Reimplement RLIMIT_MEMLOCK on top of ucounts
The rlimit counter is tied to uid in the user_namespace. This allows rlimit values to be specified in userns even if they are already globally exceeded by the user. However, the value of the previous user_namespaces cannot be exceeded. Changelog v11: * Fix issue found by lkp robot. v8: * Fix issues found by lkp-tests project. v7: * Keep only ucounts for RLIMIT_MEMLOCK checks instead of struct cred. v6: * Fix bug in hugetlb_file_setup() detected by trinity. Reported-by: kernel test robot <oliver.sang@intel.com> Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: Alexey Gladkov <legion@kernel.org> Link: https://lkml.kernel.org/r/970d50c70c71bfd4496e0e8d2a0a32feebebb350.1619094428.git.legion@kernel.org Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
This commit is contained in:
Родитель
d646969055
Коммит
d7c9e99aee
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@ -1443,7 +1443,7 @@ static int get_hstate_idx(int page_size_log)
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* otherwise hugetlb_reserve_pages reserves one less hugepages than intended.
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*/
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struct file *hugetlb_file_setup(const char *name, size_t size,
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vm_flags_t acctflag, struct user_struct **user,
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vm_flags_t acctflag, struct ucounts **ucounts,
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int creat_flags, int page_size_log)
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{
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struct inode *inode;
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@ -1455,20 +1455,20 @@ struct file *hugetlb_file_setup(const char *name, size_t size,
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if (hstate_idx < 0)
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return ERR_PTR(-ENODEV);
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*user = NULL;
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*ucounts = NULL;
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mnt = hugetlbfs_vfsmount[hstate_idx];
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if (!mnt)
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return ERR_PTR(-ENOENT);
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if (creat_flags == HUGETLB_SHMFS_INODE && !can_do_hugetlb_shm()) {
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*user = current_user();
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if (user_shm_lock(size, *user)) {
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*ucounts = current_ucounts();
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if (user_shm_lock(size, *ucounts)) {
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task_lock(current);
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pr_warn_once("%s (%d): Using mlock ulimits for SHM_HUGETLB is deprecated\n",
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current->comm, current->pid);
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task_unlock(current);
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} else {
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*user = NULL;
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*ucounts = NULL;
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return ERR_PTR(-EPERM);
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}
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}
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@ -1495,9 +1495,9 @@ struct file *hugetlb_file_setup(const char *name, size_t size,
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iput(inode);
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out:
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if (*user) {
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user_shm_unlock(size, *user);
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*user = NULL;
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if (*ucounts) {
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user_shm_unlock(size, *ucounts);
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*ucounts = NULL;
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}
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return file;
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}
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@ -434,7 +434,7 @@ static inline struct hugetlbfs_inode_info *HUGETLBFS_I(struct inode *inode)
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extern const struct file_operations hugetlbfs_file_operations;
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extern const struct vm_operations_struct hugetlb_vm_ops;
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struct file *hugetlb_file_setup(const char *name, size_t size, vm_flags_t acct,
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struct user_struct **user, int creat_flags,
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struct ucounts **ucounts, int creat_flags,
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int page_size_log);
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static inline bool is_file_hugepages(struct file *file)
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@ -454,7 +454,7 @@ static inline struct hstate *hstate_inode(struct inode *i)
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#define is_file_hugepages(file) false
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static inline struct file *
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hugetlb_file_setup(const char *name, size_t size, vm_flags_t acctflag,
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struct user_struct **user, int creat_flags,
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struct ucounts **ucounts, int creat_flags,
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int page_size_log)
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{
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return ERR_PTR(-ENOSYS);
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@ -1670,8 +1670,8 @@ extern bool can_do_mlock(void);
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#else
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static inline bool can_do_mlock(void) { return false; }
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#endif
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extern int user_shm_lock(size_t, struct user_struct *);
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extern void user_shm_unlock(size_t, struct user_struct *);
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extern int user_shm_lock(size_t, struct ucounts *);
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extern void user_shm_unlock(size_t, struct ucounts *);
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/*
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* Parameter block passed down to zap_pte_range in exceptional cases.
