Merge branch 'for-linus' of git://git.o-hand.com/linux-rpurdie-backlight
[pandora-kernel.git] / fs / exec.c
index 9badbc0..e19de6a 100644 (file)
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -768,7 +768,6 @@ static int de_thread(struct task_struct *tsk)
        struct signal_struct *sig = tsk->signal;
        struct sighand_struct *oldsighand = tsk->sighand;
        spinlock_t *lock = &oldsighand->siglock;
-       int count;
 
        if (thread_group_empty(tsk))
                goto no_thread_group;
@@ -785,13 +784,13 @@ static int de_thread(struct task_struct *tsk)
                spin_unlock_irq(lock);
                return -EAGAIN;
        }
+
        sig->group_exit_task = tsk;
-       zap_other_threads(tsk);
+       sig->notify_count = zap_other_threads(tsk);
+       if (!thread_group_leader(tsk))
+               sig->notify_count--;
 
-       /* Account for the thread group leader hanging around: */
-       count = thread_group_leader(tsk) ? 1 : 2;
-       sig->notify_count = count;
-       while (atomic_read(&sig->count) > count) {
+       while (sig->notify_count) {
                __set_current_state(TASK_UNINTERRUPTIBLE);
                spin_unlock_irq(lock);
                schedule();
@@ -1662,12 +1661,15 @@ static int coredump_wait(int exit_code, struct core_state *core_state)
        struct task_struct *tsk = current;
        struct mm_struct *mm = tsk->mm;
        struct completion *vfork_done;
-       int core_waiters;
+       int core_waiters = -EBUSY;
 
        init_completion(&core_state->startup);
        core_state->dumper.task = tsk;
        core_state->dumper.next = NULL;
-       core_waiters = zap_threads(tsk, mm, core_state, exit_code);
+
+       down_write(&mm->mmap_sem);
+       if (!mm->core_state)
+               core_waiters = zap_threads(tsk, mm, core_state, exit_code);
        up_write(&mm->mmap_sem);
 
        if (unlikely(core_waiters < 0))
@@ -1787,21 +1789,61 @@ static void wait_for_dump_helpers(struct file *file)
 }
 
 
+/*
+ * uhm_pipe_setup
+ * helper function to customize the process used
+ * to collect the core in userspace.  Specifically
+ * it sets up a pipe and installs it as fd 0 (stdin)
+ * for the process.  Returns 0 on success, or
+ * PTR_ERR on failure.
+ * Note that it also sets the core limit to 1.  This
+ * is a special value that we use to trap recursive
+ * core dumps
+ */
+static int umh_pipe_setup(struct subprocess_info *info)
+{
+       struct file *rp, *wp;
+       struct fdtable *fdt;
+       struct coredump_params *cp = (struct coredump_params *)info->data;
+       struct files_struct *cf = current->files;
+
+       wp = create_write_pipe(0);
+       if (IS_ERR(wp))
+               return PTR_ERR(wp);
+
+       rp = create_read_pipe(wp, 0);
+       if (IS_ERR(rp)) {
+               free_write_pipe(wp);
+               return PTR_ERR(rp);
+       }
+
+       cp->file = wp;
+
+       sys_close(0);
+       fd_install(0, rp);
+       spin_lock(&cf->file_lock);
+       fdt = files_fdtable(cf);
+       FD_SET(0, fdt->open_fds);
+       FD_CLR(0, fdt->close_on_exec);
+       spin_unlock(&cf->file_lock);
+
+       /* and disallow core files too */
+       current->signal->rlim[RLIMIT_CORE] = (struct rlimit){1, 1};
+
+       return 0;
+}
+
 void do_coredump(long signr, int exit_code, struct pt_regs *regs)
 {
        struct core_state core_state;
        char corename[CORENAME_MAX_SIZE + 1];
        struct mm_struct *mm = current->mm;
        struct linux_binfmt * binfmt;
-       struct inode * inode;
        const struct cred *old_cred;
        struct cred *cred;
        int retval = 0;
        int flag = 0;
-       int ispipe = 0;
-       char **helper_argv = NULL;
-       int helper_argc = 0;
-       int dump_count = 0;
+       int ispipe;
        static atomic_t core_dump_count = ATOMIC_INIT(0);
        struct coredump_params cprm = {
                .signr = signr,
@@ -1820,23 +1862,12 @@ void do_coredump(long signr, int exit_code, struct pt_regs *regs)
        binfmt = mm->binfmt;
        if (!binfmt || !binfmt->core_dump)
                goto fail;
-
-       cred = prepare_creds();
-       if (!cred) {
-               retval = -ENOMEM;
+       if (!__get_dumpable(cprm.mm_flags))
                goto fail;
-       }
 
