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2022-01-21bpf: support BPF_PROG_QUERY for progs attached to sockmapDi Zhu1-7/+70
Right now there is no way to query whether BPF programs are attached to a sockmap or not. we can use the standard interface in libbpf to query, such as: bpf_prog_query(mapFd, BPF_SK_SKB_STREAM_PARSER, 0, NULL, ...); the mapFd is the fd of sockmap. Signed-off-by: Di Zhu <zhudi2@huawei.com> Acked-by: Yonghong Song <yhs@fb.com> Reviewed-by: Jakub Sitnicki <jakub@cloudflare.com> Link: https://lore.kernel.org/r/20220119014005.1209-1-zhudi2@huawei.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-01-05bpf, sockmap: Fix double bpf_prog_put on error case in map_linkJohn Fastabend1-8/+13
sock_map_link() is called to update a sockmap entry with a sk. But, if the sock_map_init_proto() call fails then we return an error to the map_update op against the sockmap. In the error path though we need to cleanup psock and dec the refcnt on any programs associated with the map, because we refcnt them early in the update process to ensure they are pinned for the psock. (This avoids a race where user deletes programs while also updating the map with new socks.) In current code we do the prog refcnt dec explicitely by calling bpf_prog_put() when the program was found in the map. But, after commit '38207a5e81230' in this error path we've already done the prog to psock assignment so the programs have a reference from the psock as well. This then causes the psock tear down logic, invoked by sk_psock_put() in the error path, to similarly call bpf_prog_put on the programs there. To be explicit this logic does the prog->psock assignment: if (msg_*) psock_set_prog(...) Then the error path under the out_progs label does a similar check and dec with: if (msg_*) bpf_prog_put(...) And the teardown logic sk_psock_put() does ... psock_set_prog(msg_*, NULL) ... triggering another bpf_prog_put(...). Then KASAN gives us this splat, found by syzbot because we've created an inbalance between bpf_prog_inc and bpf_prog_put calling put twice on the program. BUG: KASAN: vmalloc-out-of-bounds in __bpf_prog_put kernel/bpf/syscall.c:1812 [inline] BUG: KASAN: vmalloc-out-of-bounds in __bpf_prog_put kernel/bpf/syscall.c:1812 [inline] kernel/bpf/syscall.c:1829 BUG: KASAN: vmalloc-out-of-bounds in bpf_prog_put+0x8c/0x4f0 kernel/bpf/syscall.c:1829 kernel/bpf/syscall.c:1829 Read of size 8 at addr ffffc90000e76038 by task syz-executor020/3641 To fix clean up error path so it doesn't try to do the bpf_prog_put in the error path once progs are assigned then it relies on the normal psock tear down logic to do complete cleanup. For completness we also cover the case whereh sk_psock_init_strp() fails, but this is not expected because it indicates an incorrect socket type and should be caught earlier. Fixes: 38207a5e8123 ("bpf, sockmap: Attach map progs to psock early for feature probes") Reported-by: syzbot+bb73e71cf4b8fd376a4f@syzkaller.appspotmail.com Signed-off-by: John Fastabend <john.fastabend@gmail.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20220104214645.290900-1-john.fastabend@gmail.com
2021-12-19bpf: Introduce MEM_RDONLY flagHao Luo1-1/+1
This patch introduce a flag MEM_RDONLY to tag a reg value pointing to read-only memory. It makes the following changes: 1. PTR_TO_RDWR_BUF -> PTR_TO_BUF 2. PTR_TO_RDONLY_BUF -> PTR_TO_BUF | MEM_RDONLY Signed-off-by: Hao Luo <haoluo@google.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20211217003152.48334-6-haoluo@google.com
2021-12-19bpf: Replace PTR_TO_XXX_OR_NULL with PTR_TO_XXX | PTR_MAYBE_NULLHao Luo1-1/+1
We have introduced a new type to make bpf_reg composable, by allocating bits in the type to represent flags. One of the flags is PTR_MAYBE_NULL which indicates a pointer may be NULL. This patch switches the qualified reg_types to use this flag. The reg_types changed in this patch include: 1. PTR_TO_MAP_VALUE_OR_NULL 2. PTR_TO_SOCKET_OR_NULL 3. PTR_TO_SOCK_COMMON_OR_NULL 4. PTR_TO_TCP_SOCK_OR_NULL 5. PTR_TO_BTF_ID_OR_NULL 6. PTR_TO_MEM_OR_NULL 7. PTR_TO_RDONLY_BUF_OR_NULL 8. PTR_TO_RDWR_BUF_OR_NULL Signed-off-by: Hao Luo <haoluo@google.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/r/20211217003152.48334-5-haoluo@google.com
2021-11-20bpf, sockmap: Re-evaluate proto ops when psock is removed from sockmapJohn Fastabend1-1/+4
When a sock is added to a sock map we evaluate what proto op hooks need to be used. However, when the program is removed from the sock map we have not been evaluating if that changes the required program layout. Before the patch listed in the 'fixes' tag this was not causing failures because the base program set handles all cases. Specifically, the case with a stream parser and the case with out a stream parser are both handled. With the fix below we identified a race when running with a proto op that attempts to read skbs off both the stream parser and the skb->receive_queue. Namely, that a race existed where when the stream parser is empty checking the skb->receive_queue from recvmsg at the precies moment when the parser is paused and the receive_queue is not empty could result in skipping the stream parser. This may break a RX policy depending on the parser to run. The fix tag then loads a specific proto ops that resolved this race. But, we missed removing that proto ops recv hook when the sock is removed from the sockmap. The result is the stream parser is stopped so no more skbs will be aggregated there, but the hook and BPF program continues to be attached on the psock. User space will then get an EBUSY when trying to read the socket because the recvmsg() handler is now waiting on a stopped stream parser. To fix we rerun the proto ops init() function which will look at the new set of progs attached to the psock and rest the proto ops hook to the correct handlers. And in the above case where we remove the sock from the sock map the RX prog will no longer be listed so the proto ops is removed. Fixes: c5d2177a72a16 ("bpf, sockmap: Fix race in ingress receive verdict with redirect to self") Signed-off-by: John Fastabend <john.fastabend@gmail.