Re: [PATCH ghak90 (was ghak32) V4 05/10] 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(a)redhat.com&gt; Acked-by: Serge Hallyn <serge(a)hallyn.com&gt; --- 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 4f514ed..1f340ad 100644 --- a/include/linux/audit.h +++ b/include/linux/audit.h @@ -234,7 +234,9 @@ struct audit_task_info { extern struct audit_task_info init_struct_audit; extern void __init audit_task_init(void); extern int audit_alloc(struct task_struct *task); +extern struct audit_context *audit_alloc_local(gfp_t gfpflags); extern void audit_free(struct task_struct *task); +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); @@ -495,6 +497,12 @@ static inline int audit_alloc(struct task_struct *task) { return 0; } +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_free(struct task_struct *task) { } static inline void audit_syscall_entry(int major, unsigned long a0, diff --git a/kernel/audit.h b/kernel/audit.h index 1cf1c35..a6d00a5 100644 --- a/kernel/audit.h +++ b/kernel/audit.h @@ -110,6 +110,7 @@ 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 cdb24cf..7627f21 100644 --- a/kernel/auditsc.c +++ b/kernel/auditsc.c @@ -913,11 +913,13 @@ 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; @@ -970,7 +972,8 @@ int audit_alloc(struct task_struct *tsk) return 0; } - if (!(context = audit_alloc_context(state))) { + context = audit_alloc_context(state, GFP_KERNEL); + if (!(context)) { tsk->audit = NULL; kmem_cache_free(audit_task_cache, info); kfree(key); @@ -991,8 +994,27 @@ struct audit_task_info init_struct_audit = { .ctx = NULL, }; -static inline void audit_free_context(struct audit_context *context) +struct audit_context *audit_alloc_local(gfp_t gfpflags) { + struct audit_context *context; + + if (!audit_ever_enabled) + return NULL; /* Return if not auditing. */ + + context = audit_alloc_context(AUDIT_RECORD_CONTEXT, gfpflags); + if (!context) + return NULL; + context->serial = audit_serial(); + context->ctime = current_kernel_time64(); + context->local = true; + return context; +} +EXPORT_SYMBOL(audit_alloc_local); + +void audit_free_context(struct audit_context *context) +{ + if (!context) + return; audit_free_names(context); unroll_tree_refs(context, NULL, 0); free_tree_refs(context); @@ -1002,6 +1024,7 @@ 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, @@ -2024,7 +2047,7 @@ 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();