UBUNTU: Ubuntu-4.10.0-4.6

[mirror_ubuntu-zesty-kernel.git] / kernel / fork.c

diff --git a/kernel/fork.c b/kernel/fork.c
index a439ac4296697d656f24f20f678e0bfdd209d887..af0ab7e8328bb9b63ddbfd9bc94b9d13228a1fe9 100644 (file)
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -79,7 +79,7 @@
 
 #include <asm/pgtable.h>
 #include <asm/pgalloc.h>
-#include <asm/uaccess.h>
+#include <linux/uaccess.h>
 #include <asm/mmu_context.h>
 #include <asm/cacheflush.h>
 #include <asm/tlbflush.h>
@@ -88,6 +88,11 @@
 
 #define CREATE_TRACE_POINTS
 #include <trace/events/task.h>
+#ifdef CONFIG_USER_NS
+extern int unprivileged_userns_clone;
+#else
+#define unprivileged_userns_clone 0
+#endif
 
 /*
  * Minimum number of threads to boot the kernel
@@ -626,7 +631,7 @@ static __latent_entropy int dup_mmap(struct mm_struct *mm,
                        struct inode *inode = file_inode(file);
                        struct address_space *mapping = file->f_mapping;
 
-                       get_file(file);
+                       vma_get_file(tmp);
                        if (tmp->vm_flags & VM_DENYWRITE)
                                atomic_dec(&inode->i_writecount);
                        i_mmap_lock_write(mapping);
@@ -747,7 +752,8 @@ static void mm_init_owner(struct mm_struct *mm, struct task_struct *p)
 #endif
 }
 
-static struct mm_struct *mm_init(struct mm_struct *mm, struct task_struct *p)
+static struct mm_struct *mm_init(struct mm_struct *mm, struct task_struct *p,
+       struct user_namespace *user_ns)
 {
        mm->mmap = NULL;
        mm->mm_rb = RB_ROOT;
@@ -787,6 +793,7 @@ static struct mm_struct *mm_init(struct mm_struct *mm, struct task_struct *p)
        if (init_new_context(p, mm))
                goto fail_nocontext;
 
+       mm->user_ns = get_user_ns(user_ns);
        return mm;
 
 fail_nocontext:
@@ -832,7 +839,7 @@ struct mm_struct *mm_alloc(void)
                return NULL;
 
        memset(mm, 0, sizeof(*mm));
-       return mm_init(mm, current);
+       return mm_init(mm, current, current_user_ns());
 }
 
 /*
@@ -847,6 +854,7 @@ void __mmdrop(struct mm_struct *mm)
        destroy_context(mm);
        mmu_notifier_mm_destroy(mm);
        check_mm(mm);
+       put_user_ns(mm->user_ns);
        free_mm(mm);
 }
 EXPORT_SYMBOL_GPL(__mmdrop);
@@ -1128,7 +1136,7 @@ static struct mm_struct *dup_mm(struct task_struct *tsk)
 
        memcpy(mm, oldmm, sizeof(*mm));
 
-       if (!mm_init(mm, tsk))
+       if (!mm_init(mm, tsk, mm->user_ns))
                goto fail_nomem;
 
        err = dup_mmap(mm, oldmm);
@@ -1468,6 +1476,10 @@ static __latent_entropy struct task_struct *copy_process(
        if ((clone_flags & (CLONE_NEWUSER|CLONE_FS)) == (CLONE_NEWUSER|CLONE_FS))
                return ERR_PTR(-EINVAL);
 
+       if ((clone_flags & CLONE_NEWUSER) && !unprivileged_userns_clone)
+               if (!capable(CAP_SYS_ADMIN))
+                       return ERR_PTR(-EPERM);
+
        /*
         * Thread groups must share signals as well, and detached threads
         * can only be started up within the thread group.
@@ -2206,6 +2218,12 @@ SYSCALL_DEFINE1(unshare, unsigned long, unshare_flags)
        if (unshare_flags & CLONE_NEWNS)
                unshare_flags |= CLONE_FS;
 
+       if ((unshare_flags & CLONE_NEWUSER) && !unprivileged_userns_clone) {
+               err = -EPERM;
+               if (!capable(CAP_SYS_ADMIN))
+                       goto bad_unshare_out;
+       }
+
        err = check_unshare_flags(unshare_flags);
        if (err)
                goto bad_unshare_out;