/* * x_tables core - Backend for {ip,ip6,arp}_tables * * Copyright (C) 2006-2006 Harald Welte * Copyright (C) 2006-2012 Patrick McHardy * * Based on existing ip_tables code which is * Copyright (C) 1999 Paul `Rusty' Russell & Michael J. Neuling * Copyright (C) 2000-2005 Netfilter Core Team * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. * */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include MODULE_LICENSE("GPL"); MODULE_AUTHOR("Harald Welte "); MODULE_DESCRIPTION("{ip,ip6,arp,eb}_tables backend module"); struct compat_delta { unsigned int offset; /* offset in kernel */ int delta; /* delta in 32bit user land */ }; struct xt_af { struct mutex mutex; struct list_head match; struct list_head target; #ifdef CONFIG_COMPAT struct mutex compat_mutex; struct compat_delta *compat_tab; unsigned int number; /* number of slots in compat_tab[] */ unsigned int cur; /* number of used slots in compat_tab[] */ #endif }; static struct xt_af *xt; static const char *const xt_prefix[NFPROTO_NUMPROTO] = { [NFPROTO_UNSPEC] = "x", [NFPROTO_IPV4] = "ip", [NFPROTO_ARP] = "arp", [NFPROTO_BRIDGE] = "eb", [NFPROTO_IPV6] = "ip6", }; /* Allow this many total (re)entries. */ static const unsigned int xt_jumpstack_multiplier = 2; /* Registration hooks for targets. */ int xt_register_target(struct xt_target *target) { u_int8_t af = target->family; mutex_lock(&xt[af].mutex); list_add(&target->list, &xt[af].target); mutex_unlock(&xt[af].mutex); return 0; } EXPORT_SYMBOL(xt_register_target); void xt_unregister_target(struct xt_target *target) { u_int8_t af = target->family; mutex_lock(&xt[af].mutex); list_del(&target->list); mutex_unlock(&xt[af].mutex); } EXPORT_SYMBOL(xt_unregister_target); int xt_register_targets(struct xt_target *target, unsigned int n) { unsigned int i; int err = 0; for (i = 0; i < n; i++) { err = xt_register_target(&target[i]); if (err) goto err; } return err; err: if (i > 0) xt_unregister_targets(target, i); return err; } EXPORT_SYMBOL(xt_register_targets); void xt_unregister_targets(struct xt_target *target, unsigned int n) { while (n-- > 0) xt_unregister_target(&target[n]); } EXPORT_SYMBOL(xt_unregister_targets); int xt_register_match(struct xt_match *match) { u_int8_t af = match->family; mutex_lock(&xt[af].mutex); list_add(&match->list, &xt[af].match); mutex_unlock(&xt[af].mutex); return 0; } EXPORT_SYMBOL(xt_register_match); void xt_unregister_match(struct xt_match *match) { u_int8_t af = match->family; mutex_lock(&xt[af].mutex); list_del(&match->list); mutex_unlock(&xt[af].mutex); } EXPORT_SYMBOL(xt_unregister_match); int xt_register_matches(struct xt_match *match, unsigned int n) { unsigned int i; int err = 0; for (i = 0; i < n; i++) { err = xt_register_match(&match[i]); if (err) goto err; } return err; err: if (i > 0) xt_unregister_matches(match, i); return err; } EXPORT_SYMBOL(xt_register_matches); void xt_unregister_matches(struct xt_match *match, unsigned int n) { while (n-- > 0) xt_unregister_match(&match[n]); } EXPORT_SYMBOL(xt_unregister_matches); /* * These are weird, but module loading must not be done with mutex * held (since they will register), and we have to have a single * function to use. */ /* Find match, grabs ref. Returns ERR_PTR() on error. */ struct xt_match *xt_find_match(u8 af, const char *name, u8 revision) { struct xt_match *m; int err = -ENOENT; mutex_lock(&xt[af].mutex); list_for_each_entry(m, &xt[af].match, list) { if (strcmp(m->name, name) == 0) { if (m->revision == revision) { if (try_module_get(m->me)) { mutex_unlock(&xt[af].mutex); return m; } } else err = -EPROTOTYPE; /* Found something. */ } } mutex_unlock(&xt[af].mutex); if (af != NFPROTO_UNSPEC) /* Try searching again in the family-independent list */ return xt_find_match(NFPROTO_UNSPEC, name, revision); return ERR_PTR(err); } EXPORT_SYMBOL(xt_find_match); struct xt_match * xt_request_find_match(uint8_t nfproto, const char *name, uint8_t revision) { struct xt_match *match; if (strnlen(name, XT_EXTENSION_MAXNAMELEN) == XT_EXTENSION_MAXNAMELEN) return ERR_PTR(-EINVAL); match = xt_find_match(nfproto, name, revision); if (IS_ERR(match)) { request_module("%st_%s", xt_prefix[nfproto], name); match = xt_find_match(nfproto, name, revision); } return match; } EXPORT_SYMBOL_GPL(xt_request_find_match); /* Find target, grabs ref. Returns ERR_PTR() on error. */ struct xt_target *xt_find_target(u8 af, const char *name, u8 revision) { struct xt_target *t; int err = -ENOENT; mutex_lock(&xt[af].mutex); list_for_each_entry(t, &xt[af].target, list) { if (strcmp(t->name, name) == 0) { if (t->revision == revision) { if (try_module_get(t->me)) { mutex_unlock(&xt[af].mutex); return t; } } else err = -EPROTOTYPE; /* Found something. */ } } mutex_unlock(&xt[af].mutex); if (af != NFPROTO_UNSPEC) /* Try searching again in the family-independent list */ return xt_find_target(NFPROTO_UNSPEC, name, revision); return