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20211119181418.353932-3-john.fastabend@gmail.com
2021-11-20bpf, sockmap: Attach map progs to psock early for feature probesJohn Fastabend1-4/+6
When a TCP socket is added to a sock map we look at the programs attached to the map to determine what proto op hooks need to be changed. Before the patch in the 'fixes' tag there were only two categories -- the empty set of programs or a TX policy. In any case the base set handled the receive case. After the fix we have an optimized program for receive that closes a small, but possible, race on receive. This program is loaded only when the map the psock is being added to includes a RX policy. Otherwise, the race is not possible so we don't need to handle the race condition. In order for the call to sk_psock_init() to correctly evaluate the above conditions all progs need to be set in the psock before the call. However, in the current code this is not the case. We end up evaluating the requirements on the old prog state. If your psock is attached to multiple maps -- for example a tx map and rx map -- then the second update would pull in the correct maps. But, the other pattern with a single rx enabled map the correct receive hooks are not used. The result is the race fixed by the patch in the fixes tag below may still be seen in this case. To fix we simply set all psock->progs before doing the call into sock_map_init(). With this the init() call gets the full list of programs and chooses the correct proto ops on the first iteration instead of requiring the second update to pull them in. This fixes the race case when only a single map is used. Fixes: c5d2177a72a16 ("bpf, sockmap: Fix race in ingress receive verdict with redirect to self") Signed-off-by: John Fastabend <john.fastabend@gmail.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20211119181418.353932-2-john.fastabend@gmail.com
2021-11-09bpf, sockmap: Use stricter sk state checks in sk_lookup_assignJohn Fastabend1-6/+0
In order to fix an issue with sockets in TCP sockmap redirect cases we plan to allow CLOSE state sockets to exist in the sockmap. However, the check in bpf_sk_lookup_assign() currently only invalidates sockets in the TCP_ESTABLISHED case relying on the checks on sockmap insert to ensure we never SOCK_CLOSE state sockets in the map. To prepare for this change we flip the logic in bpf_sk_lookup_assign() to explicitly test for the accepted cases. Namely, a tcp socket in TCP_LISTEN or a udp socket in TCP_CLOSE state. This also makes the code more resilent to future changes. Suggested-by: Jakub Sitnicki <jakub@cloudflare.com> Signed-off-by: John Fastabend <john.fastabend@gmail.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Reviewed-by: Jakub Sitnicki <jakub@cloudflare.com> Link: https://lore.kernel.org/bpf/20211103204736.248403-2-john.fastabend@gmail.com
2021-08-17af_unix: Add unix_stream_proto for sockmapJiang Wang1-0/+1
Previously, sockmap for AF_UNIX protocol only supports dgram type. This patch add unix stream type support, which is similar to unix_dgram_proto. To support sockmap, dgram and stream cannot share the same unix_proto anymore, because they have different implementations, such as unhash for stream type (which will remove closed or disconnected sockets from the map), so rename unix_proto to unix_dgram_proto and add a new unix_stream_proto. Also implement stream related sockmap functions. And add dgram key words to those dgram specific functions. Signed-off-by: Jiang Wang <jiang.wang@bytedance.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Reviewed-by: Cong Wang <cong.wang@bytedance.com> Acked-by: Jakub Sitnicki <jakub@cloudflare.com> Acked-by: John Fastabend <john.fastabend@gmail.com> Link: https://lore.kernel.org/bpf/20210816190327.2739291-3-jiang.wang@bytedance.com
2021-07-16af_unix: Implement ->psock_update_sk_prot()Cong Wang1-0/+1
Now we can implement unix_bpf_update_proto() to update sk_prot, especially prot->close(). Signed-off-by: Cong Wang <cong.wang@bytedance.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20210704190252.11866-7-xiyou.wangcong@gmail.com
2021-07-16sock_map: Lift socket state restriction for datagram socketsCong Wang1-20/+1
