diff options
-rw-r--r-- | fs/exec.c | 6 | ||||
-rw-r--r-- | fs/hugetlbfs/inode.c | 16 | ||||
-rw-r--r-- | fs/proc/array.c | 2 | ||||
-rw-r--r-- | include/linux/cred.h | 4 | ||||
-rw-r--r-- | include/linux/hugetlb.h | 4 | ||||
-rw-r--r-- | include/linux/mm.h | 4 | ||||
-rw-r--r-- | include/linux/sched/user.h | 7 | ||||
-rw-r--r-- | include/linux/shmem_fs.h | 2 | ||||
-rw-r--r-- | include/linux/signal_types.h | 4 | ||||
-rw-r--r-- | include/linux/user_namespace.h | 31 | ||||
-rw-r--r-- | ipc/mqueue.c | 40 | ||||
-rw-r--r-- | ipc/shm.c | 26 | ||||
-rw-r--r-- | kernel/cred.c | 51 | ||||
-rw-r--r-- | kernel/exit.c | 2 | ||||
-rw-r--r-- | kernel/fork.c | 18 | ||||
-rw-r--r-- | kernel/signal.c | 25 | ||||
-rw-r--r-- | kernel/sys.c | 14 | ||||
-rw-r--r-- | kernel/ucount.c | 116 | ||||
-rw-r--r-- | kernel/user.c | 3 | ||||
-rw-r--r-- | kernel/user_namespace.c | 9 | ||||
-rw-r--r-- | mm/memfd.c | 4 | ||||
-rw-r--r-- | mm/mlock.c | 22 | ||||
-rw-r--r-- | mm/mmap.c | 4 | ||||
-rw-r--r-- | mm/shmem.c | 10 | ||||
-rw-r--r-- | tools/testing/selftests/Makefile | 1 | ||||
-rw-r--r-- | tools/testing/selftests/rlimits/.gitignore | 2 | ||||
-rw-r--r-- | tools/testing/selftests/rlimits/Makefile | 6 | ||||
-rw-r--r-- | tools/testing/selftests/rlimits/config | 1 | ||||
-rw-r--r-- | tools/testing/selftests/rlimits/rlimits-per-userns.c | 161 |
29 files changed, 468 insertions, 127 deletions
diff --git a/fs/exec.c b/fs/exec.c index 18594f11c31f..f2bcdbeb3afb 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -1360,6 +1360,10 @@ int begin_new_exec(struct linux_binprm * bprm) WRITE_ONCE(me->self_exec_id, me->self_exec_id + 1); flush_signal_handlers(me, 0); + retval = set_cred_ucounts(bprm->cred); + if (retval < 0) + goto out_unlock; + /* * install the new credentials for this executable */ @@ -1874,7 +1878,7 @@ static int do_execveat_common(int fd, struct filename *filename, * whether NPROC limit is still exceeded. */ if ((current->flags & PF_NPROC_EXCEEDED) && - atomic_read(¤t_user()->processes) > rlimit(RLIMIT_NPROC)) { + is_ucounts_overlimit(current_ucounts(), UCOUNT_RLIMIT_NPROC, rlimit(RLIMIT_NPROC))) { retval = -EAGAIN; goto out_ret; } diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c index 30dee68458c7..926eeb9bf4eb 100644 --- a/fs/hugetlbfs/inode.c +++ b/fs/hugetlbfs/inode.c @@ -1446,7 +1446,7 @@ static int get_hstate_idx(int page_size_log) * otherwise hugetlb_reserve_pages reserves one less hugepages than intended. */ struct file *hugetlb_file_setup(const char *name, size_t size, - vm_flags_t acctflag, struct user_struct **user, + vm_flags_t acctflag, struct ucounts **ucounts, int creat_flags, int page_size_log) { struct inode *inode; @@ -1458,20 +1458,20 @@ struct file *hugetlb_file_setup(const char *name, size_t size, if (hstate_idx < 0) return ERR_PTR(-ENODEV); - *user = NULL; + *ucounts = NULL; mnt = hugetlbfs_vfsmount[hstate_idx]; if (!mnt) return ERR_PTR(-ENOENT); if (creat_flags == HUGETLB_SHMFS_INODE && !can_do_hugetlb_shm()) { - *user = current_user(); - if (user_shm_lock(size, *user)) { + *ucounts = current_ucounts(); + if (user_shm_lock(size, *ucounts)) { task_lock(current); pr_warn_once("%s (%d): Using mlock ulimits for SHM_HUGETLB is deprecated\n", current->comm, current->pid); task_unlock(current); } else { - *user = NULL; + *ucounts = NULL; return ERR_PTR(-EPERM); } } @@ -1498,9 +1498,9 @@ struct file *hugetlb_file_setup(const char *name, size_t size, iput(inode); out: - if (*user) { - user_shm_unlock(size, *user); - *user = NULL; + if (*ucounts) { + user_shm_unlock(size, *ucounts); + *ucounts = NULL; } return file; } diff --git a/fs/proc/array.c b/fs/proc/array.c index 7ec59171f197..ee0ce8cecc4a 100644 --- a/fs/proc/array.c +++ b/fs/proc/array.c @@ -284,7 +284,7 @@ static inline void task_sig(struct seq_file *m, struct task_struct *p) collect_sigign_sigcatch(p, &ignored, &caught); num_threads = get_nr_threads(p); rcu_read_lock(); /* FIXME: is this correct? */ - qsize = atomic_read(&__task_cred(p)->user->sigpending); + qsize = get_ucounts_value(task_ucounts(p), UCOUNT_RLIMIT_SIGPENDING); rcu_read_unlock(); qlim = task_rlimit(p, RLIMIT_SIGPENDING); unlock_task_sighand(p, &flags); diff --git a/include/linux/cred.h b/include/linux/cred.h index 14971322e1a0..fcbc6885cc09 100644 --- a/include/linux/cred.h +++ b/include/linux/cred.h @@ -143,6 +143,7 @@ struct cred { #endif struct user_struct *user; /* real user ID subscription */ struct user_namespace *user_ns; /* user_ns the caps and keyrings are relative to. */ + struct ucounts *ucounts; struct group_info *group_info; /* supplementary groups for euid/fsgid */ /* RCU deletion */ union { @@ -169,6 +170,7 @@ extern int set_security_override_from_ctx(struct cred *, const char *); extern int set_create_files_as(struct cred *, struct inode *); extern int cred_fscmp(const struct cred *, const struct cred *); extern void __init cred_init(void); +extern int set_cred_ucounts(struct cred *); /* * check for validity of credentials @@ -369,6 +371,7 @@ static inline void put_cred(const struct cred *_cred) #define task_uid(task) (task_cred_xxx((task), uid)) #define task_euid(task) (task_cred_xxx((task), euid)) +#define task_ucounts(task) (task_cred_xxx((task), ucounts)) #define current_cred_xxx(xxx) \ ({ \ @@ -385,6 +388,7 @@ static inline void put_cred(const struct cred *_cred) #define current_fsgid() (current_cred_xxx(fsgid)) #define current_cap() (current_cred_xxx(cap_effective)) #define current_user() (current_cred_xxx(user)) +#define current_ucounts() (current_cred_xxx(ucounts)) extern struct user_namespace init_user_ns; #ifdef CONFIG_USER_NS diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h index 3c0117656745..8ba79dc64ab8 100644 --- a/include/linux/hugetlb.h +++ b/include/linux/hugetlb.h @@ -451,7 +451,7 @@ static inline struct hugetlbfs_inode_info *HUGETLBFS_I(struct inode *inode) extern const struct file_operations hugetlbfs_file_operations; extern const struct vm_operations_struct hugetlb_vm_ops; struct file *hugetlb_file_setup(const char *name, size_t size, vm_flags_t acct, - struct user_struct **user, int creat_flags, + struct ucounts **ucounts, int creat_flags, int page_size_log); static inline bool is_file_hugepages(struct file *file) @@ -471,7 +471,7 @@ static inline struct hstate *hstate_inode(struct inode *i) #define is_file_hugepages(file) false static inline struct file * hugetlb_file_setup(const char *name, size_t size, vm_flags_t acctflag, - struct user_struct **user, int creat_flags, + struct ucounts **ucounts, int creat_flags, int page_size_log) { return ERR_PTR(-ENOSYS); diff --git a/include/linux/mm.h b/include/linux/mm.h index 8ae31622deef..01ecf9e3603c 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1709,8 +1709,8 @@ extern bool can_do_mlock(void); #else static inline bool can_do_mlock(void) { return false; } #endif -extern int user_shm_lock(size_t, struct user_struct *); -extern void user_shm_unlock(size_t, struct user_struct *); +extern int user_shm_lock(size_t, struct ucounts *); +extern void user_shm_unlock(size_t, struct ucounts *); /* * Parameter block passed down to zap_pte_range in exceptional cases. diff --git a/include/linux/sched/user.h b/include/linux/sched/user.h index 3632c5d6ec55..2462f7d07695 100644 --- a/include/linux/sched/user.h +++ b/include/linux/sched/user.h @@ -12,16 +12,9 @@ */ struct user_struct { refcount_t __count; /* reference count */ - atomic_t processes; /* How many processes does this user have? */ - atomic_t sigpending; /* How many pending signals does this user have? */ #ifdef CONFIG_EPOLL atomic_long_t epoll_watches; /* The number of file descriptors currently watched */ #endif -#ifdef CONFIG_POSIX_MQUEUE - /* protected by mq_lock */ - unsigned long mq_bytes; /* How many bytes can be allocated to mqueue? */ -#endif - unsigned long locked_shm; /* How many pages of mlocked shm ? */ unsigned long unix_inflight; /* How many files in flight in unix sockets */ atomic_long_t pipe_bufs; /* how many pages are allocated in pipe buffers */ diff --git a/include/linux/shmem_fs.h b/include/linux/shmem_fs.h index d82b6f396588..aa77dcd1646f 100644 --- a/include/linux/shmem_fs.h +++ b/include/linux/shmem_fs.h @@ -65,7 +65,7 @@ extern struct file *shmem_file_setup_with_mnt(struct vfsmount *mnt, extern int shmem_zero_setup(struct vm_area_struct *); extern unsigned long shmem_get_unmapped_area(struct file *, unsigned long addr, unsigned long len, unsigned long pgoff, unsigned long flags); -extern int shmem_lock(struct file *file, int lock, struct user_struct *user); +extern int shmem_lock(struct file *file, int lock, struct ucounts *ucounts); #ifdef CONFIG_SHMEM extern const struct address_space_operations shmem_aops; static inline bool shmem_mapping(struct address_space *mapping) diff --git a/include/linux/signal_types.h b/include/linux/signal_types.h index 68e06c75c5b2..34cb28b8f16c 100644 --- a/include/linux/signal_types.h +++ b/include/linux/signal_types.h @@ -13,6 +13,8 @@ typedef struct kernel_siginfo { __SIGINFO; } kernel_siginfo_t; +struct ucounts; + /* * Real Time signals may be queued. */ @@ -21,7 +23,7 @@ struct sigqueue { struct list_head list; int flags; kernel_siginfo_t info; - struct user_struct *user; + struct ucounts *ucounts; }; /* flags values. */ diff --git a/include/linux/user_namespace.h b/include/linux/user_namespace.h index 1d08dbbcfe32..eb70cabe6e7f 100644 --- a/include/linux/user_namespace.h +++ b/include/linux/user_namespace.h @@ -54,9 +54,15 @@ enum ucount_type { UCOUNT_FANOTIFY_GROUPS, UCOUNT_FANOTIFY_MARKS, #endif + UCOUNT_RLIMIT_NPROC, + UCOUNT_RLIMIT_MSGQUEUE, + UCOUNT_RLIMIT_SIGPENDING, + UCOUNT_RLIMIT_MEMLOCK, UCOUNT_COUNTS, }; +#define MAX_PER_NAMESPACE_UCOUNTS UCOUNT_RLIMIT_NPROC + struct user_namespace { struct uid_gid_map uid_map; struct uid_gid_map gid_map; @@ -92,23 +98,42 @@ struct user_namespace { struct ctl_table_header *sysctls; #endif struct ucounts *ucounts; - int ucount_max[UCOUNT_COUNTS]; + long ucount_max[UCOUNT_COUNTS]; } __randomize_layout; struct ucounts { struct hlist_node node; struct user_namespace *ns; kuid_t uid; - int count; - atomic_t ucount[UCOUNT_COUNTS]; + atomic_t count; + atomic_long_t ucount[UCOUNT_COUNTS]; }; extern struct user_namespace init_user_ns; +extern struct ucounts init_ucounts; bool setup_userns_sysctls(struct user_namespace *ns); void retire_userns_sysctls(struct user_namespace *ns); struct ucounts *inc_ucount(struct user_namespace *ns, kuid_t uid, enum ucount_type type); void dec_ucount(struct ucounts *ucounts, enum ucount_type type); +struct