ERR_PTR(err); } EXPORT_SYMBOL(xt_find_target); struct xt_target *xt_request_find_target(u8 af, const char *name, u8 revision) { struct xt_target *target; if (strnlen(name, XT_EXTENSION_MAXNAMELEN) == XT_EXTENSION_MAXNAMELEN) return ERR_PTR(-EINVAL); target = xt_find_target(af, name, revision); if (IS_ERR(target)) { request_module("%st_%s", xt_prefix[af], name); target = xt_find_target(af, name, revision); } return target; } EXPORT_SYMBOL_GPL(xt_request_find_target); static int match_revfn(u8 af, const char *name, u8 revision, int *bestp) { const struct xt_match *m; int have_rev = 0; list_for_each_entry(m, &xt[af].match, list) { if (strcmp(m->name, name) == 0) { if (m->revision > *bestp) *bestp = m->revision; if (m->revision == revision) have_rev = 1; } } if (af != NFPROTO_UNSPEC && !have_rev) return match_revfn(NFPROTO_UNSPEC, name, revision, bestp); return have_rev; } static int target_revfn(u8 af, const char *name, u8 revision, int *bestp) { const struct xt_target *t; int have_rev = 0; list_for_each_entry(t, &xt[af].target, list) { if (strcmp(t->name, name) == 0) { if (t->revision > *bestp) *bestp = t->revision; if (t->revision == revision) have_rev = 1; } } if (af != NFPROTO_UNSPEC && !have_rev) return target_revfn(NFPROTO_UNSPEC, name, revision, bestp); return have_rev; } /* Returns true or false (if no such extension at all) */ int xt_find_revision(u8 af, const char *name, u8 revision, int target, int *err) { int have_rev, best = -1; mutex_lock(&xt[af].mutex); if (target == 1) have_rev = target_revfn(af, name, revision, &best); else have_rev = match_revfn(af, name, revision, &best); mutex_unlock(&xt[af].mutex); /* Nothing at all? Return 0 to try loading module. */ if (best == -1) { *err = -ENOENT; return 0; } *err = best; if (!have_rev) *err = -EPROTONOSUPPORT; return 1; } EXPORT_SYMBOL_GPL(xt_find_revision); static char * textify_hooks(char *buf, size_t size, unsigned int mask, uint8_t nfproto) { static const char *const inetbr_names[] = { "PREROUTING", "INPUT", "FORWARD", "OUTPUT", "POSTROUTING", "BROUTING", }; static const char *const arp_names[] = { "INPUT", "FORWARD", "OUTPUT", }; const char *const *names; unsigned int i, max; char *p = buf; bool np = false; int res; names = (nfproto == NFPROTO_ARP) ? arp_names : inetbr_names; max = (nfproto == NFPROTO_ARP) ? ARRAY_SIZE(arp_names) : ARRAY_SIZE(inetbr_names); *p = '\0'; for (i = 0; i < max; ++i) { if (!(mask & (1 << i))) continue; res = snprintf(p, size, "%s%s", np ? "/" : "", names[i]); if (res > 0) { size -= res; p += res; } np = true; } return buf; } /** * xt_check_proc_name - check that name is suitable for /proc file creation * * @name: file name candidate * @size: length of buffer * * some x_tables modules wish to create a file in /proc. * This function makes sure that the name is suitable for this * purpose, it checks that name is NUL terminated and isn't a 'special' * name, like "..". * * returns negative number on error or 0 if name is useable. */ int xt_check_proc_name(const char *name, unsigned int size) { if (name[0] == '\0') return -EINVAL; if (strnlen(name, size) == size) return -ENAMETOOLONG; if (strcmp(name, ".") == 0 || strcmp(name, "..") == 0 || strchr(name, '/')) return -EINVAL; return 0; } EXPORT_SYMBOL(xt_check_proc_name); int xt_check_match(struct xt_mtchk_param *par, unsigned int size, u_int8_t proto, bool inv_proto) { int ret; if (XT_ALIGN(par->match->matchsize) != size && par->match->matchsize != -1) { /* * ebt_among is exempt from centralized matchsize checking * because it uses a dynamic-size data set. */ pr_err("%s_tables: %s.%u match: invalid size " "%u (kernel) != (user) %u\n", xt_prefix[par->family], par->match->name, par->match->revision, XT_ALIGN(par->match->matchsize), size); return -EINVAL; } if (par->match->table != NULL && strcmp(par->match->table, par->table) != 0) { pr_err("%s_tables: %s match: only valid in %s table, not %s\n", xt_prefix[par->family], par->match->name, par->match->table, par->table); return -EINVAL; } if (par->match->hooks && (par->hook_mask & ~par->match->hooks) != 0) { char used[64], allow[64]; pr_err("%s_tables: %s match: used from hooks %s, but only " "valid from %s\n", xt_prefix[par->family], par->match->name, textify_hooks(used, sizeof(used), par->hook_mask, par->family), textify_hooks(allow, sizeof(allow), par->match->hooks, par->family)); return -EINVAL; } if (par->match->proto && (par->match->proto != proto || inv_proto)) { pr_err("%s_tables: %s match: only valid for protocol %u\n", xt_prefix[par->family], par->match->name, par->match->proto); return -EINVAL; } if (par->match->checkentry != NULL) { ret = par->match->checkentry(par); if (ret < 0) return ret; else if (ret > 0) /* Flag up potential errors. */ return -EIO; } return 0; } EXPORT_SYMBOL_GPL(xt_check_match); /** xt_check_entry_match - check that matches end before start of target * * @match: beginning of xt_entry_match * @target: beginning