exec: kill ->load_binary != NULL check in search_binary_handler()

[platform/adaptation/renesas_rcar/renesas_kernel.git] / fs / exec.c

diff --git a/fs/exec.c b/fs/exec.c
index fd774c7..7b92fbf 100644 (file)
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -74,6 +74,8 @@ static DEFINE_RWLOCK(binfmt_lock);
 void __register_binfmt(struct linux_binfmt * fmt, int insert)
 {
        BUG_ON(!fmt);
+       if (WARN_ON(!fmt->load_binary))
+               return;
        write_lock(&binfmt_lock);
        insert ? list_add(&fmt->lh, &formats) :
                 list_add_tail(&fmt->lh, &formats);
@@ -266,7 +268,7 @@ static int __bprm_mm_init(struct linux_binprm *bprm)
        BUILD_BUG_ON(VM_STACK_FLAGS & VM_STACK_INCOMPLETE_SETUP);
        vma->vm_end = STACK_TOP_MAX;
        vma->vm_start = vma->vm_end - PAGE_SIZE;
-       vma->vm_flags = VM_STACK_FLAGS | VM_STACK_INCOMPLETE_SETUP;
+       vma->vm_flags = VM_SOFTDIRTY | VM_STACK_FLAGS | VM_STACK_INCOMPLETE_SETUP;
        vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
        INIT_LIST_HEAD(&vma->anon_vma_chain);
 
@@ -1370,13 +1372,11 @@ EXPORT_SYMBOL(remove_arg_zero);
  */
 int search_binary_handler(struct linux_binprm *bprm)
 {
-       unsigned int depth = bprm->recursion_depth;
-       int try,retval;
+       int try, retval;
        struct linux_binfmt *fmt;
-       pid_t old_pid, old_vpid;
 
        /* This allows 4 levels of binfmt rewrites before failing hard. */
-       if (depth > 5)
+       if (bprm->recursion_depth > 5)
                return -ELOOP;
 
        retval = security_bprm_check(bprm);
@@ -1387,37 +1387,18 @@ int search_binary_handler(struct linux_binprm *bprm)
        if (retval)
                return retval;
 
-       /* Need to fetch pid before load_binary changes it */
-       old_pid = current->pid;
-       rcu_read_lock();
-       old_vpid = task_pid_nr_ns(current, task_active_pid_ns(current->parent));
-       rcu_read_unlock();
-
        retval = -ENOENT;
        for (try=0; try<2; try++) {
                read_lock(&binfmt_lock);
                list_for_each_entry(fmt, &formats, lh) {
-                       int (*fn)(struct linux_binprm *) = fmt->load_binary;
-                       if (!fn)
-                               continue;
                        if (!try_module_get(fmt->module))
                                continue;
                        read_unlock(&binfmt_lock);
-                       bprm->recursion_depth = depth + 1;
-                       retval = fn(bprm);
-                       bprm->recursion_depth = depth;
+                       bprm->recursion_depth++;
+                       retval = fmt->load_binary(bprm);
+                       bprm->recursion_depth--;
                        if (retval >= 0) {
-                               if (depth == 0) {
-                                       trace_sched_process_exec(current, old_pid, bprm);
-                                       ptrace_event(PTRACE_EVENT_EXEC, old_vpid);
-                               }
                                put_binfmt(fmt);
-                               allow_write_access(bprm->file);
-                               if (bprm->file)
-                                       fput(bprm->file);
-                               bprm->file = NULL;
-                               current->did_exec = 1;
-                               proc_exec_connector(current);
                                return retval;
                        }
                        read_lock(&binfmt_lock);
@@ -1450,9 +1431,36 @@ int search_binary_handler(struct linux_binprm *bprm)
        }
        return retval;
 }
-
 EXPORT_SYMBOL(search_binary_handler);
 
+static int exec_binprm(struct linux_binprm *bprm)
+{
+       pid_t old_pid, old_vpid;
+       int ret;
+
+       /* Need to fetch pid before load_binary changes it */
+       old_pid = current->pid;
+       rcu_read_lock();
+       old_vpid = task_pid_nr_ns(current, task_active_pid_ns(current->parent));
+       rcu_read_unlock();
+
+       ret = search_binary_handler(bprm);
+       if (ret >= 0) {
+               trace_sched_process_exec(current, old_pid, bprm);
+               ptrace_event(PTRACE_EVENT_EXEC, old_vpid);
+               current->did_exec = 1;
+               proc_exec_connector(current);
+
+               if (bprm->file) {
+                       allow_write_access(bprm->file);
+                       fput(bprm->file);
+                       bprm->file = NULL; /* to catch use-after-free */
+               }
+       }
+
+       return ret;
+}
+
 /*
  * sys_execve() executes a new program.
  */
@@ -1541,7 +1549,7 @@ static int do_execve_common(const char *filename,
        if (retval < 0)
                goto out;
 
-       retval = search_binary_handler(bprm);
+       retval = exec_binprm(bprm);
        if (retval < 0)
                goto out;