	if (!cache)
 		goto out_unlock;
 
diff --git a/security/selinux/xfrm.c b/security/selinux/xfrm.c
index be83e5ce4469..90697317895f 100644
--- a/security/selinux/xfrm.c
+++ b/security/selinux/xfrm.c
@@ -89,7 +89,7 @@ static int selinux_xfrm_alloc_user(struct xfrm_sec_ctx **ctxp,
 	if (str_len >= PAGE_SIZE)
 		return -ENOMEM;
 
-	ctx = kmalloc(sizeof(*ctx) + str_len + 1, gfp);
+	ctx = kmalloc(struct_size(ctx, ctx_str, str_len + 1), gfp);
 	if (!ctx)
 		return -ENOMEM;
 
@@ -360,7 +360,7 @@ int selinux_xfrm_state_alloc_acquire(struct xfrm_state *x,
 	if (rc)
 		return rc;
 
-	ctx = kmalloc(sizeof(*ctx) + str_len, GFP_ATOMIC);
+	ctx = kmalloc(struct_size(ctx, ctx_str, str_len), GFP_ATOMIC);
 	if (!ctx) {
 		rc = -ENOMEM;
 		goto out;
diff --git a/security/smack/smack.h b/security/smack/smack.h
index 99c3422596ab..fc837dcebf96 100644
--- a/security/smack/smack.h
+++ b/security/smack/smack.h
@@ -389,22 +389,6 @@ static inline struct smack_known *smk_of_task(const struct task_smack *tsp)
 	return tsp->smk_task;
 }
 
-static inline struct smack_known *smk_of_task_struct_subj(
-						const struct task_struct *t)
-{
-	struct smack_known *skp;
-	const struct cred *cred;
-
-	rcu_read_lock();
-
-	cred = rcu_dereference(t->cred);
-	skp = smk_of_task(smack_cred(cred));
-
-	rcu_read_unlock();
-
-	return skp;
-}
-
 static inline struct smack_known *smk_of_task_struct_obj(
 						const struct task_struct *t)
 {
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index efd35b07c7f8..14b279cc75c9 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -2067,15 +2067,14 @@ static int smack_task_getsid(struct task_struct *p)
 }
 
 /**
- * smack_task_getsecid_subj - get the subjective secid of the task
- * @p: the task
+ * smack_current_getsecid_subj - get the subjective secid of the current task
  * @secid: where to put the result
  *
  * Sets the secid to contain a u32 version of the task's subjective smack label.
  */
-static void smack_task_getsecid_subj(struct task_struct *p, u32 *secid)
+static void smack_current_getsecid_subj(u32 *secid)
 {
-	struct smack_known *skp = smk_of_task_struct_subj(p);
+	struct smack_known *skp = smk_of_current();
 
 	*secid = skp->smk_secid;
 }
@@ -4807,7 +4806,7 @@ static struct security_hook_list smack_hooks[] __lsm_ro_after_init = {
 	LSM_HOOK_INIT(task_setpgid, smack_task_setpgid),
 	LSM_HOOK_INIT(task_getpgid, smack_task_getpgid),
 	LSM_HOOK_INIT(task_getsid, smack_task_getsid),
-	LSM_HOOK_INIT(task_getsecid_subj, smack_task_getsecid_subj),
+	LSM_HOOK_INIT(current_getsecid_subj, smack_current_getsecid_subj),
 	LSM_HOOK_INIT(task_getsecid_obj, smack_task_getsecid_obj),
 	LSM_HOOK_INIT(task_setnice, smack_task_setnice),
 	LSM_HOOK_INIT(task_setioprio, smack_task_setioprio),