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@ -18,7 +18,6 @@ struct user_struct {
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#ifdef CONFIG_EPOLL
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atomic_long_t epoll_watches; /* The number of file descriptors currently watched */
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#endif
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unsigned long locked_shm; /* How many pages of mlocked shm ? */
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unsigned long unix_inflight; /* How many files in flight in unix sockets */
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atomic_long_t pipe_bufs; /* how many pages are allocated in pipe buffers */
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@ -65,7 +65,7 @@ extern struct file *shmem_file_setup_with_mnt(struct vfsmount *mnt,
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extern int shmem_zero_setup(struct vm_area_struct *);
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extern unsigned long shmem_get_unmapped_area(struct file *, unsigned long addr,
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unsigned long len, unsigned long pgoff, unsigned long flags);
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extern int shmem_lock(struct file *file, int lock, struct user_struct *user);
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extern int shmem_lock(struct file *file, int lock, struct ucounts *ucounts);
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#ifdef CONFIG_SHMEM
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extern const struct address_space_operations shmem_aops;
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static inline bool shmem_mapping(struct address_space *mapping)
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@ -53,6 +53,7 @@ enum ucount_type {
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UCOUNT_RLIMIT_NPROC,
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UCOUNT_RLIMIT_MSGQUEUE,
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UCOUNT_RLIMIT_SIGPENDING,
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UCOUNT_RLIMIT_MEMLOCK,
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UCOUNT_COUNTS,
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};
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26
ipc/shm.c
26
ipc/shm.c
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@ -60,7 +60,7 @@ struct shmid_kernel /* private to the kernel */
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time64_t shm_ctim;
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struct pid *shm_cprid;
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struct pid *shm_lprid;
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struct user_struct *mlock_user;
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struct ucounts *mlock_ucounts;
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/* The task created the shm object. NULL if the task is dead. */
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struct task_struct *shm_creator;
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@ -286,10 +286,10 @@ static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp)
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shm_rmid(ns, shp);
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shm_unlock(shp);
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if (!is_file_hugepages(shm_file))
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shmem_lock(shm_file, 0, shp->mlock_user);
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else if (shp->mlock_user)
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shmem_lock(shm_file, 0, shp->mlock_ucounts);
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else if (shp->mlock_ucounts)
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user_shm_unlock(i_size_read(file_inode(shm_file)),
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shp->mlock_user);
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shp->mlock_ucounts);
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fput(shm_file);
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ipc_update_pid(&shp->shm_cprid, NULL);
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ipc_update_pid(&shp->shm_lprid, NULL);
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@ -625,7 +625,7 @@ static int newseg(struct ipc_namespace *ns, struct ipc_params *params)
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shp->shm_perm.key = key;
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shp->shm_perm.mode = (shmflg & S_IRWXUGO);
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shp->mlock_user = NULL;
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shp->mlock_ucounts = NULL;
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shp->shm_perm.security = NULL;
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error = security_shm_alloc(&shp->shm_perm);
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@ -650,7 +650,7 @@ static int newseg(struct ipc_namespace *ns, struct ipc_params *params)
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if (shmflg & SHM_NORESERVE)
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acctflag = VM_NORESERVE;
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file = hugetlb_file_setup(name, hugesize, acctflag,
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&shp->mlock_user, HUGETLB_SHMFS_INODE,
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&shp->mlock_ucounts, HUGETLB_SHMFS_INODE,
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(shmflg >> SHM_HUGE_SHIFT) & SHM_HUGE_MASK);
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} else {
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/*
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@ -698,8 +698,8 @@ static int newseg(struct ipc_namespace *ns, struct ipc_params *params)
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no_id:
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ipc_update_pid(&shp->shm_cprid, NULL);
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ipc_update_pid(&shp->shm_lprid, NULL);
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if (is_file_hugepages(file) && shp->mlock_user)
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user_shm_unlock(size, shp->mlock_user);
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if (is_file_hugepages(file) && shp->mlock_ucounts)
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user_shm_unlock(size, shp->mlock_ucounts);
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fput(file);
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ipc_rcu_putref(&shp->shm_perm, shm_rcu_free);
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return error;
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@ -1105,12 +1105,12 @@ static int shmctl_do_lock(struct ipc_namespace *ns, int shmid, int cmd)
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goto out_unlock0;