-       down_write(&mm->mmap_sem);
-       /*
-        * If another thread got here first, or we are not dumpable, bail out.
-        */
-       if (mm->core_state || !__get_dumpable(cprm.mm_flags)) {
-               up_write(&mm->mmap_sem);
-               put_cred(cred);
+       cred = prepare_creds();
+       if (!cred)
                goto fail;
-       }
-
        /*
         *      We cannot trust fsuid as being the "true" uid of the
         *      process nor do we know its entire history. We only know it
@@ -1849,10 +1880,8 @@ void do_coredump(long signr, int exit_code, struct pt_regs *regs)
        }
 
        retval = coredump_wait(exit_code, &core_state);
-       if (retval < 0) {
-               put_cred(cred);
-               goto fail;
-       }
+       if (retval < 0)
+               goto fail_creds;
 
        old_cred = override_creds(cred);
 
@@ -1870,19 +1899,19 @@ void do_coredump(long signr, int exit_code, struct pt_regs *regs)
        ispipe = format_corename(corename, signr);
        unlock_kernel();
 
-       if ((!ispipe) && (cprm.limit < binfmt->min_coredump))
-               goto fail_unlock;
-
        if (ispipe) {
-               if (cprm.limit == 0) {
+               int dump_count;
+               char **helper_argv;
+
+               if (cprm.limit == 1) {
                        /*
                         * Normally core limits are irrelevant to pipes, since
                         * we're not writing to the file system, but we use
-                        * cprm.limit of 0 here as a speacial value. Any
-                        * non-zero limit gets set to RLIM_INFINITY below, but
+                        * cprm.limit of 1 here as a speacial value. Any
+                        * non-1 limit gets set to RLIM_INFINITY below, but
                         * a limit of 0 skips the dump.  This is a consistent
                         * way to catch recursive crashes.  We can still crash
-                        * if the core_pattern binary sets RLIM_CORE =  !0
+                        * if the core_pattern binary sets RLIM_CORE =  !1
                         * but it runs as root, and can do lots of stupid things
                         * Note that we use task_tgid_vnr here to grab the pid
                         * of the process group leader.  That way we get the
@@ -1890,11 +1919,12 @@ void do_coredump(long signr, int exit_code, struct pt_regs *regs)
                         * core_pattern process dies.
                         */
                        printk(KERN_WARNING
-                               "Process %d(%s) has RLIMIT_CORE set to 0\n",
+                               "Process %d(%s) has RLIMIT_CORE set to 1\n",
                                task_tgid_vnr(current), current->comm);
                        printk(KERN_WARNING "Aborting core\n");
                        goto fail_unlock;
                }
+               cprm.limit = RLIM_INFINITY;
 
                dump_count = atomic_inc_return(&core_dump_count);
                if (core_pipe_limit && (core_pipe_limit < dump_count)) {
@@ -1904,71 +1934,74 @@ void do_coredump(long signr, int exit_code, struct pt_regs *regs)
                        goto fail_dropcount;
                }
 
-               helper_argv = argv_split(GFP_KERNEL, corename+1, &helper_argc);
+               helper_argv = argv_split(GFP_KERNEL, corename+1, NULL);
                if (!helper_argv) {
                        printk(KERN_WARNING "%s failed to allocate memory\n",
                               __func__);
                        goto fail_dropcount;
                }
 