TCP and other connection oriented sockets have accept() for each incoming connection on the server side, hence they can just insert those fd's from accept() to sockmap, which are of course established. Now with datagram sockets begin to support sockmap and redirection, the restriction is no longer applicable to them, as they have no accept(). So we have to lift this restriction for them. This is fine, because inside bpf_sk_redirect_map() we still have another socket status check, sock_map_redirect_allowed(), as a guard. This also means they do not have to be removed from sockmap when disconnecting. Signed-off-by: Cong Wang <cong.wang@bytedance.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20210704190252.11866-3-xiyou.wangcong@gmail.com
2021-06-22bpf: Fix integer overflow in argument calculation for bpf_map_area_allocBui Quang Minh1-1/+1
In 32-bit architecture, the result of sizeof() is a 32-bit integer so the expression becomes the multiplication between 2 32-bit integer which can potentially leads to integer overflow. As a result, bpf_map_area_alloc() allocates less memory than needed. Fix this by casting 1 operand to u64. Fixes: 0d2c4f964050 ("bpf: Eliminate rlimit-based memory accounting for sockmap and sockhash maps") Fixes: 99c51064fb06 ("devmap: Use bpf_map_area_alloc() for allocating hash buckets") Fixes: 546ac1ffb70d ("bpf: add devmap, a map for storing net device references") Signed-off-by: Bui Quang Minh <minhquangbui99@gmail.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20210613143440.71975-1-minhquangbui99@gmail.com
2021-04-12sock_map: Fix a potential use-after-free in sock_map_close()Cong Wang1-1/+2
The last refcnt of the psock can be gone right after sock_map_remove_links(), so sk_psock_stop() could trigger a UAF. The reason why I placed sk_psock_stop() there is to avoid RCU read critical section, and more importantly, some callee of sock_map_remove_links() is supposed to be called with RCU read lock, we can not simply get rid of RCU read lock here. Therefore, the only choice we have is to grab an additional refcnt with sk_psock_get() and put it back after sk_psock_stop(). Fixes: 799aa7f98d53 ("skmsg: Avoid lock_sock() in sk_psock_backlog()") Reported-by: syzbot+7b6548ae483d6f4c64ae@syzkaller.appspotmail.com Signed-off-by: Cong Wang <cong.wang@bytedance.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: John Fastabend <john.fastabend@gmail.com> Acked-by: Jakub Sitnicki <jakub@cloudflare.com> Link: https://lore.kernel.org/bpf/20210408030556.45134-1-xiyou.wangcong@gmail.com
2021-04-12skmsg: Pass psock pointer to ->psock_update_sk_prot()Cong Wang1-1/+1
Using sk_psock() to retrieve psock pointer from sock requires RCU read lock, but we already get psock pointer before calling ->psock_update_sk_prot() in both cases, so we can just pass it without bothering sk_psock(). Fixes: 8a59f9d1e3d4 ("sock: Introduce sk->sk_prot->psock_update_sk_prot()") Reported-by: syzbot+320a3bc8d80f478c37e4@syzkaller.appspotmail.com Signed-off-by: Cong Wang <cong.wang@bytedance.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Tested-by: syzbot+320a3bc8d80f478c37e4@syzkaller.appspotmail.com Reviewed-by: Jakub Sitnicki <jakub@cloudflare.com> Acked-by: John Fastabend <john.fastabend@gmail.com> Link: https://lore.kernel.org/bpf/20210407032111.33398-1-xiyou.wangcong@gmail.com
2021-04-01sock_map: Update sock type checks for UDPCong Wang1-1/+4
Now UDP supports sockmap and redirection, we can safely update the sock type checks for it accordingly. Signed-off-by: Cong Wang <cong.wang@bytedance.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: John Fastabend <john.fastabend@gmail.com> Link: https://lore.kernel.org/bpf/20210331023237.41094-15-xiyou.wangcong@gmail.com
2021-04-01sock: Introduce sk->sk_prot->psock_update_sk_prot()Cong Wang1-20/+4
Currently sockmap calls into each protocol to update the struct proto and replace it. This certainly won't work when the protocol is implemented as a module, for example, AF_UNIX. Introduce a new ops sk->sk_prot->psock_update_sk_prot(), so each protocol can implement its own way to replace the struct proto. This also helps get rid of symbol dependencies on CONFIG_INET. Signed-off-by: Cong Wang <cong.wang@bytedance.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20210331023237.41094-11-xiyou.wangcong@gmail.com
2021-04-01sock_map: Introduce BPF_SK_SKB_VERDICTCong Wang1-0/+28
Reusing BPF_SK_SKB_STREAM_VERDICT is possible but its name is confusing and more importantly we still want to distinguish them from user-space. So we can just reuse the stream verdict code but introduce a new type of eBPF program, skb_verdict. Users are not allowed to attach stream_verdict and skb_verdict programs to the same map. Signed-off-by: Cong Wang <cong.wang@bytedance.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: John Fastabend <john.fastabend@gmail.com> Link: https://lore.kernel.org/bpf/20210331023237.41094-10-xiyou.wangcong@gmail.com
2021-04-01sock_map: Kill sock_map_link_no_progs()Cong Wang1-40/+15
Now we can fold sock_map_link_no_progs() into sock_map_link() and get rid of sock_map_link_no_progs(). Signed-off-by: Cong Wang <cong.wang@bytedance.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20210331023237.41094-9-xiyou.wangcong@gmail.com
2021-04-01sock_map: Simplify sock_map_link() a bitCong Wang1-4/+5
sock_map_link() passes down map progs, but it is confusing to see both map progs and psock progs. Make the map progs more obvious by retrieving it directly with sock_map_progs() inside sock_map_link(). Now it is aligned with sock_map_link_no_progs() too. Signed-off-by: Cong Wang <cong.wang@bytedance.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: John Fastabend <john.fastabend@gmail.com> Link: https://lore.kernel.org/bpf/20210331023237.41094-8-xiyou.wangcong@gmail.com
