cdrom: Fix info leak/OOB read in cdrom_ioctl_drive_status

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

diff --git a/kernel/fork.c b/kernel/fork.c
index 432eadf6b58c18d9de6a3d09f3fef36089b4b5a2..dd8b59857b71245254f19b11248dc292da03f1ae 100644 (file)
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -102,6 +102,11 @@
 
 #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
@@ -676,7 +681,7 @@ 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);
@@ -721,8 +726,7 @@ static __latent_entropy int dup_mmap(struct mm_struct *mm,
                        goto out;
        }
        /* a new mm has just been created */
-       arch_dup_mmap(oldmm, mm);
-       retval = 0;
+       retval = arch_dup_mmap(oldmm, mm);
 out:
        up_write(&mm->mmap_sem);
        flush_tlb_mm(oldmm);
@@ -1551,6 +1555,10 @@ 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.
@@ -1718,6 +1726,9 @@ static __latent_entropy struct task_struct *copy_process(
        p->sequential_io        = 0;
        p->sequential_io_avg    = 0;
 #endif
+#ifdef CONFIG_SECURITY
+       p->security = NULL;
+#endif
 
        /* Perform scheduler related setup. Assign this task to a CPU. */
        retval = sched_fork(clone_flags, p);
@@ -2344,6 +2355,12 @@ 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;