[v31,13/28] LSM: Use lsmblob in security_cred_getsecid

Commit Message

Casey Schaufler Dec. 13, 2021, 11:40 p.m. UTC

Change the security_cred_getsecid() interface to fill in a
lsmblob instead of a u32 secid. The associated data elements
in the audit sub-system are changed from a secid to a lsmblob
to accommodate multiple possible LSM audit users.

Reviewed-by: Kees Cook <[e-mail]>
Reviewed-by: John Johansen <[e-mail]>
Acked-by: Stephen Smalley <[e-mail]>
Acked-by: Paul Moore <[e-mail]>
Signed-off-by: Casey Schaufler <[e-mail]>
Cc: [e-mail]
Cc: [e-mail]
---
 drivers/android/binder.c          | 12 +----------
 include/linux/security.h          |  2 +-
 kernel/audit.c                    | 25 +++++++----------------
 kernel/audit.h                    |  3 ++-
 kernel/auditsc.c                  | 33 +++++++++++--------------------
 security/integrity/ima/ima_main.c |  8 ++++----
 security/security.c               | 12 ++++++++---
 7 files changed, 36 insertions(+), 59 deletions(-)

Comments

kernel test robot Dec. 15, 2021, 9:14 a.m. UTC | #1

Hi Casey,

I love your patch! Perhaps something to improve:

[auto build test WARNING on nf-next/master]
[also build test WARNING on nf/master linus/master v5.16-rc5]
[cannot apply to pcmoore-audit/next jmorris-security/next-testing next-20211214]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Casey-Schaufler/integrity-disassociate-ima_filter_rule-from-security_audit_rule/20211214-084057
base:   https://git.kernel.org/pub/scm/linux/kernel/git/pablo/nf-next.git master
config: microblaze-randconfig-s032-20211214 (https://download.01.org/0day-ci/archive/20211215/[e-mail]/config)
compiler: microblaze-linux-gcc (GCC) 11.2.0
reproduce:
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # apt-get install sparse
        # sparse version: v0.6.4-dirty
        # https://github.com/0day-ci/linux/commit/e66d6e6a2f53e0b36b78003ee8399a554ae82e3c
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Casey-Schaufler/integrity-disassociate-ima_filter_rule-from-security_audit_rule/20211214-084057
        git checkout e66d6e6a2f53e0b36b78003ee8399a554ae82e3c
        # save the config file to linux build tree
        mkdir build_dir
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' O=build_dir ARCH=microblaze SHELL=/bin/bash

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <[e-mail]>


sparse warnings: (new ones prefixed by >>)
>> kernel/audit.c:128:25: sparse: sparse: symbol 'audit_sig_lsm' was not declared. Should it be static?
   kernel/audit.c:2181:9: sparse: sparse: incorrect type in argument 1 (different address spaces) @@     expected struct spinlock [usertype] *lock @@     got struct spinlock [noderef] __rcu * @@
   kernel/audit.c:2181:9: sparse:     expected struct spinlock [usertype] *lock
   kernel/audit.c:2181:9: sparse:     got struct spinlock [noderef] __rcu *
   kernel/audit.c:2184:40: sparse: sparse: incorrect type in argument 1 (different address spaces) @@     expected struct spinlock [usertype] *lock @@     got struct spinlock [noderef] __rcu * @@
   kernel/audit.c:2184:40: sparse:     expected struct spinlock [usertype] *lock
   kernel/audit.c:2184:40: sparse:     got struct spinlock [noderef] __rcu *

vim +/audit_sig_lsm +128 kernel/audit.c

   124	
   125	/* The identity of the user shutting down the audit system. */
   126	static kuid_t		audit_sig_uid = INVALID_UID;
   127	static pid_t		audit_sig_pid = -1;
 > 128	struct lsmblob		audit_sig_lsm;
   129	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/[e-mail]

Patch

diff --git a/drivers/android/binder.c b/drivers/android/binder.c
index 916a42c68b58..27b53e5f71a1 100644
--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -2720,18 +2720,8 @@  static void binder_transaction(struct binder_proc *proc,
 	if (target_node && target_node->txn_security_ctx) {
 		struct lsmblob blob;
 		size_t added_size;
-		u32 secid;
 
