diff options
Diffstat (limited to 'fs/exec.c')
-rw-r--r-- | fs/exec.c | 22 |
1 files changed, 19 insertions, 3 deletions
diff --git a/fs/exec.c b/fs/exec.c index d820a7272a76..0e46ec57fe0a 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -1010,16 +1010,26 @@ ssize_t read_code(struct file *file, unsigned long addr, loff_t pos, size_t len) } EXPORT_SYMBOL(read_code); +/* + * Maps the mm_struct mm into the current task struct. + * On success, this function returns with the mutex + * exec_update_mutex locked. + */ static int exec_mmap(struct mm_struct *mm) { struct task_struct *tsk; struct mm_struct *old_mm, *active_mm; + int ret; /* Notify parent that we're no longer interested in the old VM */ tsk = current; old_mm = current->mm; exec_mm_release(tsk, old_mm); + ret = mutex_lock_killable(&tsk->signal->exec_update_mutex); + if (ret) + return ret; + if (old_mm) { sync_mm_rss(old_mm); /* @@ -1031,9 +1041,11 @@ static int exec_mmap(struct mm_struct *mm) down_read(&old_mm->mmap_sem); if (unlikely(old_mm->core_state)) { up_read(&old_mm->mmap_sem); + mutex_unlock(&tsk->signal->exec_update_mutex); return -EINTR; } } + task_lock(tsk); active_mm = tsk->active_mm; membarrier_exec_mmap(mm); @@ -1288,11 +1300,12 @@ int flush_old_exec(struct linux_binprm * bprm) goto out; /* - * After clearing bprm->mm (to mark that current is using the - * prepared mm now), we have nothing left of the original + * After setting bprm->called_exec_mmap (to mark that current is + * using the prepared mm now), we have nothing left of the original * process. If anything from here on returns an error, the check * in search_binary_handler() will SEGV current. */ + bprm->called_exec_mmap = 1; bprm->mm = NULL; #ifdef CONFIG_POSIX_TIMERS @@ -1438,6 +1451,8 @@ static void free_bprm(struct linux_binprm *bprm) { free_arg_pages(bprm); if (bprm->cred) { + if (bprm->called_exec_mmap) + mutex_unlock(¤t->signal->exec_update_mutex); mutex_unlock(¤t->signal->cred_guard_mutex); abort_creds(bprm->cred); } @@ -1487,6 +1502,7 @@ void install_exec_creds(struct linux_binprm *bprm) * credentials; any time after this it may be unlocked. */ security_bprm_committed_creds(bprm); + mutex_unlock(¤t->signal->exec_update_mutex); mutex_unlock(¤t->signal->cred_guard_mutex); } EXPORT_SYMBOL(install_exec_creds); @@ -1678,7 +1694,7 @@ int search_binary_handler(struct linux_binprm *bprm) read_lock(&binfmt_lock); put_binfmt(fmt); - if (retval < 0 && !bprm->mm) { + if (retval < 0 && bprm->called_exec_mmap) { /* we got to flush_old_exec() and failed after it */ read_unlock(&binfmt_lock); force_sigsegv(SIGSEGV); |