2021-04-01skmsg: Avoid lock_sock() in sk_psock_backlog()Cong Wang1-0/+1
We do not have to lock the sock to avoid losing sk_socket, instead we can purge all the ingress queues when we close the socket. Sending or receiving packets after orphaning socket makes no sense. We do purge these queues when psock refcnt reaches zero but here we want to purge them explicitly in sock_map_close(). There are also some nasty race conditions on testing bit SK_PSOCK_TX_ENABLED and queuing/canceling the psock work, we can expand psock->ingress_lock a bit to protect them too. As noticed by John, we still have to lock the psock->work, because the same work item could be running concurrently on different CPU's. Signed-off-by: Cong Wang <cong.wang@bytedance.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: John Fastabend <john.fastabend@gmail.com> Link: https://lore.kernel.org/bpf/20210331023237.41094-5-xiyou.wangcong@gmail.com
2021-02-26sock_map: Make sock_map_prog_update() staticCong Wang1-2/+5
It is only used within sock_map.c so can become static. Suggested-by: Jakub Sitnicki <jakub@cloudflare.com> Signed-off-by: Cong Wang <cong.wang@bytedance.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Jakub Sitnicki <jakub@cloudflare.com> Link: https://lore.kernel.org/bpf/20210223184934.6054-7-xiyou.wangcong@gmail.com
2021-02-26sock_map: Rename skb_parser and skb_verdictCong Wang1-30/+30
These two eBPF programs are tied to BPF_SK_SKB_STREAM_PARSER and BPF_SK_SKB_STREAM_VERDICT, rename them to reflect the fact they are only used for TCP. And save the name 'skb_verdict' for general use later. Signed-off-by: Cong Wang <cong.wang@bytedance.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Reviewed-by: Lorenz Bauer <lmb@cloudflare.com> Acked-by: John Fastabend <john.fastabend@gmail.com> Acked-by: Jakub Sitnicki <jakub@cloudflare.com> Link: https://lore.kernel.org/bpf/20210223184934.6054-6-xiyou.wangcong@gmail.com
2021-02-26skmsg: Move sk_redir from TCP_SKB_CB to skbCong Wang1-6/+2
Currently TCP_SKB_CB() is hard-coded in skmsg code, it certainly does not work for any other non-TCP protocols. We can move them to skb ext, but it introduces a memory allocation on fast path. Fortunately, we only need to a word-size to store all the information, because the flags actually only contains 1 bit so can be just packed into the lowest bit of the "pointer", which is stored as unsigned long. Inside struct sk_buff, '_skb_refdst' can be reused because skb dst is no longer needed after ->sk_data_ready() so we can just drop it. Signed-off-by: Cong Wang <cong.wang@bytedance.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: John Fastabend <john.fastabend@gmail.com> Acked-by: Jakub Sitnicki <jakub@cloudflare.com> Link: https://lore.kernel.org/bpf/20210223184934.6054-5-xiyou.wangcong@gmail.com
2021-02-26skmsg: Get rid of struct sk_psock_parserCong Wang1-4/+4
struct sk_psock_parser is embedded in sk_psock, it is unnecessary as skb verdict also uses ->saved_data_ready. We can simply fold these fields into sk_psock, and get rid of ->enabled. Signed-off-by: Cong Wang <cong.wang@bytedance.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: John Fastabend <john.fastabend@gmail.com> Acked-by: Jakub Sitnicki <jakub@cloudflare.com> Link: https://lore.kernel.org/bpf/20210223184934.6054-3-xiyou.wangcong@gmail.com
2021-02-26bpf: Clean up sockmap related KconfigsCong Wang1-0/+2
As suggested by John, clean up sockmap related Kconfigs: Reduce the scope of CONFIG_BPF_STREAM_PARSER down to TCP stream parser, to reflect its name. Make the rest sockmap code simply depend on CONFIG_BPF_SYSCALL and CONFIG_INET, the latter is still needed at this point because of TCP/UDP proto update. And leave CONFIG_NET_SOCK_MSG untouched, as it is used by non-sockmap cases. Signed-off-by: Cong Wang <cong.wang@bytedance.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Reviewed-by: Lorenz Bauer <lmb@cloudflare.com> Acked-by: John Fastabend <john.fastabend@gmail.com> Acked-by: Jakub Sitnicki <jakub@cloudflare.com> Link: https://lore.kernel.org/bpf/20210223184934.6054-2-xiyou.wangcong@gmail.com
2021-01-09bpf: Replace fput with sockfd_put in sock mapZheng Yongjun1-1/+1
The function sockfd_lookup uses fget on the value that is stored in the file field of the returned structure, so fput should ultimately be applied to this value. This can be done directly, but it seems better to use the specific macro sockfd_put, which does the same thing. The cleanup was done using the following semantic patch: (http://www.emn.fr/x-info/coccinelle/) // <smpl> @@ expression s; @@ s = sockfd_lookup(...) ... + sockfd_put(s); ?- fput(s->file); // </smpl> Signed-off-by: Zheng Yongjun <zhengyongjun3@huawei.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20201229134834.22962-1-zhengyongjun3@huawei.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2020-12-03bpf: Eliminate rlimit-based memory accounting for sockmap and sockhash mapsRoman Gushchin1-27/+6
Do not use rlimit-based memory accounting for sockmap and sockhash maps. It has been replaced with the memcg-based memory accounting. Signed-off-by: Roman Gushchin <guro@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Song Liu <songliubraving@fb.com> Link: https://lore.kernel.org/bpf/20201201215900.3569844-29-guro@fb.com
