diff options
| -rw-r--r-- | include/linux/sched.h | 1 | ||||
| -rw-r--r-- | include/linux/utsname.h | 11 | ||||
| -rw-r--r-- | kernel/fork.c | 20 | ||||
| -rw-r--r-- | kernel/nsproxy.c | 2 | ||||
| -rw-r--r-- | kernel/utsname.c | 53 |
5 files changed, 83 insertions, 4 deletions
diff --git a/include/linux/sched.h b/include/linux/sched.h index 46d6f5b..a973e70 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -24,6 +24,7 @@ #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_STOPPED 0x02000000 /* Start in stopped state */ +#define CLONE_NEWUTS 0x04000000 /* New utsname group? */ /* * Scheduling policies diff --git a/include/linux/utsname.h b/include/linux/utsname.h index 99e5223..02e4b69 100644 --- a/include/linux/utsname.h +++ b/include/linux/utsname.h @@ -47,6 +47,8 @@ static inline void get_uts_ns(struct uts_namespace *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 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); } #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) { return 0; diff --git a/kernel/fork.c b/kernel/fork.c index 33fcf07..c08cf05 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -1607,13 +1607,14 @@ asmlinkage long sys_unshare(unsigned long unshare_flags) struct files_struct *fd, *new_fd = NULL; struct sem_undo_list *new_ulist = NULL; struct nsproxy *new_nsproxy, *old_nsproxy; + struct uts_namespace *uts, *new_uts = NULL; check_unshare_flags(&unshare_flags); /* Return -EINVAL for all unsupported flags */ err = -EINVAL; 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; if ((err = unshare_thread(unshare_flags))) @@ -1630,14 +1631,17 @@ asmlinkage long sys_unshare(unsigned long unshare_flags) goto bad_unshare_cleanup_vm; if ((err = unshare_semundo(unshare_flags, &new_ulist))) 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; new_nsproxy = dup_namespaces(old_nsproxy); if (!new_nsproxy) { err = -ENOMEM; - goto bad_unshare_cleanup_semundo; + goto bad_unshare_cleanup_uts; } task_lock(current); @@ -1676,10 +1680,20 @@ asmlinkage long sys_unshare(unsigned long unshare_flags) new_fd = fd; } + if (new_uts) { + uts = current->nsproxy->uts_ns; + current->nsproxy->uts_ns = new_uts; + new_uts = uts; + } + task_unlock(current); put_nsproxy(old_nsproxy); } +bad_unshare_cleanup_uts: + if (new_uts) + put_uts_ns(new_uts); + bad_unshare_cleanup_semundo: bad_unshare_cleanup_fd: if (new_fd) diff --git a/kernel/nsproxy.c b/kernel/nsproxy.c index 47c1928..8246813 100644 --- a/kernel/nsproxy.c +++ b/kernel/nsproxy.c @@ -82,7 +82,7 @@ int copy_namespaces(int flags, struct task_struct *tsk) get_nsproxy(old_ns); - if (!(flags & CLONE_NEWNS)) + if (!(flags & (CLONE_NEWNS | CLONE_NEWUTS))) return 0; new_ns = clone_namespaces(old_ns); diff --git a/kernel/utsname.c b/kernel/utsname.c index 1824384..c859164 100644 --- a/kernel/utsname.c +++ b/kernel/utsname.c @@ -15,6 +15,41 @@ #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 * specifies CLONE_NEWUTS. In latter case, changes to the * utsname of this process won't be seen by parent, and vice @@ -23,6 +58,7 @@ int copy_utsname(int flags, struct task_struct *tsk) { struct uts_namespace *old_ns = tsk->nsproxy->uts_ns; + struct uts_namespace *new_ns; int err = 0; if (!old_ns) @@ -30,6 +66,23 @@ int copy_utsname(int flags, struct task_struct *tsk) 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; } |