-		security_cred_getsecid(proc->cred, &secid);
-		/*
-		 * Later in this patch set security_cred_getsecid() will
-		 * provide a lsmblob instead of a secid. lsmblob_init
-		 * is used to ensure that all the secids in the lsmblob
-		 * get the value returned from security_cred_getsecid(),
-		 * which means that the one expected by
-		 * security_secid_to_secctx() will be set.
-		 */
-		lsmblob_init(&blob, secid);
+		security_cred_getsecid(proc->cred, &blob);
 		ret = security_secid_to_secctx(&blob, &secctx, &secctx_sz);
 		if (ret) {
 			return_error = BR_FAILED_REPLY;
diff --git a/include/linux/security.h b/include/linux/security.h
index 3433850a3f9e..3b653fe331dd 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -484,7 +484,7 @@  int security_cred_alloc_blank(struct cred *cred, gfp_t gfp);
 void security_cred_free(struct cred *cred);
 int security_prepare_creds(struct cred *new, const struct cred *old, gfp_t gfp);
 void security_transfer_creds(struct cred *new, const struct cred *old);
-void security_cred_getsecid(const struct cred *c, u32 *secid);
+void security_cred_getsecid(const struct cred *c, struct lsmblob *blob);
 int security_kernel_act_as(struct cred *new, struct lsmblob *blob);
 int security_kernel_create_files_as(struct cred *new, struct inode *inode);
 int security_kernel_module_request(char *kmod_name);
diff --git a/kernel/audit.c b/kernel/audit.c
index d92c7b894183..8ec64e6e8bc0 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -125,7 +125,7 @@  static u32	audit_backlog_wait_time = AUDIT_BACKLOG_WAIT_TIME;
 /* The identity of the user shutting down the audit system. */
 static kuid_t		audit_sig_uid = INVALID_UID;
 static pid_t		audit_sig_pid = -1;
-static u32		audit_sig_sid;
+struct lsmblob		audit_sig_lsm;
 
 /* Records can be lost in several ways:
    0) [suppressed in audit_alloc]
@@ -1441,29 +1441,21 @@  static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 	}
 	case AUDIT_SIGNAL_INFO:
 		len = 0;
-		if (audit_sig_sid) {
-			struct lsmblob blob;
-
-			/*
-			 * lsmblob_init sets all values in the lsmblob
-			 * to audit_sig_sid. This is temporary until
-			 * audit_sig_sid is converted to a lsmblob, which
-			 * happens later in this patch set.
-			 */
-			lsmblob_init(&blob, audit_sig_sid);
-			err = security_secid_to_secctx(&blob, &ctx, &len);
+		if (lsmblob_is_set(&audit_sig_lsm)) {
+			err = security_secid_to_secctx(&audit_sig_lsm, &ctx,
+						       &len);
 			if (err)
 				return err;
 		}
 		sig_data = kmalloc(sizeof(*sig_data) + len, GFP_KERNEL);
 		if (!sig_data) {
-			if (audit_sig_sid)
+			if (lsmblob_is_set(&audit_sig_lsm))
 				security_release_secctx(ctx, len);
 			return -ENOMEM;
 		}
 		sig_data->uid = from_kuid(&init_user_ns, audit_sig_uid);
 		sig_data->pid = audit_sig_pid;
-		if (audit_sig_sid) {
+		if (lsmblob_is_set(&audit_sig_lsm)) {
 			memcpy(sig_data->ctx, ctx, len);
 			security_release_secctx(ctx, len);
 		}
@@ -2352,7 +2344,6 @@  int audit_set_loginuid(kuid_t loginuid)
 int audit_signal_info(int sig, struct task_struct *t)
 {
 	kuid_t uid = current_uid(), auid;
-	struct lsmblob blob;
 
 	if (auditd_test_task(t) &&
 	    (sig == SIGTERM || sig == SIGHUP ||
@@ -2363,9 +2354,7 @@  int audit_signal_info(int sig, struct task_struct *t)
 			audit_sig_uid = auid;
 		else
 			audit_sig_uid = uid;
-		security_task_getsecid_subj(current, &blob);
-		/* scaffolding until audit_sig_sid is converted */
-		audit_sig_sid = blob.secid[0];
+		security_task_getsecid_subj(current, &audit_sig_lsm);
 	}
 
