kernel/linux.git/net/netfilter, branch linux-4.20.y

netfilter: nft_compat: don't use refcount_inc on newly allocated entry

2019-03-13T21:04:17+00:00

[ Upstream commit 947e492c0fc2132ae5fca081a9c2952ccaab0404 ] When I moved the refcount to refcount_t type I missed the fact that refcount_inc() will result in use-after-free warning with CONFIG_REFCOUNT_FULL=y builds. The correct fix would be to init the reference count to 1 at allocation time, but, unfortunately we cannot do this, as we can't undo that in case something else fails later in the batch. So only solution I see is to special-case the 'new entry' condition and replace refcount_inc() with a "delayed" refcount_set(1) in this case, as done here. The .activate callback can be removed to simplify things, we only need to make sure that deactivate() decrements/unlinks the entry from the list at end of transaction phase (commit or abort). Fixes: 12c44aba6618 ("netfilter: nft_compat: use refcnt_t type for nft_xt reference count") Reported-by: Jordan Glover Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso Signed-off-by: Sasha Levin

netfilter: nf_tables: unbind set in rule from commit path

2019-03-13T21:04:17+00:00

[ Upstream commit f6ac8585897684374a19863fff21186a05805286 ] Anonymous sets that are bound to rules from the same transaction trigger a kernel splat from the abort path due to double set list removal and double free. This patch updates the logic to search for the transaction that is responsible for creating the set and disable the set list removal and release, given the rule is now responsible for this. Lookup is reverse since the transaction that adds the set is likely to be at the tail of the list. Moreover, this patch adds the unbind step to deliver the event from the commit path. This should not be done from the worker thread, since we have no guarantees of in-order delivery to the listener. This patch removes the assumption that both activate and deactivate callbacks need to be provided. Fixes: cd5125d8f518 ("netfilter: nf_tables: split set destruction in deactivate and destroy phase") Reported-by: Mikhail Morfikov Signed-off-by: Pablo Neira Ayuso Signed-off-by: Sasha Levin

netfilter: nf_nat: skip nat clash resolution for same-origin entries

2019-03-13T21:04:15+00:00

[ Upstream commit 4e35c1cb9460240e983a01745b5f29fe3a4d8e39 ] It is possible that two concurrent packets originating from the same socket of a connection-less protocol (e.g. UDP) can end up having different IP_CT_DIR_REPLY tuples which results in one of the packets being dropped. To illustrate this, consider the following simplified scenario: 1. Packet A and B are sent at the same time from two different threads by same UDP socket. No matching conntrack entry exists yet. Both packets cause allocation of a new conntrack entry. 2. get_unique_tuple gets called for A. No clashing entry found. conntrack entry for A is added to main conntrack table. 3. get_unique_tuple is called for B and will find that the reply tuple of B is already taken by A. It will allocate a new UDP source port for B to resolve the clash. 4. conntrack entry for B cannot be added to main conntrack table because its ORIGINAL direction is clashing with A and the REPLY directions of A and B are not the same anymore due to UDP source port reallocation done in step 3. This patch modifies nf_conntrack_tuple_taken so it doesn't consider colliding reply tuples if the IP_CT_DIR_ORIGINAL tuples are equal. [ Florian: simplify patch to not use .allow_clash setting and always ignore identical flows ] Signed-off-by: Martynas Pumputis Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso Signed-off-by: Sasha Levin

ipvs: Fix signed integer overflow when setsockopt timeout

2019-03-13T21:04:01+00:00

[ Upstream commit 53ab60baa1ac4f20b080a22c13b77b6373922fd7 ] There is a UBSAN bug report as below: UBSAN: Undefined behaviour in net/netfilter/ipvs/ip_vs_ctl.c:2227:21 signed integer overflow: -2147483647 * 1000 cannot be represented in type 'int' Reproduce program: #include #include #include #define IPPROTO_IP 0 #define IPPROTO_RAW 255 #define IP_VS_BASE_CTL (64+1024+64) #define IP_VS_SO_SET_TIMEOUT (IP_VS_BASE_CTL+10) /* The argument to IP_VS_SO_GET_TIMEOUT */ struct ipvs_timeout_t { int tcp_timeout; int tcp_fin_timeout; int udp_timeout; }; int main() { int ret = -1; int sockfd = -1; struct ipvs_timeout_t to; sockfd = socket(AF_INET, SOCK_RAW, IPPROTO_RAW); if (sockfd == -1) { printf("socket init error\n"); return -1; } to.tcp_timeout = -2147483647; to.tcp_fin_timeout = -2147483647; to.udp_timeout = -2147483647; ret = setsockopt(sockfd, IPPROTO_IP, IP_VS_SO_SET_TIMEOUT, (char *)(&to), sizeof(to)); printf("setsockopt return %d\n", ret); return ret; } Return -EINVAL if the timeout value is negative or max than 'INT_MAX / HZ'. Signed-off-by: ZhangXiaoxu Acked-by: Simon Horman Signed-off-by: Pablo Neira Ayuso Signed-off-by: Sasha Levin

