X-Git-Url: https://gerrit.opnfv.org/gerrit/gitweb?a=blobdiff_plain;ds=sidebyside;f=kernel%2Fnet%2Fnetfilter%2Fx_tables.c;fp=kernel%2Fnet%2Fnetfilter%2Fx_tables.c;h=2fc6ca9d12866432f09d01d8807698b77723e168;hb=52f993b8e89487ec9ee15a7fb4979e0f09a45b27;hp=d4aaad747ea99b0aa877016f437a5fd46ec768ee;hpb=c189ccac5702322ed843fe17057035b7222a59b6;p=kvmfornfv.git diff --git a/kernel/net/netfilter/x_tables.c b/kernel/net/netfilter/x_tables.c index d4aaad747..2fc6ca9d1 100644 --- a/kernel/net/netfilter/x_tables.c +++ b/kernel/net/netfilter/x_tables.c @@ -415,6 +415,47 @@ int xt_check_match(struct xt_mtchk_param *par, } 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) { @@ -484,13 +525,14 @@ int xt_compat_match_offset(const struct xt_match *match) } EXPORT_SYMBOL_GPL(xt_compat_match_offset); -int xt_compat_match_from_user(struct xt_entry_match *m, void **dstptr, - unsigned int *size) +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)); @@ -504,10 +546,12 @@ int xt_compat_match_from_user(struct xt_entry_match *m, void **dstptr, 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; - return 0; } EXPORT_SYMBOL_GPL(xt_compat_match_from_user); @@ -538,8 +582,125 @@ int xt_compat_match_to_user(const struct xt_entry_match *m, 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); + int xt_check_target(struct xt_tgchk_param *par, unsigned int size, u_int8_t proto, bool inv_proto) { @@ -590,6 +751,80 @@ int xt_check_target(struct xt_tgchk_param *par, } 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) { @@ -605,6 +840,7 @@ void xt_compat_target_from_user(struct xt_entry_target *t, void **dstptr, 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)); @@ -618,6 +854,9 @@ void xt_compat_target_from_user(struct xt_entry_target *t, void **dstptr, 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; @@ -658,6 +897,12 @@ struct xt_table_info *xt_alloc_table_info(unsigned int size) struct xt_table_info *info = NULL; size_t sz = sizeof(*info) + size; + if (sz < sizeof(*info)) + return NULL; + + if (sz < sizeof(*info)) + return NULL; + /* Pedantry: prevent them from hitting BUG() in vmalloc.c --RR */ if ((SMP_ALIGN(size) >> PAGE_SHIFT) + 2 > totalram_pages) return NULL;