of this rules target (alleged end of matches) * @alignment: alignment requirement of match structures * * Validates that all matches add up to the beginning of the target, * and that each match covers at least the base structure size. * * Return: 0 on success, negative errno on failure. */ static int xt_check_entry_match(const char *match, const char *target, const size_t alignment) { const struct xt_entry_match *pos; int length = target - match; if (length == 0) /* no matches */ return 0; pos = (struct xt_entry_match *)match; do { if ((unsigned long)pos % alignment) return -EINVAL; if (length < (int)sizeof(struct xt_entry_match)) return -EINVAL; if (pos->u.match_size < sizeof(struct xt_entry_match)) return -EINVAL; if (pos->u.match_size > length) return -EINVAL; length -= pos->u.match_size; pos = ((void *)((char *)(pos) + (pos)->u.match_size)); } while (length > 0); return 0; } #ifdef CONFIG_COMPAT int xt_compat_add_offset(u_int8_t af, unsigned int offset, int delta) { struct xt_af *xp = &xt[af]; if (!xp->compat_tab) { if (!xp->number) return -EINVAL; xp->compat_tab = vmalloc(sizeof(struct compat_delta) * xp->number); if (!xp->compat_tab) return -ENOMEM; xp->cur = 0; } if (xp->cur >= xp->number) return -EINVAL; if (xp->cur) delta += xp->compat_tab[xp->cur - 1].delta; xp->compat_tab[xp->cur].offset = offset; xp->compat_tab[xp->cur].delta = delta; xp->cur++; return 0; } EXPORT_SYMBOL_GPL(xt_compat_add_offset); void xt_compat_flush_offsets(u_int8_t af) { if (xt[af].compat_tab) { vfree(xt[af].compat_tab); xt[af].compat_tab = NULL; xt[af].number = 0; xt[af].cur = 0; } } EXPORT_SYMBOL_GPL(xt_compat_flush_offsets); int xt_compat_calc_jump(u_int8_t af, unsigned int offset) { struct compat_delta *tmp = xt[af].compat_tab; int mid, left = 0, right = xt[af].cur - 1; while (left <= right) { mid = (left + right) >> 1; if (offset > tmp[mid].offset) left = mid + 1; else if (offset < tmp[mid].offset) right = mid - 1; else return mid ? tmp[mid - 1].delta : 0; } return left ? tmp[left - 1].delta : 0; } EXPORT_SYMBOL_GPL(xt_compat_calc_jump); void xt_compat_init_offsets(u_int8_t af, unsigned int number) { xt[af].number = number; xt[af].cur = 0; } EXPORT_SYMBOL(xt_compat_init_offsets); int xt_compat_match_offset(const struct xt_match *match) { u_int16_t csize = match->compatsize ? : match->matchsize; return XT_ALIGN(match->matchsize) - COMPAT_XT_ALIGN(csize); } EXPORT_SYMBOL_GPL(xt_compat_match_offset); void xt_compat_match_from_user(struct xt_entry_match *m, void **dstptr, unsigned int *size) { const struct xt_match *match = m->u.kernel.match; struct compat_xt_entry_match *cm = (struct compat_xt_entry_match *)m; int pad, off = xt_compat_match_offset(match); u_int16_t msize = cm->u.user.match_size; char name[sizeof(m->u.user.name)]; m = *dstptr; memcpy(m, cm, sizeof(*cm)); if (match->compat_from_user) match->compat_from_user(m->data, cm->data); else memcpy(m->data, cm->data, msize - sizeof(*cm)); pad = XT_ALIGN(match->matchsize) - match->matchsize; if (pad > 0) memset(m->data + match->matchsize, 0, pad); msize += off; m->u.user.match_size = msize; strlcpy(name, match->name, sizeof(name)); module_put(match->me); strncpy(m->u.user.name, name, sizeof(m->u.user.name)); *size += off; *dstptr += msize; } EXPORT_SYMBOL_GPL(xt_compat_match_from_user); int xt_compat_match_to_user(const struct xt_entry_match *m, void __user **dstptr, unsigned int *size) { const struct xt_match *match = m->u.kernel.match; struct compat_xt_entry_match __user *cm = *dstptr; int off = xt_compat_match_offset(match); u_int16_t msize = m->u.user.match_size - off; if (copy_to_user(cm, m, sizeof(*cm)) || put_user(msize, &cm->u.user.match_size) || copy_to_user(cm->u.user.name, m->u.kernel.match->name, strlen(m->u.kernel.match->name) + 1)) return -EFAULT; if (match->compat_to_user) { if (match->compat_to_user((void __user *)cm->data, m->data)) return -EFAULT; } else { if (copy_to_user(cm->data, m->data, msize - sizeof(*cm))) return -EFAULT; } *size -= off; *dstptr += msize; return 0; } EXPORT_SYMBOL_GPL(xt_compat_match_to_user); /* non-compat version may have padding after verdict */ struct compat_xt_standard_target { struct compat_xt_entry_target t; compat_uint_t verdict; }; int xt_compat_check_entry_offsets(const void *base, const char *elems, unsigned int target_offset, unsigned int next_offset) { long size_of_base_struct = elems - (const char *)base; const struct compat_xt_entry_target *t; const char *e = base; if (target_offset < size_of_base_struct) return -EINVAL; if (target_offset + sizeof(*t) > next_offset) return -EINVAL; t = (void *)(e + target_offset); if (t->u.target_size < sizeof(*t)) return -EINVAL; if (target_offset + t->u.target_size > next_offset) return -EINVAL; if (strcmp(t->u.user.name, XT_STANDARD_TARGET) == 0 && COMPAT_XT_ALIGN(target_offset + sizeof(struct compat_xt_standard_target)) != next_offset) return -EINVAL; /* compat_xt_entry