ucounts *alloc_ucounts(struct user_namespace *ns, kuid_t uid); +struct ucounts * __must_check get_ucounts(struct ucounts *ucounts); +void put_ucounts(struct ucounts *ucounts); + +static inline long get_ucounts_value(struct ucounts *ucounts, enum ucount_type type) +{ + return atomic_long_read(&ucounts->ucount[type]); +} + +long inc_rlimit_ucounts(struct ucounts *ucounts, enum ucount_type type, long v); +bool dec_rlimit_ucounts(struct ucounts *ucounts, enum ucount_type type, long v); +bool is_ucounts_overlimit(struct ucounts *ucounts, enum ucount_type type, unsigned long max); + +static inline void set_rlimit_ucount_max(struct user_namespace *ns, + enum ucount_type type, unsigned long max) +{ + ns->ucount_max[type] = max <= LONG_MAX ? max : LONG_MAX; +} #ifdef CONFIG_USER_NS diff --git a/ipc/mqueue.c b/ipc/mqueue.c index 4e4e61111500..5becca9be867 100644 --- a/ipc/mqueue.c +++ b/ipc/mqueue.c @@ -144,7 +144,7 @@ struct mqueue_inode_info { struct pid *notify_owner; u32 notify_self_exec_id; struct user_namespace *notify_user_ns; - struct user_struct *user; /* user who created, for accounting */ + struct ucounts *ucounts; /* user who created, for accounting */ struct sock *notify_sock; struct sk_buff *notify_cookie; @@ -292,7 +292,6 @@ static struct inode *mqueue_get_inode(struct super_block *sb, struct ipc_namespace *ipc_ns, umode_t mode, struct mq_attr *attr) { - struct user_struct *u = current_user(); struct inode *inode; int ret = -ENOMEM; @@ -321,7 +320,7 @@ static struct inode *mqueue_get_inode(struct super_block *sb, info->notify_owner = NULL; info->notify_user_ns = NULL; info->qsize = 0; - info->user = NULL; /* set when all is ok */ + info->ucounts = NULL; /* set when all is ok */ info->msg_tree = RB_ROOT; info->msg_tree_rightmost = NULL; info->node_cache = NULL; @@ -371,19 +370,23 @@ static struct inode *mqueue_get_inode(struct super_block *sb, if (mq_bytes + mq_treesize < mq_bytes) goto out_inode; mq_bytes += mq_treesize; - spin_lock(&mq_lock); - if (u->mq_bytes + mq_bytes < u->mq_bytes || - u->mq_bytes + mq_bytes > rlimit(RLIMIT_MSGQUEUE)) { + info->ucounts = get_ucounts(current_ucounts()); + if (info->ucounts) { + long msgqueue; + + spin_lock(&mq_lock); + msgqueue = inc_rlimit_ucounts(info->ucounts, UCOUNT_RLIMIT_MSGQUEUE, mq_bytes); + if (msgqueue == LONG_MAX || msgqueue > rlimit(RLIMIT_MSGQUEUE)) { + dec_rlimit_ucounts(info->ucounts, UCOUNT_RLIMIT_MSGQUEUE, mq_bytes); + spin_unlock(&mq_lock); + put_ucounts(info->ucounts); + info->ucounts = NULL; + /* mqueue_evict_inode() releases info->messages */ + ret = -EMFILE; + goto out_inode; + } spin_unlock(&mq_lock); - /* mqueue_evict_inode() releases info->messages */ - ret = -EMFILE; - goto out_inode; } - u->mq_bytes += mq_bytes; - spin_unlock(&mq_lock); - - /* all is ok */ - info->user = get_uid(u); } else if (S_ISDIR(mode)) { inc_nlink(inode); /* Some things misbehave if size == 0 on a directory */ @@ -497,7 +500,6 @@ static void mqueue_free_inode(struct inode *inode) static void mqueue_evict_inode(struct inode *inode) { struct mqueue_inode_info *info; - struct user_struct *user; struct ipc_namespace *ipc_ns; struct msg_msg *msg, *nmsg; LIST_HEAD(tmp_msg); @@ -520,8 +522,7 @@ static void mqueue_evict_inode(struct inode *inode) free_msg(msg); } - user = info->user; - if (user) { + if (info->ucounts) { unsigned long mq_bytes, mq_treesize; /* Total amount of bytes accounted for the mqueue */ @@ -533,7 +534,7 @@ static void mqueue_evict_inode(struct inode *inode) info->attr.mq_msgsize); spin_lock(&mq_lock); - user->mq_bytes -= mq_bytes; + dec_rlimit_ucounts(info->ucounts, UCOUNT_RLIMIT_MSGQUEUE, mq_bytes); /* * get_ns_from_inode() ensures that the * (ipc_ns = sb->s_fs_info) is either a valid ipc_ns @@ -543,7 +544,8 @@ static void mqueue_evict_inode(struct inode *inode) if (ipc_ns) ipc_ns->mq_queues_count--; spin_unlock(&mq_lock); - free_uid(user); + put_ucounts(info->ucounts); + info->ucounts = NULL; } if (ipc_ns) put_ipc_ns(ipc_ns); diff --git a/ipc/shm.c b/ipc/shm.c index febd88daba8c..003234fbbd17 100644 --- a/ipc/shm.c +++ b/ipc/shm.c @@ -60,7 +60,7 @@ struct shmid_kernel /* private to the kernel */ time64_t shm_ctim; struct pid *shm_cprid; struct pid *shm_lprid; - struct user_struct *mlock_user; + struct ucounts *mlock_ucounts; /* The task created the shm object. NULL if the task is dead. */ struct task_struct *shm_creator; @@ -286,10 +286,10 @@ static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp) shm_rmid(ns, shp); shm_unlock(shp); if (!is_file_hugepages(shm_file)) - shmem_lock(shm_file, 0, shp->mlock_user); - else if (shp->mlock_user) + shmem_lock(shm_file, 0, shp->mlock_ucounts); + else if (shp->mlock_ucounts) user_shm_unlock(i_size_read(file_inode(shm_file)), - shp->mlock_user); + shp->mlock_ucounts); fput(shm_file); ipc_update_pid(&shp->shm_cprid, NULL); ipc_update_pid(&shp->shm_lprid, NULL); @@ -625,7 +625,7 @@ static int newseg(struct ipc_namespace *ns, struct ipc_params *params) shp->shm_perm.key = key; shp->shm_perm.mode = (shmflg & S_IRWXUGO); - shp->mlock_user = NULL; + shp->mlock_ucounts = NULL; shp->shm_perm.security = NULL; error = security_shm_alloc(&shp->shm_perm); @@ -650,7 +650,7 @@ static int newseg(struct ipc_namespace *ns, struct ipc_params *params) if (shmflg & SHM_NORESERVE) acctflag = VM_NORESERVE; file = hugetlb_file_setup(name, hugesize, acctflag, - &shp->mlock_user, HUGETLB_SHMFS_INODE, + &shp->mlock_ucounts, HUGETLB_SHMFS_INODE, (shmflg >> SHM_HUGE_SHIFT) & SHM_HUGE_MASK); } else { /* @@ -698,8 +698,8 @@ static int newseg(struct ipc_namespace *ns, struct ipc_params *params) no_id: ipc_update_pid(&shp->shm_cprid, NULL); ipc_update_pid(&shp->shm_lprid, NULL); - if (is_file_hugepages(file) && shp->mlock_user) - user_shm_unlock(size, shp->mlock_user); + if (is_file_hugepages(file) && shp->mlock_ucounts) + user_shm_unlock(size, shp->mlock_ucounts); fput(file); ipc_rcu_putref(&shp->shm_perm, shm_rcu_free); return error; @@ -1105,12 +1105,12 @@ static int shmctl_do_lock(struct ipc_namespace *ns, int shmid, int cmd) goto out_unlock0; if (cmd == SHM_LOCK) { - struct user_struct *user = current_user(); + struct ucounts *ucounts = current_ucounts(); - err = shmem_lock(shm_file, 1, user); + err = shmem_lock(shm_file, 1, ucounts); if (!err && !(shp->shm_perm.mode & SHM_LOCKED)) { shp->shm_perm.mode |= SHM_LOCKED; - shp->mlock_user = user; + shp->mlock_ucounts = ucounts; } goto out_unlock0; } @@ -1118,9 +1118,9 @@ static int shmctl_do_lock(struct ipc_namespace *ns, int shmid, int cmd) /* SHM_UNLOCK */ if (!(shp->shm_perm.mode & SHM_LOCKED)) goto out_unlock0; - shmem_lock(shm_file, 0, shp->mlock_user); + shmem_lock(shm_file, 0, shp->mlock_ucounts); shp->shm_perm.mode &= ~SHM_LOCKED; - shp->mlock_user = NULL; + shp->mlock_ucounts = NULL; get_file(shm_file); ipc_unlock_object(&shp->shm_perm); rcu_read_unlock(); diff --git a/kernel/cred.c b/kernel/cred.c index e1d274cd741b..e6fd2b3fc31f 100644 --- a/kernel/cred.c +++ b/kernel/cred.c @@ -60,6 +60,7 @@ struct cred init_cred = { .user = INIT_USER, .user_ns = &init_user_ns, .group_info = &init_groups, + .ucounts = &init_ucounts, }; static inline void set_cred_subscribers(struct cred *cred, int n) @@ -119,6 +120,8 @@ static void put_cred_rcu(struct rcu_head *rcu) if (cred->group_info) put_group_info(cred->group_info); free_uid(cred->user); + if (cred->ucounts) + put_ucounts(cred->ucounts); put_user_ns(cred->user_ns); kmem_cache_free(cred_jar, cred); } @@ -222,6 +225,7 @@ struct cred *cred_alloc_blank(void) #ifdef CONFIG_DEBUG_CREDENTIALS new->magic = CRED_MAGIC; #endif + new->ucounts = get_ucounts(&init_ucounts); if (security_cred_alloc_blank(new, GFP_KERNEL_ACCOUNT) < 0) goto error; @@ -284,6 +288,11 @@ struct cred *prepare_creds(void) if (security_prepare_creds(new, old, GFP_KERNEL_ACCOUNT) < 0) goto error; + + new->ucounts = get_ucounts(new->ucounts); + if (!new->ucounts) + goto error; + validate_creds(new); return new; @@ -351,7 +360,7 @@ int copy_creds(struct task_struct *p, unsigned long clone_flags) kdebug("share_creds(%p{%d,%d})", p->cred, atomic_read(&p->cred->usage), read_cred_subscribers(p->cred)); - atomic_inc(&p->cred->user->processes); + inc_rlimit_ucounts(task_ucounts(p), UCOUNT_RLIMIT_NPROC, 1); return 0; } @@ -363,6 +372,9 @@ int copy_creds(struct task_struct *p, unsigned long clone_flags) ret = create_user_ns(new); if (ret < 0) goto error_put; + ret = set_cred_ucounts(new); + if (ret < 0) + goto error_put; } #ifdef CONFIG_KEYS @@ -384,8 +396,8 @@ int copy_creds(struct task_struct *p, unsigned long clone_flags) } #endif - atomic_inc(&new->user->processes); p->cred = p->real_cred = get_cred(new); + inc_rlimit_ucounts(task_ucounts(p), UCOUNT_RLIMIT_NPROC, 1); alter_cred_subscribers(new, 2); validate_creds(new); return 0; @@ -485,12 +497,12 @@ int commit_creds(struct cred *new) * in set_user(). */ alter_cred_subscribers(new, 2); - if (new->user != old->user) - atomic_inc(&new->user->processes); + if (new->user != old->user || new->user_ns != old->user_ns) + inc_rlimit_ucounts(new->ucounts, UCOUNT_RLIMIT_NPROC, 1); rcu_assign_pointer(task->real_cred, new); rcu_assign_pointer(task->cred, new); if (new->user != old->user) - atomic_dec(&old->user->processes); + dec_rlimit_ucounts(old->ucounts, UCOUNT_RLIMIT_NPROC, 1); alter_cred_subscribers(old, -2); /* send notifications */ @@ -653,6 +665,31 @@ int cred_fscmp(const struct cred *a, const struct cred *b) } EXPORT_SYMBOL(cred_fscmp); +int set_cred_ucounts(struct cred *new) +{ + struct task_struct *task = current; + const struct cred *old = task->real_cred; + struct ucounts *old_ucounts = new->ucounts; + + if (new->user == old->user && new->user_ns == old->user_ns) + return 0; + + /* + * This optimization is needed because alloc_ucounts() uses locks + * for table lookups. + */ + if (old_ucounts && old_ucounts->ns == new->user_ns && uid_eq(old_ucounts->uid, new->euid)) + return 0; + + if (!