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if (cmd == SHM_LOCK) {
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struct user_struct *user = current_user();
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struct ucounts *ucounts = current_ucounts();
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err = shmem_lock(shm_file, 1, user);
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err = shmem_lock(shm_file, 1, ucounts);
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if (!err && !(shp->shm_perm.mode & SHM_LOCKED)) {
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shp->shm_perm.mode |= SHM_LOCKED;
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shp->mlock_user = user;
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shp->mlock_ucounts = ucounts;
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}
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goto out_unlock0;
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}
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@ -1118,9 +1118,9 @@ static int shmctl_do_lock(struct ipc_namespace *ns, int shmid, int cmd)
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/* SHM_UNLOCK */
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if (!(shp->shm_perm.mode & SHM_LOCKED))
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goto out_unlock0;
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shmem_lock(shm_file, 0, shp->mlock_user);
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shmem_lock(shm_file, 0, shp->mlock_ucounts);
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shp->shm_perm.mode &= ~SHM_LOCKED;
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shp->mlock_user = NULL;
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shp->mlock_ucounts = NULL;
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get_file(shm_file);
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ipc_unlock_object(&shp->shm_perm);
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rcu_read_unlock();
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@ -825,6 +825,7 @@ void __init fork_init(void)
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init_user_ns.ucount_max[UCOUNT_RLIMIT_NPROC] = task_rlimit(&init_task, RLIMIT_NPROC);
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init_user_ns.ucount_max[UCOUNT_RLIMIT_MSGQUEUE] = task_rlimit(&init_task, RLIMIT_MSGQUEUE);
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init_user_ns.ucount_max[UCOUNT_RLIMIT_SIGPENDING] = task_rlimit(&init_task, RLIMIT_SIGPENDING);
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init_user_ns.ucount_max[UCOUNT_RLIMIT_MEMLOCK] = task_rlimit(&init_task, RLIMIT_MEMLOCK);
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#ifdef CONFIG_VMAP_STACK
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cpuhp_setup_state(CPUHP_BP_PREPARE_DYN, "fork:vm_stack_cache",
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@ -83,6 +83,7 @@ static struct ctl_table user_table[] = {
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{ },
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{ },
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{ },
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{ },
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{ }
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};
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#endif /* CONFIG_SYSCTL */
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@ -98,7 +98,6 @@ static DEFINE_SPINLOCK(uidhash_lock);
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/* root_user.__count is 1, for init task cred */
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struct user_struct root_user = {
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.__count = REFCOUNT_INIT(1),
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.locked_shm = 0,
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.uid = GLOBAL_ROOT_UID,
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.ratelimit = RATELIMIT_STATE_INIT(root_user.ratelimit, 0, 0),
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};
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@ -125,6 +125,7 @@ int create_user_ns(struct cred *new)
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ns->ucount_max[UCOUNT_RLIMIT_NPROC] = rlimit(RLIMIT_NPROC);
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ns->ucount_max[UCOUNT_RLIMIT_MSGQUEUE] = rlimit(RLIMIT_MSGQUEUE);
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ns->ucount_max[UCOUNT_RLIMIT_SIGPENDING] = rlimit(RLIMIT_SIGPENDING);
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ns->ucount_max[UCOUNT_RLIMIT_MEMLOCK] = rlimit(RLIMIT_MEMLOCK);
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ns->ucounts = ucounts;
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/* Inherit USERNS_SETGROUPS_ALLOWED from our parent */
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@ -297,9 +297,9 @@ SYSCALL_DEFINE2(memfd_create,
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}
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if (flags & MFD_HUGETLB) {
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struct user_struct *user = NULL;
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struct ucounts *ucounts = NULL;
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file = hugetlb_file_setup(name, 0, VM_NORESERVE, &user,
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file = hugetlb_file_setup(name, 0, VM_NORESERVE, &ucounts,
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HUGETLB_ANONHUGE_INODE,
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(flags >> MFD_HUGE_SHIFT) &
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MFD_HUGE_MASK);
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22
mm/mlock.c
22
mm/mlock.c
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@ -817,9 +817,10 @@ SYSCALL_DEFINE0(munlockall)
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*/
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static DEFINE_SPINLOCK(shmlock_user_lock);
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int user_shm_lock(size_t size, struct user_struct *user)
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int user_shm_lock(size_t size, struct ucounts *ucounts)
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{
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unsigned long lock_limit, locked;
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long memlock;
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int allowed = 0;
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locked = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
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@ -828,21 +829,26 @@ int user_shm_lock(size_t size, struct user_struct *user)
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allowed = 1;
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lock_limit >>= PAGE_SHIFT;
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spin_lock(&shmlock_user_lock);
