[PATCH] namespaces: utsname: implement CLONE_NEWUTS flag (071df104) · Commits · e / devices / android_kernel_xiaomi_nabu

include/linux/sched.h

+1 −0

Original line number	Original line	Diff line number	Diff line
	@@ -24,6 +24,7 @@
	#define CLONE_UNTRACED 0x00800000 /* set if the tracing process can't force CLONE_PTRACE on this clone */		#define CLONE_UNTRACED 0x00800000 /* set if the tracing process can't force CLONE_PTRACE on this clone */
	#define CLONE_CHILD_SETTID 0x01000000 /* set the TID in the child */		#define CLONE_CHILD_SETTID 0x01000000 /* set the TID in the child */
	#define CLONE_STOPPED 0x02000000 /* Start in stopped state */		#define CLONE_STOPPED 0x02000000 /* Start in stopped state */
			#define CLONE_NEWUTS 0x04000000 /* New utsname group? */

	/*		/*
	* Scheduling policies		* Scheduling policies

include/linux/utsname.h

+11 −0

Original line number	Original line	Diff line number	Diff line
	@@ -47,6 +47,8 @@ static inline void get_uts_ns(struct uts_namespace *ns)
	}		}

	#ifdef CONFIG_UTS_NS		#ifdef CONFIG_UTS_NS
			extern int unshare_utsname(unsigned long unshare_flags,
			struct uts_namespace **new_uts);
	extern int copy_utsname(int flags, struct task_struct *tsk);		extern int copy_utsname(int flags, struct task_struct *tsk);
	extern void free_uts_ns(struct kref *kref);		extern void free_uts_ns(struct kref *kref);

	@@ -55,6 +57,15 @@ static inline void put_uts_ns(struct uts_namespace *ns)
	kref_put(&ns->kref, free_uts_ns);		kref_put(&ns->kref, free_uts_ns);
	}		}
	#else		#else
			static inline int unshare_utsname(unsigned long unshare_flags,
			struct uts_namespace **new_uts)
			{
			if (unshare_flags & CLONE_NEWUTS)
			return -EINVAL;

			return 0;
			}

	static inline int copy_utsname(int flags, struct task_struct *tsk)		static inline int copy_utsname(int flags, struct task_struct *tsk)
	{		{
	return 0;		return 0;

kernel/fork.c

+17 −3

Original line number	Original line	Diff line number	Diff line
	@@ -1607,13 +1607,14 @@ asmlinkage long sys_unshare(unsigned long unshare_flags)
	struct files_struct fd, new_fd = NULL;		struct files_struct fd, new_fd = NULL;
	struct sem_undo_list *new_ulist = NULL;		struct sem_undo_list *new_ulist = NULL;
	struct nsproxy new_nsproxy, old_nsproxy;		struct nsproxy new_nsproxy, old_nsproxy;
			struct uts_namespace uts, new_uts = NULL;

	check_unshare_flags(&unshare_flags);		check_unshare_flags(&unshare_flags);

	/* Return -EINVAL for all unsupported flags */		/* Return -EINVAL for all unsupported flags */
	err = -EINVAL;		err = -EINVAL;
	if (unshare_flags & ~(CLONE_THREAD\|CLONE_FS\|CLONE_NEWNS\|CLONE_SIGHAND\|		if (unshare_flags & ~(CLONE_THREAD\|CLONE_FS\|CLONE_NEWNS\|CLONE_SIGHAND\|
	CLONE_VM\|CLONE_FILES\|CLONE_SYSVSEM))		CLONE_VM\|CLONE_FILES\|CLONE_SYSVSEM\|CLONE_NEWUTS))
	goto bad_unshare_out;		goto bad_unshare_out;

	if ((err = unshare_thread(unshare_flags)))		if ((err = unshare_thread(unshare_flags)))
	@@ -1630,14 +1631,17 @@ asmlinkage long sys_unshare(unsigned long unshare_flags)
	goto bad_unshare_cleanup_vm;		goto bad_unshare_cleanup_vm;
	if ((err = unshare_semundo(unshare_flags, &new_ulist)))		if ((err = unshare_semundo(unshare_flags, &new_ulist)))
	goto bad_unshare_cleanup_fd;		goto bad_unshare_cleanup_fd;
			if ((err = unshare_utsname(unshare_flags, &new_uts)))
			goto bad_unshare_cleanup_semundo;

	if (new_fs \|\| new_ns \|\| new_sigh \|\| new_mm \|\| new_fd \|\| new_ulist) {		if (new_fs \|\| new_ns \|\| new_sigh \|\| new_mm \|\| new_fd \|\| new_ulist \|\|
			new_uts) {

