X-Git-Url: https://git.saurik.com/apple/xnu.git/blobdiff_plain/5ba3f43ea354af8ad55bea84372a2bc834d8757c..a991bd8d3e7fe02dbca0644054bab73c5b75324a:/bsd/kern/posix_shm.c?ds=sidebyside diff --git a/bsd/kern/posix_shm.c b/bsd/kern/posix_shm.c index 169eba5c5..bffc46999 100644 --- a/bsd/kern/posix_shm.c +++ b/bsd/kern/posix_shm.c @@ -2,7 +2,7 @@ * Copyright (c) 2000-2007 Apple Inc. All rights reserved. * * @APPLE_OSREFERENCE_LICENSE_HEADER_START@ - * + * * This file contains Original Code and/or Modifications of Original Code * as defined in and that are subject to the Apple Public Source License * Version 2.0 (the 'License'). You may not use this file except in @@ -11,10 +11,10 @@ * unlawful or unlicensed copies of an Apple operating system, or to * circumvent, violate, or enable the circumvention or violation of, any * terms of an Apple operating system software license agreement. - * + * * Please obtain a copy of the License at * http://www.opensource.apple.com/apsl/ and read it before using this file. - * + * * The Original Code and all software distributed under the License are * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, @@ -22,7 +22,7 @@ * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. * Please see the License for the specific language governing rights and * limitations under the License. - * + * * @APPLE_OSREFERENCE_LICENSE_HEADER_END@ */ /* @@ -67,7 +67,9 @@ #include #include #include +#include #include +#include #if CONFIG_MACF #include @@ -84,130 +86,124 @@ #include #include -#define f_flag f_fglob->fg_flag -#define f_type f_fglob->fg_ops->fo_type -#define f_msgcount f_fglob->fg_msgcount -#define f_cred f_fglob->fg_cred -#define f_ops f_fglob->fg_ops -#define f_offset f_fglob->fg_offset -#define f_data f_fglob->fg_data -#define PSHMNAMLEN 31 /* maximum name segment length we bother with */ - -struct pshmobj { - void * pshmo_memobject; - memory_object_size_t pshmo_size; - struct pshmobj * pshmo_next; -}; +#define f_flag fp_glob->fg_flag +#define f_ops fp_glob->fg_ops +#define f_data fp_glob->fg_data -struct pshminfo { - unsigned int pshm_flags; - unsigned int pshm_usecount; - off_t pshm_length; - mode_t pshm_mode; - uid_t pshm_uid; - gid_t pshm_gid; - char pshm_name[PSHMNAMLEN + 1]; /* segment name */ - struct pshmobj *pshm_memobjects; -#if DIAGNOSTIC - unsigned int pshm_readcount; - unsigned int pshm_writecount; - proc_t pshm_proc; -#endif /* DIAGNOSTIC */ - struct label* pshm_label; -}; -#define PSHMINFO_NULL (struct pshminfo *)0 - -#define PSHM_NONE 0x001 -#define PSHM_DEFINED 0x002 -#define PSHM_ALLOCATED 0x004 -#define PSHM_MAPPED 0x008 -#define PSHM_INUSE 0x010 -#define PSHM_REMOVED 0x020 -#define PSHM_INCREATE 0x040 -#define PSHM_INDELETE 0x080 -#define PSHM_ALLOCATING 0x100 - -struct pshmcache { - LIST_ENTRY(pshmcache) pshm_hash; /* hash chain */ - struct pshminfo *pshminfo; /* vnode the name refers to */ - int pshm_nlen; /* length of name */ - char pshm_name[PSHMNAMLEN + 1]; /* segment name */ -}; -#define PSHMCACHE_NULL (struct pshmcache *)0 - -#define PSHMCACHE_NOTFOUND (0) -#define PSHMCACHE_FOUND (-1) -#define PSHMCACHE_NEGATIVE (ENOENT) - -struct pshmstats { - long goodhits; /* hits that we can really use */ - long neghits; /* negative hits that we can use */ - long badhits; /* hits we must drop */ - long falsehits; /* hits with id mismatch */ - long miss; /* misses */ - long longnames; /* long names that ignore cache */ -}; +/* + * Used to construct the list of memory objects + * assigned to a populated shared memory segment. + */ +typedef struct pshm_mobj { + void *pshmo_memobject; + memory_object_size_t pshmo_size; + SLIST_ENTRY(pshm_mobj) pshmo_next; +} pshm_mobj_t; -struct pshmname { - char *pshm_nameptr; /* pointer to looked up name */ - long pshm_namelen; /* length of looked up component */ - u_long pshm_hash; /* hash value of looked up name */ -}; +/* + * This represents an existing Posix shared memory object. + * + * It comes into existence with a shm_open(...O_CREAT...) + * call and goes away only after it has been shm_unlink()ed + * and the last remaining shm_open() file reference is closed. + * + * To keep track of that lifetime, pshm_usecount is used as a reference + * counter. It's incremented for every successful shm_open() and + * one extra time for the shm_unlink() to release. Internally + * you can temporarily use an additional reference whenever the + * subsystem lock has to be dropped for other reasons. + */ +typedef struct internal_pshminfo { + struct pshminfo pshm_hdr; + SLIST_HEAD(pshm_mobjhead, pshm_mobj) pshm_mobjs; + RB_ENTRY(internal_pshminfo) pshm_links; /* links for red/black tree */ +} pshm_info_t; +#define pshm_flags pshm_hdr.pshm_flags +#define pshm_usecount pshm_hdr.pshm_usecount +#define pshm_length pshm_hdr.pshm_length +#define pshm_mode pshm_hdr.pshm_mode +#define pshm_uid pshm_hdr.pshm_uid +#define pshm_gid pshm_hdr.pshm_gid +#define pshm_label pshm_hdr.pshm_label + +/* Values for pshm_flags that are still used */ +#define PSHM_ALLOCATED 0x004 /* backing storage is allocated */ +#define PSHM_MAPPED 0x008 /* mapped at least once */ +#define PSHM_INUSE 0x010 /* mapped at least once */ +#define PSHM_REMOVED 0x020 /* no longer in the name cache due to shm_unlink() */ +#define PSHM_ALLOCATING 0x100 /* storage is being allocated */ -struct pshmnode { - off_t mapp_addr; - user_size_t map_size; /* XXX unused ? */ - struct pshminfo *pinfo; - unsigned int pshm_usecount; -#if DIAGNOSTIC - unsigned int readcnt; - unsigned int writecnt; -#endif -}; -#define PSHMNODE_NULL (struct pshmnode *)0 +/* + * These handle reference counting pshm_info_t structs using pshm_usecount. + */ +static int pshm_ref(pshm_info_t *pinfo); +static void pshm_deref(pshm_info_t *pinfo); +#define PSHM_MAXCOUNT UINT_MAX +/* + * For every shm_open, we get a new one of these. + * The only reason we don't just use pshm_info directly is that + * you can query the mapped memory objects via proc_pidinfo to + * query the mapped address. Note that even this is a hack. If + * you mmap() the same fd multiple times, we only save/report + * one address. + */ +typedef struct pshmnode { + off_t mapp_addr; + pshm_info_t *pinfo; +} pshmnode_t; -#define PSHMHASH(pnp) \ - (&pshmhashtbl[(pnp)->pshm_hash & pshmhash]) -LIST_HEAD(pshmhashhead, pshmcache) *pshmhashtbl; /* Hash Table */ -u_long pshmhash; /* size of hash table - 1 */ -long pshmnument; /* number of cache entries allocated */ -struct pshmstats pshmstats; /* cache effectiveness statistics */ +/* compare function for the red black tree */ +static int +pshm_compare(pshm_info_t *a, pshm_info_t *b) +{ + int cmp = strncmp(a->pshm_hdr.pshm_name, b->pshm_hdr.pshm_name, PSHMNAMLEN + 1); -static int pshm_read (struct fileproc *fp, struct uio *uio, - int flags, vfs_context_t ctx); -static int pshm_write (struct fileproc *fp, struct uio *uio, - int flags, vfs_context_t ctx); -static int pshm_ioctl (struct fileproc *fp, u_long com, - caddr_t data, vfs_context_t ctx); -static int pshm_select (struct fileproc *fp, int which, void *wql, vfs_context_t ctx); -static int pshm_close(struct pshminfo *pinfo, int dropref); -static int pshm_closefile (struct fileglob *fg, vfs_context_t ctx); + if (cmp < 0) { + return -1; + } + if (cmp > 0) { + return 1; + } + return 0; +} + + +/* + * shared memory "paths" are stored in a red black tree for lookup + */ +u_long pshmnument; /* count of entries allocated in the red black tree */ +RB_HEAD(pshmhead, internal_pshminfo) pshm_head; +RB_PROTOTYPE(pshmhead, internal_pshminfo, pshm_links, pshm_compare) +RB_GENERATE(pshmhead, internal_pshminfo, pshm_links, pshm_compare) + +/* lookup, add, remove functions */ +static pshm_info_t *pshm_cache_search(pshm_info_t * look); +static void pshm_cache_add(pshm_info_t *entry); +static void pshm_cache_delete(pshm_info_t *entry); -static int pshm_kqfilter(struct fileproc *fp, struct knote *kn, - struct kevent_internal_s *kev, vfs_context_t ctx); +static int pshm_closefile(struct fileglob *fg, vfs_context_t ctx); -int pshm_access(struct pshminfo *pinfo, int mode, kauth_cred_t cred, proc_t p); +static int pshm_access(pshm_info_t *pinfo, int mode, kauth_cred_t cred, proc_t p); int pshm_cache_purge_all(proc_t p); -static int pshm_cache_add(struct pshminfo *pshmp, struct pshmname *pnp, struct pshmcache *pcp); -static void pshm_cache_delete(struct pshmcache *pcp); -static int pshm_cache_search(struct pshminfo **pshmp, struct pshmname *pnp, - struct pshmcache **pcache, int addref); -static int pshm_unlink_internal(struct pshminfo *pinfo, struct pshmcache *pcache); +static int pshm_unlink_internal(pshm_info_t *pinfo); static const struct fileops pshmops = { - .fo_type = DTYPE_PSXSHM, - .fo_read = pshm_read, - .fo_write = pshm_write, - .fo_ioctl = pshm_ioctl, - .fo_select = pshm_select, - .fo_close = pshm_closefile, - .fo_kqfilter = pshm_kqfilter, - .fo_drain = NULL, + .fo_type = DTYPE_PSXSHM, + .fo_read = fo_no_read, + .fo_write = fo_no_write, + .fo_ioctl = fo_no_ioctl, + .fo_select = fo_no_select, + .fo_close = pshm_closefile, + .fo_drain = fo_no_drain, + .fo_kqfilter = fo_no_kqfilter, }; +/* + * Everything here is protected by a single mutex. + */ static lck_grp_t *psx_shm_subsys_lck_grp; static lck_grp_attr_t *psx_shm_subsys_lck_grp_attr; static lck_attr_t *psx_shm_subsys_lck_attr; @@ -218,150 +214,87 @@ static lck_mtx_t psx_shm_subsys_mutex; #define PSHM_SUBSYS_ASSERT_HELD() LCK_MTX_ASSERT(&psx_shm_subsys_mutex, LCK_MTX_ASSERT_OWNED) -/* Initialize the mutex governing access to the posix shm subsystem */ __private_extern__ void pshm_lock_init( void ) { + psx_shm_subsys_lck_grp_attr = lck_grp_attr_alloc_init(); - psx_shm_subsys_lck_grp_attr = lck_grp_attr_alloc_init(); - - psx_shm_subsys_lck_grp = lck_grp_alloc_init("posix shared memory", psx_shm_subsys_lck_grp_attr); + psx_shm_subsys_lck_grp = + lck_grp_alloc_init("posix shared memory", psx_shm_subsys_lck_grp_attr); - psx_shm_subsys_lck_attr = lck_attr_alloc_init(); - lck_mtx_init(& psx_shm_subsys_mutex, psx_shm_subsys_lck_grp, psx_shm_subsys_lck_attr); + psx_shm_subsys_lck_attr = lck_attr_alloc_init(); + lck_mtx_init(&psx_shm_subsys_mutex, psx_shm_subsys_lck_grp, psx_shm_subsys_lck_attr); } /* - * Lookup an entry in the cache - * - * - * status of -1 is returned if matches - * If the lookup determines that the name does not exist - * (negative cacheing), a status of ENOENT is returned. If the lookup - * fails, a status of zero is returned. + * Lookup an entry in the cache. Only the name is used from "look". */ - -static int -pshm_cache_search(struct pshminfo **pshmp, struct pshmname *pnp, - struct pshmcache **pcache, int addref) +static pshm_info_t * +pshm_cache_search(pshm_info_t *look) { - struct pshmcache *pcp, *nnp; - struct pshmhashhead *pcpp; - - if (pnp->pshm_namelen > PSHMNAMLEN) { - pshmstats.longnames++; - return PSHMCACHE_NOTFOUND; - } - - pcpp = PSHMHASH(pnp); - for (pcp = pcpp->lh_first; pcp != 0; pcp = nnp) { - nnp = pcp->pshm_hash.le_next; - if (pcp->pshm_nlen == pnp->pshm_namelen && - !bcmp(pcp->pshm_name, pnp->pshm_nameptr, (u_int)pcp-> pshm_nlen)) - break; - } - - if (pcp == 0) { - pshmstats.miss++; - return PSHMCACHE_NOTFOUND; - } - - /* We found a "positive" match, return the vnode */ - if (pcp->pshminfo) { - pshmstats.goodhits++; - /* TOUCH(ncp); */ - *pshmp = pcp->pshminfo; - *pcache = pcp; - if (addref) - pcp->pshminfo->pshm_usecount++; - return PSHMCACHE_FOUND; - } - - /* - * We found a "negative" match, ENOENT notifies client of this match. - */ - pshmstats.neghits++; - return PSHMCACHE_NEGATIVE; + PSHM_SUBSYS_ASSERT_HELD(); + return RB_FIND(pshmhead, &pshm_head, look); } /* - * Add an entry to the cache. - * XXX should be static? + * Add a new entry to the cache. */ -static int -pshm_cache_add(struct pshminfo *pshmp, struct pshmname *pnp, struct pshmcache *pcp) +static void +pshm_cache_add(pshm_info_t *entry) { - struct pshmhashhead *pcpp; - struct pshminfo *dpinfo; - struct pshmcache *dpcp; - -#if DIAGNOSTIC - if (pnp->pshm_namelen > PSHMNAMLEN) - panic("cache_enter: name too long"); -#endif + pshm_info_t *conflict; - - /* if the entry has already been added by some one else return */ - if (pshm_cache_search(&dpinfo, pnp, &dpcp, 0) == PSHMCACHE_FOUND) { - return EEXIST; + PSHM_SUBSYS_ASSERT_HELD(); + conflict = RB_INSERT(pshmhead, &pshm_head, entry); + if (conflict != NULL) { + panic("pshm_cache_add() found %p", conflict); } pshmnument++; +} - /* - * Fill in cache info, if vp is NULL this is a "negative" cache entry. - */ - pcp->pshminfo = pshmp; - pcp->pshm_nlen = pnp->pshm_namelen; - bcopy(pnp->pshm_nameptr, pcp->pshm_name, (unsigned)pcp->pshm_nlen); - pcpp = PSHMHASH(pnp); -#if DIAGNOSTIC - { - struct pshmcache *p; - - for (p = pcpp->lh_first; p != 0; p = p->pshm_hash.le_next) - if (p == pcp) - panic("cache_enter: duplicate"); - } -#endif - LIST_INSERT_HEAD(pcpp, pcp, pshm_hash); - return 0; +/* + * Remove the given entry from the red black tree. + */ +static void +pshm_cache_delete(pshm_info_t *entry) +{ + PSHM_SUBSYS_ASSERT_HELD(); + assert(!