From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AH8x227iu5amjsdCqIEvLPJb1834/va4Ryk0NdpSDH9Y8+KfpkS4y/WERLMFZbeoTJPkaa5+m7b6 ARC-Seal: i=1; a=rsa-sha256; t=1517256605; cv=none; d=google.com; s=arc-20160816; b=YM187UqABEMWeUCx5nwotNZM73yOG3/u5CmleatxBCW035MLKvQTZNNPf/J9/w91qb C0DH+gc6c46P2W48X42QI5xl+dHeCMWczB76NVYb9NAWXg0B/HIZKHwYu1kOVHMxfBLX rA2Gaa9w0rQefa6WWJnDSnZnxT6TovKegiPLeqawXN5s8pzbTcycdqifBVBBlZva1Oga /4CAPuXu9LccTnQM1XClLtargLvzkQiqFTrhvNlcZRJATc/hzMGnJBRXZawYvI0b648H 4v4xUdzd7vdJqTPiyTOBGDVcH2LWD6eSEYTc4YOxOfAZcJfQkESayOcpIbIEncg3aC0P dOaA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=mime-version:user-agent:references:in-reply-to:message-id:date :subject:cc:to:from:arc-authentication-results; bh=HNxOEvFeD+rgrObWpNCuxEcd0BXMCBOOrAzgltj2AIY=; b=MRPeCBj02OJqVC5iqST8rQEyPctsjFR1qHEDsYqXUh9W4WVVHTVgkaSNCF10rgb8bZ dH93EaBwuIqLJFkZ6NE1sGXIlH91K1rRCoLvcKZaxvwkCBqQWRvZJrQBH7w6eMXL0hla FqmiamxuC1lH9eHpTXiUC9TKUfh+puWX452tqmpx3aEef/PQ70Mmz54NRHkT3UL1eGCv 5ed9hf8vycP0CqEn5gvsEfUI0PcB4Df9ICXd4Ky0o/krA7TrlU/e4fVQFLXRG1zoHXuK 3ixx/vZlj2574Odyp+XKyxW1G1LwdqeZAWnQcEqFbfheYTP1Rf1WeZ9RtGAH7KJB3r6n XeZQ== ARC-Authentication-Results: i=1; mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 90.92.71.90 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org Authentication-Results: mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 90.92.71.90 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jeff Wu , Florian Westphal , Pablo Neira Ayuso , Michal Kubecek Subject: [PATCH 4.4 30/74] netfilter: x_tables: speed up jump target validation Date: Mon, 29 Jan 2018 13:56:35 +0100 Message-Id: <20180129123848.967336367@linuxfoundation.org> X-Mailer: git-send-email 2.16.1 In-Reply-To: <20180129123847.507563674@linuxfoundation.org> References: <20180129123847.507563674@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-LABELS: =?utf-8?b?IlxcU2VudCI=?= X-GMAIL-THRID: =?utf-8?q?1590958862112747826?= X-GMAIL-MSGID: =?utf-8?q?1590958862112747826?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Florian Westphal commit f4dc77713f8016d2e8a3295e1c9c53a21f296def upstream. The dummy ruleset I used to test the original validation change was broken, most rules were unreachable and were not tested by mark_source_chains(). In some cases rulesets that used to load in a few seconds now require several minutes. sample ruleset that shows the behaviour: echo "*filter" for i in $(seq 0 100000);do printf ":chain_%06x - [0:0]\n" $i done for i in $(seq 0 100000);do printf -- "-A INPUT -j chain_%06x\n" $i printf -- "-A INPUT -j chain_%06x\n" $i printf -- "-A INPUT -j chain_%06x\n" $i done echo COMMIT [ pipe result into iptables-restore ] This ruleset will be about 74mbyte in size, with ~500k searches though all 500k[1] rule entries. iptables-restore will take forever (gave up after 10 minutes) Instead of always searching the entire blob for a match, fill an array with the start offsets of every single ipt_entry struct, then do a binary search to check if the jump target is present or not. After this change ruleset restore times get again close to what one gets when reverting 36472341017529e (~3 seconds on my workstation). [1] every user-defined rule gets an implicit RETURN, so we get 300k jumps + 100k userchains + 100k returns -> 500k rule entries