	old_nsproxy = current->nsproxy;		old_nsproxy = current->nsproxy;
	new_nsproxy = dup_namespaces(old_nsproxy);		new_nsproxy = dup_namespaces(old_nsproxy);
	if (!new_nsproxy) {		if (!new_nsproxy) {
	err = -ENOMEM;		err = -ENOMEM;
	goto bad_unshare_cleanup_semundo;		goto bad_unshare_cleanup_uts;
	}		}

	task_lock(current);		task_lock(current);
	@@ -1676,10 +1680,20 @@ asmlinkage long sys_unshare(unsigned long unshare_flags)
	new_fd = fd;		new_fd = fd;
	}		}

			if (new_uts) {
			uts = current->nsproxy->uts_ns;
			current->nsproxy->uts_ns = new_uts;
			new_uts = uts;
			}

	task_unlock(current);		task_unlock(current);
	put_nsproxy(old_nsproxy);		put_nsproxy(old_nsproxy);
	}		}

			bad_unshare_cleanup_uts:
			if (new_uts)
			put_uts_ns(new_uts);

	bad_unshare_cleanup_semundo:		bad_unshare_cleanup_semundo:
	bad_unshare_cleanup_fd:		bad_unshare_cleanup_fd:
	if (new_fd)		if (new_fd)

kernel/nsproxy.c

+1 −1

Original line number	Original line	Diff line number	Diff line
	@@ -82,7 +82,7 @@ int copy_namespaces(int flags, struct task_struct *tsk)

	get_nsproxy(old_ns);		get_nsproxy(old_ns);

	if (!(flags & CLONE_NEWNS))		if (!(flags & (CLONE_NEWNS \| CLONE_NEWUTS)))
	return 0;		return 0;

	new_ns = clone_namespaces(old_ns);		new_ns = clone_namespaces(old_ns);

kernel/utsname.c

+53 −0

Original line number	Original line	Diff line number	Diff line
	@@ -14,6 +14,41 @@
	#include <linux/utsname.h>		#include <linux/utsname.h>
	#include <linux/version.h>		#include <linux/version.h>

			/*
			* Clone a new ns copying an original utsname, setting refcount to 1
			* @old_ns: namespace to clone
			* Return NULL on error (failure to kmalloc), new ns otherwise
			*/
			static struct uts_namespace clone_uts_ns(struct uts_namespace old_ns)
			{
			struct uts_namespace *ns;

			ns = kmalloc(sizeof(struct uts_namespace), GFP_KERNEL);
			if (ns) {
			memcpy(&ns->name, &old_ns->name, sizeof(ns->name));
			kref_init(&ns->kref);
			}
			return ns;
			}

			/*
			* unshare the current process' utsname namespace.
			* called only in sys_unshare()
			*/
			int unshare_utsname(unsigned long unshare_flags, struct uts_namespace **new_uts)
			{
			if (unshare_flags & CLONE_NEWUTS) {
			if (!capable(CAP_SYS_ADMIN))
			return -EPERM;

			*new_uts = clone_uts_ns(current->nsproxy->uts_ns);
			if (!*new_uts)
			return -ENOMEM;
			}

			return 0;
			}

	/*		/*
	* Copy task tsk's utsname namespace, or clone it if flags		* Copy task tsk's utsname namespace, or clone it if flags
	* specifies CLONE_NEWUTS. In latter case, changes to the		* specifies CLONE_NEWUTS. In latter case, changes to the
	@@ -23,6 +58,7 @@
	int copy_utsname(int flags, struct task_struct *tsk)		int copy_utsname(int flags, struct task_struct *tsk)
	{		{
	struct uts_namespace *old_ns = tsk->nsproxy->uts_ns;		struct uts_namespace *old_ns = tsk->nsproxy->uts_ns;
			struct uts_namespace *new_ns;
	int err = 0;		int err = 0;

	if (!old_ns)		if (!old_ns)
	@@ -30,6 +66,23 @@ int copy_utsname(int flags, struct task_struct *tsk)

	get_uts_ns(old_ns);		get_uts_ns(old_ns);

			if (!(flags & CLONE_NEWUTS))
			return 0;

			if (!capable(CAP_SYS_ADMIN)) {
			err = -EPERM;
			goto out;
			}

			new_ns = clone_uts_ns(old_ns);
			if (!new_ns) {
			err = -ENOMEM;
			goto out;
			}
			tsk->nsproxy->uts_ns = new_ns;

			out:
			put_uts_ns(old_ns);
	return err;		return err;
	}		}