setup_arg_pages: diagnose excessive argument size

[net-next-2.6.git] / fs / exec.c

diff --git a/fs/exec.c b/fs/exec.c
index 05c7d6b84df7c770f07aa7148b9f47e6aacd060f..1b63237fc6dced1062c392523fed094ce7dacc56 100644 (file)
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -594,6 +594,11 @@ int setup_arg_pages(struct linux_binprm *bprm,
 #else
        stack_top = arch_align_stack(stack_top);
        stack_top = PAGE_ALIGN(stack_top);
+
+       if (unlikely(stack_top < mmap_min_addr) ||
+           unlikely(vma->vm_end - vma->vm_start >= stack_top - mmap_min_addr))
+               return -ENOMEM;
+
        stack_shift = vma->vm_end - stack_top;
 
        bprm->p -= stack_shift;
@@ -1118,7 +1123,7 @@ int check_unsafe_exec(struct linux_binprm *bprm)
        bprm->unsafe = tracehook_unsafe_exec(p);
 
        n_fs = 1;
-       write_lock(&p->fs->lock);
+       spin_lock(&p->fs->lock);
        rcu_read_lock();
        for (t = next_thread(p); t != p; t = next_thread(t)) {
                if (t->fs == p->fs)
@@ -1135,7 +1140,7 @@ int check_unsafe_exec(struct linux_binprm *bprm)
                        res = 1;
                }
        }
-       write_unlock(&p->fs->lock);
+       spin_unlock(&p->fs->lock);
 
        return res;
 }