X-Git-Url: http://review.tizen.org/git/?a=blobdiff_plain;f=ipc%2Fshm.c;h=28d19f4ece4ba32bb075467d1e53d17ddc0e2d97;hb=c2c737a0461e61a34676bd0bd1bc1a70a1b4e396;hp=c6b4ad5ce3b7b53df40b5934bb823fff4de9f9c8;hpb=b0ec636c93ddd77235bf0f023a8a95d78cb6cafe;p=platform%2Fadaptation%2Frenesas_rcar%2Frenesas_kernel.git diff --git a/ipc/shm.c b/ipc/shm.c index c6b4ad5..28d19f4 100644 --- a/ipc/shm.c +++ b/ipc/shm.c @@ -19,6 +19,9 @@ * namespaces support * OpenVZ, SWsoft Inc. * Pavel Emelianov + * + * Better ipc lock (kern_ipc_perm.lock) handling + * Davidlohr Bueso , June 2013. */ #include @@ -124,6 +127,26 @@ void __init shm_init (void) IPC_SHM_IDS, sysvipc_shm_proc_show); } +static inline struct shmid_kernel *shm_obtain_object(struct ipc_namespace *ns, int id) +{ + struct kern_ipc_perm *ipcp = ipc_obtain_object(&shm_ids(ns), id); + + if (IS_ERR(ipcp)) + return ERR_CAST(ipcp); + + return container_of(ipcp, struct shmid_kernel, shm_perm); +} + +static inline struct shmid_kernel *shm_obtain_object_check(struct ipc_namespace *ns, int id) +{ + struct kern_ipc_perm *ipcp = ipc_obtain_object_check(&shm_ids(ns), id); + + if (IS_ERR(ipcp)) + return ERR_CAST(ipcp); + + return container_of(ipcp, struct shmid_kernel, shm_perm); +} + /* * shm_lock_(check_) routines are called in the paths where the rw_mutex * is not necessarily held. @@ -760,11 +783,10 @@ static int shmctl_down(struct ipc_namespace *ns, int shmid, int cmd, down_write(&shm_ids(ns).rw_mutex); rcu_read_lock(); - ipcp = ipcctl_pre_down(ns, &shm_ids(ns), shmid, cmd, - &shmid64.shm_perm, 0); + ipcp = ipcctl_pre_down_nolock(ns, &shm_ids(ns), shmid, cmd, + &shmid64.shm_perm, 0); if (IS_ERR(ipcp)) { err = PTR_ERR(ipcp); - /* the ipc lock is not held upon failure */ goto out_unlock1; } @@ -772,14 +794,16 @@ static int shmctl_down(struct ipc_namespace *ns, int shmid, int cmd, err = security_shm_shmctl(shp, cmd); if (err) - goto out_unlock0; + goto out_unlock1; switch (cmd) { case IPC_RMID: + ipc_lock_object(&shp->shm_perm); /* do_shm_rmid unlocks the ipc object and rcu */ do_shm_rmid(ns, ipcp); goto out_up; case IPC_SET: + ipc_lock_object(&shp->shm_perm); err = ipc_update_perm(&shmid64.shm_perm, ipcp); if (err) goto out_unlock0; @@ -787,6 +811,7 @@ static int shmctl_down(struct ipc_namespace *ns, int shmid, int cmd, break; default: err = -EINVAL; + goto out_unlock1; } out_unlock0: @@ -798,29 +823,24 @@ out_up: return err; } -SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf) +static int shmctl_nolock(struct ipc_namespace *ns, int shmid, + int cmd, int version, void __user *buf) { + int err; struct shmid_kernel *shp; - int err, version; - struct ipc_namespace *ns; - if (cmd < 0 || shmid < 0) { - err = -EINVAL; - goto out; + /* preliminary security checks for *_INFO */ + if (cmd == IPC_INFO || cmd == SHM_INFO) { + err = security_shm_shmctl(NULL, cmd); + if (err) + return err; } - version = ipc_parse_version(&cmd); - ns = current->nsproxy->ipc_ns; - - switch (cmd) { /* replace with proc interface ? */ + switch (cmd) { case IPC_INFO: { struct shminfo64 shminfo; - err = security_shm_shmctl(NULL, cmd); - if (err) - return err; - memset(&shminfo, 0, sizeof(shminfo)); shminfo.shmmni = shminfo.shmseg = ns->shm_ctlmni; shminfo.shmmax = ns->shm_ctlmax; @@ -842,10 +862,6 @@ SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf) { struct shm_info shm_info; - err = security_shm_shmctl(NULL, cmd); - if (err) - return err; - memset(&shm_info, 0, sizeof(shm_info)); down_read(&shm_ids(ns).rw_mutex); shm_info.used_ids = shm_ids(ns).in_use; @@ -869,27 +885,31 @@ SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf) struct shmid64_ds tbuf; int result; + rcu_read_lock(); if (cmd == SHM_STAT) { - shp = shm_lock(ns, shmid); + shp = shm_obtain_object(ns, shmid); if (IS_ERR(shp)) { err = PTR_ERR(shp); - goto out; + goto out_unlock; } result = shp->shm_perm.id; } else { - shp = shm_lock_check(ns, shmid); + shp = shm_obtain_object_check(ns, shmid); if (IS_ERR(shp)) { err = PTR_ERR(shp); - goto out; + goto out_unlock; } result = 0; } + err = -EACCES; if (ipcperms(ns, &shp->shm_perm, S_IRUGO)) goto out_unlock; + err = security_shm_shmctl(shp, cmd); if (err) goto out_unlock; + memset(&tbuf, 0, sizeof(tbuf)); kernel_to_ipc64_perm(&shp->shm_perm, &tbuf.shm_perm); tbuf.shm_segsz = shp->shm_segsz; @@ -899,43 +919,76 @@ SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf) tbuf.shm_cpid = shp->shm_cprid; tbuf.shm_lpid = shp->shm_lprid; tbuf.shm_nattch = shp->shm_nattch; - shm_unlock(shp); - if(copy_shmid_to_user (buf, &tbuf, version)) + rcu_read_unlock(); + + if (copy_shmid_to_user(buf, &tbuf, version)) err = -EFAULT; else err = result; goto out; } + default: + return -EINVAL; + } + +out_unlock: + rcu_read_unlock(); +out: + return err; +} + +SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf) +{ + struct shmid_kernel *shp; + int err, version; + struct ipc_namespace *ns; + + if (cmd < 0 || shmid < 0) + return -EINVAL; + + version = ipc_parse_version(&cmd); + ns = current->nsproxy->ipc_ns; + + switch (cmd) { + case IPC_INFO: + case SHM_INFO: + case SHM_STAT: + case IPC_STAT: + return shmctl_nolock(ns, shmid, cmd, version, buf); + case IPC_RMID: + case IPC_SET: + return shmctl_down(ns, shmid, cmd, buf, version); case SHM_LOCK: case SHM_UNLOCK: { struct file *shm_file; - shp = shm_lock_check(ns, shmid); + rcu_read_lock(); + shp = shm_obtain_object_check(ns, shmid); if (IS_ERR(shp)) { err = PTR_ERR(shp); - goto out; + goto out_unlock1; } audit_ipc_obj(&(shp->shm_perm)); + err = security_shm_shmctl(shp, cmd); + if (err) + goto out_unlock1; + ipc_lock_object(&shp->shm_perm); if (!ns_capable(ns->user_ns, CAP_IPC_LOCK)) { kuid_t euid = current_euid(); err = -EPERM; if (!uid_eq(euid, shp->shm_perm.uid) && !uid_eq(euid, shp->shm_perm.cuid)) - goto out_unlock; + goto out_unlock0; if (cmd == SHM_LOCK && !rlimit(RLIMIT_MEMLOCK)) - goto out_unlock; + goto out_unlock0; } - err = security_shm_shmctl(shp, cmd); - if (err) - goto out_unlock; - shm_file = shp->shm_file; if (is_file_hugepages(shm_file)) - goto out_unlock; + goto out_unlock0; if (cmd == SHM_LOCK) { struct user_struct *user = current_user(); @@ -944,32 +997,31 @@ SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf) shp->shm_perm.mode |= SHM_LOCKED; shp->mlock_user = user; } - goto out_unlock; + goto out_unlock0; } /* SHM_UNLOCK */ if (!(shp->shm_perm.mode & SHM_LOCKED)) - goto out_unlock; + goto out_unlock0; shmem_lock(shm_file, 0, shp->mlock_user); shp->shm_perm.mode &= ~SHM_LOCKED; shp->mlock_user = NULL; get_file(shm_file); - shm_unlock(shp); + ipc_unlock_object(&shp->shm_perm); + rcu_read_unlock(); shmem_unlock_mapping(shm_file->f_mapping); + fput(shm_file); - goto out; - } - case IPC_RMID: - case IPC_SET: - err = shmctl_down(ns, shmid, cmd, buf, version); return err; + } default: return -EINVAL; } -out_unlock: - shm_unlock(shp); -out: +out_unlock0: + ipc_unlock_object(&shp->shm_perm); +out_unlock1: + rcu_read_unlock(); return err; } @@ -1037,10 +1089,11 @@ long do_shmat(int shmid, char __user *shmaddr, int shmflg, ulong *raddr, * additional creator id... */ ns = current->nsproxy->ipc_ns; - shp = shm_lock_check(ns, shmid); + rcu_read_lock(); + shp = shm_obtain_object_check(ns, shmid); if (IS_ERR(shp)) { err = PTR_ERR(shp); - goto out; + goto out_unlock; } err = -EACCES; @@ -1051,24 +1104,31 @@ long do_shmat(int shmid, char __user *shmaddr, int shmflg, ulong *raddr, if (err) goto out_unlock; + ipc_lock_object(&shp->shm_perm); path = shp->shm_file->f_path; path_get(&path); shp->shm_nattch++; size = i_size_read(path.dentry->d_inode); - shm_unlock(shp); + ipc_unlock_object(&shp->shm_perm); + rcu_read_unlock(); err = -ENOMEM; sfd = kzalloc(sizeof(*sfd), GFP_KERNEL); - if (!sfd) - goto out_put_dentry; + if (!sfd) { + path_put(&path); + goto out_nattch; + } file = alloc_file(&path, f_mode, is_file_hugepages(shp->shm_file) ? &shm_file_operations_huge : &shm_file_operations); err = PTR_ERR(file); - if (IS_ERR(file)) - goto out_free; + if (IS_ERR(file)) { + kfree(sfd); + path_put(&path); + goto out_nattch; + } file->private_data = sfd; file->f_mapping = shp->shm_file->f_mapping; @@ -1094,7 +1154,7 @@ long do_shmat(int shmid, char __user *shmaddr, int shmflg, ulong *raddr, addr > current->mm->start_stack - size - PAGE_SIZE * 5) goto invalid; } - + addr = do_mmap_pgoff(file, addr, size, prot, flags, 0, &populate); *raddr = addr; err = 0; @@ -1118,19 +1178,12 @@ out_nattch: else shm_unlock(shp); up_write(&shm_ids(ns).rw_mutex); - -out: return err; out_unlock: - shm_unlock(shp); - goto out; - -out_free: - kfree(sfd); -out_put_dentry: - path_put(&path); - goto out_nattch; + rcu_read_unlock(); +out: + return err; } SYSCALL_DEFINE3(shmat, int, shmid, char __user *, shmaddr, int, shmflg)