Fixes: 36472341017529e ("netfilter: x_tables: validate targets of jumps") Reported-by: Jeff Wu Tested-by: Jeff Wu Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso Acked-by: Michal Kubecek Signed-off-by: Greg Kroah-Hartman --- include/linux/netfilter/x_tables.h | 4 ++ net/ipv4/netfilter/arp_tables.c | 47 ++++++++++++++++++---------------- net/ipv4/netfilter/ip_tables.c | 45 +++++++++++++++++---------------- net/ipv6/netfilter/ip6_tables.c | 45 +++++++++++++++++---------------- net/netfilter/x_tables.c | 50 +++++++++++++++++++++++++++++++++++++ 5 files changed, 127 insertions(+), 64 deletions(-) --- a/include/linux/netfilter/x_tables.h +++ b/include/linux/netfilter/x_tables.h @@ -243,6 +243,10 @@ int xt_check_entry_offsets(const void *b unsigned int target_offset, unsigned int next_offset); +unsigned int *xt_alloc_entry_offsets(unsigned int size); +bool xt_find_jump_offset(const unsigned int *offsets, + unsigned int target, unsigned int size); + int xt_check_match(struct xt_mtchk_param *, unsigned int size, u_int8_t proto, bool inv_proto); int xt_check_target(struct xt_tgchk_param *, unsigned int size, u_int8_t proto, --- a/net/ipv4/netfilter/arp_tables.c +++ b/net/ipv4/netfilter/arp_tables.c @@ -367,23 +367,12 @@ static inline bool unconditional(const s memcmp(&e->arp, &uncond, sizeof(uncond)) == 0; } -static bool find_jump_target(const struct xt_table_info *t, - const struct arpt_entry *target) -{ - struct arpt_entry *iter; - - xt_entry_foreach(iter, t->entries, t->size) { - if (iter == target) - return true; - } - return false; -} - /* Figures out from what hook each rule can be called: returns 0 if * there are loops. Puts hook bitmask in comefrom. */ static int mark_source_chains(const struct xt_table_info *newinfo, - unsigned int valid_hooks, void *entry0) + unsigned int valid_hooks, void *entry0, + unsigned int *offsets) { unsigned int hook; @@ -472,10 +461,11 @@ static int mark_source_chains(const stru /* This a jump; chase it. */ duprintf("Jump rule %u -> %u\n", pos, newpos); + if (!xt_find_jump_offset(offsets, newpos, + newinfo->number)) + return 0; e = (struct arpt_entry *) (entry0 + newpos); - if (!find_jump_target(newinfo, e)) - return 0; } else { /* ... this is a fallthru */ newpos = pos + e->next_offset; @@ -642,6 +632,7 @@ static int translate_table(struct xt_tab const struct arpt_replace *repl) { struct arpt_entry *iter; + unsigned int *offsets; unsigned int i; int ret = 0; @@ -655,6 +646,9 @@ static int translate_table(struct xt_tab } duprintf("translate_table: size %u\n", newinfo->size); + offsets = xt_alloc_entry_offsets(newinfo->number); + if (!offsets) + return -ENOMEM; i = 0; /* Walk through entries, checking offsets. */ @@ -665,7 +659,9 @@ static int translate_table(struct xt_tab repl->underflow, repl->valid_hooks); if (ret != 0) - break; + goto out_free; + if (i < repl->num_entries) + offsets[i] = (void *)iter - entry0; ++i; if (strcmp(arpt_get_target(iter)->u.user.name, XT_ERROR_TARGET) == 0) @@ -673,12 +669,13 @@ static int translate_table(struct xt_tab } duprintf("translate_table: ARPT_ENTRY_ITERATE gives %d\n", ret); if (ret != 0) - return ret; + goto out_free; + ret = -EINVAL; if (i != repl->num_entries) { duprintf("translate_table: %u not %u entries\n", i, repl->num_entries); - return -EINVAL; + goto