netfilter: nft_compat: destroy function must not have side effects

2019-03-13T21:03:59+00:00

[ Upstream commit b2e3d68d1251a051a620f9086e18f7ffa6833b5b ] The nft_compat destroy function deletes the nft_xt object from a list. This isn't allowed anymore. Destroy functions are called asynchronously, i.e. next batch can find the object that has a pending ->destroy() invocation: cpu0 cpu1 worker ->destroy for_each_entry() if (x == ... return x->ops; list_del(x) kfree_rcu(x) expr->ops->... // ops was free'd To resolve this, the list_del needs to occur before the transaction mutex gets released. nf_tables has a 'deactivate' hook for this purpose, so use that to unlink the object from the list. Fixes: 0935d5588400 ("netfilter: nf_tables: asynchronous release") Reported-by: Taehee Yoo Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso Signed-off-by: Sasha Levin

netfilter: nft_compat: make lists per netns

2019-03-13T21:03:59+00:00

[ Upstream commit cf52572ebbd7189a1966c2b5fc34b97078cd1dce ] There are two problems with nft_compat since the netlink config plane uses a per-netns mutex: 1. Concurrent add/del accesses to the same list 2. accesses to a list element after it has been free'd already. This patch fixes the first problem. Freeing occurs from a work queue, after transaction mutexes have been released, i.e., it still possible for a new transaction (even from same net ns) to find the to-be-deleted expression in the list. The ->destroy functions are not allowed to have any such side effects, i.e. the list_del() in the destroy function is not allowed. This part of the problem is solved in the next patch. I tried to make this work by serializing list access via mutex and by moving list_del() to a deactivate callback, but Taehee spotted following race on this approach: NET #0 NET #1 >select_ops() ->init() ->select_ops() ->deactivate() ->destroy() nft_xt_put() kfree_rcu(xt, rcu_head); ->init() <-- use-after-free occurred. Unfortunately, we can't increment reference count in select_ops(), because we can't undo the refcount increase in case a different expression fails in the same batch. (The destroy hook will only be called in case the expression was initialized successfully). Fixes: f102d66b335a ("netfilter: nf_tables: use dedicated mutex to guard transactions") Reported-by: Taehee Yoo Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso Signed-off-by: Sasha Levin

netfilter: nft_compat: use refcnt_t type for nft_xt reference count

2019-03-13T21:03:59+00:00

[ Upstream commit 12c44aba6618b7f6c437076e5722237190f6cd5f ] Using standard integer type was fine while all operations on it were guarded by the nftnl subsys mutex. This isn't true anymore: 1. transactions are guarded only by a pernet mutex, so concurrent rule manipulation in different netns is racy 2. the ->destroy hook runs from a work queue after the transaction mutex has been released already. cpu0 cpu1 (net 1) cpu2 (net 2) kworker nft_compat->destroy nft_compat->init nft_compat->init if (--nft_xt->ref == 0) nft_xt->ref++ nft_xt->ref++ Switch to refcount_t. Doing this however only fixes a minor aspect, nft_compat also performs linked-list operations in an unsafe way. This is addressed in the next two patches. Fixes: f102d66b335a ("netfilter: nf_tables: use dedicated mutex to guard transactions") Fixes: 0935d5588400 ("netfilter: nf_tables: asynchronous release") Reported-by: Taehee Yoo Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso Signed-off-by: Sasha Levin

netfilter: nfnetlink_osf: add missing fmatch check

2019-02-27T09:09:58+00:00

commit 1a6a0951fc009f6d9fe8ebea2d2417d80d54097b upstream. When we check the tcp options of a packet and it doesn't match the current fingerprint, the tcp packet option pointer must be restored to its initial value in order to do the proper tcp options check for the next fingerprint. Here we can see an example. Assumming the following fingerprint base with two lines: S10:64:1:60:M*,S,T,N,W6: Linux:3.0::Linux 3.0 S20:64:1:60:M*,S,T,N,W7: Linux:4.19:arch:Linux 4.1 Where TCP options are the last field in the OS signature, all of them overlap except by the last one, ie. 'W6' versus 'W7'. In case a packet for Linux 4.19 kicks in, the osf finds no matching because the TCP options pointer is updated after checking for the TCP options in the first line. Therefore, reset pointer back to where it should be. Fixes: 11eeef41d5f6 ("netfilter: passive OS fingerprint xtables match") Signed-off-by: Fernando Fernandez Mancera Signed-off-by: Pablo Neira Ayuso Signed-off-by: Greg Kroah-Hartman

netfilter: nft_compat: use-after-free when deleting targets

2019-02-27T09:09:57+00:00

commit 753c111f655e38bbd52fc01321266633f022ebe2 upstream. Fetch pointer to module before target object is released. Fixes: 29e3880109e3 ("netfilter: nf_tables: fix use-after-free when deleting compat expressions") Fixes: 0ca743a55991 ("netfilter: nf_tables: add compatibility layer for x_tables") Signed-off-by: Pablo Neira Ayuso Signed-off-by: Greg Kroah-Hartman

netfilter: nf_tables: fix flush after rule deletion in the same batch

2019-02-27T09:09:57+00:00

commit 23b7ca4f745f21c2b9cfcb67fdd33733b3ae7e66 upstream. Flush after rule deletion bogusly hits -ENOENT. Skip rules that have been already from nft_delrule_by_chain() which is always called from the flush path. Fixes: cf9dc09d0949 ("netfilter: nf_tables: fix missing rules flushing per table") Reported-by: Phil Sutter Acked-by: Phil Sutter Signed-off-by: Pablo Neira Ayuso Signed-off-by: Greg Kroah-Hartman