-               cprm.limit = RLIM_INFINITY;
-
-               /* SIGPIPE can happen, but it's just never processed */
-               if (call_usermodehelper_pipe(helper_argv[0], helper_argv, NULL,
-                               &cprm.file)) {
+               retval = call_usermodehelper_fns(helper_argv[0], helper_argv,
+                                       NULL, UMH_WAIT_EXEC, umh_pipe_setup,
+                                       NULL, &cprm);
+               argv_free(helper_argv);
+               if (retval) {
                        printk(KERN_INFO "Core dump to %s pipe failed\n",
                               corename);
-                       goto fail_dropcount;
+                       goto close_fail;
                }
-       } else
+       } else {
+               struct inode *inode;
+
+               if (cprm.limit < binfmt->min_coredump)
+                       goto fail_unlock;
+
                cprm.file = filp_open(corename,
                                 O_CREAT | 2 | O_NOFOLLOW | O_LARGEFILE | flag,
                                 0600);
-       if (IS_ERR(cprm.file))
-               goto fail_dropcount;
-       inode = cprm.file->f_path.dentry->d_inode;
-       if (inode->i_nlink > 1)
-               goto close_fail;        /* multiple links - don't dump */
-       if (!ispipe && d_unhashed(cprm.file->f_path.dentry))
-               goto close_fail;
-
-       /* AK: actually i see no reason to not allow this for named pipes etc.,
-          but keep the previous behaviour for now. */
-       if (!ispipe && !S_ISREG(inode->i_mode))
-               goto close_fail;
-       /*
-        * Dont allow local users get cute and trick others to coredump
-        * into their pre-created files:
-        * Note, this is not relevant for pipes
-        */
-       if (!ispipe && (inode->i_uid != current_fsuid()))
-               goto close_fail;
-       if (!cprm.file->f_op)
-               goto close_fail;
-       if (!cprm.file->f_op->write)
-               goto close_fail;
-       if (!ispipe &&
-           do_truncate(cprm.file->f_path.dentry, 0, 0, cprm.file) != 0)
-               goto close_fail;
+               if (IS_ERR(cprm.file))
+                       goto fail_unlock;
 
-       retval = binfmt->core_dump(&cprm);
+               inode = cprm.file->f_path.dentry->d_inode;
+               if (inode->i_nlink > 1)
+                       goto close_fail;
+               if (d_unhashed(cprm.file->f_path.dentry))
+                       goto close_fail;
+               /*
+                * AK: actually i see no reason to not allow this for named
+                * pipes etc, but keep the previous behaviour for now.
+                */
+               if (!S_ISREG(inode->i_mode))
+                       goto close_fail;
+               /*
+                * Dont allow local users get cute and trick others to coredump
+                * into their pre-created files.
+                */
+               if (inode->i_uid != current_fsuid())
+                       goto close_fail;
+               if (!cprm.file->f_op || !cprm.file->f_op->write)
+                       goto close_fail;
+               if (do_truncate(cprm.file->f_path.dentry, 0, 0, cprm.file))
+                       goto close_fail;
+       }
 
+       retval = binfmt->core_dump(&cprm);
        if (retval)
                current->signal->group_exit_code |= 0x80;
-close_fail:
+
        if (ispipe && core_pipe_limit)
                wait_for_dump_helpers(cprm.file);
-       filp_close(cprm.file, NULL);
+close_fail:
+       if (cprm.file)
+               filp_close(cprm.file, NULL);
 fail_dropcount:
-       if (dump_count)
+       if (ispipe)
                atomic_dec(&core_dump_count);
 fail_unlock:
-       if (helper_argv)
-               argv_free(helper_argv);
-
+       coredump_finish(mm);
        revert_creds(old_cred);
+fail_creds:
        put_cred(cred);
-       coredump_finish(mm);
 fail:
        return;
 }