From 2a1fe215e7300c7ebd6a7a24afcab71db5107bb0 Mon Sep 17 00:00:00 2001 From: Paul Moore Date: Mon, 26 Nov 2018 18:40:07 -0500 Subject: audit: use current whenever possible There are many places, notably audit_log_task_info() and audit_log_exit(), that take task_struct pointers but in reality they are always working on the current task. This patch eliminates the task_struct arguments and uses current directly which allows a number of cleanups as well. Acked-by: Richard Guy Briggs Signed-off-by: Paul Moore --- kernel/auditsc.c | 131 ++++++++++++++++++++++++++----------------------------- 1 file changed, 63 insertions(+), 68 deletions(-) (limited to 'kernel/auditsc.c') diff --git a/kernel/auditsc.c b/kernel/auditsc.c index 51e735aedf58..6593a5207fb0 100644 --- a/kernel/auditsc.c +++ b/kernel/auditsc.c @@ -830,44 +830,6 @@ void audit_filter_inodes(struct task_struct *tsk, struct audit_context *ctx) rcu_read_unlock(); } -/* Transfer the audit context pointer to the caller, clearing it in the tsk's struct */ -static inline struct audit_context *audit_take_context(struct task_struct *tsk, - int return_valid, - long return_code) -{ - struct audit_context *context = tsk->audit_context; - - if (!context) - return NULL; - context->return_valid = return_valid; - - /* - * we need to fix up the return code in the audit logs if the actual - * return codes are later going to be fixed up by the arch specific - * signal handlers - * - * This is actually a test for: - * (rc == ERESTARTSYS ) || (rc == ERESTARTNOINTR) || - * (rc == ERESTARTNOHAND) || (rc == ERESTART_RESTARTBLOCK) - * - * but is faster than a bunch of || - */ - if (unlikely(return_code <= -ERESTARTSYS) && - (return_code >= -ERESTART_RESTARTBLOCK) && - (return_code != -ENOIOCTLCMD)) - context->return_code = -EINTR; - else - context->return_code = return_code; - - if (context->in_syscall && !context->dummy) { - audit_filter_syscall(tsk, context, &audit_filter_list[AUDIT_FILTER_EXIT]); - audit_filter_inodes(tsk, context); - } - - audit_set_context(tsk, NULL); - return context; -} - static inline void audit_proctitle_free(struct audit_context *context) { kfree(context->proctitle.value); @@ -1296,15 +1258,18 @@ static inline int audit_proctitle_rtrim(char *proctitle, int len) return len; } -static void audit_log_proctitle(struct task_struct *tsk, - struct audit_context *context) +static void audit_log_proctitle(void) { int res; char *buf; char *msg = "(null)"; int len = strlen(msg); + struct audit_context *context = audit_context(); struct audit_buffer *ab; + if (!context || context->dummy) + return; + ab = audit_log_start(context, GFP_KERNEL, AUDIT_PROCTITLE); if (!ab) return; /* audit_panic or being filtered */ @@ -1317,7 +1282,7 @@ static void audit_log_proctitle(struct task_struct *tsk, if (!buf) goto out; /* Historically called this from procfs naming */ - res = get_cmdline(tsk, buf, MAX_PROCTITLE_AUDIT_LEN); + res = get_cmdline(current, buf, MAX_PROCTITLE_AUDIT_LEN); if (res == 0) { kfree(buf); goto out; @@ -1337,15 +1302,15 @@ out: audit_log_end(ab); } -static void audit_log_exit(struct audit_context *context, struct task_struct *tsk) +static void audit_log_exit(void) { int i, call_panic = 0; + struct audit_context *context = audit_context(); struct audit_buffer *ab; struct audit_aux_data *aux; struct audit_names *n; - /* tsk == current */ - context->personality = tsk->personality; + context->personality = current->personality; ab = audit_log_start(context, GFP_KERNEL, AUDIT_SYSCALL); if (!ab) @@ -1367,7 +1332,7 @@ static void audit_log_exit(struct audit_context *context, struct task_struct *ts context->argv[3], context->name_count); - audit_log_task_info(ab, tsk); + audit_log_task_info(ab); audit_log_key(ab, context->filterkey); audit_log_end(ab); @@ -1456,7 +1421,7 @@ static void audit_log_exit(struct audit_context *context, struct task_struct *ts audit_log_name(context, n, NULL, i++, &call_panic); } - audit_log_proctitle(tsk, context); + audit_log_proctitle(); /* Send end of event record to help user space know we are finished */ ab = audit_log_start(context, GFP_KERNEL, AUDIT_EOE); @@ -1474,22 +1439,31 @@ static void audit_log_exit(struct audit_context *context, struct task_struct *ts */ void __audit_free(struct task_struct *tsk) { - struct audit_context *context; + struct audit_context *context = tsk->audit_context; - context = audit_take_context(tsk, 0, 0); if (!context) return; - /* Check for system calls that do not go through the exit - * function (e.g., exit_group), then free context block. - * We use GFP_ATOMIC here because we might be doing this - * in the context of the idle thread */ - /* that can happen only if we are called from do_exit() */ - if (context->in_syscall && context->current_state == AUDIT_RECORD_CONTEXT) - audit_log_exit(context, tsk); + /* We are called either by do_exit() or the fork() error handling code; + * in the former case tsk == current and in the latter tsk is a + * random task_struct that doesn't doesn't have any meaningful data we + * need to log via audit_log_exit(). + */ + if (tsk == current && !context->dummy && context->in_syscall) { + context->return_valid = 0; + context->return_code = 0; + + audit_filter_syscall(tsk, context, + &audit_filter_list[AUDIT_FILTER_EXIT]); + audit_filter_inodes(tsk, context); + if (context->current_state == AUDIT_RECORD_CONTEXT) + audit_log_exit(); + } + if (!list_empty(&context->killed_trees)) audit_kill_trees(&context->killed_trees); + audit_set_context(tsk, NULL); audit_free_context(context); } @@ -1559,17 +1533,40 @@ void __audit_syscall_exit(int success, long return_code) { struct audit_context *context; - if (success) - success = AUDITSC_SUCCESS; - else - success = AUDITSC_FAILURE; - - context = audit_take_context(current, success, return_code); + context = audit_context(); if (!context) return; - if (context->in_syscall && context->current_state == AUDIT_RECORD_CONTEXT) - audit_log_exit(context, current); + if (!context->dummy && context->in_syscall) { + if (success) + context->return_valid = AUDITSC_SUCCESS; + else + context->return_valid = AUDITSC_FAILURE; + + /* + * we need to fix up the return code in the audit logs if the + * actual return codes are later going to be fixed up by the + * arch specific signal handlers + * + * This is actually a test for: + * (rc == ERESTARTSYS ) || (rc == ERESTARTNOINTR) || + * (rc == ERESTARTNOHAND) || (rc == ERESTART_RESTARTBLOCK) + * + * but is faster than a bunch of || + */ + if (unlikely(return_code <= -ERESTARTSYS) && + (return_code >= -ERESTART_RESTARTBLOCK) && + (return_code != -ENOIOCTLCMD)) + context->return_code = -EINTR; + else + context->return_code = return_code; + + audit_filter_syscall(current, context, + &audit_filter_list[AUDIT_FILTER_EXIT]); + audit_filter_inodes(current, context); + if (context->current_state == AUDIT_RECORD_CONTEXT) + audit_log_exit(); + } context->in_syscall = 0; context->prio = context->state == AUDIT_RECORD_CONTEXT ? ~0ULL : 0; @@ -1591,7 +1588,6 @@ void __audit_syscall_exit(int success, long return_code) kfree(context->filterkey); context->filterkey = NULL; } - audit_set_context(current, context); } static inline void handle_one(const struct inode *inode) @@ -2025,7 +2021,7 @@ static void audit_log_set_loginuid(kuid_t koldloginuid, kuid_t kloginuid, uid = from_kuid(&init_user_ns, task_uid(current)); oldloginuid = from_kuid(&init_user_ns, koldloginuid); loginuid = from_kuid(&init_user_ns, kloginuid), - tty = audit_get_tty(current); + tty = audit_get_tty(); audit_log_format(ab, "pid=%d uid=%u", task_tgid_nr(current), uid); audit_log_task_context(ab); @@ -2046,7 +2042,6 @@ static void audit_log_set_loginuid(kuid_t koldloginuid, kuid_t kloginuid, */ int audit_set_loginuid(kuid_t loginuid) { - struct task_struct *task = current; unsigned int oldsessionid, sessionid = AUDIT_SID_UNSET; kuid_t oldloginuid; int rc; @@ -2065,8 +2060,8 @@ int audit_set_loginuid(kuid_t loginuid) sessionid = (unsigned int)atomic_inc_return(&session_id); } - task->sessionid = sessionid; - task->loginuid = loginuid; + current->sessionid = sessionid; + current->loginuid = loginuid; out: audit_log_set_loginuid(oldloginuid, loginuid, oldsessionid, sessionid, rc); return rc; -- cgit