(new->ucounts = alloc_ucounts(new->user_ns, new->euid))) + return -EAGAIN; + + if (old_ucounts) + put_ucounts(old_ucounts); + + return 0; +} + /* * initialise the credentials stuff */ @@ -719,6 +756,10 @@ struct cred *prepare_kernel_cred(struct task_struct *daemon) if (security_prepare_creds(new, old, GFP_KERNEL_ACCOUNT) < 0) goto error; + new->ucounts = get_ucounts(new->ucounts); + if (!new->ucounts) + goto error; + put_cred(old); validate_creds(new); return new; diff --git a/kernel/exit.c b/kernel/exit.c index 65809fac3038..9a89e7f36acb 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -188,7 +188,7 @@ repeat: /* don't need to get the RCU readlock here - the process is dead and * can't be modifying its own credentials. But shut RCU-lockdep up */ rcu_read_lock(); - atomic_dec(&__task_cred(p)->user->processes); + dec_rlimit_ucounts(task_ucounts(p), UCOUNT_RLIMIT_NPROC, 1); rcu_read_unlock(); cgroup_release(p); diff --git a/kernel/fork.c b/kernel/fork.c index 4820c2aaeb5a..b4386ff6a641 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -825,9 +825,14 @@ void __init fork_init(void) init_task.signal->rlim[RLIMIT_SIGPENDING] = init_task.signal->rlim[RLIMIT_NPROC]; - for (i = 0; i < UCOUNT_COUNTS; i++) + for (i = 0; i < MAX_PER_NAMESPACE_UCOUNTS; i++) init_user_ns.ucount_max[i] = max_threads/2; + set_rlimit_ucount_max(&init_user_ns, UCOUNT_RLIMIT_NPROC, task_rlimit(&init_task, RLIMIT_NPROC)); + set_rlimit_ucount_max(&init_user_ns, UCOUNT_RLIMIT_MSGQUEUE, task_rlimit(&init_task, RLIMIT_MSGQUEUE)); + set_rlimit_ucount_max(&init_user_ns, UCOUNT_RLIMIT_SIGPENDING, task_rlimit(&init_task, RLIMIT_SIGPENDING)); + set_rlimit_ucount_max(&init_user_ns, UCOUNT_RLIMIT_MEMLOCK, task_rlimit(&init_task, RLIMIT_MEMLOCK)); + #ifdef CONFIG_VMAP_STACK cpuhp_setup_state(CPUHP_BP_PREPARE_DYN, "fork:vm_stack_cache", NULL, free_vm_stack_cache); @@ -1978,8 +1983,7 @@ static __latent_entropy struct task_struct *copy_process( DEBUG_LOCKS_WARN_ON(!p->softirqs_enabled); #endif retval = -EAGAIN; - if (atomic_read(&p->real_cred->user->processes) >= - task_rlimit(p, RLIMIT_NPROC)) { + if (is_ucounts_overlimit(task_ucounts(p), UCOUNT_RLIMIT_NPROC, rlimit(RLIMIT_NPROC))) { if (p->real_cred->user != INIT_USER && !capable(CAP_SYS_RESOURCE) && !capable(CAP_SYS_ADMIN)) goto bad_fork_free; @@ -2388,7 +2392,7 @@ bad_fork_cleanup_threadgroup_lock: #endif delayacct_tsk_free(p); bad_fork_cleanup_count: - atomic_dec(&p->cred->user->processes); + dec_rlimit_ucounts(task_ucounts(p), UCOUNT_RLIMIT_NPROC, 1); exit_creds(p); bad_fork_free: WRITE_ONCE(p->__state, TASK_DEAD); @@ -3001,6 +3005,12 @@ int ksys_unshare(unsigned long unshare_flags) if (err) goto bad_unshare_cleanup_cred; + if (new_cred) { + err = set_cred_ucounts(new_cred); + if (err) + goto bad_unshare_cleanup_cred; + } + if (new_fs || new_fd || do_sysvsem || new_cred || new_nsproxy) { if (do_sysvsem) { /* diff --git a/kernel/signal.c b/kernel/signal.c index 20d1d896d5b0..de0920353d30 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -412,8 +412,8 @@ __sigqueue_alloc(int sig, struct task_struct *t, gfp_t gfp_flags, int override_rlimit, const unsigned int sigqueue_flags) { struct sigqueue *q = NULL; - struct user_struct *user; - int sigpending; + struct ucounts *ucounts = NULL; + long sigpending; /* * Protect access to @t credentials. This can go away when all @@ -424,27 +424,26 @@ __sigqueue_alloc(int sig, struct task_struct *t, gfp_t gfp_flags, * changes from/to zero. */ rcu_read_lock(); - user = __task_cred(t)->user; - sigpending = atomic_inc_return(&user->sigpending); + ucounts = task_ucounts(t); + sigpending = inc_rlimit_ucounts(ucounts, UCOUNT_RLIMIT_SIGPENDING, 1); if (sigpending == 1) - get_uid(user); + ucounts = get_ucounts(ucounts); rcu_read_unlock(); - if (override_rlimit || likely(sigpending <= task_rlimit(t, RLIMIT_SIGPENDING))) { + if (override_rlimit || (sigpending < LONG_MAX && sigpending <= task_rlimit(t, RLIMIT_SIGPENDING))) { q = kmem_cache_alloc(sigqueue_cachep, gfp_flags); } else { print_dropped_signal(sig); } if (unlikely(q == NULL)) { - if (atomic_dec_and_test(&user->sigpending)) - free_uid(user); + if (ucounts && dec_rlimit_ucounts(ucounts, UCOUNT_RLIMIT_SIGPENDING, 1)) + put_ucounts(ucounts); } else { INIT_LIST_HEAD(&q->list); q->flags = sigqueue_flags; - q->user = user; + q->ucounts = ucounts; } - return q; } @@ -452,8 +451,10 @@ static void __sigqueue_free(struct sigqueue *q) { if (q->flags & SIGQUEUE_PREALLOC) return; - if (atomic_dec_and_test(&q->user->sigpending)) - free_uid(q->user); + if (q->ucounts && dec_rlimit_ucounts(q->ucounts, UCOUNT_RLIMIT_SIGPENDING, 1)) { + put_ucounts(q->ucounts); + q->ucounts = NULL; + } kmem_cache_free(sigqueue_cachep, q); } diff --git a/kernel/sys.c b/kernel/sys.c index 9de46a4bf492..ef1a78f5d71c 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -479,7 +479,7 @@ static int set_user(struct cred *new) * for programs doing set*uid()+execve() by harmlessly deferring the * failure to the execve() stage. */ - if (atomic_read(&new_user->processes) >= rlimit(RLIMIT_NPROC) && + if (is_ucounts_overlimit(new->ucounts, UCOUNT_RLIMIT_NPROC, rlimit(RLIMIT_NPROC)) && new_user != INIT_USER) current->flags |= PF_NPROC_EXCEEDED; else @@ -558,6 +558,10 @@ long __sys_setreuid(uid_t ruid, uid_t euid) if (retval < 0) goto error; + retval = set_cred_ucounts(new); + if (retval < 0) + goto error; + return commit_creds(new); error: @@ -616,6 +620,10 @@ long __sys_setuid(uid_t uid) if (retval < 0) goto error; + retval = set_cred_ucounts(new); + if (retval < 0) + goto error; + return commit_creds(new); error: @@ -691,6 +699,10 @@ long __sys_setresuid(uid_t ruid, uid_t euid, uid_t suid) if (retval < 0) goto error; + retval = set_cred_ucounts(new); + if (retval < 0) + goto error; + return commit_creds(new); error: diff --git a/kernel/ucount.c b/kernel/ucount.c index 8d8874f1c35e..87799e2379bd 100644 --- a/kernel/ucount.c +++ b/kernel/ucount.c @@ -8,6 +8,12 @@ #include <linux/kmemleak.h> #include <linux/user_namespace.h> +struct ucounts init_ucounts = { + .ns = &init_user_ns, + .uid = GLOBAL_ROOT_UID, + .count = ATOMIC_INIT(1), +}; + #define UCOUNTS_HASHTABLE_BITS 10 static struct hlist_head ucounts_hashtable[(1 << UCOUNTS_HASHTABLE_BITS)]; static DEFINE_SPINLOCK(ucounts_lock); @@ -78,6 +84,10 @@ static struct ctl_table user_table[] = { UCOUNT_ENTRY("max_fanotify_groups"), UCOUNT_ENTRY("max_fanotify_marks"), #endif + { }, + { }, + { }, + { }, { } }; #endif /* CONFIG_SYSCTL */ @@ -129,7 +139,24 @@ static struct ucounts *find_ucounts(struct user_namespace *ns, kuid_t uid, struc return NULL; } -static struct ucounts *get_ucounts(struct user_namespace *ns, kuid_t uid) +static void hlist_add_ucounts(struct ucounts *ucounts) +{ + struct hlist_head *hashent = ucounts_hashentry(ucounts->ns, ucounts->uid); + spin_lock_irq(&ucounts_lock); + hlist_add_head(&ucounts->node, hashent); + spin_unlock_irq(&ucounts_lock); +} + +struct ucounts *get_ucounts(struct ucounts *ucounts) +{ + if (ucounts && atomic_add_negative(1, &ucounts->count)) { + put_ucounts(ucounts); + ucounts = NULL; + } + return ucounts; +} + +struct ucounts *alloc_ucounts(struct user_namespace *ns, kuid_t uid) { struct hlist_head *hashent = ucounts_hashentry(ns, uid); struct ucounts *ucounts, *new; @@ -145,7 +172,7 @@ static struct ucounts *get_ucounts(struct user_namespace *ns, kuid_t uid) new->ns = ns; new->uid = uid; - new->count = 0; + atomic_set(&new->count, 1); spin_lock_irq(&ucounts_lock); ucounts = find_ucounts(ns, uid, hashent); @@ -153,40 +180,35 @@ static struct ucounts *get_ucounts(struct user_namespace *ns, kuid_t uid) kfree(new); } else { hlist_add_head(&new->node, hashent); - ucounts = new; + spin_unlock_irq(&ucounts_lock); + return new; } } - if (ucounts->count == INT_MAX) - ucounts = NULL; - else - ucounts->count += 1; spin_unlock_irq(&ucounts_lock); + ucounts = get_ucounts(ucounts); return ucounts; } -static void put_ucounts(struct ucounts *ucounts) +void put_ucounts(struct ucounts *ucounts) { unsigned long flags; - spin_lock_irqsave(&ucounts_lock, flags); - ucounts->count -= 1; - if (!ucounts->count) + if (atomic_dec_and_test(&ucounts->count)) { + spin_lock_irqsave(&ucounts_lock, flags); hlist_del_init(&ucounts->node); - else - ucounts = NULL; - spin_unlock_irqrestore(&ucounts_lock, flags); - - kfree(ucounts); + spin_unlock_irqrestore(&ucounts_lock, flags); + kfree(ucounts); + } } -static inline bool atomic_inc_below(atomic_t *v, int u) +static inline bool atomic_long_inc_below(atomic_long_t *v, int u) { - int c, old; - c = atomic_read(v); + long c, old; + c = atomic_long_read(v); for (;;) { if (unlikely(c >= u)) return false; - old = atomic_cmpxchg(v, c, c+1); + old = atomic_long_cmpxchg(v, c, c+1); if (likely(old == c)) return true; c = old; @@ -198,19 +220,19 @@ struct ucounts *inc_ucount(struct user_namespace *ns, kuid_t uid, { struct ucounts *ucounts, *iter, *bad; struct user_namespace *tns; - ucounts = get_ucounts(ns, uid); + ucounts = alloc_ucounts(ns, uid); for (iter = ucounts; iter; iter = tns->ucounts) { - int max; + long max; tns = iter->ns; max = READ_ONCE(tns->ucount_max[type]); - if (!atomic_inc_below(&iter->ucount[type], max)) + if (!atomic_long_inc_below(&iter->ucount[type], max)) goto fail; } return ucounts; fail: bad = iter; for (iter = ucounts; iter != bad; iter = iter->ns->ucounts) - atomic_dec(&iter->ucount[type]); + atomic_long_dec(&iter->ucount[type]); put_ucounts(ucounts); return NULL; @@ -220,12 +242,54 @@ void dec_ucount(struct ucounts *ucounts, enum ucount_type type) { struct ucounts *iter; for (iter = ucounts; iter; iter = iter->ns->ucounts) { - int dec = atomic_dec_if_positive(&iter->ucount[type]); + long dec = atomic_long_dec_if_positive(&iter->ucount[type]); WARN_ON_ONCE(dec < 0); } put_ucounts(ucounts); } +long inc_rlimit_ucounts(struct ucounts *ucounts, enum ucount_type type, long v) +{ + struct ucounts *iter; + long ret = 0; + + for (iter = ucounts; iter; iter = iter->ns->ucounts) { + long max = READ_ONCE(iter->ns->ucount_max[type]); + long new = atomic_long_add_return(v, &iter->ucount[type]); + if (new < 0 || new > max) + ret = LONG_MAX; + else if (iter == ucounts) + ret = new; + } + return ret; +} + +bool dec_rlimit_ucounts(struct ucounts *ucounts, enum ucount_type type, long v) +{ + struct ucounts *iter; + long new = -1; /* Silence compiler warning */ + for (iter = ucounts; iter; iter = iter->ns->ucounts) { + long dec = atomic_long_add_return(-v, &iter->ucount[type]); + WARN_ON_ONCE(dec < 0); + if (iter == ucounts) + new = dec; + } + return (new == 0); +} + +bool is_ucounts_overlimit(struct ucounts *ucounts, enum ucount_type type, unsigned long max) +{ + struct ucounts *iter; + if (get_ucounts_value(ucounts, type) > max) + return true; + for (iter = ucounts; iter; iter = iter->ns->ucounts) { + max = READ_ONCE(iter->ns->ucount_max[type]); + if (get_ucounts_value(iter, type) > max) + return true; + } + return false; +} + static __init int user_namespace_sysctl_init(void) { #ifdef CONFIG_SYSCTL @@ -241,6 +305,8 @@ static __init int user_namespace_sysctl_init(void) BUG_ON(!user_header); BUG_ON(!setup_userns_sysctls(&init_user_ns)); #endif + hlist_add_ucounts(&init_ucounts); + inc_rlimit_ucounts(&init_ucounts, UCOUNT_RLIMIT_NPROC, 1); return 0; } subsys_initcall(user_namespace_sysctl_init); diff --git a/kernel/user.c b/kernel/user.c index a2478cddf536..c82399c1618a 100644 --- a/kernel/user.c +++ b/kernel/user.c @@ -98,9 +98,6 @@ static DEFINE_SPINLOCK(uidhash_lock); /* root_user.