From 7d35812c3214afa5b37a675113555259cfd67b98 Mon Sep 17 00:00:00 2001 From: Florian Westphal Date: Fri, 1 Apr 2016 14:17:23 +0200 Subject: netfilter: x_tables: add and use xt_check_entry_offsets Currently arp/ip and ip6tables each implement a short helper to check that the target offset is large enough to hold one xt_entry_target struct and that t->u.target_size fits within the current rule. Unfortunately these checks are not sufficient. To avoid adding new tests to all of ip/ip6/arptables move the current checks into a helper, then extend this helper in followup patches. Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso --- include/linux/netfilter/x_tables.h | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'include/linux') diff --git a/include/linux/netfilter/x_tables.h b/include/linux/netfilter/x_tables.h index 80a305b85323..0de0862897a4 100644 --- a/include/linux/netfilter/x_tables.h +++ b/include/linux/netfilter/x_tables.h @@ -242,6 +242,10 @@ void xt_unregister_match(struct xt_match *target); int xt_register_matches(struct xt_match *match, unsigned int n); void xt_unregister_matches(struct xt_match *match, unsigned int n); +int xt_check_entry_offsets(const void *base, + unsigned int target_offset, + unsigned int next_offset); + 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, -- cgit v1.2.3 From fc1221b3a163d1386d1052184202d5dc50d302d1 Mon Sep 17 00:00:00 2001 From: Florian Westphal Date: Fri, 1 Apr 2016 14:17:26 +0200 Subject: netfilter: x_tables: add compat version of xt_check_entry_offsets 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 Signed-off-by: Pablo Neira Ayuso --- include/linux/netfilter/x_tables.h | 3 +++ 1 file changed, 3 insertions(+) (limited to 'include/linux') diff --git a/include/linux/netfilter/x_tables.h b/include/linux/netfilter/x_tables.h index 0de0862897a4..08de48bbe92e 100644 --- a/include/linux/netfilter/x_tables.h +++ b/include/linux/netfilter/x_tables.h @@ -494,6 +494,9 @@ void xt_compat_target_from_user(struct xt_entry_target *t, void **dstptr, 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 */ -- cgit v1.2.3 From ce683e5f9d045e5d67d1312a42b359cb2ab2a13c Mon Sep 17 00:00:00 2001 From: Florian Westphal Date: Fri, 1 Apr 2016 14:17:28 +0200 Subject: netfilter: x_tables: check for bogus target offset We're currently asserting that targetoff + targetsize <= nextoff. Extend it to also check that targetoff is >= sizeof(xt_entry). Since this is generic code, add an argument pointing to the start of the match/target, we can then derive the base structure size from the delta. We also need the e->elems pointer in a followup change to validate matches. Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso --- include/linux/netfilter/x_tables.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'include/linux') diff --git a/include/linux/netfilter/x_tables.h b/include/linux/netfilter/x_tables.h index 08de48bbe92e..30cfb1e943fb 100644 --- a/include/linux/netfilter/x_tables.h +++ b/include/linux/netfilter/x_tables.h @@ -242,7 +242,7 @@ void xt_unregister_match(struct xt_match *target); int xt_register_matches(struct xt_match *match, unsigned int n); void xt_unregister_matches(struct xt_match *match, unsigned int n); -int xt_check_entry_offsets(const void *base, +int xt_check_entry_offsets(const void *base, const char *elems, unsigned int target_offset, unsigned int next_offset); @@ -494,7 +494,7 @@ void xt_compat_target_from_user(struct xt_entry_target *t, void **dstptr, 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, +int xt_compat_check_entry_offsets(const void *base, const char *elems, unsigned int target_offset, unsigned int next_offset); -- cgit v1.2.3 From 0188346f21e6546498c2a0f84888797ad4063fc5 Mon Sep 17 00:00:00 2001 From: Florian Westphal Date: Fri, 1 Apr 2016 14:17:33 +0200 Subject: netfilter: x_tables: xt_compat_match_from_user doesn't need a retval Always returned 0. Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso --- include/linux/netfilter/x_tables.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/linux') diff --git a/include/linux/netfilter/x_tables.h b/include/linux/netfilter/x_tables.h index 30cfb1e943fb..e2da9b90f1b8 100644 --- a/include/linux/netfilter/x_tables.h +++ b/include/linux/netfilter/x_tables.h @@ -484,7 +484,7 @@ void xt_compat_init_offsets(u_int8_t af, unsigned int number); int xt_compat_calc_jump(u_int8_t af, unsigned int offset); int xt_compat_match_offset(const struct xt_match *match); -int xt_compat_match_from_user(struct xt_entry_match *m, void **dstptr, +void xt_compat_match_from_user(struct xt_entry_match *m, void **dstptr, unsigned int *size); int xt_compat_match_to_user(const struct xt_entry_match *m, void __user **dstptr, unsigned int *size); -- cgit v1.2.3 From d7591f0c41ce3e67600a982bab6989ef0f07b3ce Mon Sep 17 00:00:00 2001 From: Florian Westphal Date: Fri, 1 Apr 2016 15:37:59 +0200 Subject: 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 +++ 1 file changed, 3 insertions(+) (limited to 'include/linux') 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, -- cgit v1.2.3