match has less strict aligment requirements, * otherwise they are identical. In case of padding differences * we need to add compat version of xt_check_entry_match. */ BUILD_BUG_ON(sizeof(struct compat_xt_entry_match) != sizeof(struct xt_entry_match)); return xt_check_entry_match(elems, base + target_offset, __alignof__(struct compat_xt_entry_match)); } EXPORT_SYMBOL(xt_compat_check_entry_offsets); #endif /* CONFIG_COMPAT */ /** * xt_check_entry_offsets - validate arp/ip/ip6t_entry * * @base: pointer to arp/ip/ip6t_entry * @elems: pointer to first xt_entry_match, i.e. ip(6)t_entry->elems * @target_offset: the arp/ip/ip6_t->target_offset * @next_offset: the arp/ip/ip6_t->next_offset * * validates that target_offset and next_offset are sane and that all * match sizes (if any) align with the target offset. * * This function does not validate the targets or matches themselves, it * only tests that all the offsets and sizes are correct, that all * match structures are aligned, and that the last structure ends where * the target structure begins. * * Also see xt_compat_check_entry_offsets for CONFIG_COMPAT version. * * The arp/ip/ip6t_entry structure @base must have passed following tests: * - it must point to a valid memory location * - base to base + next_offset must be accessible, i.e. not exceed allocated * length. * * A well-formed entry looks like this: * * ip(6)t_entry match [mtdata] match [mtdata] target [tgdata] ip(6)t_entry * e->elems[]-----' | | * matchsize | | * matchsize | | * | | * target_offset---------------------------------' | * next_offset---------------------------------------------------' * * elems[]: flexible array member at end of ip(6)/arpt_entry struct. * This is where matches (if any) and the target reside. * target_offset: beginning of target. * next_offset: start of the next rule; also: size of this rule. * Since targets have a minimum size, target_offset + minlen <= next_offset. * * Every match stores its size, sum of sizes must not exceed target_offset. * * Return: 0 on success, negative errno on failure. */ int xt_check_entry_offsets(const void *base, const char *elems, unsigned int target_offset, unsigned int next_offset) { long size_of_base_struct = elems - (const char *)base; const struct xt_entry_target *t; const char *e = base; /* target start is within the ip/ip6/arpt_entry struct */ if (target_offset < size_of_base_struct) return -EINVAL; if (target_offset + sizeof(*t) > next_offset) return -EINVAL; t = (void *)(e + target_offset); if (t->u.target_size < sizeof(*t)) return -EINVAL; if (target_offset + t->u.target_size > next_offset) return -EINVAL; if (strcmp(t->u.user.name, XT_STANDARD_TARGET) == 0 && XT_ALIGN(target_offset + sizeof(struct xt_standard_target)) != next_offset) return -EINVAL; return xt_check_entry_match(elems, base + target_offset, __alignof__(struct xt_entry_match)); } EXPORT_SYMBOL(xt_check_entry_offsets); /** * xt_alloc_entry_offsets - allocate array to store rule head offsets * * @size: number of entries * * Return: NULL or kmalloc'd or vmalloc'd array */ unsigned int *xt_alloc_entry_offsets(unsigned int size) { unsigned int *off; off = kcalloc(size, sizeof(unsigned int), GFP_KERNEL | __GFP_NOWARN); if (off) return off; if (size < (SIZE_MAX / sizeof(unsigned int))) off = vmalloc(size * sizeof(unsigned int)); return off; } EXPORT_SYMBOL(xt_alloc_entry_offsets); /** * xt_find_jump_offset - check if target is a valid jump offset * * @offsets: array containing all valid rule start offsets of a rule blob * @target: the jump target to search for * @size: entries in @offset */ bool xt_find_jump_offset(const unsigned int *offsets, unsigned int target, unsigned int size) { int m, low = 0, hi = size; while (hi > low) { m = (low + hi) / 2u; if (offsets[m] > target) hi = m; else if (offsets[m] < target) low = m + 1; else return true; } return false; } EXPORT_SYMBOL(xt_find_jump_offset); int xt_check_target(struct xt_tgchk_param *par, unsigned int size, u_int8_t proto, bool inv_proto) { int ret; if (XT_ALIGN(par->target->targetsize) != size) { pr_err("%s_tables: %s.%u target: invalid size " "%u (kernel) != (user) %u\n", xt_prefix[par->family], par->target->name, par->target->revision, XT_ALIGN(par->target->targetsize), size); return -EINVAL; } if (par->target->table != NULL && strcmp(par->target->table, par->table) != 0) { pr_err("%s_tables: %s target: only valid in %s table, not %s\n", xt_prefix[par->family], par->target->name, par->target->table, par->table); return -EINVAL; } if (par->target->hooks && (par->hook_mask & ~par->target->hooks) != 0) { char used[64], allow[64]; pr_err("%s_tables: %s target: used from hooks %s, but only " "usable from %s\n", xt_prefix[par->family], par->target->name, textify_hooks(used, sizeof(used), par->hook_mask, par->family), textify_hooks(allow, sizeof(allow), par->target->hooks, par->family)); return -EINVAL; } if (par->target->proto && (par->target->proto != proto || inv_proto)) { pr_err("%s_tables: %s target: only valid for protocol %u\n", xt_prefix[par->family], par->target->name, par->target->proto); return -EINVAL; } if (par->target->checkentry != NULL) { ret = par->target->checkentry(par); if (ret < 0) return ret; else if (ret > 0) /* Flag up potential errors. */ return -EIO; } return 0; } EXPORT_SYMBOL_GPL(xt_check_target); /** * xt_copy_counters_from_user - copy counters and metadata from userspace * * @user: src pointer to userspace memory * @len: alleged size of userspace memory * @info: where to store the xt_counters_info metadata * @compat: true if we setsockopt call is done by 32bit task on 64bit kernel * * Copies counter meta data from @user and stores it in @info. * * vmallocs memory to hold the counters, then copies the counter data * from @user to the new memory and returns a pointer to it. * * If @compat is true, @info gets converted automatically to the 64bit * representation. * * The metadata associated with the counters is stored in @info. * * Return: returns pointer that caller has to test via IS_ERR(). * If IS_ERR is false, caller has to vfree the pointer. */ void *xt_copy_counters_from_user(const void __user *user, unsigned int len, struct xt_counters_info *info, bool compat) { void *mem; u64 size; #ifdef CONFIG_COMPAT if (compat) { /* structures only differ in size due to alignment */ struct compat_xt_counters_info compat_tmp; if (len <= sizeof(compat_tmp)) return ERR_PTR(-EINVAL); len -= sizeof(compat_tmp); if (copy_from_user(&compat_tmp, user, sizeof(compat_tmp)) != 0) return ERR_PTR(-EFAULT); strlcpy(info->name, compat_tmp.name, sizeof(info->name)); info->num_counters = compat_tmp.num_counters; user += sizeof(compat_tmp); } else #endif { if (len <= sizeof(*info)) return ERR_PTR(-EINVAL); len -= sizeof(*info); if (copy_from_user(info, user, sizeof(*info)) != 0) return ERR_PTR(-EFAULT); info->name[sizeof(info->name) - 1] = '\0'; user += sizeof(*info); } size = sizeof(struct xt_counters); size *= info->num_counters; if (size != (u64)len) return ERR_PTR(-EINVAL); mem = vmalloc(len); if (!mem) return ERR_PTR(-ENOMEM); if (copy_from_user(mem, user, len) == 0) return mem; vfree(mem); return ERR_PTR(-EFAULT); } EXPORT_SYMBOL_GPL(xt_copy_counters_from_user); #ifdef CONFIG_COMPAT int xt_compat_target_offset(const struct xt_target *target) { u_int16_t csize = target->compatsize ? : target->targetsize; return XT_ALIGN(target->targetsize) - COMPAT_XT_ALIGN(csize); } EXPORT_SYMBOL_GPL(xt_compat_target_offset); void xt_compat_target_from_user(struct xt_entry_target *t, void **dstptr, unsigned int *size) { const struct xt_target *target = t->u.kernel.target; struct compat_xt_entry_target *ct = (struct compat_xt_entry_target *)t; int pad, off = xt_compat_target_offset(target); u_int16_t tsize = ct->u.user.target_size; char name[sizeof(t->u.user.name)]; t = *dstptr; memcpy(t, ct, sizeof(*ct)); if (target->compat_from_user) target->compat_from_user(t->data, ct->data); else memcpy(t->data, ct->data, tsize - sizeof(*ct)); pad = XT_ALIGN(target->targetsize) - target->targetsize; if (pad > 0) memset(t->data + target->targetsize, 0, pad); tsize += off; t->u.user.target_size = tsize; strlcpy(name, target->name, sizeof(name)); module_put(target->me); strncpy(t->u.user.name, name, sizeof(t->u.user.name)); *size += off; *dstptr += tsize; } EXPORT_SYMBOL_GPL(xt_compat_target_from_user); int xt_compat_target_to_user(const struct xt_entry_target *t, void __user **dstptr, unsigned int *size) { const struct xt_target *target = t->u.kernel.target; struct compat_xt_entry_target __user *ct = *dstptr; int off = xt_compat_target_offset(target); u_int16_t tsize = t->u.user.target_size - off; if (copy_to_user(ct, t, sizeof(*ct)) || put_user(tsize, &ct->u.user.target_size) || copy_to_user(ct->u.user.name, t->u.kernel.target->name, strlen(t->u.kernel.target->name) + 1)) return -EFAULT; if (target->compat_to_user) { if (target->compat_to_user((void __user *)ct->data, t->data)) return -EFAULT; } else { if (copy_to_user(ct->data, t->data, tsize - sizeof(*ct))) return -EFAULT; } *size -= off; *dstptr += tsize; return 0; } EXPORT_SYMBOL_GPL(xt_compat_target_to_user); #endif struct xt_table_info *xt_alloc_table_info(unsigned int size) { struct xt_table_info *newinfo; int cpu; /* Pedantry: prevent them from hitting BUG() in vmalloc.c --RR */ if ((size >> PAGE_SHIFT) + 2 > totalram_pages) return NULL; newinfo = kzalloc(XT_TABLE_INFO_SZ, GFP_KERNEL); if (!newinfo) return NULL; newinfo->size = size; for_each_possible_cpu(cpu) { if (size <= PAGE_SIZE) newinfo->entries[cpu] = kmalloc_node(size, GFP_KERNEL, cpu_to_node(cpu)); else newinfo->entries[cpu] = vmalloc_node(size, cpu_to_node(cpu)); if (newinfo->entries[cpu] == NULL) { xt_free_table_info(newinfo); return NULL; } } return newinfo; } EXPORT_SYMBOL(xt_alloc_table_info); void xt_free_table_info(struct