X-Git-Url: https://git.proxmox.com/?a=blobdiff_plain;f=kernel%2Ffork.c;h=dd8b59857b71245254f19b11248dc292da03f1ae;hb=00ab3ffb35c4472bc415dc90fc3a646c2b40630d;hp=2295fc69717f6c3d877ef3cac15b55336d7746c6;hpb=e100ff380ce936fc1e7ae8ba16621ddf5dddffcb;p=mirror_ubuntu-bionic-kernel.git

diff --git a/kernel/fork.c b/kernel/fork.c
index 2295fc69717f..dd8b59857b71 100644
--- 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);
@@ -1550,6 +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.
@@ -1717,6 +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);
@@ -2343,6 +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;