2020-12-03bpf: Refine memcg-based memory accounting for sockmap and sockhash mapsRoman Gushchin1-4/+5
Include internal metadata into the memcg-based memory accounting. Also include the memory allocated on updating an element. Signed-off-by: Roman Gushchin <guro@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20201201215900.3569844-17-guro@fb.com
2020-10-15net, sockmap: Don't call bpf_prog_put() on NULL pointerAlex Dewar1-7/+9
If bpf_prog_inc_not_zero() fails for skb_parser, then bpf_prog_put() is called unconditionally on skb_verdict, even though it may be NULL. Fix and tidy up error path. Fixes: 743df8b7749f ("bpf, sockmap: Check skb_verdict and skb_parser programs explicitly") Addresses-Coverity-ID: 1497799: Null pointer dereferences (FORWARD_NULL) Signed-off-by: Alex Dewar <alex.dewar90@gmail.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Jakub Sitnicki <jakub@cloudflare.com> Acked-by: John Fastabend <john.fastabend@gmail.com> Link: https://lore.kernel.org/bpf/20201012170952.60750-1-alex.dewar90@gmail.com
2020-10-15bpf, sockmap: Add locking annotations to iteratorLorenz Bauer1-0/+8
The sparse checker currently outputs the following warnings: include/linux/rcupdate.h:632:9: sparse: sparse: context imbalance in 'sock_hash_seq_start' - wrong count at exit include/linux/rcupdate.h:632:9: sparse: sparse: context imbalance in 'sock_map_seq_start' - wrong count at exit Add the necessary __acquires and __release annotations to make the iterator locking schema palatable to sparse. Also add __must_hold for good measure. The kernel codebase uses both __acquires(rcu) and __acquires(RCU). I couldn't find any guidance which one is preferred, so I used what is easier to type out. Fixes: 0365351524d7 ("net: Allow iterating sockmap and sockhash") Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: Lorenz Bauer <lmb@cloudflare.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: John Fastabend <john.fastabend@gmail.com> Acked-by: Jakub Sitnicki <jakub@cloudflare.com> Link: https://lore.kernel.org/bpf/20201012091850.67452-1-lmb@cloudflare.com
2020-10-12bpf, sockmap: Allow skipping sk_skb parser programJohn Fastabend1-7/+15
Currently, we often run with a nop parser namely one that just does this, 'return skb->len'. This happens when either our verdict program can handle streaming data or it is only looking at socket data such as IP addresses and other metadata associated with the flow. The second case is common for a L3/L4 proxy for instance. So lets allow loading programs without the parser then we can skip the stream parser logic and avoid having to add a BPF program that is effectively a nop. Signed-off-by: John Fastabend <john.fastabend@gmail.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/160239297866.8495.13345662302749219672.stgit@john-Precision-5820-Tower
2020-10-12bpf, sockmap: Check skb_verdict and skb_parser programs explicitlyJohn Fastabend1-7/+8
We are about to allow skb_verdict to run without skb_parser programs as a first step change code to check each program type specifically. This should be a mechanical change without any impact to actual result. Signed-off-by: John Fastabend <john.fastabend@gmail.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/160239294756.8495.5796595770890272219.stgit@john-Precision-5820-Tower
2020-09-30bpf, net: Rework cookie generator as per-cpu oneDaniel Borkmann1-2/+2
With its use in BPF, the cookie generator can be called very frequently in particular when used out of cgroup v2 hooks (e.g. connect / sendmsg) and attached to the root cgroup, for example, when used in v1/v2 mixed environments. In particular, when there's a high churn on sockets in the system there can be many parallel requests to the bpf_get_socket_cookie() and bpf_get_netns_cookie() helpers which then cause contention on the atomic counter. As similarly done in f991bd2e1421 ("fs: introduce a per-cpu last_ino allocator"), add a small helper library that both can use for the 64 bit counters. Given this can be called from different contexts, we also need to deal with potential nested calls even though in practice they are considered extremely rare. One idea as suggested by Eric Dumazet was to use a reverse counter for this situation since we don't expect 64 bit overflows anyways; that way, we can avoid bigger gaps in the 64 bit counter space compared to just batch-wise increase. Even on machines with small number of cores (e.g. 4) the cookie generation shrinks from min/max/med/avg (ns) of 22/50/40/38.9 down to 10/35/14/17.3 when run in parallel from multiple CPUs. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Reviewed-by: Eric Dumazet <edumazet@google.com> Acked-by: Martin KaFai Lau <kafai@fb.com> Cc: Eric Dumazet <eric.dumazet@gmail.com> Link: https://lore.kernel.org/bpf/8a80b8d27d3c49f9a14e1d5213c19d8be87d1dc8.1601477936.git.daniel@iogearbox.net
2020-09-29bpf: sockmap: Enable map_update_elem from bpf_iterLorenz Bauer1-0/+3
Allow passing a pointer to a BTF struct sock_common* when updating a sockmap or sockhash. Since BTF pointers can fault and therefore be NULL at runtime we need to add an additional !sk check to sock_map_update_elem. Since we may be passed a request or timewait socket we also need to check sk_fullsock. Doing this allows calling map_update_elem on sockmap from bpf_iter context, which uses BTF pointers. Signed-off-by: Lorenz Bauer <lmb@cloudflare.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20200928090805.23343-2-lmb@cloudflare.com