__count is 1, for init task cred */ struct user_struct root_user = { .__count = REFCOUNT_INIT(1), - .processes = ATOMIC_INIT(1), - .sigpending = ATOMIC_INIT(0), - .locked_shm = 0, .uid = GLOBAL_ROOT_UID, .ratelimit = RATELIMIT_STATE_INIT(root_user.ratelimit, 0, 0), }; diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c index 8d62863721b0..ef82d401dde8 100644 --- a/kernel/user_namespace.c +++ b/kernel/user_namespace.c @@ -119,9 +119,13 @@ int create_user_ns(struct cred *new) ns->owner = owner; ns->group = group; INIT_WORK(&ns->work, free_user_ns); - for (i = 0; i < UCOUNT_COUNTS; i++) { + for (i = 0; i < MAX_PER_NAMESPACE_UCOUNTS; i++) { ns->ucount_max[i] = INT_MAX; } + set_rlimit_ucount_max(ns, UCOUNT_RLIMIT_NPROC, rlimit(RLIMIT_NPROC)); + set_rlimit_ucount_max(ns, UCOUNT_RLIMIT_MSGQUEUE, rlimit(RLIMIT_MSGQUEUE)); + set_rlimit_ucount_max(ns, UCOUNT_RLIMIT_SIGPENDING, rlimit(RLIMIT_SIGPENDING)); + set_rlimit_ucount_max(ns, UCOUNT_RLIMIT_MEMLOCK, rlimit(RLIMIT_MEMLOCK)); ns->ucounts = ucounts; /* Inherit USERNS_SETGROUPS_ALLOWED from our parent */ @@ -1340,6 +1344,9 @@ static int userns_install(struct nsset *nsset, struct ns_common *ns) put_user_ns(cred->user_ns); set_cred_user_ns(cred, get_user_ns(user_ns)); + if (set_cred_ucounts(cred) < 0) + return -EINVAL; + return 0; } diff --git a/mm/memfd.c b/mm/memfd.c index 2647c898990c..081dd33e6a61 100644 --- a/mm/memfd.c +++ b/mm/memfd.c @@ -297,9 +297,9 @@ SYSCALL_DEFINE2(memfd_create, } if (flags & MFD_HUGETLB) { - struct user_struct *user = NULL; + struct ucounts *ucounts = NULL; - file = hugetlb_file_setup(name, 0, VM_NORESERVE, &user, + file = hugetlb_file_setup(name, 0, VM_NORESERVE, &ucounts, HUGETLB_ANONHUGE_INODE, (flags >> MFD_HUGE_SHIFT) & MFD_HUGE_MASK); diff --git a/mm/mlock.c b/mm/mlock.c index df590fda5688..e338ebc4ad29 100644 --- a/mm/mlock.c +++ b/mm/mlock.c @@ -817,9 +817,10 @@ SYSCALL_DEFINE0(munlockall) */ static DEFINE_SPINLOCK(shmlock_user_lock); -int user_shm_lock(size_t size, struct user_struct *user) +int user_shm_lock(size_t size, struct ucounts *ucounts) { unsigned long lock_limit, locked; + long memlock; int allowed = 0; locked = (size + PAGE_SIZE - 1) >> PAGE_SHIFT; @@ -828,21 +829,26 @@ int user_shm_lock(size_t size, struct user_struct *user) allowed = 1; lock_limit >>= PAGE_SHIFT; spin_lock(&shmlock_user_lock); - if (!allowed && - locked + user->locked_shm > lock_limit && !capable(CAP_IPC_LOCK)) + memlock = inc_rlimit_ucounts(ucounts, UCOUNT_RLIMIT_MEMLOCK, locked); + + if (!allowed && (memlock == LONG_MAX || memlock > lock_limit) && !capable(CAP_IPC_LOCK)) { + dec_rlimit_ucounts(ucounts, UCOUNT_RLIMIT_MEMLOCK, locked); + goto out; + } + if (!get_ucounts(ucounts)) { + dec_rlimit_ucounts(ucounts, UCOUNT_RLIMIT_MEMLOCK, locked); goto out; - get_uid(user); - user->locked_shm += locked; + } allowed = 1; out: spin_unlock(&shmlock_user_lock); return allowed; } -void user_shm_unlock(size_t size, struct user_struct *user) +void user_shm_unlock(size_t size, struct ucounts *ucounts) { spin_lock(&shmlock_user_lock); - user->locked_shm -= (size + PAGE_SIZE - 1) >> PAGE_SHIFT; + dec_rlimit_ucounts(ucounts, UCOUNT_RLIMIT_MEMLOCK, (size + PAGE_SIZE - 1) >> PAGE_SHIFT); spin_unlock(&shmlock_user_lock); - free_uid(user); + put_ucounts(ucounts); } diff --git a/mm/mmap.c b/mm/mmap.c index 0584e540246e..bc88d1674364 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -1611,7 +1611,7 @@ unsigned long ksys_mmap_pgoff(unsigned long addr, unsigned long len, goto out_fput; } } else if (flags & MAP_HUGETLB) { - struct user_struct *user = NULL; + struct ucounts *ucounts = NULL; struct hstate *hs; hs = hstate_sizelog((flags >> MAP_HUGE_SHIFT) & MAP_HUGE_MASK); @@ -1627,7 +1627,7 @@ unsigned long ksys_mmap_pgoff(unsigned long addr, unsigned long len, */ file = hugetlb_file_setup(HUGETLB_ANON_FILE, len, VM_NORESERVE, - &user, HUGETLB_ANONHUGE_INODE, + &ucounts, HUGETLB_ANONHUGE_INODE, (flags >> MAP_HUGE_SHIFT) & MAP_HUGE_MASK); if (IS_ERR(file)) return PTR_ERR(file); diff --git a/mm/shmem.c b/mm/shmem.c index 5d46611cba8d..14997a98410c 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -2227,7 +2227,7 @@ static struct mempolicy *shmem_get_policy(struct vm_area_struct *vma, } #endif -int shmem_lock(struct file *file, int lock, struct user_struct *user) +int shmem_lock(struct file *file, int lock, struct ucounts *ucounts) { struct inode *inode = file_inode(file); struct shmem_inode_info *info = SHMEM_I(inode); @@ -2239,13 +2239,13 @@ int shmem_lock(struct file *file, int lock, struct user_struct *user) * no serialization needed when called from shm_destroy(). */ if (lock && !