| From | Ben Hutchings <> | Date | Sat, 13 Aug 2016 18:42:51 +0100 | Subject | [PATCH 3.16 293/305] netfilter: x_tables: add compat version of xt_check_entry_offsets |
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3.16.37-rc1 review patch. If anyone has any objections, please let me know.
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From: Florian Westphal <fw@strlen.de>
commit fc1221b3a163d1386d1052184202d5dc50d302d1 upstream.
32bit rulesets have different layout and alignment requirements, so once more integrity checks get added to xt_check_entry_offsets it will reject well-formed 32bit rulesets.
Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> --- include/linux/netfilter/x_tables.h | 3 +++ net/ipv4/netfilter/arp_tables.c | 3 ++- net/ipv4/netfilter/ip_tables.c | 3 ++- net/ipv6/netfilter/ip6_tables.c | 3 ++- net/netfilter/x_tables.c | 22 ++++++++++++++++++++++ 5 files changed, 31 insertions(+), 3 deletions(-)
--- a/include/linux/netfilter/x_tables.h +++ b/include/linux/netfilter/x_tables.h @@ -435,6 +435,9 @@ void xt_compat_target_from_user(struct x unsigned int *size); int xt_compat_target_to_user(const struct xt_entry_target *t, void __user **dstptr, unsigned int *size); +int xt_compat_check_entry_offsets(const void *base, + unsigned int target_offset, + unsigned int next_offset); #endif /* CONFIG_COMPAT */ #endif /* _X_TABLES_H */ --- a/net/ipv4/netfilter/arp_tables.c +++ b/net/ipv4/netfilter/arp_tables.c @@ -1245,7 +1245,8 @@ check_compat_entry_size_and_hooks(struct if (!arp_checkentry(&e->arp)) return -EINVAL; - ret = xt_check_entry_offsets(e, e->target_offset, e->next_offset); + ret = xt_compat_check_entry_offsets(e, e->target_offset, + e->next_offset); if (ret) return ret; --- a/net/ipv4/netfilter/ip_tables.c +++ b/net/ipv4/netfilter/ip_tables.c @@ -1510,7 +1510,8 @@ check_compat_entry_size_and_hooks(struct if (!ip_checkentry(&e->ip)) return -EINVAL; - ret = xt_check_entry_offsets(e, e->target_offset, e->next_offset); + ret = xt_compat_check_entry_offsets(e, + e->target_offset, e->next_offset); if (ret) return ret; --- a/net/ipv6/netfilter/ip6_tables.c +++ b/net/ipv6/netfilter/ip6_tables.c @@ -1522,7 +1522,8 @@ check_compat_entry_size_and_hooks(struct if (!ip6_checkentry(&e->ipv6)) return -EINVAL; - ret = xt_check_entry_offsets(e, e->target_offset, e->next_offset); + ret = xt_compat_check_entry_offsets(e, + e->target_offset, e->next_offset); if (ret) return ret; --- a/net/netfilter/x_tables.c +++ b/net/netfilter/x_tables.c @@ -558,6 +558,27 @@ int xt_compat_match_to_user(const struct return 0; } EXPORT_SYMBOL_GPL(xt_compat_match_to_user); + +int xt_compat_check_entry_offsets(const void *base, + unsigned int target_offset, + unsigned int next_offset) +{ + const struct compat_xt_entry_target *t; + const char *e = base; + + 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; + + return 0; +} +EXPORT_SYMBOL(xt_compat_check_entry_offsets); #endif /* CONFIG_COMPAT */ /** @@ -568,6 +589,7 @@ EXPORT_SYMBOL_GPL(xt_compat_match_to_use * @next_offset: the arp/ip/ip6_t->next_offset * * validates that target_offset and next_offset are sane. + * 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
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