2020-09-10net: Allow iterating sockmap and sockhashLorenz Bauer1-2/+278
Add bpf_iter support for sockmap / sockhash, based on the bpf_sk_storage and hashtable implementation. sockmap and sockhash share the same iteration context: a pointer to an arbitrary key and a pointer to a socket. Both pointers may be NULL, and so BPF has to perform a NULL check before accessing them. Technically it's not possible for sockhash iteration to yield a NULL socket, but we ignore this to be able to use a single iteration point. Iteration will visit all keys that remain unmodified during the lifetime of the iterator. It may or may not visit newly added ones. Switch from using rcu_dereference_raw to plain rcu_dereference, so we gain another guard rail if CONFIG_PROVE_RCU is enabled. Signed-off-by: Lorenz Bauer <lmb@cloudflare.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/bpf/20200909162712.221874-3-lmb@cloudflare.com
2020-09-10net: sockmap: Remove unnecessary sk_fullsock checksLorenz Bauer1-2/+2
The lookup paths for sockmap and sockhash currently include a check that returns NULL if the socket we just found is not a full socket. However, this check is not necessary. On insertion we ensure that we have a full socket (caveat around sock_ops), so request sockets are not a problem. Time-wait sockets are allocated separate from the original socket and then fed into the hashdance. They don't affect the sockets already stored in the sockmap. Suggested-by: Jakub Sitnicki <jakub@cloudflare.com> Signed-off-by: Lorenz Bauer <lmb@cloudflare.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20200909162712.221874-2-lmb@cloudflare.com
2020-08-28bpf: Add map_meta_equal map opsMartin KaFai Lau1-0/+2
Some properties of the inner map is used in the verification time. When an inner map is inserted to an outer map at runtime, bpf_map_meta_equal() is currently used to ensure those properties of the inserting inner map stays the same as the verification time. In particular, the current bpf_map_meta_equal() checks max_entries which turns out to be too restrictive for most of the maps which do not use max_entries during the verification time. It limits the use case that wants to replace a smaller inner map with a larger inner map. There are some maps do use max_entries during verification though. For example, the map_gen_lookup in array_map_ops uses the max_entries to generate the inline lookup code. To accommodate differences between maps, the map_meta_equal is added to bpf_map_ops. Each map-type can decide what to check when its map is used as an inner map during runtime. Also, some map types cannot be used as an inner map and they are currently black listed in bpf_map_meta_alloc() in map_in_map.c. It is not unusual that the new map types may not aware that such blacklist exists. This patch enforces an explicit opt-in and only allows a map to be used as an inner map if it has implemented the map_meta_equal ops. It is based on the discussion in [1]. All maps that support inner map has its map_meta_equal points to bpf_map_meta_equal in this patch. A later patch will relax the max_entries check for most maps. bpf_types.h counts 28 map types. This patch adds 23 ".map_meta_equal" by using coccinelle. -5 for BPF_MAP_TYPE_PROG_ARRAY BPF_MAP_TYPE_(PERCPU)_CGROUP_STORAGE BPF_MAP_TYPE_STRUCT_OPS BPF_MAP_TYPE_ARRAY_OF_MAPS BPF_MAP_TYPE_HASH_OF_MAPS The "if (inner_map->inner_map_meta)" check in bpf_map_meta_alloc() is moved such that the same error is returned. [1]: https://lore.kernel.org/bpf/20200522022342.899756-1-kafai@fb.com/ Signed-off-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20200828011806.1970400-1-kafai@fb.com
2020-08-22bpf: sockmap: Allow update from BPFLorenz Bauer1-0/+24
Allow calling bpf_map_update_elem on sockmap and sockhash from a BPF context. The synchronization required for this is a bit fiddly: we need to prevent the socket from changing its state while we add it to the sockmap, since we rely on getting a callback via sk_prot->unhash. However, we can't just lock_sock like in sock_map_sk_acquire because that might sleep. So instead we disable softirq processing and use bh_lock_sock to prevent further modification. Yet, this is still not enough. BPF can be called in contexts where the current CPU might have locked a socket. If the BPF can get a hold of such a socket, inserting it into a sockmap would lead to a deadlock. One straight forward example are sock_ops programs that have ctx->sk, but the same problem exists for kprobes, etc. We deal with this by allowing sockmap updates only from known safe contexts. Improper usage is rejected by the verifier. I've audited the enabled contexts to make sure they can't run in a locked context. It's possible that CGROUP_SKB and others are safe as well, but the auditing here is much more difficult. In any case, we can extend the safe contexts when the need arises. Signed-off-by: Lorenz Bauer <lmb@cloudflare.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/bpf/20200821102948.21918-6-lmb@cloudflare.com
2020-08-22bpf: sockmap: Call sock_map_update_elem directlyLorenz Bauer1-4/+2