(info->flags & VM_LOCKED)) { - if (!user_shm_lock(inode->i_size, user)) + if (!user_shm_lock(inode->i_size, ucounts)) goto out_nomem; info->flags |= VM_LOCKED; mapping_set_unevictable(file->f_mapping); } - if (!lock && (info->flags & VM_LOCKED) && user) { - user_shm_unlock(inode->i_size, user); + if (!lock && (info->flags & VM_LOCKED) && ucounts) { + user_shm_unlock(inode->i_size, ucounts); info->flags &= ~VM_LOCKED; mapping_clear_unevictable(file->f_mapping); } @@ -4092,7 +4092,7 @@ int shmem_unuse(unsigned int type, bool frontswap, return 0; } -int shmem_lock(struct file *file, int lock, struct user_struct *user) +int shmem_lock(struct file *file, int lock, struct ucounts *ucounts) { return 0; } diff --git a/tools/testing/selftests/Makefile b/tools/testing/selftests/Makefile index bc3299a20338..fb010a35d61a 100644 --- a/tools/testing/selftests/Makefile +++ b/tools/testing/selftests/Makefile @@ -49,6 +49,7 @@ TARGETS += proc TARGETS += pstore TARGETS += ptrace TARGETS += openat2 +TARGETS += rlimits TARGETS += rseq TARGETS += rtc TARGETS += seccomp diff --git a/tools/testing/selftests/rlimits/.gitignore b/tools/testing/selftests/rlimits/.gitignore new file mode 100644 index 000000000000..091021f255b3 --- /dev/null +++ b/tools/testing/selftests/rlimits/.gitignore @@ -0,0 +1,2 @@ +# SPDX-License-Identifier: GPL-2.0-only +rlimits-per-userns diff --git a/tools/testing/selftests/rlimits/Makefile b/tools/testing/selftests/rlimits/Makefile new file mode 100644 index 000000000000..03aadb406212 --- /dev/null +++ b/tools/testing/selftests/rlimits/Makefile @@ -0,0 +1,6 @@ +# SPDX-License-Identifier: GPL-2.0-or-later + +CFLAGS += -Wall -O2 -g +TEST_GEN_PROGS := rlimits-per-userns + +include ../lib.mk diff --git a/tools/testing/selftests/rlimits/config b/tools/testing/selftests/rlimits/config new file mode 100644 index 000000000000..416bd53ce982 --- /dev/null +++ b/tools/testing/selftests/rlimits/config @@ -0,0 +1 @@ +CONFIG_USER_NS=y diff --git a/tools/testing/selftests/rlimits/rlimits-per-userns.c b/tools/testing/selftests/rlimits/rlimits-per-userns.c new file mode 100644 index 000000000000..26dc949e93ea --- /dev/null +++ b/tools/testing/selftests/rlimits/rlimits-per-userns.c @@ -0,0 +1,161 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Author: Alexey Gladkov <gladkov.alexey@gmail.com> + */ +#define _GNU_SOURCE +#include <sys/types.h> +#include <sys/wait.h> +#include <sys/time.h> +#include <sys/resource.h> +#include <sys/prctl.h> +#include <sys/stat.h> + +#include <unistd.h> +#include <stdlib.h> +#include <stdio.h> +#include <string.h> +#include <sched.h> +#include <signal.h> +#include <limits.h> +#include <fcntl.h> +#include <errno.h> +#include <err.h> + +#define NR_CHILDS 2 + +static char *service_prog; +static uid_t user = 60000; +static uid_t group = 60000; + +static void setrlimit_nproc(rlim_t n) +{ + pid_t pid = getpid(); + struct rlimit limit = { + .rlim_cur = n, + .rlim_max = n + }; + + warnx("(pid=%d): Setting RLIMIT_NPROC=%ld", pid, n); + + if (setrlimit(RLIMIT_NPROC, &limit) < 0) + err(EXIT_FAILURE, "(pid=%d): setrlimit(RLIMIT_NPROC)", pid); +} + +static pid_t fork_child(void) +{ + pid_t pid = fork(); + + if (pid < 0) + err(EXIT_FAILURE, "fork"); + + if (pid > 0) + return pid; + + pid = getpid(); + + warnx("(pid=%d): New process starting ...", pid); + + if (prctl(PR_SET_PDEATHSIG, SIGKILL) < 0) + err(EXIT_FAILURE, "(pid=%d): prctl(PR_SET_PDEATHSIG)", pid); + + signal(SIGUSR1, SIG_DFL); + + warnx("(pid=%d): Changing to uid=%d, gid=%d", pid, user, group); + + if (setgid(group) < 0) + err(EXIT_FAILURE, "(pid=%d): setgid(%d)", pid, group); + if (setuid(user) < 0) + err(EXIT_FAILURE, "(pid=%d): setuid(%d)", pid, user); + + warnx("(pid=%d): Service running ...", pid); + + warnx("(pid=%d): Unshare user namespace", pid); + if (unshare(CLONE_NEWUSER) < 0) + err(EXIT_FAILURE, "unshare(CLONE_NEWUSER)"); + + char *const argv[] = { "service", NULL }; + char *const envp[] = { "I_AM_SERVICE=1", NULL }; + + warnx("(pid=%d): Executing real service ...", pid); + + execve(service_prog, argv, envp); + err(EXIT_FAILURE, "(pid=%d): execve", pid); +} + +int main(int argc, char **argv) +{ + size_t i; + pid_t child[NR_CHILDS]; + int wstatus[NR_CHILDS]; + int childs = NR_CHILDS; + pid_t pid; + + if (getenv("I_AM_SERVICE")) { + pause(); + exit(EXIT_SUCCESS); + } + + service_prog = argv[0]; + pid = getpid(); + + warnx("(pid=%d) Starting testcase", pid); + + /* + * This rlimit is not a problem for root because it can be exceeded. + */ + setrlimit_nproc(1); + + for (i = 0; i < NR_CHILDS; i++) { + child[i] = fork_child(); + wstatus[i] = 0; + usleep(250000); + } + + while (1) { + for (i = 0; i < NR_CHILDS; i++) { + if (child[i] <= 0) + continue; + + errno = 0; + pid_t ret = waitpid(child[i], &wstatus[i], WNOHANG); + + if (!ret || (!WIFEXITED(wstatus[i]) && !WIFSIGNALED(wstatus[i]))) + continue; + + if (ret < 0 && errno != ECHILD) + warn("(pid=%d): waitpid(%d)", pid, child[i]); + + child[i] *= -1; + childs -= 1; + } + + if (!childs) + break; + + usleep(250000); + + for (i = 0; i < NR_CHILDS; i++) { + if (child[i] <= 0) + continue; + kill(child[i], SIGUSR1); + } + } + + for (i = 0; i < NR_CHILDS; i++) { + if (WIFEXITED(wstatus[i])) + warnx("(pid=%d): pid %d exited, status=%d", + pid, -child[i], WEXITSTATUS(wstatus[i])); + else if (WIFSIGNALED(wstatus[i])) + warnx("(pid=%d): pid %d killed by signal %d", + pid, -child[i], WTERMSIG(wstatus[i])); + + if (WIFSIGNALED(wstatus[i]) && WTERMSIG(wstatus[i]) == SIGUSR1) + continue; + + warnx("(pid=%d): Test failed", pid); + exit(EXIT_FAILURE); + } + + warnx("(pid=%d): Test passed", pid); + exit(EXIT_SUCCESS); +} |