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Message-Id: <20210513200807.15910-22-casey@schaufler-ca.com>
Date: Thu, 13 May 2021 13:08:03 -0700
From: Casey Schaufler <casey@...aufler-ca.com>
To: casey.schaufler@...el.com, jmorris@...ei.org,
linux-security-module@...r.kernel.org, selinux@...r.kernel.org
Cc: casey@...aufler-ca.com, linux-audit@...hat.com,
keescook@...omium.org, john.johansen@...onical.com,
penguin-kernel@...ove.sakura.ne.jp, paul@...l-moore.com,
sds@...ho.nsa.gov, linux-kernel@...r.kernel.org,
Richard Guy Briggs <rgb@...hat.com>
Subject: [PATCH v26 21/25] audit: add support for non-syscall auxiliary records
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@...hat.com>
Signed-off-by: Casey Schaufler <casey@...aufler-ca.com>
Cc: linux-audit@...hat.com
To: Richard Guy Briggs <rgb@...hat.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 23a85a470121..27ef690afd30 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 67da23f6bebd..d4e061f95da8 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -925,11 +925,13 @@ 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;
@@ -965,7 +967,8 @@ 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;
@@ -977,8 +980,27 @@ 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);
@@ -989,6 +1011,7 @@ 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,
@@ -2210,7 +2233,7 @@ 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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