Revert "printk: return -EINVAL if the message len is bigger than the buf size"

[karo-tx-linux.git] / kernel / sys.c

diff --git a/kernel/sys.c b/kernel/sys.c
index 9ff89cb9657a681d15714447d7d3c64939fbbe50..e0c8ffc50d7fc48bfaa73f43946638a47c947fdb 100644 (file)
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -1786,27 +1786,13 @@ SYSCALL_DEFINE1(umask, int, mask)
 }
 
 #ifdef CONFIG_CHECKPOINT_RESTORE
-static bool vma_flags_mismatch(struct vm_area_struct *vma,
-                              unsigned long required,
-                              unsigned long banned)
-{
-       return (vma->vm_flags & required) != required ||
-               (vma->vm_flags & banned);
-}
-
 static int prctl_set_mm_exe_file(struct mm_struct *mm, unsigned int fd)
 {
+       struct vm_area_struct *vma;
        struct file *exe_file;
        struct dentry *dentry;
        int err;
 
-       /*
-        * Setting new mm::exe_file is only allowed when no VM_EXECUTABLE vma's
-        * remain. So perform a quick test first.
-        */
-       if (mm->num_exe_file_vmas)
-               return -EBUSY;
-
        exe_file = fget(fd);
        if (!exe_file)
                return -EBADF;
@@ -1827,17 +1813,30 @@ static int prctl_set_mm_exe_file(struct mm_struct *mm, unsigned int fd)
        if (err)
                goto exit;
 
+       down_write(&mm->mmap_sem);
+
+       /*
+        * Forbid mm->exe_file change if there are mapped other files.
+        */
+       err = -EBUSY;
+       for (vma = mm->mmap; vma; vma = vma->vm_next) {
+               if (vma->vm_file && !path_equal(&vma->vm_file->f_path,
+                                               &exe_file->f_path))
+                       goto exit_unlock;
+       }
+
        /*
         * The symlink can be changed only once, just to disallow arbitrary
         * transitions malicious software might bring in. This means one
         * could make a snapshot over all processes running and monitor
         * /proc/pid/exe changes to notice unusual activity if needed.
         */
-       down_write(&mm->mmap_sem);
-       if (likely(!mm->exe_file))
-               set_mm_exe_file(mm, exe_file);
-       else
-               err = -EBUSY;
+       err = -EPERM;
+       if (test_and_set_bit(MMF_EXE_FILE_CHANGED, &mm->flags))
+               goto exit_unlock;
+
+       set_mm_exe_file(mm, exe_file);
+exit_unlock:
        up_write(&mm->mmap_sem);
 
 exit:
@@ -1862,7 +1861,7 @@ static int prctl_set_mm(int opt, unsigned long addr,
        if (opt == PR_SET_MM_EXE_FILE)
                return prctl_set_mm_exe_file(mm, (unsigned int)addr);
 
-       if (addr >= TASK_SIZE)
+       if (addr >= TASK_SIZE || addr < mmap_min_addr)
                return -EINVAL;
 
        error = -EINVAL;
@@ -1924,12 +1923,6 @@ static int prctl_set_mm(int opt, unsigned long addr,
                        error = -EFAULT;
                        goto out;
                }
-#ifdef CONFIG_STACK_GROWSUP
-               if (vma_flags_mismatch(vma, VM_READ | VM_WRITE | VM_GROWSUP, 0))
-#else
-               if (vma_flags_mismatch(vma, VM_READ | VM_WRITE | VM_GROWSDOWN, 0))
-#endif
-                       goto out;
                if (opt == PR_SET_MM_START_STACK)
                        mm->start_stack = addr;
                else if (opt == PR_SET_MM_ARG_START)
@@ -1981,12 +1974,22 @@ out:
        up_read(&mm->mmap_sem);
        return error;
 }
+
+static int prctl_get_tid_address(struct task_struct *me, int __user **tid_addr)
+{
+       return put_user(me->clear_child_tid, tid_addr);
+}
+
 #else /* CONFIG_CHECKPOINT_RESTORE */
 static int prctl_set_mm(int opt, unsigned long addr,
                        unsigned long arg4, unsigned long arg5)
 {
        return -EINVAL;
 }
+static int prctl_get_tid_address(struct task_struct *me, int __user **tid_addr)
+{
+       return -EINVAL;
+}
 #endif
 
 SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3,
@@ -2141,6 +2144,9 @@ SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3,
                case PR_SET_MM:
                        error = prctl_set_mm(arg2, arg3, arg4, arg5);
                        break;
+               case PR_GET_TID_ADDRESS:
+                       error = prctl_get_tid_address(me, (int __user **)arg2);
+                       break;
                case PR_SET_CHILD_SUBREAPER:
                        me->signal->is_child_subreaper = !!arg2;
                        error = 0;