netns xfrm: fix "ip xfrm state|policy count" misreport

[safe/jmp/linux-2.6] / kernel / acct.c

diff --git a/kernel/acct.c b/kernel/acct.c
index 0feba97..a6605ca 100644 (file)
--- a/kernel/acct.c
+++ b/kernel/acct.c
@@ -215,6 +215,7 @@ static void acct_file_reopen(struct bsd_acct_struct *acct, struct file *file,
 static int acct_on(char *name)
 {
        struct file *file;
+       struct vfsmount *mnt;
        int error;
        struct pid_namespace *ns;
        struct bsd_acct_struct *acct = NULL;
@@ -256,11 +257,12 @@ static int acct_on(char *name)
                acct = NULL;
        }
 
-       mnt_pin(file->f_path.mnt);
+       mnt = file->f_path.mnt;
+       mnt_pin(mnt);
        acct_file_reopen(ns->bacct, file, ns);
        spin_unlock(&acct_lock);
 
-       mntput(file->f_path.mnt); /* it's pinned, now give up active reference */
+       mntput(mnt); /* it's pinned, now give up active reference */
        kfree(acct);
 
        return 0;
@@ -277,7 +279,7 @@ static int acct_on(char *name)
  * should be written. If the filename is NULL, accounting will be
  * shutdown.
  */
-asmlinkage long sys_acct(const char __user *name)
+SYSCALL_DEFINE1(acct, const char __user *, name)
 {
        int error;
 
@@ -489,13 +491,17 @@ static void do_acct_process(struct bsd_acct_struct *acct,
        u64 run_time;
        struct timespec uptime;
        struct tty_struct *tty;
+       const struct cred *orig_cred;
+
+       /* Perform file operations on behalf of whoever enabled accounting */
+       orig_cred = override_creds(file->f_cred);
 
        /*
         * First check to see if there is enough free_space to continue
         * the process accounting system.
         */
        if (!check_free_space(acct, file))
-               return;
+               goto out;
 
        /*
         * Fill the accounting struct with the needed info as recorded
@@ -530,15 +536,15 @@ static void do_acct_process(struct bsd_acct_struct *acct,
        do_div(elapsed, AHZ);
        ac.ac_btime = get_seconds() - elapsed;
        /* we really need to bite the bullet and change layout */
-       ac.ac_uid = current->uid;
-       ac.ac_gid = current->gid;
+       ac.ac_uid = orig_cred->uid;
+       ac.ac_gid = orig_cred->gid;
 #if ACCT_VERSION==2
        ac.ac_ahz = AHZ;
 #endif
 #if ACCT_VERSION==1 || ACCT_VERSION==2
        /* backward-compatible 16 bit fields */
-       ac.ac_uid16 = current->uid;
-       ac.ac_gid16 = current->gid;
+       ac.ac_uid16 = ac.ac_uid;
+       ac.ac_gid16 = ac.ac_gid;
 #endif
 #if ACCT_VERSION==3
        ac.ac_pid = task_tgid_nr_ns(current, ns);
@@ -548,7 +554,7 @@ static void do_acct_process(struct bsd_acct_struct *acct,
 #endif
 
        spin_lock_irq(&current->sighand->siglock);
-       tty = current->signal->tty;
+       tty = current->signal->tty;     /* Safe as we hold the siglock */
        ac.ac_tty = tty ? old_encode_dev(tty_devnum(tty)) : 0;
        ac.ac_utime = encode_comp_t(jiffies_to_AHZ(cputime_to_jiffies(pacct->ac_utime)));
        ac.ac_stime = encode_comp_t(jiffies_to_AHZ(cputime_to_jiffies(pacct->ac_stime)));
@@ -577,6 +583,8 @@ static void do_acct_process(struct bsd_acct_struct *acct,
                               sizeof(acct_t), &file->f_pos);
        current->signal->rlim[RLIMIT_FSIZE].rlim_cur = flim;
        set_fs(fs);
+out:
+       revert_creds(orig_cred);
 }
 
 /**
@@ -657,7 +665,8 @@ static void acct_process_in_ns(struct pid_namespace *ns)
 }
 
 /**
- * acct_process - now just a wrapper around do_acct_process
+ * acct_process - now just a wrapper around acct_process_in_ns,
+ * which in turn is a wrapper around do_acct_process.
  *
  * handles process accounting for an exiting task
  */
@@ -665,6 +674,11 @@ void acct_process(void)
 {
        struct pid_namespace *ns;
 
+       /*
+        * This loop is safe lockless, since current is still
+        * alive and holds its namespace, which in turn holds
+        * its parent.
+        */
        for (ns = task_active_pid_ns(current); ns != NULL; ns = ns->parent)
                acct_process_in_ns(ns);
 }