xt_table_info *info) { int cpu; for_each_possible_cpu(cpu) kvfree(info->entries[cpu]); if (info->jumpstack != NULL) { for_each_possible_cpu(cpu) kvfree(info->jumpstack[cpu]); kvfree(info->jumpstack); } free_percpu(info->stackptr); kfree(info); } EXPORT_SYMBOL(xt_free_table_info); /* Find table by name, grabs mutex & ref. Returns ERR_PTR() on error. */ struct xt_table *xt_find_table_lock(struct net *net, u_int8_t af, const char *name) { struct xt_table *t; mutex_lock(&xt[af].mutex); list_for_each_entry(t, &net->xt.tables[af], list) if (strcmp(t->name, name) == 0 && try_module_get(t->me)) return t; mutex_unlock(&xt[af].mutex); return NULL; } EXPORT_SYMBOL_GPL(xt_find_table_lock); void xt_table_unlock(struct xt_table *table) { mutex_unlock(&xt[table->af].mutex); } EXPORT_SYMBOL_GPL(xt_table_unlock); #ifdef CONFIG_COMPAT void xt_compat_lock(u_int8_t af) { mutex_lock(&xt[af].compat_mutex); } EXPORT_SYMBOL_GPL(xt_compat_lock); void xt_compat_unlock(u_int8_t af) { mutex_unlock(&xt[af].compat_mutex); } EXPORT_SYMBOL_GPL(xt_compat_unlock); #endif DEFINE_PER_CPU(seqcount_t, xt_recseq); EXPORT_PER_CPU_SYMBOL_GPL(xt_recseq); static int xt_jumpstack_alloc(struct xt_table_info *i) { unsigned int size; int cpu; i->stackptr = alloc_percpu(unsigned int); if (i->stackptr == NULL) return -ENOMEM; size = sizeof(void **) * nr_cpu_ids; if (size > PAGE_SIZE) i->jumpstack = vzalloc(size); else i->jumpstack = kzalloc(size, GFP_KERNEL); if (i->jumpstack == NULL) return -ENOMEM; i->stacksize *= xt_jumpstack_multiplier; size = sizeof(void *) * i->stacksize; for_each_possible_cpu(cpu) { if (size > PAGE_SIZE) i->jumpstack[cpu] = vmalloc_node(size, cpu_to_node(cpu)); else i->jumpstack[cpu] = kmalloc_node(size, GFP_KERNEL, cpu_to_node(cpu)); if (i->jumpstack[cpu] == NULL) /* * Freeing will be done later on by the callers. The * chain is: xt_replace_table -> __do_replace -> * do_replace -> xt_free_table_info. */ return -ENOMEM; } return 0; } struct xt_table_info * xt_replace_table(struct xt_table *table, unsigned int num_counters, struct xt_table_info *newinfo, int *error) { struct xt_table_info *private; int ret; ret = xt_jumpstack_alloc(newinfo); if (ret < 0) { *error = ret; return NULL; } /* Do the substitution. */ local_bh_disable(); private = table->private; /* Check inside lock: is the old number correct? */ if (num_counters != private->number) { pr_debug("num_counters != table->private->number (%u/%u)\n", num_counters, private->number); local_bh_enable(); *error = -EAGAIN; return NULL; } newinfo->initial_entries = private->initial_entries; /* * Ensure contents of newinfo are visible before assigning to * private. */ smp_wmb(); table->private = newinfo; /* * Even though table entries have now been swapped, other CPU's * may still be using the old entries. This is okay, because * resynchronization happens because of the locking done * during the get_counters() routine. */ local_bh_enable(); #ifdef CONFIG_AUDIT if (audit_enabled) { struct audit_buffer *ab; ab = audit_log_start(current->audit_context, GFP_KERNEL, AUDIT_NETFILTER_CFG); if (ab) { audit_log_format(ab, "table=%s family=%u entries=%u", table->name, table->af, private->number); audit_log_end(ab); } } #endif return private; } EXPORT_SYMBOL_GPL(xt_replace_table); struct xt_table *xt_register_table(struct net *net, const struct xt_table *input_table, struct xt_table_info *bootstrap, struct xt_table_info *newinfo) { int ret; struct xt_table_info *private; struct xt_table *t, *table; /* Don't add one object to multiple lists. */ table = kmemdup(input_table, sizeof(struct xt_table), GFP_KERNEL); if (!table) { ret = -ENOMEM; goto out; } mutex_lock(&xt[table->af].mutex); /* Don't autoload: we'd eat our tail... */ list_for_each_entry(t, &net->xt.tables[table->af], list) { if (strcmp(t->name, table->name) == 0) { ret = -EEXIST; goto unlock; } } /* Simplifies replace_table code. */ table->private = bootstrap; if (!xt_replace_table(table, 0, newinfo, &ret)) goto unlock; private = table->private; pr_debug("table->private->number = %u\n", private->number); /* save number of initial entries */ private->initial_entries = private->number; list_add(&table->list, &net->xt.tables[table->af]); mutex_unlock(&xt[table->af].mutex); return table; unlock: mutex_unlock(&xt[table->af].mutex); kfree(table); out: return ERR_PTR(ret); } EXPORT_SYMBOL_GPL(xt_register_table); void *xt_unregister_table(struct xt_table *table) { struct xt_table_info *private; mutex_lock(&xt[table->af].mutex); private = table->private; list_del(&table->list); mutex_unlock(&xt[table->af].mutex); kfree(table); return private; } EXPORT_SYMBOL_GPL(xt_unregister_table); #ifdef CONFIG_PROC_FS struct xt_names_priv { struct seq_net_private p; u_int8_t af; }; static void *xt_table_seq_start(struct seq_file *seq, loff_t *pos) { struct xt_names_priv *priv = seq->private; struct net *net = seq_file_net(seq); u_int8_t af = priv->af; mutex_lock(&xt[af].mutex); return seq_list_start(&net->xt.tables[af], *pos); } static void *xt_table_seq_next(struct seq_file *seq, void *v, loff_t *pos) { struct xt_names_priv *priv = seq->private; struct net *net = seq_file_net(seq); u_int8_t af = priv->af; return seq_list_next(v, &net->xt.tables[af], pos); } static void xt_table_seq_stop(struct seq_file *seq, void *v) { struct xt_names_priv *priv = seq->private; u_int8_t af = priv->af; mutex_unlock(&xt[af].mutex); } static int xt_table_seq_show(struct seq_file *seq, void *v) { struct xt_table *table = list_entry(v, struct xt_table, list); if (strlen(table->name)) { seq_printf(seq, "%s\n", table->name); return seq_has_overflowed(seq); } else return 0; } static const struct seq_operations xt_table_seq_ops = { .start = xt_table_seq_start, .next = xt_table_seq_next, .stop = xt_table_seq_stop, .show = xt_table_seq_show, }; static int xt_table_open(struct inode *inode, struct file *file) { int ret; struct xt_names_priv *priv; ret = seq_open_net(inode, file, &xt_table_seq_ops, sizeof(struct xt_names_priv)); if (!ret) { priv = ((struct seq_file *)file->private_data)->private; priv->af = (unsigned long)PDE_DATA(inode); } return ret; } static const struct file_operations xt_table_ops = { .owner = THIS_MODULE, .open = xt_table_open, .read = seq_read, .llseek = seq_lseek, .release = seq_release_net, }; /* * Traverse state for ip{,6}_{tables,matches} for helping crossing * the multi-AF mutexes. */ struct nf_mttg_trav { struct list_head *head, *curr; uint8_t class, nfproto; }; enum { MTTG_TRAV_INIT, MTTG_TRAV_NFP_UNSPEC, MTTG_TRAV_NFP_SPEC, MTTG_TRAV_DONE, }; static void *xt_mttg_seq_next(struct seq_file *seq, void *v, loff_t *ppos, bool is_target) { static const uint8_t next_class[] = { [MTTG_TRAV_NFP_UNSPEC] = MTTG_TRAV_NFP_SPEC, [MTTG_TRAV_NFP_SPEC] = MTTG_TRAV_DONE, }; struct nf_mttg_trav *trav = seq->private; switch (trav->class) { case MTTG_TRAV_INIT: trav->class = MTTG_TRAV_NFP_UNSPEC; mutex_lock(&xt[NFPROTO_UNSPEC].mutex); trav->head = trav->curr = is_target ? &xt[NFPROTO_UNSPEC].target : &xt[NFPROTO_UNSPEC].match; break; case MTTG_TRAV_NFP_UNSPEC: trav->curr = trav->curr->next; if (trav->curr != trav->head) break; mutex_unlock(&xt[NFPROTO_UNSPEC].mutex); mutex_lock(&xt[trav->nfproto].mutex); trav->head = trav->curr = is_target ? &xt[trav->nfproto].target : &xt[trav->nfproto].match; trav->class = next_class[trav->class]; break; case MTTG_TRAV_NFP_SPEC: trav->curr = trav->curr->next; if (trav->curr != trav->head) break; /* fallthru, _stop will unlock */ default: return NULL; } if (ppos != NULL) ++*ppos; return trav; } static void *xt_mttg_seq_start(struct seq_file *seq, loff_t *pos, bool is_target) { struct nf_mttg_trav *trav = seq->private; unsigned int j; trav->class = MTTG_TRAV_INIT; for (j = 0; j < *pos; ++j) if (xt_mttg_seq_next(seq, NULL, NULL, is_target) == NULL) return NULL; return trav; } static void xt_mttg_seq_stop(struct seq_file *seq, void *v) { struct nf_mttg_trav *trav = seq->private; switch (trav->class) { case MTTG_TRAV_NFP_UNSPEC: mutex_unlock(&xt[NFPROTO_UNSPEC].mutex); break; case MTTG_TRAV_NFP_SPEC: mutex_unlock(&xt[trav->nfproto].mutex); break; } } static void *xt_match_seq_start(struct seq_file *seq, loff_t *pos) { return xt_mttg_seq_start(seq, pos, false); } static void *xt_match_seq_next(struct seq_file *seq, void *v, loff_t *ppos) { return xt_mttg_seq_next(seq, v, ppos, false); } static int xt_match_seq_show(struct seq_file *seq, void *v) { const struct nf_mttg_trav *trav = seq->private; const struct xt_match *match; switch (trav->class) { case MTTG_TRAV_NFP_UNSPEC: case MTTG_TRAV_NFP_SPEC: if (trav->curr == trav->head) return 0; match = list_entry(trav->curr, struct xt_match, list); if (*match->name == '\0') return 0; seq_printf(seq, "%s\n", match->name); return seq_has_overflowed(seq); } return 0; } static const struct seq_operations xt_match_seq_ops = { .start = xt_match_seq_start, .next = xt_match_seq_next, .stop = xt_mttg_seq_stop, .show = xt_match_seq_show, }; static int xt_match_open(struct inode *inode, struct file *file) { struct nf_mttg_trav *trav; trav = __seq_open_private(file, &xt_match_seq_ops, sizeof(*trav)); if (!trav) return -ENOMEM; trav->nfproto = (unsigned long)PDE_DATA(inode); return 0; } static const struct file_operations xt_match_ops = { .owner = THIS_MODULE, .open = xt_match_open, .read = seq_read, .llseek = seq_lseek, .release = seq_release_private, }; static void *xt_target_seq_start(struct seq_file *seq, loff_t *pos) { return xt_mttg_seq_start(seq, pos, true); } static void *xt_target_seq_next(struct seq_file *seq, void *v, loff_t *ppos) { return xt_mttg_seq_next(seq, v, ppos, true); } static int xt_target_seq_show(struct seq_file *seq, void *v) { const struct nf_mttg_trav *trav = seq->private; const struct xt_target *target; switch (trav->class) { case MTTG_TRAV_NFP_UNSPEC: case MTTG_TRAV_NFP_SPEC: if (trav->curr == trav->head) return 0; target = list_entry(trav->curr, struct xt_target, list); if (*target->name == '\0') return 0; seq_printf(seq, "%s\n", target->name); return seq_has_overflowed(seq); } return 0; } static const struct seq_operations xt_target_seq_ops = { .start = xt_target_seq_start, .next = xt_target_seq_next, .stop = xt_mttg_seq_stop, .show = xt_target_seq_show, }; static int xt_target_open(struct inode *inode, struct file *file) { struct nf_mttg_trav *trav; trav = __seq_open_private(file, &xt_target_seq_ops, sizeof(*trav)); if (!trav) return -ENOMEM; trav->nfproto = (unsigned long)PDE_DATA(inode); return 0; } static const struct file_operations xt_target_ops = { .owner = THIS_MODULE, .open = xt_target_open, .read = seq_read, .llseek = seq_lseek, .release = seq_release_private, }; #define FORMAT_TABLES "_tables_names" #define FORMAT_MATCHES "_tables_matches" #define FORMAT_TARGETS "_tables_targets" #endif /* CONFIG_PROC_FS */ /** * xt_hook_link - set up hooks for a new table * @table: table with metadata needed to set up hooks * @fn: Hook function * * This function will take care of creating and registering the necessary * Netfilter hooks for XT tables. */ struct nf_hook_ops *xt_hook_link(const struct xt_table *table, nf_hookfn *fn) { unsigned int hook_mask = table->valid_hooks; uint8_t i, num_hooks = hweight32(hook_mask); uint8_t hooknum; struct nf_hook_ops *ops; int ret; ops = kmalloc(sizeof(*ops) * num_hooks, GFP_KERNEL); if (ops == NULL) return ERR_PTR(-ENOMEM); for (i = 0, hooknum = 0; i < num_hooks && hook_mask != 0; hook_mask >>= 1, ++hooknum) { if (!(hook_mask & 1)) continue; ops[i].hook = fn; ops[i].owner = table->me; ops[i].pf = table->af; ops[i].hooknum = hooknum; ops[i].priority = table->priority; ++i; } ret = nf_register_hooks(ops, num_hooks); if (ret < 0) { kfree(ops); return ERR_PTR(ret); } return ops; } EXPORT_SYMBOL_GPL(xt_hook_link); /** * xt_hook_unlink - remove hooks for a table * @ops: nf_hook_ops array as returned by nf_hook_link * @hook_mask: the very same mask that was passed to nf_hook_link */ void xt_hook_unlink(const struct xt_table *table, struct nf_hook_ops *ops) { nf_unregister_hooks(ops, hweight32(table->valid_hooks)); kfree(ops); } EXPORT_SYMBOL_GPL(xt_hook_unlink); int xt_proto_init(struct net *net, u_int8_t af) { #ifdef CONFIG_PROC_FS char buf[XT_FUNCTION_MAXNAMELEN]; struct proc_dir_entry *proc; #endif if (af >= ARRAY_SIZE(xt_prefix)) return -EINVAL; #ifdef CONFIG_PROC_FS strlcpy(buf, xt_prefix[af], sizeof(buf)); strlcat(buf, FORMAT_TABLES, sizeof(buf)); proc = proc_create_data(buf, 0440, net->proc_net, &xt_table_ops, (void *)(unsigned long)af); if (!proc) goto out; strlcpy(buf, xt_prefix[af], sizeof(buf)); strlcat(buf, FORMAT_MATCHES, sizeof(buf)); proc = proc_create_data(buf, 0440, net->proc_net, &xt_match_ops, (void *)(unsigned long)af); if (!proc) goto out_remove_tables; strlcpy(buf, xt_prefix[af], sizeof(buf)); strlcat(buf, FORMAT_TARGETS, sizeof(buf)); proc = proc_create_data(buf, 0440, net->proc_net, &xt_target_ops, (void *)(unsigned long)af); if (!proc) goto out_remove_matches; #endif return 0; #ifdef CONFIG_PROC_FS out_remove_matches: strlcpy(buf, xt_prefix[af], sizeof(buf)); strlcat(buf, FORMAT_MATCHES, sizeof(buf)); remove_proc_entry(buf, net->proc_net); out_remove_tables: strlcpy(buf, xt_prefix[af], sizeof(buf)); strlcat(buf, FORMAT_TABLES, sizeof(buf)); remove_proc_entry(buf, net->proc_net); out: return -1; #endif } EXPORT_SYMBOL_GPL(xt_proto_init); void xt_proto_fini(struct net *net, u_int8_t af) { #ifdef CONFIG_PROC_FS char buf[XT_FUNCTION_MAXNAMELEN]; strlcpy(buf, xt_prefix[af], sizeof(buf)); strlcat(buf, FORMAT_TABLES, sizeof(buf)); remove_proc_entry(buf, net->proc_net); strlcpy(buf, xt_prefix[af], sizeof(buf)); strlcat(buf, FORMAT_TARGETS, sizeof(buf)); remove_proc_entry(buf, net->proc_net); strlcpy(buf, xt_prefix[af], sizeof(buf)); strlcat(buf, FORMAT_MATCHES, sizeof(buf)); remove_proc_entry(buf, net->proc_net); #endif /*CONFIG_PROC_FS*/ } EXPORT_SYMBOL_GPL(xt_proto_fini); static int __net_init xt_net_init(struct net *net) { int i; for (i = 0; i < NFPROTO_NUMPROTO; i++) INIT_LIST_HEAD(&net->xt.tables[i]); return 0; } static struct pernet_operations xt_net_ops = { .init = xt_net_init, }; static int __init xt_init(void) { unsigned int i; int rv; for_each_possible_cpu(i) { seqcount_init(&per_cpu(xt_recseq, i)); } xt = kmalloc(sizeof(struct xt_af) * NFPROTO_NUMPROTO, GFP_KERNEL); if (!xt) return -ENOMEM; for (i = 0; i < NFPROTO_NUMPROTO; i++) { mutex_init(&xt[i].mutex); #ifdef CONFIG_COMPAT mutex_init(&xt[i].compat_mutex); xt[i].compat_tab = NULL; #endif INIT_LIST_HEAD(&xt[i].target); INIT_LIST_HEAD(&xt[i].match); } rv = register_pernet_subsys(&xt_net_ops); if (rv < 0) kfree(xt); return rv; } static void __exit xt_fini(void) { unregister_pernet_subsys(&xt_net_ops); kfree(xt); } module_init(xt_init); module_exit(xt_fini);