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From: Casey Schaufler <casey@schaufler-ca.com>
To: casey.schaufler@intel.com, jmorris@namei.org,
	linux-security-module@vger.kernel.org, selinux@vger.kernel.org
Cc: john.johansen@canonical.com, linux-kernel@vger.kernel.org,
	Richard Guy Briggs <rgb@redhat.com>,
	linux-audit@redhat.com, sds@tycho.nsa.gov
Subject: [PATCH v25 21/25] audit: add support for non-syscall auxiliary records
Date: Tue,  9 Mar 2021 06:42:39 -0800
Message-ID: <20210309144243.12519-22-casey@schaufler-ca.com> (raw)
In-Reply-To: <20210309144243.12519-1-casey@schaufler-ca.com>

Standalone audit records have the timestamp and serial number generated
on the fly and as such are unique, making them standalone.  This new
function audit_alloc_local() generates a local audit context that will
be used only for a standalone record and its auxiliary record(s).  The
context is discarded immediately after the local associated records are
produced.

Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Cc: linux-audit@redhat.com
To: Richard Guy Briggs <rgb@redhat.com>
---
 include/linux/audit.h |  8 ++++++++
 kernel/audit.h        |  1 +
 kernel/auditsc.c      | 33 ++++++++++++++++++++++++++++-----
 3 files changed, 37 insertions(+), 5 deletions(-)

diff --git a/include/linux/audit.h b/include/linux/audit.h
index 418a485af114..97cd7471e572 100644
--- a/include/linux/audit.h
+++ b/include/linux/audit.h
@@ -289,6 +289,8 @@ static inline int audit_signal_info(int sig, struct task_struct *t)
 				/* Public API */
 extern int  audit_alloc(struct task_struct *task);
 extern void __audit_free(struct task_struct *task);
+extern struct audit_context *audit_alloc_local(gfp_t gfpflags);
+extern void audit_free_context(struct audit_context *context);
 extern void __audit_syscall_entry(int major, unsigned long a0, unsigned long a1,
 				  unsigned long a2, unsigned long a3);
 extern void __audit_syscall_exit(int ret_success, long ret_value);
@@ -552,6 +554,12 @@ static inline void audit_log_nfcfg(const char *name, u8 af,
 extern int audit_n_rules;
 extern int audit_signals;
 #else /* CONFIG_AUDITSYSCALL */
++static inline struct audit_context *audit_alloc_local(gfp_t gfpflags)
+{
+	return NULL;
+}
+static inline void audit_free_context(struct audit_context *context)
+{ }
 static inline int audit_alloc(struct task_struct *task)
 {
 	return 0;
diff --git a/kernel/audit.h b/kernel/audit.h
index ce41886807bb..3f2285e1c6e0 100644
--- a/kernel/audit.h
+++ b/kernel/audit.h
@@ -99,6 +99,7 @@ struct audit_proctitle {
 struct audit_context {
 	int		    dummy;	/* must be the first element */
 	int		    in_syscall;	/* 1 if task is in a syscall */
+	bool		    local;	/* local context needed */
 	enum audit_state    state, current_state;
 	unsigned int	    serial;     /* serial number for record */
 	int		    major;      /* syscall number */
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index 3db1ec97720e..8994d4f4672e 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -927,11 +927,13 @@ static inline void audit_free_aux(struct audit_context *context)
 	}
 }
 
-static inline struct audit_context *audit_alloc_context(enum audit_state state)
+static inline struct audit_context *audit_alloc_context(enum audit_state state,
+							gfp_t gfpflags)
 {
 	struct audit_context *context;
 
-	context = kzalloc(sizeof(*context), GFP_KERNEL);
+	/* We can be called in atomic context via audit_tg() */
+	context = kzalloc(sizeof(*context), gfpflags);
 	if (!context)
 		return NULL;
 	context->state = state;
@@ -967,7 +969,8 @@ int audit_alloc(struct task_struct *tsk)
 		return 0;
 	}
 
-	if (!(context = audit_alloc_context(state))) {
+	context = audit_alloc_context(state, GFP_KERNEL);
+	if (!context) {
 		kfree(key);
 		audit_log_lost("out of memory in audit_alloc");
 		return -ENOMEM;
@@ -979,8 +982,27 @@ int audit_alloc(struct task_struct *tsk)
 	return 0;
 }
 