 	return audit_signal_info_syscall(t);
diff --git a/kernel/audit.h b/kernel/audit.h
index c4498090a5bd..527d4c4acb12 100644
--- a/kernel/audit.h
+++ b/kernel/audit.h
@@ -12,6 +12,7 @@ 
 #include <linux/fs.h>
 #include <linux/audit.h>
 #include <linux/skbuff.h>
+#include <linux/security.h>
 #include <uapi/linux/mqueue.h>
 #include <linux/tty.h>
 #include <uapi/linux/openat2.h> // struct open_how
@@ -143,7 +144,7 @@  struct audit_context {
 	kuid_t		    target_auid;
 	kuid_t		    target_uid;
 	unsigned int	    target_sessionid;
-	u32		    target_sid;
+	struct lsmblob	    target_lsm;
 	char		    target_comm[TASK_COMM_LEN];
 
 	struct audit_tree_refs *trees, *first_trees;
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index 34cec4cd3dbf..930254bca7b5 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -99,7 +99,7 @@  struct audit_aux_data_pids {
 	kuid_t			target_auid[AUDIT_AUX_PIDS];
 	kuid_t			target_uid[AUDIT_AUX_PIDS];
 	unsigned int		target_sessionid[AUDIT_AUX_PIDS];
-	u32			target_sid[AUDIT_AUX_PIDS];
+	struct lsmblob		target_lsm[AUDIT_AUX_PIDS];
 	char 			target_comm[AUDIT_AUX_PIDS][TASK_COMM_LEN];
 	int			pid_count;
 };
@@ -1009,7 +1009,7 @@  static void audit_reset_context(struct audit_context *ctx)
 	ctx->target_pid = 0;
 	ctx->target_auid = ctx->target_uid = KUIDT_INIT(0);
 	ctx->target_sessionid = 0;
-	ctx->target_sid = 0;
+	lsmblob_init(&ctx->target_lsm, 0);
 	ctx->target_comm[0] = '\0';
 	unroll_tree_refs(ctx, NULL, 0);
 	WARN_ON(!list_empty(&ctx->killed_trees));
@@ -1107,14 +1107,14 @@  static inline void audit_free_context(struct audit_context *context)
 }
 
 static int audit_log_pid_context(struct audit_context *context, pid_t pid,
-				 kuid_t auid, kuid_t uid, unsigned int sessionid,
-				 u32 sid, char *comm)
+				 kuid_t auid, kuid_t uid,
+				 unsigned int sessionid,
+				 struct lsmblob *blob, char *comm)
 {
 	struct audit_buffer *ab;
 	char *ctx = NULL;
 	u32 len;
 	int rc = 0;
-	struct lsmblob blob;
 
 	ab = audit_log_start(context, GFP_KERNEL, AUDIT_OBJ_PID);
 	if (!ab)
@@ -1123,9 +1123,8 @@  static int audit_log_pid_context(struct audit_context *context, pid_t pid,
 	audit_log_format(ab, "opid=%d oauid=%d ouid=%d oses=%d", pid,
 			 from_kuid(&init_user_ns, auid),
 			 from_kuid(&init_user_ns, uid), sessionid);
-	if (sid) {
-		lsmblob_init(&blob, sid);
-		if (security_secid_to_secctx(&blob, &ctx, &len)) {
+	if (lsmblob_is_set(blob)) {
+		if (security_secid_to_secctx(blob, &ctx, &len)) {
 			audit_log_format(ab, " obj=(none)");
 			rc = 1;
 		} else {
@@ -1753,7 +1752,7 @@  static void audit_log_exit(void)
 						  axs->target_auid[i],
 						  axs->target_uid[i],
 						  axs->target_sessionid[i],
-						  axs->target_sid[i],
+						  &axs->target_lsm[i],
 						  axs->target_comm[i]))
 				call_panic = 1;
 	}
@@ -1762,7 +1761,7 @@  static void audit_log_exit(void)
 	    audit_log_pid_context(context, context->target_pid,
 				  context->target_auid, context->target_uid,
 				  context->target_sessionid,
-				  context->target_sid, context->target_comm))
+				  &context->target_lsm, context->target_comm))
 			call_panic = 1;
 
 	if (context->pwd.dentry && context->pwd.mnt) {
@@ -2698,15 +2697,12 @@  int __audit_sockaddr(int len, void *a)
 void __audit_ptrace(struct task_struct *t)
 {
 	struct audit_context *context = audit_context();
-	struct lsmblob blob;
 
 	context->target_pid = task_tgid_nr(t);
 	context->target_auid = audit_get_loginuid(t);
 	context->target_uid = task_uid(t);
 	context->target_sessionid = audit_get_sessionid(t);
-	security_task_getsecid_obj(t, &blob);
-	/* scaffolding - until target_sid is converted */
-	context->target_sid = blob.secid[0];
+	security_task_getsecid_obj(t, &context->target_lsm);
 	memcpy(context->target_comm, t->comm, TASK_COMM_LEN);
 }
 