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if (!allowed &&
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locked + user->locked_shm > lock_limit && !capable(CAP_IPC_LOCK))
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memlock = inc_rlimit_ucounts(ucounts, UCOUNT_RLIMIT_MEMLOCK, locked);
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if (!allowed && (memlock == LONG_MAX || memlock > lock_limit) && !capable(CAP_IPC_LOCK)) {
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dec_rlimit_ucounts(ucounts, UCOUNT_RLIMIT_MEMLOCK, locked);
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goto out;
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get_uid(user);
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user->locked_shm += locked;
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}
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if (!get_ucounts(ucounts)) {
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dec_rlimit_ucounts(ucounts, UCOUNT_RLIMIT_MEMLOCK, locked);
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goto out;
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}
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allowed = 1;
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out:
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spin_unlock(&shmlock_user_lock);
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return allowed;
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}
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void user_shm_unlock(size_t size, struct user_struct *user)
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void user_shm_unlock(size_t size, struct ucounts *ucounts)
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{
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spin_lock(&shmlock_user_lock);
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user->locked_shm -= (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
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dec_rlimit_ucounts(ucounts, UCOUNT_RLIMIT_MEMLOCK, (size + PAGE_SIZE - 1) >> PAGE_SHIFT);
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spin_unlock(&shmlock_user_lock);
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free_uid(user);
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put_ucounts(ucounts);
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}
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@ -1605,7 +1605,7 @@ unsigned long ksys_mmap_pgoff(unsigned long addr, unsigned long len,
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goto out_fput;
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}
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} else if (flags & MAP_HUGETLB) {
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struct user_struct *user = NULL;
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struct ucounts *ucounts = NULL;
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struct hstate *hs;
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hs = hstate_sizelog((flags >> MAP_HUGE_SHIFT) & MAP_HUGE_MASK);
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@ -1621,7 +1621,7 @@ unsigned long ksys_mmap_pgoff(unsigned long addr, unsigned long len,
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*/
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file = hugetlb_file_setup(HUGETLB_ANON_FILE, len,
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VM_NORESERVE,
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&user, HUGETLB_ANONHUGE_INODE,
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&ucounts, HUGETLB_ANONHUGE_INODE,
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(flags >> MAP_HUGE_SHIFT) & MAP_HUGE_MASK);
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if (IS_ERR(file))
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return PTR_ERR(file);
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10
mm/shmem.c
10
mm/shmem.c
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@ -2227,7 +2227,7 @@ static struct mempolicy *shmem_get_policy(struct vm_area_struct *vma,
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}
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#endif
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int shmem_lock(struct file *file, int lock, struct user_struct *user)
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int shmem_lock(struct file *file, int lock, struct ucounts *ucounts)
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{
|
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struct inode *inode = file_inode(file);
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struct shmem_inode_info *info = SHMEM_I(inode);
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|
@ -2239,13 +2239,13 @@ int shmem_lock(struct file *file, int lock, struct user_struct *user)
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* no serialization needed when called from shm_destroy().
|
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*/
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if (lock && !(info->flags & VM_LOCKED)) {
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if (!user_shm_lock(inode->i_size, user))
|
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if (!user_shm_lock(inode->i_size, ucounts))
|
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goto out_nomem;
|
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info->flags |= VM_LOCKED;
|
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mapping_set_unevictable(file->f_mapping);
|
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}
|
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if (!lock && (info->flags & VM_LOCKED) && user) {
|
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user_shm_unlock(inode->i_size, user);
|
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if (!lock && (info->flags & VM_LOCKED) && ucounts) {
|
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user_shm_unlock(inode->i_size, ucounts);
|
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info->flags &= ~VM_LOCKED;
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mapping_clear_unevictable(file->f_mapping);
|
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}
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@ -4093,7 +4093,7 @@ int shmem_unuse(unsigned int type, bool frontswap,
|
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return 0;
|
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}
|
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|
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int shmem_lock(struct file *file, int lock, struct user_struct *user)
|
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int shmem_lock(struct file *file, int lock, struct ucounts *ucounts)
|
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{
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return 0;
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}
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