-static inline void audit_free_context(struct audit_context *context)
+struct audit_context *audit_alloc_local(gfp_t gfpflags)
 {
+	struct audit_context *context = NULL;
+
+	context = audit_alloc_context(AUDIT_RECORD_CONTEXT, gfpflags);
+	if (!context) {
+		audit_log_lost("out of memory in audit_alloc_local");
+		goto out;
+	}
+	context->serial = audit_serial();
+	ktime_get_coarse_real_ts64(&context->ctime);
+	context->local = true;
+out:
+	return context;
+}
+EXPORT_SYMBOL(audit_alloc_local);
+
+void audit_free_context(struct audit_context *context)
+{
+	if (!context)
+		return;
 	audit_free_module(context);
 	audit_free_names(context);
 	unroll_tree_refs(context, NULL, 0);
@@ -991,6 +1013,7 @@ static inline void audit_free_context(struct audit_context *context)
 	audit_proctitle_free(context);
 	kfree(context);
 }
+EXPORT_SYMBOL(audit_free_context);
 
 static int audit_log_pid_context(struct audit_context *context, pid_t pid,
 				 kuid_t auid, kuid_t uid,
@@ -2214,7 +2237,7 @@ EXPORT_SYMBOL_GPL(__audit_inode_child);
 int auditsc_get_stamp(struct audit_context *ctx,
 		       struct timespec64 *t, unsigned int *serial)
 {
-	if (!ctx->in_syscall)
+	if (!ctx->in_syscall && !ctx->local)
 		return 0;
 	if (!ctx->serial)
 		ctx->serial = audit_serial();
-- 
2.29.2

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  parent reply index

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20210309144243.12519-1-casey.ref@schaufler-ca.com>
2021-03-09 14:42 ` [PATCH v25 00/25] LSM: Module stacking for AppArmor Casey Schaufler
2021-03-09 14:42   ` [PATCH v25 01/25] LSM: Infrastructure management of the sock security Casey Schaufler
2021-03-09 14:42   ` [PATCH v25 02/25] LSM: Add the lsmblob data structure Casey Schaufler
2021-03-09 14:42   ` [PATCH v25 03/25] LSM: provide lsm name and id slot mappings Casey Schaufler
2021-03-09 14:42   ` [PATCH v25 04/25] IMA: avoid label collisions with stacked LSMs Casey Schaufler
2021-03-09 14:42   ` [PATCH v25 05/25] LSM: Use lsmblob in security_audit_rule_match Casey Schaufler
2021-03-09 14:42   ` [PATCH v25 06/25] LSM: Use lsmblob in security_kernel_act_as Casey Schaufler
2021-03-09 14:42   ` [PATCH v25 07/25] LSM: Use lsmblob in security_secctx_to_secid Casey Schaufler
2021-03-09 14:42   ` [PATCH v25 08/25] LSM: Use lsmblob in security_secid_to_secctx Casey Schaufler
2021-03-09 14:42   ` [PATCH v25 09/25] LSM: Use lsmblob in security_ipc_getsecid Casey Schaufler
2021-03-09 14:42   ` [PATCH v25 10/25] LSM: Use lsmblob in security_task_getsecid Casey Schaufler
2021-03-09 14:42   ` [PATCH v25 11/25] LSM: Use lsmblob in security_inode_getsecid Casey Schaufler
2021-03-09 14:42   ` [PATCH v25 12/25] LSM: Use lsmblob in security_cred_getsecid Casey Schaufler
2021-03-09 19:46     ` kernel test robot
2021-03-09 19:46     ` [RFC PATCH] LSM: audit_sig_lsm can be static kernel test robot
2021-03-09 14:42   ` [PATCH v25 13/25] IMA: Change internal interfaces to use lsmblobs Casey Schaufler
2021-03-09 14:42   ` [PATCH v25 14/25] LSM: Specify which LSM to display Casey Schaufler
2021-03-09 14:42   ` [PATCH v25 15/25] LSM: Ensure the correct LSM context releaser Casey Schaufler
2021-03-09 14:42   ` [PATCH v25 16/25] LSM: Use lsmcontext in security_secid_to_secctx Casey Schaufler
2021-03-09 14:42   ` [PATCH v25 17/25] LSM: Use lsmcontext in security_inode_getsecctx Casey Schaufler
2021-03-12 16:16     ` Chuck Lever III
2021-03-09 14:42   ` [PATCH v25 18/25] LSM: security_secid_to_secctx in netlink netfilter Casey Schaufler
2021-03-09 14:42   ` [PATCH v25 19/25] NET: Store LSM netlabel data in a lsmblob Casey Schaufler
2021-03-09 14:42   ` [PATCH v25 20/25] LSM: Verify LSM display sanity in binder Casey Schaufler
2021-03-09 14:42   ` Casey Schaufler [this message]
2021-03-09 17:55     ` [PATCH v25 21/25] audit: add support for non-syscall auxiliary records kernel test robot
2021-03-09 14:42   ` [PATCH v25 22/25] Audit: Add new record for multiple process LSM attributes Casey Schaufler
2021-03-09 17:04     ` kernel test robot
2021-03-09 17:19     ` kernel test robot
2021-03-09 14:42   ` [PATCH v25 23/25] Audit: Add a new record for multiple object " Casey Schaufler
2021-03-09 14:42   ` [PATCH v25 24/25] LSM: Add /proc attr entry for full LSM context Casey Schaufler
2021-03-09 14:42   ` [PATCH v25 25/25] AppArmor: Remove the exclusive flag Casey Schaufler

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