Don't go via map->ops to call sock_map_update_elem, since we know what function to call in bpf_map_update_value. Since we currently don't allow calling map_update_elem from BPF context, we can remove ops->map_update_elem and rename the function to sock_map_update_elem_sys. Signed-off-by: Lorenz Bauer <lmb@cloudflare.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Yonghong Song <yhs@fb.com> Acked-by: John Fastabend <john.fastabend@gmail.com> Link: https://lore.kernel.org/bpf/20200821102948.21918-4-lmb@cloudflare.com
2020-08-22bpf: sockmap: Merge sockmap and sockhash update functionsLorenz Bauer1-42/+7
Merge the two very similar functions sock_map_update_elem and sock_hash_update_elem into one. Signed-off-by: Lorenz Bauer <lmb@cloudflare.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: John Fastabend <john.fastabend@gmail.com> Acked-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/bpf/20200821102948.21918-3-lmb@cloudflare.com
2020-08-22net: sk_msg: Simplify sk_psock initializationLorenz Bauer1-10/+4
Initializing psock->sk_proto and other saved callbacks is only done in sk_psock_update_proto, after sk_psock_init has returned. The logic for this is difficult to follow, and needlessly complex. Instead, initialize psock->sk_proto whenever we allocate a new psock. Additionally, assert the following invariants: * The SK has no ULP: ULP does it's own finagling of sk->sk_prot * sk_user_data is unused: we need it to store sk_psock Protect our access to sk_user_data with sk_callback_lock, which is what other users like reuseport arrays, etc. do. The result is that an sk_psock is always fully initialized, and that psock->sk_proto is always the "original" struct proto. The latter allows us to use psock->sk_proto when initializing IPv6 TCP / UDP callbacks for sockmap. Signed-off-by: Lorenz Bauer <lmb@cloudflare.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: John Fastabend <john.fastabend@gmail.com> Link: https://lore.kernel.org/bpf/20200821102948.21918-2-lmb@cloudflare.com
2020-07-11Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netDavid S. Miller1-5/+48
All conflicts seemed rather trivial, with some guidance from Saeed Mameed on the tc_ct.c one. Signed-off-by: David S. Miller <davem@davemloft.net>
2020-06-30bpf: sockmap: Require attach_bpf_fd when detaching a programLorenz Bauer1-5/+45
The sockmap code currently ignores the value of attach_bpf_fd when detaching a program. This is contrary to the usual behaviour of checking that attach_bpf_fd represents the currently attached program. Ensure that attach_bpf_fd is indeed the currently attached program. It turns out that all sockmap selftests already do this, which indicates that this is unlikely to cause breakage. Fixes: 604326b41a6f ("bpf, sockmap: convert to generic sk_msg interface") Signed-off-by: Lorenz Bauer <lmb@cloudflare.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20200629095630.7933-5-lmb@cloudflare.com
2020-06-30bpf: sockmap: Check value of unused args to BPF_PROG_ATTACHLorenz Bauer1-0/+3
Using BPF_PROG_ATTACH on a sockmap program currently understands no flags or replace_bpf_fd, but accepts any value. Return EINVAL instead. Fixes: 604326b41a6f ("bpf, sockmap: convert to generic sk_msg interface") Signed-off-by: Lorenz Bauer <lmb@cloudflare.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20200629095630.7933-4-lmb@cloudflare.com
2020-06-22bpf: Set map_btf_{name, id} for all map typesAndrey Ignatov1-0/+6
Set map_btf_name and map_btf_id for all map types so that map fields can be accessed by bpf programs. Signed-off-by: Andrey Ignatov <rdna@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: John Fastabend <john.fastabend@gmail.com> Acked-by: Martin KaFai Lau <kafai@fb.com> Link: https://lore.kernel.org/bpf/a825f808f22af52b018dbe82f1c7d29dab5fc978.1592600985.git.rdna@fb.com
2020-06-22bpf: Rename bpf_htab to bpf_shtab in sock_mapAndrey Ignatov1-41/+41
There are two different `struct bpf_htab` in bpf code in the following files: - kernel/bpf/hashtab.c - net/core/sock_map.c It makes it impossible to find proper btf_id by name = "bpf_htab" and kind = BTF_KIND_STRUCT what is needed to support access to map ptr so that bpf program can access `struct bpf_htab` fields. To make it possible one of the struct-s should be renamed, sock_map.c looks like a better candidate for rename since it's specialized version of hashtab. Rename it to bpf_shtab ("sh" stands for Sock Hash). Signed-off-by: Andrey Ignatov <rdna@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: John Fastabend <john.fastabend@gmail.com> Acked-by: Martin KaFai Lau <kafai@fb.com> Link: https://lore.kernel.org/bpf/c006a639e03c64ca50fc87c4bb627e0bfba90f4e.1592600985.git.rdna@fb.com
2020-06-13bpf: Fix memlock accounting for sock_hashAndrey Ignatov1-0/+4
Add missed bpf_map_charge_init() in sock_hash_alloc() and correspondingly bpf_map_charge_finish() on ENOMEM. It was found accidentally while working on unrelated selftest that checks "map->memory.pages > 0" is true for all map types. Before: # bpftool m l ... 3692: sockhash name m_sockhash flags 0x0 key 4B value 4B max_entries 8 memlock 0B After: # bpftool m l ... 84: sockmap name m_sockmap flags 0x0 key 4B value 4B max_entries 8 memlock 4096B Fixes: 604326b41a6f ("bpf, sockmap: convert to generic sk_msg interface") Signed-off-by: Andrey Ignatov <rdna@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20200612000857.2881453-1-rdna@fb.com
