The audit-related parameters in struct task_struct should ideally be collected together and accessed through a standard audit API and the audit structures made opaque to other kernel subsystems.
Collect the existing loginuid, sessionid and audit_context together in a new opaque struct audit_task_info called "audit" in struct task_struct. Use kmem_cache to manage this pool of memory. Un-inline audit_free() to be able to always recover that memory. Please see the upstream github issues https://github.com/linux-audit/audit-kernel/issues/81 https://github.com/linux-audit/audit-kernel/issues/90 Signed-off-by: Richard Guy Briggs <r...@redhat.com> --- Acks removed due to significant code changes hiding audit task struct: Acked-by: Neil Horman <nhor...@tuxdriver.com> Reviewed-by: Ondrej Mosnacek <omosn...@redhat.com> --- fs/io-wq.c | 8 +-- fs/io_uring.c | 16 ++--- include/linux/audit.h | 49 +++++--------- include/linux/sched.h | 7 +- init/init_task.c | 3 +- init/main.c | 2 + kernel/audit.c | 154 +++++++++++++++++++++++++++++++++++++++++- kernel/audit.h | 7 ++ kernel/auditsc.c | 24 ++++--- kernel/fork.c | 1 - 10 files changed, 205 insertions(+), 66 deletions(-) diff --git a/fs/io-wq.c b/fs/io-wq.c index a564f36e260c..0c57a20f4feb 100644 --- a/fs/io-wq.c +++ b/fs/io-wq.c @@ -499,8 +499,8 @@ static void io_impersonate_work(struct io_worker *worker, current->signal->rlim[RLIMIT_FSIZE].rlim_cur = RLIM_INFINITY; io_wq_switch_blkcg(worker, work); #ifdef CONFIG_AUDIT - current->loginuid = work->identity->loginuid; - current->sessionid = work->identity->sessionid; + audit_set_loginuid_iouring(work->identity->loginuid); + audit_set_sessionid_iouring(work->identity->sessionid); #endif } @@ -515,8 +515,8 @@ static void io_assign_current_work(struct io_worker *worker, } #ifdef CONFIG_AUDIT - current->loginuid = KUIDT_INIT(AUDIT_UID_UNSET); - current->sessionid = AUDIT_SID_UNSET; + audit_set_loginuid_iouring(KUIDT_INIT(AUDIT_UID_UNSET)); + audit_set_sessionid_iouring(AUDIT_SID_UNSET); #endif spin_lock_irq(&worker->lock); diff --git a/fs/io_uring.c b/fs/io_uring.c index ca46f314640b..7aaff14d2859 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -1216,8 +1216,8 @@ static void io_init_identity(struct io_identity *id) id->fs = current->fs; id->fsize = rlimit(RLIMIT_FSIZE); #ifdef CONFIG_AUDIT - id->loginuid = current->loginuid; - id->sessionid = current->sessionid; + id->loginuid = audit_get_loginuid(current); + id->sessionid = audit_get_sessionid(current); #endif refcount_set(&id->count, 1); } @@ -1473,8 +1473,8 @@ static bool io_grab_identity(struct io_kiocb *req) req->work.flags |= IO_WQ_WORK_CREDS; } #ifdef CONFIG_AUDIT - if (!uid_eq(current->loginuid, id->loginuid) || - current->sessionid != id->sessionid) + if (!uid_eq(audit_get_loginuid(current), id->loginuid) || + audit_get_sessionid(current) != id->sessionid) return false; #endif if (!(req->work.flags & IO_WQ_WORK_FS) && @@ -7016,8 +7016,8 @@ static int io_sq_thread(void *data) } io_sq_thread_associate_blkcg(ctx, &cur_css); #ifdef CONFIG_AUDIT - current->loginuid = ctx->loginuid; - current->sessionid = ctx->sessionid; + audit_set_loginuid_iouring(ctx->loginuid); + audit_set_sessionid_iouring(ctx->sessionid); #endif ret = __io_sq_thread(ctx, cap_entries); @@ -9528,8 +9528,8 @@ static int io_uring_create(unsigned entries, struct io_uring_params *p, ctx->user = user; ctx->creds = get_current_cred(); #ifdef CONFIG_AUDIT - ctx->loginuid = current->loginuid; - ctx->sessionid = current->sessionid; + ctx->loginuid = audit_get_loginuid(current); + ctx->sessionid = audit_get_sessionid(current); #endif ctx->sqo_task = get_task_struct(current); diff --git a/include/linux/audit.h b/include/linux/audit.h index 82b7c1116a85..515cc89a7e0c 100644 --- a/include/linux/audit.h +++ b/include/linux/audit.h @@ -154,6 +154,9 @@ struct filename; #ifdef CONFIG_AUDIT /* These are defined in audit.c */ /* Public API */ +extern int audit_alloc(struct task_struct *task); +extern void audit_free(struct task_struct *task); +extern void __init audit_task_init(void); extern __printf(4, 5) void audit_log(struct audit_context *ctx, gfp_t gfp_mask, int type, const char *fmt, ...); @@ -194,22 +197,26 @@ extern int audit_rule_change(int type, int seq, void *data, size_t datasz); extern int audit_list_rules_send(struct sk_buff *request_skb, int seq); extern int audit_set_loginuid(kuid_t loginuid); +extern void audit_set_loginuid_iouring(kuid_t loginuid); -static inline kuid_t audit_get_loginuid(struct task_struct *tsk) -{ - return tsk->loginuid; -} +extern kuid_t audit_get_loginuid(struct task_struct *tsk); -static inline unsigned int audit_get_sessionid(struct task_struct *tsk) -{ - return tsk->sessionid; -} +extern unsigned int audit_get_sessionid(struct task_struct *tsk); +extern void audit_set_sessionid_iouring(unsigned int sessionid); extern u32 audit_enabled; extern int audit_signal_info(int sig, struct task_struct *t); #else /* CONFIG_AUDIT */ +static inline int audit_alloc(struct task_struct *task) +{ + return 0; +} +static inline void audit_free(struct task_struct *task) +{ } +static inline void __init audit_task_init(void) +{ } static inline __printf(4, 5) void audit_log(struct audit_context *ctx, gfp_t gfp_mask, int type, const char *fmt, ...) @@ -285,8 +292,6 @@ static inline int audit_signal_info(int sig, struct task_struct *t) /* These are defined in auditsc.c */ /* Public API */ -extern int audit_alloc(struct task_struct *task); -extern void __audit_free(struct task_struct *task); 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); @@ -303,26 +308,14 @@ extern void audit_seccomp_actions_logged(const char *names, const char *old_names, int res); extern void __audit_ptrace(struct task_struct *t); -static inline void audit_set_context(struct task_struct *task, struct audit_context *ctx) -{ - task->audit_context = ctx; -} - -static inline struct audit_context *audit_context(void) -{ - return current->audit_context; -} +extern struct audit_context *audit_context(void); static inline bool audit_dummy_context(void) { void *p = audit_context(); return !p || *(int *)p; } -static inline void audit_free(struct task_struct *task) -{ - if (unlikely(task->audit_context)) - __audit_free(task); -} + static inline void audit_syscall_entry(int major, unsigned long a0, unsigned long a1, unsigned long a2, unsigned long a3) @@ -550,12 +543,6 @@ 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 int audit_alloc(struct task_struct *task) -{ - return 0; -} -static inline void audit_free(struct task_struct *task) -{ } static inline void audit_syscall_entry(int major, unsigned long a0, unsigned long a1, unsigned long a2, unsigned long a3) @@ -566,8 +553,6 @@ static inline bool audit_dummy_context(void) { return true; } -static inline void audit_set_context(struct task_struct *task, struct audit_context *ctx) -{ } static inline struct audit_context *audit_context(void) { return NULL; diff --git a/include/linux/sched.h b/include/linux/sched.h index 6e3a5eeec509..1d10d81b8fd5 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -38,7 +38,6 @@ #include <asm/kmap_size.h> /* task_struct member predeclarations (sorted alphabetically): */ -struct audit_context; struct backing_dev_info; struct bio_list; struct blk_plug; @@ -994,11 +993,7 @@ struct task_struct { struct callback_head *task_works; #ifdef CONFIG_AUDIT -#ifdef CONFIG_AUDITSYSCALL - struct audit_context *audit_context; -#endif - kuid_t loginuid; - unsigned int sessionid; + void *audit; #endif struct seccomp seccomp; struct syscall_user_dispatch syscall_dispatch; diff --git a/init/init_task.c b/init/init_task.c index 8a992d73e6fb..431e9e7a0b5c 100644 --- a/init/init_task.c +++ b/init/init_task.c @@ -134,8 +134,7 @@ struct task_struct init_task .thread_group = LIST_HEAD_INIT(init_task.thread_group), .thread_node = LIST_HEAD_INIT(init_signals.thread_head), #ifdef CONFIG_AUDIT - .loginuid = INVALID_UID, - .sessionid = AUDIT_SID_UNSET, + .audit = NULL, #endif #ifdef CONFIG_PERF_EVENTS .perf_event_mutex = __MUTEX_INITIALIZER(init_task.perf_event_mutex), diff --git a/init/main.c b/init/main.c index 