-stable review patch. If anyone has any objections, please let us know. ------------------ From: Dmitry Mishin Commit 590bdf7fd2292b47c428111cb1360e312eff207e introduced a regression in match/target hook validation. mark_source_chains builds a bitmask for each rule representing the hooks it can be reached from, which is then used by the matches and targets to make sure they are only called from valid hooks. The patch moved the match/target specific validation before the mark_source_chains call, at which point the mask is always zero. This patch returns back to the old order and moves the standard checks to mark_source_chains. This allows to get rid of a special case for standard targets as a nice side-effect. Signed-off-by: Dmitry Mishin Signed-off-by: Patrick McHardy Signed-off-by: Chris Wright --- commit 756c508367e95d6f963502e4feecb8c76aeee332 tree 2be0ffb477e890a713eb48f3993a2f425baf5683 parent 0215ffb08ce99e2bb59eca114a99499a4d06e704 author Dmitry Mishin Mon, 04 Dec 2006 12:19:27 +0100 committer Patrick McHardy Mon, 04 Dec 2006 12:19:27 +0100 net/ipv4/netfilter/arp_tables.c | 48 ++++++++++++++-------------- net/ipv4/netfilter/ip_tables.c | 68 ++++++++++++++-------------------------- net/ipv6/netfilter/ip6_tables.c | 59 +++++++++++++--------------------- 3 files changed, 72 insertions(+), 103 deletions(-) --- linux-2.6.19.orig/net/ipv4/netfilter/arp_tables.c +++ linux-2.6.19/net/ipv4/netfilter/arp_tables.c @@ -375,6 +375,13 @@ static int mark_source_chains(struct xt_ && unconditional(&e->arp)) { unsigned int oldpos, size; + if (t->verdict < -NF_MAX_VERDICT - 1) { + duprintf("mark_source_chains: bad " + "negative verdict (%i)\n", + t->verdict); + return 0; + } + /* Return: backtrack through the last * big jump. */ @@ -404,6 +411,14 @@ static int mark_source_chains(struct xt_ if (strcmp(t->target.u.user.name, ARPT_STANDARD_TARGET) == 0 && newpos >= 0) { + if (newpos > newinfo->size - + sizeof(struct arpt_entry)) { + duprintf("mark_source_chains: " + "bad verdict (%i)\n", + newpos); + return 0; + } + /* This a jump; chase it. */ duprintf("Jump rule %u -> %u\n", pos, newpos); @@ -426,8 +441,6 @@ static int mark_source_chains(struct xt_ static inline int standard_check(const struct arpt_entry_target *t, unsigned int max_offset) { - struct arpt_standard_target *targ = (void *)t; - /* Check standard info. */ if (t->u.target_size != ARPT_ALIGN(sizeof(struct arpt_standard_target))) { @@ -437,18 +450,6 @@ static inline int standard_check(const s return 0; } - if (targ->verdict >= 0 - && targ->verdict > max_offset - sizeof(struct arpt_entry)) { - duprintf("arpt_standard_check: bad verdict (%i)\n", - targ->verdict); - return 0; - } - - if (targ->verdict < -NF_MAX_VERDICT - 1) { - duprintf("arpt_standard_check: bad negative verdict (%i)\n", - targ->verdict); - return 0; - } return 1; } @@ -627,18 +628,20 @@ static int translate_table(const char *n } } + if (!mark_source_chains(newinfo, valid_hooks, entry0)) { + duprintf("Looping hook\n"); + return -ELOOP; + } + /* Finally, each sanity check must pass */ i = 0; ret = ARPT_ENTRY_ITERATE(entry0, newinfo->size, check_entry, name, size, &i); - if (ret != 0) - goto cleanup; - - ret = -ELOOP; - if (!mark_source_chains(newinfo, valid_hooks, entry0)) { - duprintf("Looping hook\n"); - goto cleanup; + if (ret != 0) { + ARPT_ENTRY_ITERATE(entry0, newinfo->size, + cleanup_entry, &i); + return ret; } /* And one copy for every other CPU */ @@ -647,9 +650,6 @@ static int translate_table(const char *n memcpy(newinfo->entries[i], entry0, newinfo->size); } - return 0; -cleanup: - ARPT_ENTRY_ITERATE(entry0, newinfo->size, cleanup_entry, &i); return ret; } --- linux-2.6.19.orig/net/ipv4/netfilter/ip_tables.c +++ linux-2.6.19/net/ipv4/netfilter/ip_tables.c @@ -401,6 +401,13 @@ mark_source_chains(struct xt_table_info && unconditional(&e->ip)) { unsigned int oldpos, size; + if (t->verdict < -NF_MAX_VERDICT - 1) { + duprintf("mark_source_chains: bad " + "negative verdict (%i)\n", + t->verdict); + return 0; + } + /* Return: backtrack through the last big jump. */ do { @@ -438,6 +445,13 @@ mark_source_chains(struct xt_table_info if (strcmp(t->target.u.user.name, IPT_STANDARD_TARGET) == 0 && newpos >= 0) { + if (newpos > newinfo->size - + sizeof(struct ipt_entry)) { + duprintf("mark_source_chains: " + "bad verdict (%i)\n", + newpos); + return 0; + } /* This a jump; chase it. */ duprintf("Jump rule %u -> %u\n", pos, newpos); @@ -470,27 +484,6 @@ cleanup_match(struct ipt_entry_match *m, } static inline int -standard_check(const struct ipt_entry_target *t, - unsigned int max_offset) -{ - struct ipt_standard_target *targ = (void *)t; - - /* Check standard info. */ - if (targ->verdict >= 0 - && targ->verdict > max_offset - sizeof(struct ipt_entry)) { - duprintf("ipt_standard_check: bad verdict (%i)\n", - targ->verdict); - return 0; - } - if (targ->verdict < -NF_MAX_VERDICT - 1) { - duprintf("ipt_standard_check: bad negative verdict (%i)\n", - targ->verdict); - return 0; - } - return 1; -} - -static inline int check_match(struct ipt_entry_match *m, const char *name, const struct ipt_ip *ip, @@ -576,12 +569,7 @@ check_entry(struct ipt_entry *e, const c if (ret) goto err; - if (t->u.kernel.target == &ipt_standard_target) { - if (!standard_check(t, size)) { - ret = -EINVAL; - goto err; - } - } else if (t->u.kernel.target->checkentry + if (t->u.kernel.target->checkentry && !t->u.kernel.target->checkentry(name, e, target, t->data, e->comefrom)) { duprintf("ip_tables: check failed for `%s'.\n", @@ -718,17 +706,19 @@ translate_table(const char *name, } } + if (!mark_source_chains(newinfo, valid_hooks, entry0)) + return -ELOOP; + /* Finally, each sanity check must pass */ i = 0; ret = IPT_ENTRY_ITERATE(entry0, newinfo->size, check_entry, name, size, &i); - if (ret != 0) - goto cleanup; - - ret = -ELOOP; - if (!mark_source_chains(newinfo, valid_hooks, entry0)) - goto cleanup; + if (ret != 0) { + IPT_ENTRY_ITERATE(entry0, newinfo->size, + cleanup_entry, &i); + return ret; + } /* And one copy for every other CPU */ for_each_possible_cpu(i) { @@ -736,9 +726,6 @@ translate_table(const char *name, memcpy(newinfo->entries[i], entry0, newinfo->size); } - return 0; -cleanup: - IPT_ENTRY_ITERATE(entry0, newinfo->size, cleanup_entry, &i); return ret; } @@ -1591,18 +1578,13 @@ static int compat_copy_entry_from_user(s if (ret) goto err; - ret = -EINVAL; - if (t->u.kernel.target == &ipt_standard_target) { - if (!standard_check(t, *size)) - goto err; - } else if (t->u.kernel.target->checkentry + if (t->u.kernel.target->checkentry && !t->u.kernel.target->checkentry(name, de, target, t->data, de->comefrom)) { duprintf("ip_tables: compat: check failed for `%s'.\n", t->u.kernel.target->name); - goto err; + ret = -EINVAL; } - ret = 0; err: return ret; } --- linux-2.6.19.orig/net/ipv6/netfilter/ip6_tables.c +++ linux-2.6.19/net/ipv6/netfilter/ip6_tables.c @@ -440,6 +440,13 @@ mark_source_chains(struct xt_table_info && unconditional(&e->ipv6)) { unsigned int oldpos, size; + if (t->verdict < -NF_MAX_VERDICT - 1) { + duprintf("mark_source_chains: bad " + "negative verdict (%i)\n", + t->verdict); + return 0; + } + /* Return: backtrack through the last big jump. */ do { @@ -477,6 +484,13 @@ mark_source_chains(struct xt_table_info if (strcmp(t->target.u.user.name, IP6T_STANDARD_TARGET) == 0 && newpos >= 0) { + if (newpos > newinfo->size - + sizeof(struct ip6t_entry)) { + duprintf("mark_source_chains: " + "bad verdict (%i)\n", + newpos); + return 0; + } /* This a jump; chase it. */ duprintf("Jump rule %u -> %u\n", pos, newpos); @@ -509,27 +523,6 @@ cleanup_match(struct ip6t_entry_match *m } static inline int -standard_check(const struct ip6t_entry_target *t, - unsigned int max_offset) -{ - struct ip6t_standard_target *targ = (void *)t; - - /* Check standard info. */ - if (targ->verdict >= 0 - && targ->verdict > max_offset - sizeof(struct ip6t_entry)) { - duprintf("ip6t_standard_check: bad verdict (%i)\n", - targ->verdict); - return 0; - } - if (targ->verdict < -NF_MAX_VERDICT - 1) { - duprintf("ip6t_standard_check: bad negative verdict (%i)\n", - targ->verdict); - return 0; - } - return 1; -} - -static inline int check_match(struct ip6t_entry_match *m, const char *name, const struct ip6t_ip6 *ipv6, @@ -616,12 +609,7 @@ check_entry(struct ip6t_entry *e, const if (ret) goto err; - if (t->u.kernel.target == &ip6t_standard_target) { - if (!standard_check(t, size)) { - ret = -EINVAL; - goto err; - } - } else if (t->u.kernel.target->checkentry + if (t->u.kernel.target->checkentry && !t->u.kernel.target->checkentry(name, e, target, t->data, e->comefrom)) { duprintf("ip_tables: check failed for `%s'.\n", @@ -758,17 +746,19 @@ translate_table(const char *name, } } + if (!mark_source_chains(newinfo, valid_hooks, entry0)) + return -ELOOP; + /* Finally, each sanity check must pass */ i = 0; ret = IP6T_ENTRY_ITERATE(entry0, newinfo->size, check_entry, name, size, &i); - if (ret != 0) - goto cleanup; - - ret = -ELOOP; - if (!mark_source_chains(newinfo, valid_hooks, entry0)) - goto cleanup; + if (ret != 0) { + IP6T_ENTRY_ITERATE(entry0, newinfo->size, + cleanup_entry, &i); + return ret; + } /* And one copy for every other CPU */ for_each_possible_cpu(i) { @@ -777,9 +767,6 @@ translate_table(const char *name, } return 0; -cleanup: - IP6T_ENTRY_ITERATE(entry0, newinfo->size, cleanup_entry, &i); - return ret; } /* Gets counters. */ -- - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/