From d7591f0c41ce3e67600a982bab6989ef0f07b3ce Mon Sep 17 00:00:00 2001 From: Florian Westphal Date: Fri, 1 Apr 2016 15:37:59 +0200 Subject: [PATCH] netfilter: x_tables: introduce and use xt_copy_counters_from_user The three variants use same copy&pasted code, condense this into a helper and use that. Make sure info.name is 0-terminated. Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso --- include/linux/netfilter/x_tables.h | 3 ++ net/ipv4/netfilter/arp_tables.c | 48 ++----------------- net/ipv4/netfilter/ip_tables.c | 48 ++----------------- net/ipv6/netfilter/ip6_tables.c | 49 ++------------------ net/netfilter/x_tables.c | 74 ++++++++++++++++++++++++++++++ 5 files changed, 92 insertions(+), 130 deletions(-) diff --git a/include/linux/netfilter/x_tables.h b/include/linux/netfilter/x_tables.h index e2da9b90f1b8..4dd9306c9d56 100644 --- a/include/linux/netfilter/x_tables.h +++ b/include/linux/netfilter/x_tables.h @@ -251,6 +251,9 @@ int xt_check_match(struct xt_mtchk_param *, unsigned int size, u_int8_t proto, int xt_check_target(struct xt_tgchk_param *, unsigned int size, u_int8_t proto, bool inv_proto); +void *xt_copy_counters_from_user(const void __user *user, unsigned int len, + struct xt_counters_info *info, bool compat); + struct xt_table *xt_register_table(struct net *net, const struct xt_table *table, struct xt_table_info *bootstrap, diff --git a/net/ipv4/netfilter/arp_tables.c b/net/ipv4/netfilter/arp_tables.c index 8cefb7a2606b..60f5161abcb4 100644 --- a/net/ipv4/netfilter/arp_tables.c +++ b/net/ipv4/netfilter/arp_tables.c @@ -1123,55 +1123,17 @@ static int do_add_counters(struct net *net, const void __user *user, unsigned int i; struct xt_counters_info tmp; struct xt_counters *paddc; - unsigned int num_counters; - const char *name; - int size; - void *ptmp; struct xt_table *t; const struct xt_table_info *private; int ret = 0; struct arpt_entry *iter; unsigned int addend; -#ifdef CONFIG_COMPAT - struct compat_xt_counters_info compat_tmp; - - if (compat) { - ptmp = &compat_tmp; - size = sizeof(struct compat_xt_counters_info); - } else -#endif - { - ptmp = &tmp; - size = sizeof(struct xt_counters_info); - } - if (copy_from_user(ptmp, user, size) != 0) - return -EFAULT; - -#ifdef CONFIG_COMPAT - if (compat) { - num_counters = compat_tmp.num_counters; - name = compat_tmp.name; - } else -#endif - { - num_counters = tmp.num_counters; - name = tmp.name; - } - - if (len != size + num_counters * sizeof(struct xt_counters)) - return -EINVAL; - - paddc = vmalloc(len - size); - if (!paddc) - return -ENOMEM; - - if (copy_from_user(paddc, user + size, len - size) != 0) { - ret = -EFAULT; - goto free; - } + paddc = xt_copy_counters_from_user(user, len, &tmp, compat); + if (IS_ERR(paddc)) + return PTR_ERR(paddc); - t = xt_find_table_lock(net, NFPROTO_ARP, name); + t = xt_find_table_lock(net, NFPROTO_ARP, tmp.name); if (IS_ERR_OR_NULL(t)) { ret = t ? PTR_ERR(t) : -ENOENT; goto free; @@ -1179,7 +1141,7 @@ static int do_add_counters(struct net *net, const void __user *user, local_bh_disable(); private = t->private; - if (private->number != num_counters) { + if (private->number != tmp.num_counters) { ret = -EINVAL; goto unlock_up_free; } diff --git a/net/ipv4/netfilter/ip_tables.c b/net/ipv4/netfilter/ip_tables.c index 9340ce0a7549..735d1ee8c1ab 100644 --- a/net/ipv4/netfilter/ip_tables.c +++ b/net/ipv4/netfilter/ip_tables.c @@ -1307,55 +1307,17 @@ do_add_counters(struct net *net, const void __user *user, unsigned int i; struct xt_counters_info tmp; struct xt_counters *paddc; - unsigned int num_counters; - const char *name; - int size; - void *ptmp; struct xt_table *t; const struct xt_table_info *private; int ret = 0; struct ipt_entry *iter; unsigned int addend; -#ifdef CONFIG_COMPAT - struct compat_xt_counters_info compat_tmp; - - if (compat) { - ptmp = &compat_tmp; - size = sizeof(struct compat_xt_counters_info); - } else -#endif - { - ptmp = &tmp; - size = sizeof(struct xt_counters_info); - } - if (copy_from_user(ptmp, user, size) != 0) - return -EFAULT; - -#ifdef CONFIG_COMPAT - if (compat) { - num_counters = compat_tmp.num_counters; - name = compat_tmp.name; - } else -#endif - { - num_counters = tmp.num_counters; - name = tmp.name; - } - - if (len != size + num_counters * sizeof(struct xt_counters)) - return -EINVAL; - - paddc = vmalloc(len - size); - if (!paddc) - return -ENOMEM; - - if (copy_from_user(paddc, user + size, len - size) != 0) { - ret = -EFAULT; - goto free; - } + paddc = xt_copy_counters_from_user(user, len, &tmp, compat); + if (IS_ERR(paddc)) + return PTR_ERR(paddc); - t = xt_find_table_lock(net, AF_INET, name); + t = xt_find_table_lock(net, AF_INET, tmp.name); if (IS_ERR_OR_NULL(t)) { ret = t ? PTR_ERR(t) : -ENOENT; goto free; @@ -1363,7 +1325,7 @@ do_add_counters(struct net *net, const void __user *user, local_bh_disable(); private = t->private; - if (private->number != num_counters) { + if (private->number != tmp.num_counters) { ret = -EINVAL; goto unlock_up_free; } diff --git a/net/ipv6/netfilter/ip6_tables.c b/net/ipv6/netfilter/ip6_tables.c index aa010856a255..73e606c719ef 100644 --- a/net/ipv6/netfilter/ip6_tables.c +++ b/net/ipv6/netfilter/ip6_tables.c @@ -1319,55 +1319,16 @@ do_add_counters(struct net *net, const void __user *user, unsigned int len, unsigned int i; struct xt_counters_info tmp; struct xt_counters *paddc; - unsigned int num_counters; - char *name; - int size; - void *ptmp; struct xt_table *t; const struct xt_table_info *private; int ret = 0; struct ip6t_entry *iter; unsigned int addend; -#ifdef CONFIG_COMPAT - struct compat_xt_counters_info compat_tmp; - - if (compat) { - ptmp = &compat_tmp; - size = sizeof(struct compat_xt_counters_info); - } else -#endif - { - ptmp = &tmp; - size = sizeof(struct xt_counters_info); - } - - if (copy_from_user(ptmp, user, size) != 0) - return -EFAULT; - -#ifdef CONFIG_COMPAT - if (compat) { - num_counters = compat_tmp.num_counters; - name = compat_tmp.name; - } else -#endif - { - num_counters = tmp.num_counters; - name = tmp.name; - } - - if (len != size + num_counters * sizeof(struct xt_counters)) - return -EINVAL; - - paddc = vmalloc(len - size); - if (!paddc) - return -ENOMEM; - - if (copy_from_user(paddc, user + size, len - size) != 0) { - ret = -EFAULT; - goto free; - } - t = xt_find_table_lock(net, AF_INET6, name); + paddc = xt_copy_counters_from_user(user, len, &tmp, compat); + if (IS_ERR(paddc)) + return PTR_ERR(paddc); + t = xt_find_table_lock(net, AF_INET6, tmp.name); if (IS_ERR_OR_NULL(t)) { ret = t ? PTR_ERR(t) : -ENOENT; goto free; @@ -1375,7 +1336,7 @@ do_add_counters(struct net *net, const void __user *user, unsigned int len, local_bh_disable(); private = t->private; - if (private->number != num_counters) { + if (private->number != tmp.num_counters) { ret = -EINVAL; goto unlock_up_free; } diff --git a/net/netfilter/x_tables.c b/net/netfilter/x_tables.c index 9ec23ffa43b4..c69c892231d7 100644 --- a/net/netfilter/x_tables.c +++ b/net/netfilter/x_tables.c @@ -752,6 +752,80 @@ 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) { -- 2.20.1