From bfef93a5d1fb5654fe2025276c55e202d10b5255 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Thu, 10 Jan 2008 04:53:18 -0500 Subject: [PATCH] [PATCH] get rid of loginuid races Keeping loginuid in audit_context is racy and results in messier code. Taken to task_struct, out of the way of ->audit_context changes. Signed-off-by: Al Viro --- include/linux/audit.h | 2 +- include/linux/init_task.h | 7 +++++ include/linux/sched.h | 3 +++ kernel/auditsc.c | 56 +++++++++++---------------------------- 4 files changed, 26 insertions(+), 42 deletions(-) diff --git a/include/linux/audit.h b/include/linux/audit.h index f63117fab305..d7c6a12f4d1c 100644 --- a/include/linux/audit.h +++ b/include/linux/audit.h @@ -409,7 +409,7 @@ extern unsigned int audit_serial(void); extern void auditsc_get_stamp(struct audit_context *ctx, struct timespec *t, unsigned int *serial); extern int audit_set_loginuid(struct task_struct *task, uid_t loginuid); -extern uid_t audit_get_loginuid(struct task_struct *task); +#define audit_get_loginuid(t) ((t)->loginuid) extern void audit_log_task_context(struct audit_buffer *ab); extern int __audit_ipc_obj(struct kern_ipc_perm *ipcp); extern int __audit_ipc_set_perm(unsigned long qbytes, uid_t uid, gid_t gid, mode_t mode); diff --git a/include/linux/init_task.h b/include/linux/init_task.h index e6b3f7080679..ea3e9efd7396 100644 --- a/include/linux/init_task.h +++ b/include/linux/init_task.h @@ -114,6 +114,12 @@ extern struct group_info init_groups; .pid = &init_struct_pid, \ } +#ifdef CONFIG_AUDITSYSCALL +#define INIT_IDS \ + .loginuid = -1, +#else +#define INIT_IDS +#endif /* * INIT_TASK is used to set up the first task table, touch at * your own risk!. Base=0, limit=0x1fffff (=2MB) @@ -173,6 +179,7 @@ extern struct group_info init_groups; [PIDTYPE_SID] = INIT_PID_LINK(PIDTYPE_SID), \ }, \ .dirties = INIT_PROP_LOCAL_SINGLE(dirties), \ + INIT_IDS \ INIT_TRACE_IRQFLAGS \ INIT_LOCKDEP \ } diff --git a/include/linux/sched.h b/include/linux/sched.h index 6c333579d9da..5e2730389089 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1139,6 +1139,9 @@ struct task_struct { void *security; #endif struct audit_context *audit_context; +#ifdef CONFIG_AUDITSYSCALL + uid_t loginuid; +#endif seccomp_t seccomp; /* Thread group tracking */ diff --git a/kernel/auditsc.c b/kernel/auditsc.c index bd4e0a2443fb..c95173a194bf 100644 --- a/kernel/auditsc.c +++ b/kernel/auditsc.c @@ -192,7 +192,6 @@ struct audit_context { enum audit_state state; unsigned int serial; /* serial number for record */ struct timespec ctime; /* time of syscall entry */ - uid_t loginuid; /* login uid (identity) */ int major; /* syscall number */ unsigned long argv[4]; /* syscall arguments */ int return_valid; /* return code is valid */ @@ -506,7 +505,7 @@ static int audit_filter_rules(struct task_struct *tsk, case AUDIT_LOGINUID: result = 0; if (ctx) - result = audit_comparator(ctx->loginuid, f->op, f->val); + result = audit_comparator(tsk->loginuid, f->op, f->val); break; case AUDIT_SUBJ_USER: case AUDIT_SUBJ_ROLE: @@ -783,11 +782,8 @@ static inline void audit_free_aux(struct audit_context *context) static inline void audit_zero_context(struct audit_context *context, enum audit_state state) { - uid_t loginuid = context->loginuid; - memset(context, 0, sizeof(*context)); context->state = state; - context->loginuid = loginuid; } static inline struct audit_context *audit_alloc_context(enum audit_state state) @@ -826,11 +822,6 @@ int audit_alloc(struct task_struct *tsk) return -ENOMEM; } - /* Preserve login uid */ - context->loginuid = -1; - if (current->audit_context) - context->loginuid = current->audit_context->loginuid; - tsk->audit_context = context; set_tsk_thread_flag(tsk, TIF_SYSCALL_AUDIT); return 0; @@ -1047,7 +1038,7 @@ static void audit_log_exit(struct audit_context *context, struct task_struct *ts context->name_count, context->ppid, context->pid, - context->loginuid, + tsk->loginuid, context->uid, context->gid, context->euid, context->suid, context->fsuid, @@ -1779,39 +1770,22 @@ int audit_set_loginuid(struct task_struct *task, uid_t loginuid) { struct audit_context *context = task->audit_context; - if (context) { - /* Only log if audit is enabled */ - if (context->in_syscall) { - struct audit_buffer *ab; - - ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_LOGIN); - if (ab) { - audit_log_format(ab, "login pid=%d uid=%u " - "old auid=%u new auid=%u", - task->pid, task->uid, - context->loginuid, loginuid); - audit_log_end(ab); - } + if (context && context->in_syscall) { + struct audit_buffer *ab; + + ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_LOGIN); + if (ab) { + audit_log_format(ab, "login pid=%d uid=%u " + "old auid=%u new auid=%u", + task->pid, task->uid, + task->loginuid, loginuid); + audit_log_end(ab); } - context->loginuid = loginuid; } + task->loginuid = loginuid; return 0; } -/** - * audit_get_loginuid - get the loginuid for an audit_context - * @ctx: the audit_context - * - * Returns the context's loginuid or -1 if @ctx is NULL. - */ -uid_t audit_get_loginuid(struct task_struct *task) -{ - struct audit_context *ctx = task->audit_context; - return ctx ? ctx->loginuid : -1; -} - -EXPORT_SYMBOL(audit_get_loginuid); - /** * __audit_mq_open - record audit data for a POSIX MQ open * @oflag: open flag @@ -2217,8 +2191,8 @@ int __audit_signal_info(int sig, struct task_struct *t) if (audit_pid && t->tgid == audit_pid) { if (sig == SIGTERM || sig == SIGHUP || sig == SIGUSR1) { audit_sig_pid = tsk->pid; - if (ctx) - audit_sig_uid = ctx->loginuid; + if (tsk->loginuid != -1) + audit_sig_uid = tsk->loginuid; else audit_sig_uid = tsk->uid; selinux_get_task_sid(tsk, &audit_sig_sid); -- GitLab