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[PATCH] get rid of loginuid races

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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 <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2008-01-10 04:53:18 -05:00
parent 0c11b9428f
commit bfef93a5d1
4 changed files with 25 additions and 41 deletions
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2
include/linux/audit.h
View file

@ -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);

7
include/linux/init_task.h
View file

@ -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 \
}

3
include/linux/sched.h
View file

@ -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 */

54
kernel/auditsc.c
View file

@ -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;
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,
context->loginuid, loginuid);
audit_log_end(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);