@@ -2722,7 +2718,6 @@  int audit_signal_info_syscall(struct task_struct *t)
 	struct audit_aux_data_pids *axp;
 	struct audit_context *ctx = audit_context();
 	kuid_t t_uid = task_uid(t);
-	struct lsmblob blob;
 
 	if (!audit_signals || audit_dummy_context())
 		return 0;
@@ -2734,9 +2729,7 @@  int audit_signal_info_syscall(struct task_struct *t)
 		ctx->target_auid = audit_get_loginuid(t);
 		ctx->target_uid = t_uid;
 		ctx->target_sessionid = audit_get_sessionid(t);
-		security_task_getsecid_obj(t, &blob);
-		/* scaffolding until target_sid is converted */
-		ctx->target_sid = blob.secid[0];
+		security_task_getsecid_obj(t, &ctx->target_lsm);
 		memcpy(ctx->target_comm, t->comm, TASK_COMM_LEN);
 		return 0;
 	}
@@ -2757,9 +2750,7 @@  int audit_signal_info_syscall(struct task_struct *t)
 	axp->target_auid[axp->pid_count] = audit_get_loginuid(t);
 	axp->target_uid[axp->pid_count] = t_uid;
 	axp->target_sessionid[axp->pid_count] = audit_get_sessionid(t);
-	security_task_getsecid_obj(t, &blob);
-	/* scaffolding until target_sid is converted */
-	axp->target_sid[axp->pid_count] = blob.secid[0];
+	security_task_getsecid_obj(t, &axp->target_lsm[axp->pid_count]);
 	memcpy(axp->target_comm[axp->pid_count], t->comm, TASK_COMM_LEN);
 	axp->pid_count++;
 
diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
index c327f93d3962..1a4f7b00253b 100644
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c
@@ -486,7 +486,6 @@  int ima_file_mprotect(struct vm_area_struct *vma, unsigned long prot)
 int ima_bprm_check(struct linux_binprm *bprm)
 {
 	int ret;
-	u32 secid;
 	struct lsmblob blob;
 
 	security_task_getsecid_subj(current, &blob);
@@ -496,9 +495,10 @@  int ima_bprm_check(struct linux_binprm *bprm)
 	if (ret)
 		return ret;
 
-	security_cred_getsecid(bprm->cred, &secid);
-	return process_measurement(bprm->file, bprm->cred, secid, NULL, 0,
-				   MAY_EXEC, CREDS_CHECK);
+	security_cred_getsecid(bprm->cred, &blob);
+	/* scaffolding until process_measurement changes */
+	return process_measurement(bprm->file, bprm->cred, blob.secid[0],
+				   NULL, 0, MAY_EXEC, CREDS_CHECK);
 }
 
 /**
diff --git a/security/security.c b/security/security.c
index 57423c92589d..0e17620a60e2 100644
--- a/security/security.c
+++ b/security/security.c
@@ -1800,10 +1800,16 @@  void security_transfer_creds(struct cred *new, const struct cred *old)
 	call_void_hook(cred_transfer, new, old);
 }
 
-void security_cred_getsecid(const struct cred *c, u32 *secid)
+void security_cred_getsecid(const struct cred *c, struct lsmblob *blob)
 {
-	*secid = 0;
-	call_void_hook(cred_getsecid, c, secid);
+	struct security_hook_list *hp;
+
+	lsmblob_init(blob, 0);
+	hlist_for_each_entry(hp, &security_hook_heads.cred_getsecid, list) {
+		if (WARN_ON(hp->lsmid->slot < 0 || hp->lsmid->slot >= lsm_slot))
+			continue;
+		hp->hook.cred_getsecid(c, &blob->secid[hp->lsmid->slot]);
+	}
 }
 EXPORT_SYMBOL(security_cred_getsecid);