(entry->pshm_flags & PSHM_REMOVED)); + RB_REMOVE(pshmhead, &pshm_head, entry); + pshmnument--; } /* - * Name cache initialization, from vfs_init() when we are booting + * Initialize the red black tree. */ void pshm_cache_init(void) { - pshmhashtbl = hashinit(desiredvnodes / 8, M_SHM, &pshmhash); + RB_INIT(&pshm_head); } /* - * Invalidate all entries and delete all objects associated with it. Entire - * non Kernel entries are going away. Just dump'em all - * - * We actually just increment the v_id, that will do it. The entries will - * be purged by lookup as they get found. If the v_id wraps around, we - * need to ditch the entire cache, to avoid confusion. No valid vnode will - * ever have (v_id == 0). + * Invalidate all entries and delete all objects associated with them + * XXX - due to the reference counting, this only works if all userland + * references to it via file descriptors are also closed already. Is this + * known to be called after all user processes are killed? */ int -pshm_cache_purge_all(__unused proc_t p) +pshm_cache_purge_all(__unused proc_t proc) { - struct pshmcache *pcp, *tmppcp; - struct pshmhashhead *pcpp; + pshm_info_t *p; + pshm_info_t *tmp; int error = 0; - if (kauth_cred_issuser(kauth_cred_get()) == 0) + if (kauth_cred_issuser(kauth_cred_get()) == 0) { return EPERM; + } PSHM_SUBSYS_LOCK(); - for (pcpp = &pshmhashtbl[pshmhash]; pcpp >= pshmhashtbl; pcpp--) { - LIST_FOREACH_SAFE(pcp, pcpp, pshm_hash, tmppcp) { - assert(pcp->pshm_nlen); - error = pshm_unlink_internal(pcp->pshminfo, pcp); - if (error) - goto out; + RB_FOREACH_SAFE(p, pshmhead, &pshm_head, tmp) { + error = pshm_unlink_internal(p); + if (error) { /* XXX: why give up on failure, should keep going */ + goto out; } } assert(pshmnument == 0); @@ -369,105 +302,86 @@ pshm_cache_purge_all(__unused proc_t p) out: PSHM_SUBSYS_UNLOCK(); - if (error) - printf("%s: Error %d removing shm cache: %ld remain!\n", - __func__, error, pshmnument); + if (error) { + printf("%s: Error %d removing posix shm cache: %ld remain!\n", + __func__, error, pshmnument); + } return error; } -static void -pshm_cache_delete(struct pshmcache *pcp) +/* + * Utility to get the shared memory name from userspace and + * populate a pshm_info_t with it. If there's a problem + * reading the name or it's malformed, will return an error code. + */ +static int +pshm_get_name(pshm_info_t *pinfo, const user_addr_t user_addr) { -#if DIAGNOSTIC - if (pcp->pshm_hash.le_prev == 0) - panic("namecache purge le_prev"); - if (pcp->pshm_hash.le_next == pcp) - panic("namecache purge le_next"); -#endif /* DIAGNOSTIC */ - LIST_REMOVE(pcp, pshm_hash); - pcp->pshm_hash.le_prev = 0; - pshmnument--; -} + size_t bytes_copied = 0; + int error; + error = copyinstr(user_addr, &pinfo->pshm_hdr.pshm_name[0], PSHMNAMLEN + 1, &bytes_copied); + if (error != 0) { + return error; + } + assert(bytes_copied <= PSHMNAMLEN + 1); + assert(pinfo->pshm_hdr.pshm_name[bytes_copied - 1] == 0); + if (bytes_copied < 2) { /* 2: expect at least one character and terminating zero */ + return EINVAL; + } + AUDIT_ARG(text, &pinfo->pshm_hdr.pshm_name[0]); + return 0; +} + +/* + * Process a shm_open() system call. + */ int shm_open(proc_t p, struct shm_open_args *uap, int32_t *retval) { - size_t i; - int indx, error; - struct pshmname nd; - struct pshminfo *pinfo; + int indx; + int error = 0; + pshm_info_t *pinfo = NULL; + pshm_info_t *new_pinfo = NULL; + pshmnode_t *new_pnode = NULL; struct fileproc *fp = NULL; - char *pnbuf = NULL; - struct pshminfo *new_pinfo = PSHMINFO_NULL; - struct pshmnode *new_pnode = PSHMNODE_NULL; - struct pshmcache *pcache = PSHMCACHE_NULL; /* ignored on return */ - char * nameptr; - char * cp; - size_t pathlen, plen; - int fmode ; - int cmode = uap->mode; - int incache = 0; - struct pshmcache *pcp = NULL; + int fmode; + mode_t cmode = (mode_t)uap->mode; + bool incache = false; + bool have_label = false; AUDIT_ARG(fflags, uap->oflag); - AUDIT_ARG(mode, uap->mode); - - pinfo = PSHMINFO_NULL; + AUDIT_ARG(mode, cmode); /* - * Preallocate everything we might need up front to avoid taking - * and dropping the lock, opening us up to race conditions. + * Allocate data structures we need. We parse the userspace name into + * a pshm_info_t, even when we don't need to O_CREAT. */ - MALLOC_ZONE(pnbuf, caddr_t, MAXPATHLEN, M_NAMEI, M_WAITOK); - if (pnbuf == NULL) { + MALLOC(new_pinfo, pshm_info_t *, sizeof(pshm_info_t), M_SHM, M_WAITOK | M_ZERO); + if (new_pinfo == NULL) { error = ENOSPC; goto bad; } - pathlen = MAXPATHLEN; - error = copyinstr(uap->name, (void *)pnbuf, MAXPATHLEN, &pathlen); - if (error) { - goto bad; - } - AUDIT_ARG(text, pnbuf); - if (pathlen > PSHMNAMLEN) { - error = ENAMETOOLONG; - goto bad; - } -#ifdef PSXSHM_NAME_RESTRICT - nameptr = pnbuf; - if (*nameptr == '/') { - while (*(nameptr++) == '/') { - plen--; - error = EINVAL; - goto bad; - } - } else { - error = EINVAL; + /* + * Get and check the name. + */ + error = pshm_get_name(new_pinfo, uap->name); + if (error != 0) { goto bad; } -#endif /* PSXSHM_NAME_RESTRICT */ - - plen = pathlen; - nameptr = pnbuf; - nd.pshm_nameptr = nameptr; - nd.pshm_namelen = plen; - nd. pshm_hash =0; - - for (cp = nameptr, i=1; *cp != 0 && i <= plen; i++, cp++) { - nd.pshm_hash += (unsigned char)*cp * i; - } /* - * attempt to allocate a new fp; if unsuccessful, the fp will be + * Attempt to allocate a new fp. If unsuccessful, the fp will be * left unmodified (NULL). */ error = falloc(p, &fp, &indx, vfs_context_current()); - if (error) + if (error) { goto bad; + } - cmode &= ALLPERMS; + cmode &= ALLPERMS; fmode = FFLAGS(uap->oflag); if ((fmode & (FREAD | FWRITE)) == 0) { @@ -476,164 +390,107 @@ shm_open(proc_t p, struct shm_open_args *uap, int32_t *retval) } /* - * We allocate a new entry if we are less than the maximum - * allowed and the one at the front of the LRU list is in use. - * Otherwise we use the one at the front of the LRU list. + * Will need a new pnode for the file pointer */ - MALLOC(pcp, struct pshmcache *, sizeof(struct pshmcache), M_SHM, M_WAITOK|M_ZERO); - if (pcp == NULL) { + MALLOC(new_pnode, pshmnode_t *, sizeof(pshmnode_t), M_SHM, M_WAITOK | M_ZERO); + if (new_pnode == NULL) { error = ENOSPC; goto bad; } - MALLOC(new_pinfo, struct pshminfo *, sizeof(struct pshminfo), M_SHM, M_WAITOK|M_ZERO); - if (new_pinfo == PSHMINFO_NULL) { - error = ENOSPC; - goto bad; - } + /* + * If creating a new segment, fill in its information. + * If we find a pre-exisitng one in cache lookup we'll just toss this one later. + */ + if (fmode & O_CREAT) { + new_pinfo->pshm_usecount = 2; /* one each for: file pointer, shm_unlink */ + new_pinfo->pshm_length = 0; + new_pinfo->pshm_mode = cmode; + new_pinfo->pshm_uid = kauth_getuid(); + new_pinfo->pshm_gid = kauth_getgid(); + SLIST_INIT(&new_pinfo->pshm_mobjs); #if CONFIG_MACF - mac_posixshm_label_init(new_pinfo); + mac_posixshm_label_init(&new_pinfo->pshm_hdr); + have_label = true; + error = mac_posixshm_check_create(kauth_cred_get(), new_pinfo->pshm_hdr.pshm_name); + if (error) { + goto bad; + } #endif - - MALLOC(new_pnode, struct pshmnode *, sizeof(struct pshmnode), M_SHM, M_WAITOK|M_ZERO); - if (new_pnode == PSHMNODE_NULL) { - error = ENOSPC; - goto bad; } - PSHM_SUBSYS_LOCK(); - /* - * If we find the entry in the cache, this will take a reference, - * allowing us to unlock it for the permissions check. + * Look up the named shared memory segment in the cache, possibly adding + * it for O_CREAT. */ - error = pshm_cache_search(&pinfo, &nd, &pcache, 1); - - PSHM_SUBSYS_UNLOCK(); + PSHM_SUBSYS_LOCK(); - if (error == PSHMCACHE_NEGATIVE) { - error = EINVAL; - goto bad; - } + pinfo = pshm_cache_search(new_pinfo); + if (pinfo != NULL) { + incache = true; - if (error == PSHMCACHE_NOTFOUND) { - incache = 0; - if (fmode & O_CREAT) { - /* create a new one (commit the allocation) */ - pinfo = new_pinfo; - pinfo->pshm_flags = PSHM_DEFINED | PSHM_INCREATE; - pinfo->pshm_usecount = 1; /* existence reference */ - pinfo->pshm_mode = cmode; - pinfo->pshm_uid = kauth_getuid(); - pinfo->pshm_gid = kauth_getgid(); - bcopy(pnbuf, &pinfo->pshm_name[0], pathlen); - pinfo->pshm_name[pathlen]=0; -#if CONFIG_MACF - error = mac_posixshm_check_create(kauth_cred_get(), nameptr); - if (error) { - goto bad; - } - mac_posixshm_label_associate(kauth_cred_get(), pinfo, nameptr); -#endif - } - } else { - incache = 1; - if (fmode & O_CREAT) { - /* already exists */ - if ((fmode & O_EXCL)) { - AUDIT_ARG(posix_ipc_perm, pinfo->pshm_uid, - pinfo->pshm_gid, - pinfo->pshm_mode); - - /* shm obj exists and opened O_EXCL */ - error = EEXIST; - goto bad; - } - - if( pinfo->pshm_flags & PSHM_INDELETE) { - error = ENOENT; - goto bad; - } - AUDIT_ARG(posix_ipc_perm, pinfo->pshm_uid, - pinfo->pshm_gid, pinfo->pshm_mode); -#if CONFIG_MACF - if ((error = mac_posixshm_check_open(kauth_cred_get(), pinfo, fmode))) { - goto bad; - } -#endif - if ( (error = pshm_access(pinfo, fmode, kauth_cred_get(), p)) ) { - goto bad; - } - } - } - if (!(fmode & O_CREAT)) { - if (!incache) { - /* O_CREAT is not set and the object does not exist */ - error = ENOENT; - goto bad; - } - if( pinfo->pshm_flags & PSHM_INDELETE) { - error = ENOENT; - goto bad; - } -#if CONFIG_MACF - if ((error = mac_posixshm_check_open(kauth_cred_get(), pinfo, fmode))) { - goto bad; + /* Get a new reference to go with the file pointer.*/ + error = pshm_ref(pinfo); + if (error) { + pinfo = NULL; /* so cleanup code doesn't deref */ + goto bad_locked; } -#endif - if ((error = pshm_access(pinfo, fmode, kauth_cred_get(), p))) { - goto bad; + /* can't have pre-existing if O_EXCL */ + if ((fmode & (O_CREAT | O_EXCL)) == (O_CREAT | O_EXCL)) { + error = EEXIST; + goto bad_locked; } - } - if (fmode & O_TRUNC) { - error = EINVAL; - goto bad; - } - - PSHM_SUBSYS_LOCK(); + /* O_TRUNC is only valid while length is not yet set */ + if ((fmode & O_TRUNC) && + (pinfo->pshm_flags & (PSHM_ALLOCATING | PSHM_ALLOCATED))) { + error = EINVAL; + goto bad_locked; + } + } else { + incache = false; -#if DIAGNOSTIC - if (fmode & FWRITE) - pinfo->pshm_writecount++; - if (fmode & FREAD) - pinfo->pshm_readcount++; -#endif - if (!incache) { - /* if successful, this will consume the pcp */ - if ( (error = pshm_cache_add(pinfo, &nd, pcp)) ) { + /* if it wasn't found, must have O_CREAT */ + if (!(fmode & O_CREAT)) { + error = ENOENT; goto bad_locked; } - /* - * add reference for the new entry; otherwise, we obtained - * one from the cache hit earlier. - */ - pinfo->pshm_usecount++; + + /* Add the new region to the cache. */ + pinfo = new_pinfo; + pshm_cache_add(pinfo); + new_pinfo = NULL; /* so that it doesn't get free'd */ } - pinfo->pshm_flags &= ~PSHM_INCREATE; - new_pnode->pinfo = pinfo; PSHM_SUBSYS_UNLOCK(); /* - * if incache, we did not use the new pcp or new_pinfo and must - * free them + * Check we have permission to access any pre-existing segment */ if (incache) { - FREE(pcp, M_SHM); - - if (new_pinfo != PSHMINFO_NULL) { + if (fmode & O_CREAT) { + AUDIT_ARG(posix_ipc_perm, pinfo->pshm_uid, + pinfo->pshm_gid, pinfo->pshm_mode); + } #if CONFIG_MACF - mac_posixshm_label_destroy(new_pinfo); + if ((error = mac_posixshm_check_open(kauth_cred_get(), &pinfo->pshm_hdr, fmode))) { + goto bad; + } #endif - FREE(new_pinfo, M_SHM); + if ((error = pshm_access(pinfo, fmode, kauth_cred_get(), p))) { + goto bad; } + } else { +#if CONFIG_MACF + mac_posixshm_label_associate(kauth_cred_get(), &pinfo->pshm_hdr, pinfo->pshm_hdr.pshm_name); +#endif } proc_fdlock(p); fp->f_flag = fmode & FMASK; fp->f_ops = &pshmops; + new_pnode->pinfo = pinfo; fp->f_data = (caddr_t)new_pnode; *fdflags(p, indx) |= UF_EXCLOSE; procfdtbl_releasefd(p, indx, NULL); @@ -641,113 +498,137 @@ shm_open(proc_t p, struct shm_open_args *uap, int32_t *retval) proc_fdunlock(p); *retval = indx; - FREE_ZONE(pnbuf, MAXPATHLEN, M_NAMEI); - return (0); + error = 0; + goto done; bad_locked: PSHM_SUBSYS_UNLOCK(); bad: /* - * If we obtained the entry from the cache, we need to drop the - * reference; holding the reference may have prevented unlinking, - * so we need to call pshm_close() to get the full effect. + * Drop any new reference to a pre-existing shared memory region. */ - if (incache) { + if (incache && pinfo != NULL) { PSHM_SUBSYS_LOCK(); - pshm_close(pinfo, 1); + pshm_deref(pinfo); PSHM_SUBSYS_UNLOCK(); } - if (pcp != NULL) - FREE(pcp, M_SHM); - - if (new_pnode != PSHMNODE_NULL) + /* + * Delete any allocated unused data structures. + */ + if (new_pnode != NULL) { FREE(new_pnode, M_SHM); + } - if (fp != NULL) + if (fp != NULL) { fp_free(p, indx, fp); + } - if (new_pinfo != PSHMINFO_NULL) { +done: + if (new_pinfo != NULL) { #if CONFIG_MACF - mac_posixshm_label_destroy(new_pinfo); + if (have_label) { + mac_posixshm_label_destroy(&new_pinfo->pshm_hdr); + } #endif FREE(new_pinfo, M_SHM); } - if (pnbuf != NULL) - FREE_ZONE(pnbuf, MAXPATHLEN, M_NAMEI); - return (error); + return error; } +/* + * The truncate call associates memory with shared memory region. It can + * only be succesfully done with a non-zero length once per shared memory region. + */ int -pshm_truncate(__unused proc_t p, struct fileproc *fp, __unused int fd, - off_t length, __unused int32_t *retval) +pshm_truncate( + __unused proc_t p, + struct fileproc *fp, + __unused int fd, + off_t length, + __unused int32_t *retval) { - struct pshminfo * pinfo; - struct pshmnode * pnode ; - kern_return_t kret; + pshm_info_t *pinfo; + pshmnode_t *pnode; + kern_return_t kret; mem_entry_name_port_t mem_object; - mach_vm_size_t total_size, alloc_size; - memory_object_size_t mosize; - struct pshmobj *pshmobj, *pshmobj_next, **pshmobj_next_p; - vm_map_t user_map; -#if CONFIG_MACF - int error; -#endif + mach_vm_size_t total_size, alloc_size; + memory_object_size_t mosize; + pshm_mobj_t *pshmobj, *pshmobj_last; + vm_map_t user_map; + int error; user_map = current_map(); - if (fp->f_type != DTYPE_PSXSHM) { - return(EINVAL); + if (FILEGLOB_DTYPE(fp->fp_glob) != DTYPE_PSXSHM) { + return EINVAL; } - - if (((pnode = (struct pshmnode *)fp->f_data)) == PSHMNODE_NULL ) - return(EINVAL); +#if 0 + /* + * Can't enforce this yet, some third party tools don't + * specify O_RDWR like they ought to. See radar 48692182 + */ + /* ftruncate() requires write permission */ + if (!(fp->f_flag & FWRITE)) { + return EINVAL; + } +#endif PSHM_SUBSYS_LOCK(); - if ((pinfo = pnode->pinfo) == PSHMINFO_NULL) { + if (((pnode = (pshmnode_t *)fp->f_data)) == NULL) { + PSHM_SUBSYS_UNLOCK(); + return EINVAL; + } + + if ((pinfo = pnode->pinfo) == NULL) { PSHM_SUBSYS_UNLOCK(); - return(EINVAL); + return EINVAL; } - if ((pinfo->pshm_flags & (PSHM_DEFINED|PSHM_ALLOCATING|PSHM_ALLOCATED)) - != PSHM_DEFINED) { + + /* We only allow one ftruncate() per lifetime of the shm object. */ + if (pinfo->pshm_flags & (PSHM_ALLOCATING | PSHM_ALLOCATED)) { PSHM_SUBSYS_UNLOCK(); - return(EINVAL); + return EINVAL; } + #if CONFIG_MACF - error = mac_posixshm_check_truncate(kauth_cred_get(), pinfo, length); + error = mac_posixshm_check_truncate(kauth_cred_get(), &pinfo->pshm_hdr, length); if (error) { PSHM_SUBSYS_UNLOCK(); - return(error); + return error; } #endif + /* + * Grab an extra reference, so we can drop the lock while allocating and + * ensure the objects don't disappear. + */ + error = pshm_ref(pinfo); + if (error) { + PSHM_SUBSYS_UNLOCK(); + return error; + } + /* set ALLOCATING, so another truncate can't start */ pinfo->pshm_flags |= PSHM_ALLOCATING; - total_size = vm_map_round_page(length, - vm_map_page_mask(user_map)); - pshmobj_next_p = &pinfo->pshm_memobjects; - - for (alloc_size = 0; - alloc_size < total_size; - alloc_size += mosize) { + total_size = vm_map_round_page(length, vm_map_page_mask(user_map)); + pshmobj_last = NULL; + for (alloc_size = 0; alloc_size < total_size; alloc_size += mosize) { PSHM_SUBSYS_UNLOCK(); + /* get a memory object back some of the shared memory */ mosize = MIN(total_size - alloc_size, ANON_MAX_SIZE); - kret = mach_make_memory_entry_64( - VM_MAP_NULL, - &mosize, - 0, - MAP_MEM_NAMED_CREATE | VM_PROT_DEFAULT, - &mem_object, - 0); + kret = mach_make_memory_entry_64(VM_MAP_NULL, &mosize, 0, + MAP_MEM_NAMED_CREATE | VM_PROT_DEFAULT, &mem_object, 0); - if (kret != KERN_SUCCESS) + if (kret != KERN_SUCCESS) { goto out; + } - MALLOC(pshmobj, struct pshmobj *, sizeof (struct pshmobj), - M_SHM, M_WAITOK); + /* get a list entry to track the memory object */ + MALLOC(pshmobj, pshm_mobj_t *, sizeof(pshm_mobj_t), M_SHM, M_WAITOK); if (pshmobj == NULL) { kret = KERN_NO_SPACE; mach_memory_entry_port_release(mem_object); @@ -757,79 +638,86 @@ pshm_truncate(__unused proc_t p, struct fileproc *fp, __unused int fd, PSHM_SUBSYS_LOCK(); - pshmobj->pshmo_memobject = (void *) mem_object; + /* link in the new entry */ + pshmobj->pshmo_memobject = (void *)mem_object; pshmobj->pshmo_size = mosize; - pshmobj->pshmo_next = NULL; - - *pshmobj_next_p = pshmobj; - pshmobj_next_p = &pshmobj->pshmo_next; + SLIST_NEXT(pshmobj, pshmo_next) = NULL; + + if (pshmobj_last == NULL) { + SLIST_FIRST(&pinfo->pshm_mobjs) = pshmobj; + } else { + SLIST_INSERT_AFTER(pshmobj_last, pshmobj, pshmo_next); + } + pshmobj_last = pshmobj; } - + + /* all done, change flags to ALLOCATED and return success */ pinfo->pshm_flags |= PSHM_ALLOCATED; pinfo->pshm_flags &= ~(PSHM_ALLOCATING); pinfo->pshm_length = total_size; + pshm_deref(pinfo); /* drop the "allocating" reference */ PSHM_SUBSYS_UNLOCK(); - return(0); + return 0; out: + /* clean up any partially allocated objects */ PSHM_SUBSYS_LOCK(); - for (pshmobj = pinfo->pshm_memobjects; - pshmobj != NULL; - pshmobj = pshmobj_next) { - pshmobj_next = pshmobj->pshmo_next; + while ((pshmobj = SLIST_FIRST(&pinfo->pshm_mobjs)) != NULL) { + SLIST_REMOVE_HEAD(&pinfo->pshm_mobjs, pshmo_next); + PSHM_SUBSYS_UNLOCK(); mach_memory_entry_port_release(pshmobj->pshmo_memobject); FREE(pshmobj, M_SHM); + PSHM_SUBSYS_LOCK(); } - pinfo->pshm_memobjects = NULL; pinfo->pshm_flags &= ~PSHM_ALLOCATING; + pshm_deref(pinfo); /* drop the "allocating" reference */ PSHM_SUBSYS_UNLOCK(); switch (kret) { case KERN_INVALID_ADDRESS: case KERN_NO_SPACE: - return (ENOMEM); + return ENOMEM; case KERN_PROTECTION_FAILURE: - return (EACCES); + return EACCES; default: - return (EINVAL); - + return EINVAL; } } int -pshm_stat(struct pshmnode *pnode, void *ub, int isstat64) +pshm_stat(pshmnode_t *pnode, void *ub, int isstat64) { - struct stat *sb = (struct stat *)0; /* warning avoidance ; protected by isstat64 */ + struct stat *sb = (struct stat *)0; /* warning avoidance ; protected by isstat64 */ struct stat64 * sb64 = (struct stat64 *)0; /* warning avoidance ; protected by isstat64 */ - struct pshminfo *pinfo; + pshm_info_t *pinfo; #if CONFIG_MACF int error; #endif - + PSHM_SUBSYS_LOCK(); - if ((pinfo = pnode->pinfo) == PSHMINFO_NULL){ + if ((pinfo = pnode->pinfo) == NULL) { PSHM_SUBSYS_UNLOCK(); - return(EINVAL); + return EINVAL; } #if CONFIG_MACF - error = mac_posixshm_check_stat(kauth_cred_get(), pinfo); + error = mac_posixshm_check_stat(kauth_cred_get(), &pinfo->pshm_hdr); if (error) { PSHM_SUBSYS_UNLOCK(); - return(error); + return error; } #endif if (isstat64 != 0) { sb64 = (struct stat64 *)ub; - bzero(sb64, sizeof(struct stat64)); + bzero(sb64, sizeof(struct stat64)); sb64->st_mode = pinfo->pshm_mode; sb64->st_uid = pinfo->pshm_uid; sb64->st_gid = pinfo->pshm_gid; sb64->st_size = pinfo->pshm_length; } else { sb = (struct stat *)ub; - bzero(sb, sizeof(struct stat)); + bzero(sb, sizeof(struct stat)); sb->st_mode = pinfo->pshm_mode; sb->st_uid = pinfo->pshm_uid; sb->st_gid = pinfo->pshm_gid; @@ -837,105 +725,136 @@ pshm_stat(struct pshmnode *pnode, void *ub, int isstat64) } PSHM_SUBSYS_UNLOCK(); - return(0); + return 0; } /* - * This is called only from shm_open which holds pshm_lock(); - * XXX This code is repeated many times + * Verify access to a shared memory region. */ -int -pshm_access(struct pshminfo *pinfo, int mode, kauth_cred_t cred, __unused proc_t p) +static int +pshm_access(pshm_info_t *pinfo, int mode, kauth_cred_t cred, __unused proc_t p) { - int mode_req = ((mode & FREAD) ? S_IRUSR : 0) | - ((mode & FWRITE) ? S_IWUSR : 0); + mode_t mode_req = ((mode & FREAD) ? S_IRUSR : 0) | + ((mode & FWRITE) ? S_IWUSR : 0); /* Otherwise, user id 0 always gets access. */ - if (!suser(cred, NULL)) - return (0); + if (!suser(cred, NULL)) { + return 0; + } - return(posix_cred_access(cred, pinfo->pshm_uid, pinfo->pshm_gid, pinfo->pshm_mode, mode_req)); + return posix_cred_access(cred, pinfo->pshm_uid, pinfo->pshm_gid, pinfo->pshm_mode, mode_req); } int -pshm_mmap(__unused proc_t p, struct mmap_args *uap, user_addr_t *retval, struct fileproc *fp, off_t pageoff) +pshm_mmap( + __unused proc_t p, + struct mmap_args *uap, + user_addr_t *retval, + struct fileproc *fp, + off_t pageoff) { - vm_map_offset_t user_addr = (vm_map_offset_t)uap->addr; - vm_map_size_t user_size = (vm_map_size_t)uap->len ; - vm_map_offset_t user_start_addr; - vm_map_size_t map_size, mapped_size; - int prot = uap->prot; - int flags = uap->flags; + vm_map_offset_t user_addr = (vm_map_offset_t)uap->addr; + vm_map_size_t user_size = (vm_map_size_t)uap->len; + vm_map_offset_t user_start_addr; + vm_map_size_t map_size, mapped_size; + int prot = uap->prot; + int max_prot = VM_PROT_DEFAULT; + int flags = uap->flags; vm_object_offset_t file_pos = (vm_object_offset_t)uap->pos; vm_object_offset_t map_pos; - vm_map_t user_map; - int alloc_flags; + vm_map_t user_map; + int alloc_flags; vm_map_kernel_flags_t vmk_flags; - boolean_t docow; - kern_return_t kret; - struct pshminfo * pinfo; - struct pshmnode * pnode; - struct pshmobj * pshmobj; -#if CONFIG_MACF - int error; -#endif - - if (user_size == 0) - return(0); + bool docow; + kern_return_t kret = KERN_SUCCESS; + pshm_info_t *pinfo; + pshmnode_t *pnode; + pshm_mobj_t *pshmobj; + int error; + + if (user_size == 0) { + return 0; + } - if ((flags & MAP_SHARED) == 0) - return(EINVAL); + if (!(flags & MAP_SHARED)) { + return EINVAL; + } + /* Can't allow write permission if the shm_open() didn't allow them. */ + if (!(fp->f_flag & FWRITE)) { + if (prot & VM_PROT_WRITE) { + return EPERM; + } + max_prot &= ~VM_PROT_WRITE; + } - if ((prot & PROT_WRITE) && ((fp->f_flag & FWRITE) == 0)) { - return(EPERM); + PSHM_SUBSYS_LOCK(); + pnode = (pshmnode_t *)fp->f_data; + if (pnode == NULL) { + PSHM_SUBSYS_UNLOCK(); + return EINVAL; } - if (((pnode = (struct pshmnode *)fp->f_data)) == PSHMNODE_NULL ) - return(EINVAL); + pinfo = pnode->pinfo; + if (pinfo == NULL) { + PSHM_SUBSYS_UNLOCK(); + return EINVAL; + } - PSHM_SUBSYS_LOCK(); - if ((pinfo = pnode->pinfo) == PSHMINFO_NULL) { + if (!(pinfo->pshm_flags & PSHM_ALLOCATED)) { PSHM_SUBSYS_UNLOCK(); - return(EINVAL); + return EINVAL; } - if ((pinfo->pshm_flags & PSHM_ALLOCATED) != PSHM_ALLOCATED) { + if (user_size > (vm_map_size_t)pinfo->pshm_length) { PSHM_SUBSYS_UNLOCK(); - return(EINVAL); + return EINVAL; } - if ((off_t)user_size > pinfo->pshm_length) { + + vm_map_size_t end_pos = 0; + if (os_add_overflow(user_size, file_pos, &end_pos)) { PSHM_SUBSYS_UNLOCK(); - return(EINVAL); + return EINVAL; } - if ((off_t)(user_size + file_pos) > pinfo->pshm_length) { + if (end_pos > (vm_map_size_t)pinfo->pshm_length) { PSHM_SUBSYS_UNLOCK(); - return(EINVAL); + return EINVAL; } - if ((pshmobj = pinfo->pshm_memobjects) == NULL) { + + pshmobj = SLIST_FIRST(&pinfo->pshm_mobjs); + if (pshmobj == NULL) { PSHM_SUBSYS_UNLOCK(); - return(EINVAL); + return EINVAL; } #if CONFIG_MACF - error = mac_posixshm_check_mmap(kauth_cred_get(), pinfo, prot, flags); + error = mac_posixshm_check_mmap(kauth_cred_get(), &pinfo->pshm_hdr, prot, flags); if (error) { PSHM_SUBSYS_UNLOCK(); - return(error); + return error; } #endif + /* Grab an extra reference, so we can drop the lock while mapping. */ + error = pshm_ref(pinfo); + if (error) { + PSHM_SUBSYS_UNLOCK(); + return error; + } PSHM_SUBSYS_UNLOCK(); user_map = current_map(); - if ((flags & MAP_FIXED) == 0) { + if (!