2020-06-13bpf: sockmap: Don't attach programs to UDP socketsLorenz Bauer1-4/+6
The stream parser infrastructure isn't set up to deal with UDP sockets, so we mustn't try to attach programs to them. I remember making this change at some point, but I must have lost it while rebasing or something similar. Fixes: 7b98cd42b049 ("bpf: sockmap: Add UDP support") Signed-off-by: Lorenz Bauer <lmb@cloudflare.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Jakub Sitnicki <jakub@cloudflare.com> Link: https://lore.kernel.org/bpf/20200611172520.327602-1-lmb@cloudflare.com
2020-06-09bpf, sockhash: Synchronize delete from bucket list on map freeJakub Sitnicki1-2/+21
We can end up modifying the sockhash bucket list from two CPUs when a sockhash is being destroyed (sock_hash_free) on one CPU, while a socket that is in the sockhash is unlinking itself from it on another CPU it (sock_hash_delete_from_link). This results in accessing a list element that is in an undefined state as reported by KASAN: | ================================================================== | BUG: KASAN: wild-memory-access in sock_hash_free+0x13c/0x280 | Write of size 8 at addr dead000000000122 by task kworker/2:1/95 | | CPU: 2 PID: 95 Comm: kworker/2:1 Not tainted 5.7.0-rc7-02961-ge22c35ab0038-dirty #691 | Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS ?-20190727_073836-buildvm-ppc64le-16.ppc.fedoraproject.org-3.fc31 04/01/2014 | Workqueue: events bpf_map_free_deferred | Call Trace: | dump_stack+0x97/0xe0 | ? sock_hash_free+0x13c/0x280 | __kasan_report.cold+0x5/0x40 | ? mark_lock+0xbc1/0xc00 | ? sock_hash_free+0x13c/0x280 | kasan_report+0x38/0x50 | ? sock_hash_free+0x152/0x280 | sock_hash_free+0x13c/0x280 | bpf_map_free_deferred+0xb2/0xd0 | ? bpf_map_charge_finish+0x50/0x50 | ? rcu_read_lock_sched_held+0x81/0xb0 | ? rcu_read_lock_bh_held+0x90/0x90 | process_one_work+0x59a/0xac0 | ? lock_release+0x3b0/0x3b0 | ? pwq_dec_nr_in_flight+0x110/0x110 | ? rwlock_bug.part.0+0x60/0x60 | worker_thread+0x7a/0x680 | ? _raw_spin_unlock_irqrestore+0x4c/0x60 | kthread+0x1cc/0x220 | ? process_one_work+0xac0/0xac0 | ? kthread_create_on_node+0xa0/0xa0 | ret_from_fork+0x24/0x30 | ================================================================== Fix it by reintroducing spin-lock protected critical section around the code that removes the elements from the bucket on sockhash free. To do that we also need to defer processing of removed elements, until out of atomic context so that we can unlink the socket from the map when holding the sock lock. Fixes: 90db6d772f74 ("bpf, sockmap: Remove bucket->lock from sock_{hash|map}_free") Reported-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: John Fastabend <john.fastabend@gmail.com> Link: https://lore.kernel.org/bpf/20200607205229.2389672-3-jakub@cloudflare.com
2020-06-09bpf, sockhash: Fix memory leak when unlinking sockets in sock_hash_freeJakub Sitnicki1-0/+1
When sockhash gets destroyed while sockets are still linked to it, we will walk the bucket lists and delete the links. However, we are not freeing the list elements after processing them, leaking the memory. The leak can be triggered by close()'ing a sockhash map when it still contains sockets, and observed with kmemleak: unreferenced object 0xffff888116e86f00 (size 64): comm "race_sock_unlin", pid 223, jiffies 4294731063 (age 217.404s) hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 81 de e8 41 00 00 00 00 c0 69 2f 15 81 88 ff ff ...A.....i/..... backtrace: [<00000000dd089ebb>] sock_hash_update_common+0x4ca/0x760 [<00000000b8219bd5>] sock_hash_update_elem+0x1d2/0x200 [<000000005e2c23de>] __do_sys_bpf+0x2046/0x2990 [<00000000d0084618>] do_syscall_64+0xad/0x9a0 [<000000000d96f263>] entry_SYSCALL_64_after_hwframe+0x49/0xb3 Fix it by freeing the list element when we're done with it. Fixes: 604326b41a6f ("bpf, sockmap: convert to generic sk_msg interface") Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: John Fastabend <john.fastabend@gmail.com> Link: https://lore.kernel.org/bpf/20200607205229.2389672-2-jakub@cloudflare.com
2020-04-30bpf: Allow bpf_map_lookup_elem for SOCKMAP and SOCKHASHJakub Sitnicki1-2/+16
White-list map lookup for SOCKMAP/SOCKHASH from BPF. Lookup returns a pointer to a full socket and acquires a reference if necessary. To support it we need to extend the verifier to know that: (1) register storing the lookup result holds a pointer to socket, if lookup was done on SOCKMAP/SOCKHASH, and that (2) map lookup on SOCKMAP/SOCKHASH is a reference acquiring operation, which needs a corresponding reference release with bpf_sk_release. On sock_map side, lookup handlers exposed via bpf_map_ops now bump sk_refcnt if socket is reference counted. In turn, bpf_sk_select_reuseport, the only in-kernel user of SOCKMAP/SOCKHASH ops->map_lookup_elem, was updated to release the reference. Sockets fetched from a map can be used in the same way as ones returned by BPF socket lookup helpers, such as bpf_sk_lookup_tcp. In particular, they can be used with bpf_sk_assign to direct packets toward a socket on TC ingress path. Suggested-by: Lorenz Bauer <lmb@cloudflare.com> Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: John Fastabend <john.fastabend@gmail.com> Link: https://lore.kernel.org/bpf/20200429181154.479310-2-jakub@cloudflare.com
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