/* * CDDL HEADER START * * The contents of this file are subject to the terms of the * Common Development and Distribution License (the "License"). * You may not use this file except in compliance with the License. * * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE * or http://www.opensolaris.org/os/licensing. * See the License for the specific language governing permissions * and limitations under the License. * * When distributing Covered Code, include this CDDL HEADER in each * file and include the License file at usr/src/OPENSOLARIS.LICENSE. * If applicable, add the following below this CDDL HEADER, with the * fields enclosed by brackets "[]" replaced with your own identifying * information: Portions Copyright [yyyy] [name of copyright owner] * * CDDL HEADER END */ /* * Copyright (c) 1990, 2010, Oracle and/or its affiliates. All rights reserved. * Copyright 2015 Joyent, Inc. */ #include <sys/types.h> #include <sys/errno.h> #include <sys/param.h> #include <sys/t_lock.h> #include <sys/systm.h> #include <sys/sysmacros.h> #include <sys/debug.h> #include <sys/time.h> #include <sys/cmn_err.h> #include <sys/vnode.h> #include <sys/stat.h> #include <sys/vfs.h> #include <sys/cred.h> #include <sys/kmem.h> #include <sys/atomic.h> #include <sys/policy.h> #include <sys/fs/tmp.h> #include <sys/fs/tmpnode.h> #include <sys/ddi.h> #include <sys/sunddi.h> #define KILOBYTE 1024 #define MEGABYTE (1024 * KILOBYTE) #define GIGABYTE (1024 * MEGABYTE) #define MODESHIFT 3 #define VALIDMODEBITS 07777 extern pgcnt_t swapfs_minfree; int tmp_taccess(void *vtp, int mode, struct cred *cred) { struct tmpnode *tp = vtp; int shift = 0; /* * Check access based on owner, group and * public permissions in tmpnode. */ if (crgetuid(cred) != tp->tn_uid) { shift += MODESHIFT; if (groupmember(tp->tn_gid, cred) == 0) shift += MODESHIFT; } return (secpolicy_vnode_access2(cred, TNTOV(tp), tp->tn_uid, tp->tn_mode << shift, mode)); } /* * Decide whether it is okay to remove within a sticky directory. * Two conditions need to be met: write access to the directory * is needed. In sticky directories, write access is not sufficient; * you can remove entries from a directory only if you own the directory, * if you are privileged, if you own the entry or if they entry is * a plain file and you have write access to that file. * Function returns 0 if remove access is granted. */ int tmp_sticky_remove_access(struct tmpnode *dir, struct tmpnode *entry, struct cred *cr) { uid_t uid = crgetuid(cr); if ((dir->tn_mode & S_ISVTX) && uid != dir->tn_uid && uid != entry->tn_uid && (entry->tn_type != VREG || tmp_taccess(entry, VWRITE, cr) != 0)) return (secpolicy_vnode_remove(cr)); return (0); } /* * Allocate zeroed memory if tmpfs_maxkmem has not been exceeded * or the 'musthave' flag is set. 'musthave' allocations should * always be subordinate to normal allocations so that tmpfs_maxkmem * can't be exceeded by more than a few KB. Example: when creating * a new directory, the tmpnode is a normal allocation; if that * succeeds, the dirents for "." and ".." are 'musthave' allocations. */ void * tmp_memalloc(size_t size, int musthave) { static time_t last_warning; time_t now; if (atomic_add_long_nv(&tmp_kmemspace, size) < tmpfs_maxkmem || musthave) return (kmem_zalloc(size, KM_SLEEP)); atomic_add_long(&tmp_kmemspace, -size); now = gethrestime_sec(); if (last_warning != now) { last_warning = now; cmn_err(CE_WARN, "tmp_memalloc: tmpfs over memory limit"); } return (NULL); } void tmp_memfree(void *cp, size_t size) { kmem_free(cp, size); atomic_add_long(&tmp_kmemspace, -size); } /* * Convert a string containing a number (number of bytes) to a pgcnt_t, * containing the corresponding number of pages. On 32-bit kernels, the * maximum value encoded in 'str' is PAGESIZE * ULONG_MAX, while the value * returned in 'maxpg' is at most ULONG_MAX. * * The number may be followed by a magnitude suffix: "k" or "K" for kilobytes; * "m" or "M" for megabytes; "g" or "G" for gigabytes. This interface allows * for an arguably esoteric interpretation of multiple suffix characters: * namely, they cascade. For example, the caller may specify "2mk", which is * interpreted as 2 gigabytes. It would seem, at this late stage, that the * horse has left not only the barn but indeed the country, and possibly the * entire planetary system. Alternatively, the number may be followed by a * single '%' sign, indicating the size is a percentage of either the zone's * swap limit or the system's overall swap size. * * Parse and overflow errors are detected and a non-zero number returned on * error. */ int tmp_convnum(char *str, pgcnt_t *maxpg) { u_longlong_t num = 0; #ifdef _LP64 u_longlong_t max_bytes = ULONG_MAX; #else u_longlong_t max_bytes = PAGESIZE * (uint64_t)ULONG_MAX; #endif char *c; const struct convchar { char *cc_char; uint64_t cc_factor; } convchars[] = { { "kK", KILOBYTE }, { "mM", MEGABYTE }, { "gG", GIGABYTE }, { NULL, 0 } }; if (str == NULL) { return (EINVAL); } c = str; /* * Convert the initial numeric portion of the input string. */ if (ddi_strtoull(str, &c, 10, &num) != 0) { return (EINVAL); } /* * Handle a size in percent. Anything other than a single percent * modifier is invalid. We use either the zone's swap limit or the * system's total available swap size as the initial value. Perform the * intermediate calculation in pages to avoid overflow. */ if (*c == '%') { u_longlong_t cap; if (*(c + 1) != '\0') return (EINVAL); if (num > 100) return (EINVAL); cap = (u_longlong_t)curproc->p_zone->zone_max_swap_ctl; if (cap == UINT64_MAX) { /* * Use the amount of available physical and memory swap */ mutex_enter(&anoninfo_lock); cap = TOTAL_AVAILABLE_SWAP; mutex_exit(&anoninfo_lock); } else { cap = btop(cap); } num = ptob(cap * num / 100); goto done; } /* * Apply the (potentially cascading) magnitude suffixes until an * invalid character is found, or the string comes to an end. */ for (; *c != '\0'; c++) { int i; for (i = 0; convchars[i].cc_char != NULL; i++) { /* * Check if this character matches this multiplier * class: */ if (strchr(convchars[i].cc_char, *c) != NULL) { /* * Check for overflow: */ if (num > max_bytes / convchars[i].cc_factor) { return (EINVAL); } num *= convchars[i].cc_factor; goto valid_char; } } /* * This was not a valid multiplier suffix character. */ return (EINVAL); valid_char: continue; } done: /* * Since btopr() rounds up to page granularity, this round-up can * cause an overflow only if 'num' is between (max_bytes - PAGESIZE) * and (max_bytes). In this case the resulting number is zero, which * is what we check for below. */ if ((*maxpg = (pgcnt_t)btopr(num)) == 0 && num != 0) return (EINVAL); return (0); } /* * Parse an octal mode string for use as the permissions set for the root * of the tmpfs mount. */ int tmp_convmode(char *str, mode_t *mode) { ulong_t num; char *c; if (str == NULL) { return (EINVAL); } if (ddi_strtoul(str, &c, 8, &num) != 0) { return (EINVAL); } if ((num & ~VALIDMODEBITS) != 0) { return (EINVAL); } *mode = VALIDMODEBITS & num; return (0); }