out_free; } /* Check hooks all assigned */ @@ -689,17 +686,20 @@ static int translate_table(struct xt_tab if (newinfo->hook_entry[i] == 0xFFFFFFFF) { duprintf("Invalid hook entry %u %u\n", i, repl->hook_entry[i]); - return -EINVAL; + goto out_free; } if (newinfo->underflow[i] == 0xFFFFFFFF) { duprintf("Invalid underflow %u %u\n", i, repl->underflow[i]); - return -EINVAL; + goto out_free; } } - if (!mark_source_chains(newinfo, repl->valid_hooks, entry0)) - return -ELOOP; + if (!mark_source_chains(newinfo, repl->valid_hooks, entry0, offsets)) { + ret = -ELOOP; + goto out_free; + } + kvfree(offsets); /* Finally, each sanity check must pass */ i = 0; @@ -720,6 +720,9 @@ static int translate_table(struct xt_tab } return ret; + out_free: + kvfree(offsets); + return ret; } static void get_counters(const struct xt_table_info *t, --- a/net/ipv4/netfilter/ip_tables.c +++ b/net/ipv4/netfilter/ip_tables.c @@ -443,23 +443,12 @@ ipt_do_table(struct sk_buff *skb, #endif } -static bool find_jump_target(const struct xt_table_info *t, - const struct ipt_entry *target) -{ - struct ipt_entry *iter; - - xt_entry_foreach(iter, t->entries, t->size) { - if (iter == target) - return true; - } - return false; -} - /* Figures out from what hook each rule can be called: returns 0 if there are loops. Puts hook bitmask in comefrom. */ static int mark_source_chains(const struct xt_table_info *newinfo, - unsigned int valid_hooks, void *entry0) + unsigned int valid_hooks, void *entry0, + unsigned int *offsets) { unsigned int hook; @@ -552,10 +541,11 @@ mark_source_chains(const struct xt_table /* This a jump; chase it. */ duprintf("Jump rule %u -> %u\n", pos, newpos); + if (!xt_find_jump_offset(offsets, newpos, + newinfo->number)) + return 0; e = (struct ipt_entry *) (entry0 + newpos); - if (!find_jump_target(newinfo, e)) - return 0; } else { /* ... this is a fallthru */ newpos = pos + e->next_offset; @@ -811,6 +801,7 @@ translate_table(struct net *net, struct const struct ipt_replace *repl) { struct ipt_entry *iter; + unsigned int *offsets; unsigned int i; int ret = 0; @@ -824,6 +815,9 @@ translate_table(struct net *net, struct } duprintf("translate_table: size %u\n", newinfo->size); + offsets = xt_alloc_entry_offsets(newinfo->number); + if (!offsets) + return -ENOMEM; i = 0; /* Walk through entries, checking offsets. */ xt_entry_foreach(iter, entry0, newinfo->size) { @@ -833,17 +827,20 @@ translate_table(struct net *net, struct repl->underflow, repl->valid_hooks); if (ret != 0) - return ret; + goto out_free; + if (i < repl->num_entries) + offsets[i] = (void *)iter - entry0; ++i; if (strcmp(ipt_get_target(iter)->u.user.name, XT_ERROR_TARGET) == 0) ++newinfo->stacksize; } + ret = -EINVAL; if (i != repl->num_entries) { duprintf("translate_table: %u not %u entries\n", i, repl->num_entries); - return -EINVAL; + goto out_free; } /* Check hooks all assigned */ @@ -854,17 +851,20 @@ translate_table(struct net *net, struct if (newinfo->hook_entry[i] == 0xFFFFFFFF) { duprintf("Invalid hook entry %u %u\n", i, repl->hook_entry[i]); - return -EINVAL; + goto out_free; } if (newinfo->underflow[i] == 0xFFFFFFFF) { duprintf("Invalid underflow %u %u\n", i, repl->underflow[i]); - return -EINVAL; + goto out_free; } } - if (!mark_source_chains(newinfo, repl->valid_hooks, entry0)) - return -ELOOP; + if (!mark_source_chains(newinfo, repl->valid_hooks, entry0, offsets)) { + ret = -ELOOP; + goto out_free; + } + kvfree(offsets); /* Finally, each sanity check must pass */ i = 0; @@ -885,6 +885,9 @@ translate_table(struct net *net, struct } return ret; + out_free: + kvfree(offsets); + return ret; } static void --- a/net/ipv6/netfilter/ip6_tables.c +++ b/net/ipv6/netfilter/ip6_tables.c @@ -455,23 +455,12 @@ ip6t_do_table(struct sk_buff *skb, #endif } -static bool find_jump_target(const struct xt_table_info *t, - const struct ip6t_entry *target) -{ - struct ip6t_entry *iter; - - xt_entry_foreach(iter, t->entries, t->size) { - if (iter == target) - return true; - } - return false; -} - /* Figures out from what hook each rule can be called: returns 0 if there are loops. Puts hook bitmask in comefrom. */ static int mark_source_chains(const struct xt_table_info *newinfo, - unsigned int valid_hooks, void *entry0) + unsigned int valid_hooks, void *entry0, + unsigned int *offsets) { unsigned int hook; @@ -564,10 +553,11 @@ mark_source_chains(const struct xt_table /* This a jump; chase it. */ duprintf("Jump rule %u -> %u\n", pos, newpos); + if (!xt_find_jump_offset(offsets, newpos, + newinfo->number)) + return 0; e = (struct ip6t_entry *) (entry0 + newpos); - if (!find_jump_target(newinfo, e)) - return 0; } else { /* ... this is a fallthru */ newpos = pos + e->next_offset; @@ -823,6 +813,7 @@ translate_table(struct net *net, struct const struct ip6t_replace *repl) { struct ip6t_entry *iter; + unsigned int *offsets; unsigned int i; int ret = 0; @@ -836,6 +827,9 @@ translate_table(struct net *net, struct } duprintf("translate_table: size %u\n", newinfo->size); + offsets = xt_alloc_entry_offsets(newinfo->number); + if (!offsets) + return -ENOMEM; i = 0; /* Walk through entries, checking offsets. */ xt_entry_foreach(iter, entry0, newinfo->size) { @@ -845,17 +839,20 @@ translate_table(struct net *net, struct repl->underflow, repl->valid_hooks); if (ret != 0) - return ret; + goto out_free; + if (i < repl->num_entries) + offsets[i] = (void *)iter - entry0; ++i; if (strcmp(ip6t_get_target(iter)->u.user.name, XT_ERROR_TARGET) == 0) ++newinfo->stacksize; } + ret = -EINVAL; if (i != repl->num_entries) { duprintf("translate_table: %u not %u entries\n", i, repl->num_entries); - return -EINVAL; + goto out_free; } /* Check hooks all assigned */ @@ -866,17 +863,20 @@ translate_table(struct net *net, struct if (newinfo->hook_entry[i] == 0xFFFFFFFF) { duprintf("Invalid hook entry %u %u\n", i, repl->hook_entry[i]); - return -EINVAL; + goto out_free; } if (newinfo->underflow[i] == 0xFFFFFFFF) { duprintf("Invalid underflow %u %u\n", i, repl->underflow[i]); - return -EINVAL; + goto out_free; } } - if (!mark_source_chains(newinfo, repl->valid_hooks, entry0)) - return -ELOOP; + if (!mark_source_chains(newinfo, repl->valid_hooks, entry0, offsets)) { + ret = -ELOOP; + goto out_free; + } + kvfree(offsets); /* Finally, each sanity check must pass */ i = 0; @@ -897,6 +897,9 @@ translate_table(struct net *net, struct } return ret; + out_free: + kvfree(offsets); + return ret; } static void --- a/net/netfilter/x_tables.c +++ b/net/netfilter/x_tables.c @@ -701,6 +701,56 @@ int xt_check_entry_offsets(const void *b } 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) {