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 <r...@redhat.com>
Acked-by: Serge Hallyn <se...@hallyn.com>
Acked-by: Neil Horman <nhor...@tuxdriver.com>
Reviewed-by: Ondrej Mosnacek <omosn...@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 89cf7c66abe6..15d0defc5193 100644
--- a/include/linux/audit.h
+++ b/include/linux/audit.h
@@ -330,6 +330,8 @@ static inline int audit_signal_info(int sig, struct 
task_struct *t)
 
 /* These are defined in auditsc.c */
                                /* Public API */
+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);
@@ -592,6 +594,12 @@ 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 void audit_syscall_entry(int major, unsigned long a0,
                                       unsigned long a1, unsigned long a2,
                                       unsigned long a3)
diff --git a/kernel/audit.h b/kernel/audit.h
index 0c9446f8d52c..a7f88d76163f 100644
--- a/kernel/audit.h
+++ b/kernel/audit.h
@@ -98,6 +98,7 @@ 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 9e79645e5c0e..935eb3d2cde9 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -908,11 +908,13 @@ 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;
@@ -948,7 +950,8 @@ int audit_alloc_syscall(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_syscall");
                return -ENOMEM;
@@ -960,8 +963,27 @@ int audit_alloc_syscall(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);
@@ -972,6 +994,7 @@ 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, unsigned int 
sessionid,
@@ -2204,7 +2227,7 @@ void __audit_inode_child(struct inode *parent,
 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();
-- 
1.8.3.1

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