6feee7f11eaf..7e92c22fbd2e 100644 --- a/init/main.c +++ b/init/main.c @@ -97,6 +97,7 @@ #include <linux/mem_encrypt.h> #include <linux/kcsan.h> #include <linux/init_syscalls.h> +#include <linux/audit.h> #include <asm/io.h> #include <asm/bugs.h> @@ -1046,6 +1047,7 @@ asmlinkage __visible void __init __no_sanitize_address start_kernel(void) nsfs_init(); cpuset_init(); cgroup_init(); + audit_task_init(); taskstats_init_early(); delayacct_init(); diff --git a/kernel/audit.c b/kernel/audit.c index 0bc0b20c6c04..a822fa3b8da3 100644 --- a/kernel/audit.c +++ b/kernel/audit.c @@ -208,6 +208,148 @@ struct audit_reply { struct sk_buff *skb; }; +struct audit_task_info { + kuid_t loginuid; + unsigned int sessionid; +#ifdef CONFIG_AUDITSYSCALL + struct audit_context *ctx; +#endif +}; + +static struct kmem_cache *audit_task_cache; + +void __init audit_task_init(void) +{ + audit_task_cache = kmem_cache_create("audit_task", + sizeof(struct audit_task_info), + 0, SLAB_PANIC, NULL); +} + +inline kuid_t audit_get_loginuid(struct task_struct *tsk) +{ + struct audit_task_info *info = tsk->audit; + + if (!info) + return INVALID_UID; + return info->loginuid; +} + +inline void audit_set_loginuid_iouring(kuid_t loginuid) +{ + struct audit_task_info *info = current->audit; + + if (!info) + return; + info->loginuid = loginuid; +} + +inline unsigned int audit_get_sessionid(struct task_struct *tsk) +{ + struct audit_task_info *info = tsk->audit; + + if (!info) + return AUDIT_SID_UNSET; + return info->sessionid; +} + +inline void audit_set_sessionid_iouring(unsigned int sessionid) +{ + struct audit_task_info *info = current->audit; + + if (!info) + return; + info->sessionid = sessionid; +} + +inline struct audit_context *_audit_context(struct task_struct *tsk) +{ + struct audit_task_info *info = tsk->audit; + + if (!info) + return NULL; + return info->ctx; +} + +struct audit_context *audit_context(void) +{ + return _audit_context(current); +} +EXPORT_SYMBOL(audit_context); + +static void audit_alloc_task(struct task_struct *tsk) +{ + struct audit_task_info *info = tsk->audit; + + if (info && !IS_ERR(info)) + return; + info = kmem_cache_alloc(audit_task_cache, GFP_KERNEL); + if (!info) { + tsk->audit = ERR_PTR(-ENOMEM); + return; + } + info->loginuid = audit_get_loginuid(current); + info->sessionid = audit_get_sessionid(current); + tsk->audit = info; +} + +void audit_set_context(struct task_struct *tsk, struct audit_context *ctx) +{ + struct audit_task_info *info; + + audit_alloc_task(tsk); + info = tsk->audit; + if (!IS_ERR(info)) + info->ctx = ctx; + else + tsk->audit = NULL; +} + +/** + * audit_alloc - allocate an audit info block for a task + * @tsk: task + * + * Call audit_alloc_syscall to filter on the task information and + * allocate a per-task audit context if necessary. This is called from + * copy_process, so no lock is needed. + */ +int audit_alloc(struct task_struct *tsk) +{ + int ret = 0; + + tsk->audit = NULL; + audit_alloc_task(tsk); + if (IS_ERR(tsk->audit)) { + ret = PTR_ERR(tsk->audit); + tsk->audit = NULL; + goto out; + } + ret = audit_alloc_syscall(tsk); + if (ret) { + kmem_cache_free(audit_task_cache, tsk->audit); + tsk->audit = NULL; + } +out: + return ret; +} + +/** + * audit_free - free per-task audit info + * @tsk: task whose audit info block to free + * + * Called from copy_process and do_exit + */ +void audit_free(struct task_struct *tsk) +{ + struct audit_task_info *info = tsk->audit; + + audit_free_syscall(tsk); + /* Freeing the audit_task_info struct must be performed after + * audit_log_exit() due to need for loginuid and sessionid. + */ + tsk->audit = NULL; + kmem_cache_free(audit_task_cache, info); +} + /** * auditd_test_task - Check to see if a given task is an audit daemon * @task: the task to check @@ -2310,6 +2452,7 @@ int audit_set_loginuid(kuid_t loginuid) unsigned int oldsessionid, sessionid = AUDIT_SID_UNSET; kuid_t oldloginuid; int rc; + struct audit_task_info *info; oldloginuid = audit_get_loginuid(current); oldsessionid = audit_get_sessionid(current); @@ -2317,6 +2460,12 @@ int audit_set_loginuid(kuid_t loginuid) rc = audit_set_loginuid_perm(loginuid); if (rc) goto out; + audit_alloc_task(current); + if (IS_ERR(current->audit)) { + rc = PTR_ERR(current->audit); + current->audit = NULL; + goto out; + } /* are we setting or clearing? */ if (uid_valid(loginuid)) { @@ -2325,8 +2474,9 @@ int audit_set_loginuid(kuid_t loginuid) sessionid = (unsigned int)atomic_inc_return(&session_id); } - current->sessionid = sessionid; - current->loginuid = loginuid; + info = current->audit; + info->sessionid = sessionid; + info->loginuid = loginuid; out: audit_log_set_loginuid(oldloginuid, loginuid, oldsessionid, sessionid, rc); return rc; diff --git a/kernel/audit.h b/kernel/audit.h index 3b9c0945225a..aa81d913a3d2 100644 --- a/kernel/audit.h +++ b/kernel/audit.h @@ -251,6 +251,10 @@ extern void audit_put_tty(struct tty_struct *tty); extern unsigned int audit_serial(void); extern int auditsc_get_stamp(struct audit_context *ctx, struct timespec64 *t, unsigned int *serial); +extern void audit_set_context(struct task_struct *task, struct audit_context *ctx); +extern struct audit_context *_audit_context(struct task_struct *tsk); +extern int audit_alloc_syscall(struct task_struct *tsk); +extern void audit_free_syscall(struct task_struct *tsk); extern void audit_put_watch(struct audit_watch *watch); extern void audit_get_watch(struct audit_watch *watch); @@ -292,6 +296,9 @@ extern void audit_filter_inodes(struct task_struct *tsk, extern struct list_head *audit_killed_trees(void); #else /* CONFIG_AUDITSYSCALL */ #define auditsc_get_stamp(c, t, s) 0 +#define audit_alloc_syscall(t) 0 +#define audit_free_syscall(t) {} + #define audit_put_watch(w) {} #define audit_get_watch(w) {} #define audit_to_watch(k, p, l, o) (-EINVAL) diff --git a/kernel/auditsc.c b/kernel/auditsc.c index ce8c9e2279ba..018d2df70319 100644 --- a/kernel/auditsc.c +++ b/kernel/auditsc.c @@ -932,23 +932,25 @@ static inline struct audit_context *audit_alloc_context(enum audit_state state) return context; } -/** - * audit_alloc - allocate an audit context block for a task +/* + * audit_alloc_syscall - allocate an audit context block for a task * @tsk: task * * Filter on the task information and allocate a per-task audit context * if necessary. Doing so turns on system call auditing for the - * specified task. This is called from copy_process, so no lock is - * needed. + * specified task. This is called from copy_process via audit_alloc, so + * no lock is needed. */ -int audit_alloc(struct task_struct *tsk) +int audit_alloc_syscall(struct task_struct *tsk) { struct audit_context *context; enum audit_state state; char *key = NULL; - if (likely(!audit_ever_enabled)) + if (likely(!audit_ever_enabled)) { + audit_set_context(tsk, NULL); return 0; /* Return if not auditing. */ + } state = audit_filter_task(tsk, &key); if (state == AUDIT_DISABLED) { @@ -958,7 +960,7 @@ int audit_alloc(struct task_struct *tsk) if (!(context = audit_alloc_context(state))) { kfree(key); - audit_log_lost("out of memory in audit_alloc"); + audit_log_lost("out of memory in audit_alloc_syscall"); return -ENOMEM; } context->filterkey = key; @@ -1603,14 +1605,14 @@ static void audit_log_exit(void) } /** - * __audit_free - free a per-task audit context + * audit_free_syscall - free per-task audit context info * @tsk: task whose audit context block to free * - * Called from copy_process and do_exit + * Called from audit_free */ -void __audit_free(struct task_struct *tsk) +void audit_free_syscall(struct task_struct *tsk) { - struct audit_context *context = tsk->audit_context; + struct audit_context *context = _audit_context(tsk); if (!context) return; diff --git a/kernel/fork.c b/kernel/fork.c index 37720a6d04ea..eea2707fcee1 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -2028,7 +2028,6 @@ static __latent_entropy struct task_struct *copy_process( posix_cputimers_init(&p->posix_cputimers); p->io_context = NULL; - audit_set_context(p, NULL); cgroup_fork(p); #ifdef CONFIG_NUMA p->mempolicy = mpol_dup(p->mempolicy); -- 2.18.4