(flags & MAP_FIXED)) { alloc_flags = VM_FLAGS_ANYWHERE; user_addr = vm_map_round_page(user_addr, - vm_map_page_mask(user_map)); + vm_map_page_mask(user_map)); } else { if (user_addr != vm_map_round_page(user_addr, - vm_map_page_mask(user_map))) - return (EINVAL); + vm_map_page_mask(user_map))) { + error = EINVAL; + goto out_deref; + } + /* * We do not get rid of the existing mappings here because * it wouldn't be atomic (see comment in mmap()). We let @@ -944,41 +863,41 @@ pshm_mmap(__unused proc_t p, struct mmap_args *uap, user_addr_t *retval, struct */ alloc_flags = VM_FLAGS_FIXED | VM_FLAGS_OVERWRITE; } - docow = FALSE; + docow = false; mapped_size = 0; vmk_flags = VM_MAP_KERNEL_FLAGS_NONE; /* reserve the entire space first... */ kret = vm_map_enter_mem_object(user_map, - &user_addr, - user_size, - 0, - alloc_flags, - vmk_flags, - VM_KERN_MEMORY_NONE, - IPC_PORT_NULL, - 0, - FALSE, - VM_PROT_NONE, - VM_PROT_NONE, - VM_INHERIT_NONE); + &user_addr, + user_size, + 0, + alloc_flags, + vmk_flags, + VM_KERN_MEMORY_NONE, + IPC_PORT_NULL, + 0, + false, + VM_PROT_NONE, + VM_PROT_NONE, + VM_INHERIT_NONE); user_start_addr = user_addr; if (kret != KERN_SUCCESS) { - goto out; + goto out_deref; } - /* ... and overwrite with the real mappings */ - for (map_pos = 0, pshmobj = pinfo->pshm_memobjects; - user_size != 0; - map_pos += pshmobj->pshmo_size, pshmobj = pshmobj->pshmo_next) { + /* Now overwrite with the real mappings. */ + for (map_pos = 0, pshmobj = SLIST_FIRST(&pinfo->pshm_mobjs); + user_size != 0; + map_pos += pshmobj->pshmo_size, pshmobj = SLIST_NEXT(pshmobj, pshmo_next)) { if (pshmobj == NULL) { /* nothing there to map !? */ - goto out; + goto out_deref; } if (file_pos >= map_pos + pshmobj->pshmo_size) { continue; } - map_size = pshmobj->pshmo_size - (file_pos - map_pos); + map_size = (vm_map_size_t)(pshmobj->pshmo_size - (file_pos - map_pos)); if (map_size > user_size) { map_size = user_size; } @@ -995,10 +914,11 @@ pshm_mmap(__unused proc_t p, struct mmap_args *uap, user_addr_t *retval, struct file_pos - map_pos, docow, prot, - VM_PROT_DEFAULT, + max_prot, VM_INHERIT_SHARE); - if (kret != KERN_SUCCESS) - goto out; + if (kret != KERN_SUCCESS) { + goto out_deref; + } user_addr += map_size; user_size -= map_size; @@ -1008,78 +928,51 @@ pshm_mmap(__unused proc_t p, struct mmap_args *uap, user_addr_t *retval, struct PSHM_SUBSYS_LOCK(); pnode->mapp_addr = user_start_addr; - pnode->map_size = mapped_size; pinfo->pshm_flags |= (PSHM_MAPPED | PSHM_INUSE); PSHM_SUBSYS_UNLOCK(); -out: +out_deref: + PSHM_SUBSYS_LOCK(); + pshm_deref(pinfo); /* drop the extra reference we had while mapping. */ + PSHM_SUBSYS_UNLOCK(); if (kret != KERN_SUCCESS) { if (mapped_size != 0) { (void) mach_vm_deallocate(current_map(), - user_start_addr, - mapped_size); + user_start_addr, + mapped_size); } } switch (kret) { case KERN_SUCCESS: - *retval = (user_start_addr + pageoff); - return (0); + *retval = (user_addr_t)(user_start_addr + pageoff); + return 0; case KERN_INVALID_ADDRESS: case KERN_NO_SPACE: - return (ENOMEM); + return ENOMEM; case KERN_PROTECTION_FAILURE: - return (EACCES); + return EACCES; default: - return (EINVAL); + return EINVAL; } - } +/* + * Remove a shared memory region name from the name lookup cache. + */ static int -pshm_unlink_internal(struct pshminfo *pinfo, struct pshmcache *pcache) +pshm_unlink_internal(pshm_info_t *pinfo) { - struct pshmobj *pshmobj, *pshmobj_next; - PSHM_SUBSYS_ASSERT_HELD(); - if (!pinfo || !pcache) - return EINVAL; - - if ((pinfo->pshm_flags & (PSHM_DEFINED | PSHM_ALLOCATED)) == 0) + if (pinfo == NULL) { return EINVAL; + } - if (pinfo->pshm_flags & PSHM_INDELETE) - return 0; - - pinfo->pshm_flags |= PSHM_INDELETE; - pinfo->pshm_usecount--; - - pshm_cache_delete(pcache); + pshm_cache_delete(pinfo); pinfo->pshm_flags |= PSHM_REMOVED; - /* release the existence reference */ - if (!pinfo->pshm_usecount) { -#if CONFIG_MACF - mac_posixshm_label_destroy(pinfo); -#endif - /* - * If this is the last reference going away on the object, - * then we need to destroy the backing object. The name - * has an implied but uncounted reference on the object, - * once it's created, since it's used as a rendezvous, and - * therefore may be subsequently reopened. - */ - for (pshmobj = pinfo->pshm_memobjects; - pshmobj != NULL; - pshmobj = pshmobj_next) { - mach_memory_entry_port_release(pshmobj->pshmo_memobject); - pshmobj_next = pshmobj->pshmo_next; - FREE(pshmobj, M_SHM); - } - FREE(pinfo,M_SHM); - } - - FREE(pcache, M_SHM); + /* release the "unlink" reference */ + pshm_deref(pinfo); return 0; } @@ -1087,259 +980,186 @@ pshm_unlink_internal(struct pshminfo *pinfo, struct pshmcache *pcache) int shm_unlink(proc_t p, struct shm_unlink_args *uap, __unused int32_t *retval) { - size_t i; - char * pnbuf; - size_t pathlen; - int error = 0; + int error = 0; + pshm_info_t *pinfo = NULL; + pshm_info_t *name_pinfo = NULL; - struct pshmname nd; - struct pshminfo *pinfo; - char * nameptr; - char * cp; - struct pshmcache *pcache = PSHMCACHE_NULL; - - pinfo = PSHMINFO_NULL; - - - MALLOC_ZONE(pnbuf, caddr_t, MAXPATHLEN, M_NAMEI, M_WAITOK); - if (pnbuf == NULL) { - return(ENOSPC); /* XXX non-standard */ - } - pathlen = MAXPATHLEN; - error = copyinstr(uap->name, (void *)pnbuf, MAXPATHLEN, &pathlen); - if (error) { - goto bad; - } - AUDIT_ARG(text, pnbuf); - if (pathlen > PSHMNAMLEN) { - error = ENAMETOOLONG; + /* + * Get the name from user args. + */ + MALLOC(name_pinfo, pshm_info_t *, sizeof(pshm_info_t), M_SHM, M_WAITOK | M_ZERO); + if (name_pinfo == NULL) { + error = ENOSPC; goto bad; } - - nameptr = pnbuf; - -#ifdef PSXSHM_NAME_RESTRICT - if (*nameptr == '/') { - while (*(nameptr++) == '/') { - pathlen--; - error = EINVAL; - goto bad; - } - } else { + error = pshm_get_name(name_pinfo, uap->name); + if (error != 0) { error = EINVAL; goto bad; } -#endif /* PSXSHM_NAME_RESTRICT */ - - nd.pshm_nameptr = nameptr; - nd.pshm_namelen = pathlen; - nd.pshm_hash = 0; - - for (cp = nameptr, i=1; *cp != 0 && i <= pathlen; i++, cp++) { - nd.pshm_hash += (unsigned char)*cp * i; - } PSHM_SUBSYS_LOCK(); - error = pshm_cache_search(&pinfo, &nd, &pcache, 0); + pinfo = pshm_cache_search(name_pinfo); - /* During unlink lookup failure also implies ENOENT */ - if (error != PSHMCACHE_FOUND) { - PSHM_SUBSYS_UNLOCK(); + if (pinfo == NULL) { error = ENOENT; - goto bad; - - } - - if ((pinfo->pshm_flags & (PSHM_DEFINED | PSHM_ALLOCATED))==0) { - PSHM_SUBSYS_UNLOCK(); - error = EINVAL; - goto bad; - } - - if (pinfo->pshm_flags & PSHM_ALLOCATING) { - /* XXX should we wait for flag to clear and then proceed ? */ - PSHM_SUBSYS_UNLOCK(); - error = EAGAIN; - goto bad; - } - - if (pinfo->pshm_flags & PSHM_INDELETE) { - PSHM_SUBSYS_UNLOCK(); - error = 0; - goto bad; + goto bad_unlock; } #if CONFIG_MACF - error = mac_posixshm_check_unlink(kauth_cred_get(), pinfo, nameptr); + error = mac_posixshm_check_unlink(kauth_cred_get(), &pinfo->pshm_hdr, name_pinfo->pshm_hdr.pshm_name); if (error) { - PSHM_SUBSYS_UNLOCK(); - goto bad; + goto bad_unlock; } #endif - AUDIT_ARG(posix_ipc_perm, pinfo->pshm_uid, pinfo->pshm_gid, - pinfo->pshm_mode); + AUDIT_ARG(posix_ipc_perm, pinfo->pshm_uid, pinfo->pshm_gid, pinfo->pshm_mode); - /* - * following file semantics, unlink should be allowed - * for users with write permission only. + /* + * Following file semantics, unlink should normally be allowed + * for users with write permission only. We also allow the creator + * of a segment to be able to delete, even w/o write permission. + * That's because there's no equivalent of write permission for the + * directory containing a file. */ - if ( (error = pshm_access(pinfo, FWRITE, kauth_cred_get(), p)) ) { - PSHM_SUBSYS_UNLOCK(); - goto bad; + error = pshm_access(pinfo, FWRITE, kauth_cred_get(), p); + if (error != 0 && pinfo->pshm_uid != kauth_getuid()) { + goto bad_unlock; } - error = pshm_unlink_internal(pinfo, pcache); + error = pshm_unlink_internal(pinfo); +bad_unlock: PSHM_SUBSYS_UNLOCK(); - bad: - FREE_ZONE(pnbuf, MAXPATHLEN, M_NAMEI); + if (name_pinfo != NULL) { + FREE(name_pinfo, M_SHM); + } return error; } -/* already called locked */ +/* + * Add a new reference to a shared memory region. + * Fails if we will overflow the reference counter. + */ static int -pshm_close(struct pshminfo *pinfo, int dropref) +pshm_ref(pshm_info_t *pinfo) { - int error = 0; - struct pshmobj *pshmobj, *pshmobj_next; + PSHM_SUBSYS_ASSERT_HELD(); - /* - * If we are dropping the reference we took on the cache object, don't - * enforce the allocation requirement. - */ - if ( !dropref && ((pinfo->pshm_flags & PSHM_ALLOCATED) != PSHM_ALLOCATED)) { - return(EINVAL); + if (pinfo->pshm_usecount == PSHM_MAXCOUNT) { + return EMFILE; } -#if DIAGNOSTIC - if(!pinfo->pshm_usecount) { - kprintf("negative usecount in pshm_close\n"); + pinfo->pshm_usecount++; + return 0; +} + +/* + * Dereference a pshm_info_t. Delete the region if + * this was the final reference count. + */ +static void +pshm_deref(pshm_info_t *pinfo) +{ + pshm_mobj_t *pshmobj; + + PSHM_SUBSYS_ASSERT_HELD(); + if (pinfo->pshm_usecount == 0) { + panic("negative usecount in pshm_close\n"); } -#endif /* DIAGNOSTIC */ pinfo->pshm_usecount--; /* release this fd's reference */ - if ((pinfo->pshm_flags & PSHM_REMOVED) && !pinfo->pshm_usecount) { + if (pinfo->pshm_usecount == 0) { #if CONFIG_MACF - mac_posixshm_label_destroy(pinfo); + mac_posixshm_label_destroy(&pinfo->pshm_hdr); #endif PSHM_SUBSYS_UNLOCK(); + /* - * If this is the last reference going away on the object, - * then we need to destroy the backing object. + * Release references to any backing objects. */ - for (pshmobj = pinfo->pshm_memobjects; - pshmobj != NULL; - pshmobj = pshmobj_next) { + while ((pshmobj = SLIST_FIRST(&pinfo->pshm_mobjs)) != NULL) { + SLIST_REMOVE_HEAD(&pinfo->pshm_mobjs, pshmo_next); mach_memory_entry_port_release(pshmobj->pshmo_memobject); - pshmobj_next = pshmobj->pshmo_next; FREE(pshmobj, M_SHM); } + + /* free the pinfo itself */ + FREE(pinfo, M_SHM); + PSHM_SUBSYS_LOCK(); - FREE(pinfo,M_SHM); } - return (error); } /* vfs_context_t passed to match prototype for struct fileops */ static int pshm_closefile(struct fileglob *fg, __unused vfs_context_t ctx) { - int error = EINVAL; - struct pshmnode *pnode; + int error = EINVAL; + pshmnode_t *pnode; PSHM_SUBSYS_LOCK(); - if ((pnode = (struct pshmnode *)fg->fg_data) != NULL) { - if (pnode->pinfo != PSHMINFO_NULL) { - error = pshm_close(pnode->pinfo, 0); + pnode = (pshmnode_t *)fg->fg_data; + if (pnode != NULL) { + error = 0; + fg->fg_data = NULL; /* set fg_data to NULL to avoid racing close()es */ + if (pnode->pinfo != NULL) { + pshm_deref(pnode->pinfo); + pnode->pinfo = NULL; } - FREE(pnode, M_SHM); } PSHM_SUBSYS_UNLOCK(); + if (pnode != NULL) { + FREE(pnode, M_SHM); + } - return(error); -} - -static int -pshm_read(__unused struct fileproc *fp, __unused struct uio *uio, - __unused int flags, __unused vfs_context_t ctx) -{ - return(ENOTSUP); -} - -static int -pshm_write(__unused struct fileproc *fp, __unused struct uio *uio, - __unused int flags, __unused vfs_context_t ctx) -{ - return(ENOTSUP); -} - -static int -pshm_ioctl(__unused struct fileproc *fp, __unused u_long com, - __unused caddr_t data, __unused vfs_context_t ctx) -{ - return(ENOTSUP); -} - -static int -pshm_select(__unused struct fileproc *fp, __unused int which, __unused void *wql, - __unused vfs_context_t ctx) -{ - return(ENOTSUP); -} - -static int -pshm_kqfilter(__unused struct fileproc *fp, struct knote *kn, - __unused struct kevent_internal_s *kev, __unused vfs_context_t ctx) -{ - kn->kn_flags = EV_ERROR; - kn->kn_data = ENOTSUP; - return 0; + return error; } int -fill_pshminfo(struct pshmnode * pshm, struct pshm_info * info) +fill_pshminfo(pshmnode_t * pshm, struct pshm_info * info) { - struct pshminfo *pinfo; + pshm_info_t *pinfo; struct vinfo_stat *sb; - + PSHM_SUBSYS_LOCK(); - if ((pinfo = pshm->pinfo) == PSHMINFO_NULL){ + if ((pinfo = pshm->pinfo) == NULL) { PSHM_SUBSYS_UNLOCK(); - return(EINVAL); + return EINVAL; } sb = &info->pshm_stat; - bzero(sb, sizeof(struct vinfo_stat)); + bzero(sb, sizeof(struct vinfo_stat)); sb->vst_mode = pinfo->pshm_mode; sb->vst_uid = pinfo->pshm_uid; sb->vst_gid = pinfo->pshm_gid; sb->vst_size = pinfo->pshm_length; info->pshm_mappaddr = pshm->mapp_addr; - bcopy(&pinfo->pshm_name[0], &info->pshm_name[0], PSHMNAMLEN+1); + bcopy(&pinfo->pshm_hdr.pshm_name[0], &info->pshm_name[0], PSHMNAMLEN + 1); PSHM_SUBSYS_UNLOCK(); - return(0); + return 0; } #if CONFIG_MACF void pshm_label_associate(struct fileproc *fp, struct vnode *vp, vfs_context_t ctx) { - struct pshmnode *pnode; - struct pshminfo *pshm; + pshmnode_t *pnode; + pshm_info_t *pshm; PSHM_SUBSYS_LOCK(); - pnode = (struct pshmnode *)fp->f_fglob->fg_data; + pnode = (pshmnode_t *)fp->f_data; if (pnode != NULL) { pshm = pnode->pinfo; - if (pshm != NULL) + if (pshm != NULL) { mac_posixshm_vnode_label_associate( - vfs_context_ucred(ctx), pshm, pshm->pshm_label, + vfs_context_ucred(ctx), &pshm->pshm_hdr, pshm->pshm_label, vp, vp->v_label); + } } PSHM_SUBSYS_UNLOCK(); }