linux.git/net/core/sock_map.c, branch v6.12

sock_map: fix a NULL pointer dereference in sock_map_link_update_prog()

2024-10-29T01:44:14+00:00

The following race condition could trigger a NULL pointer dereference:

sock_map_link_detach():		sock_map_link_update_prog():
   mutex_lock(&sockmap_mutex);
   ...
   sockmap_link->map = NULL;
   mutex_unlock(&sockmap_mutex);
   				   mutex_lock(&sockmap_mutex);
				   ...
				   sock_map_prog_link_lookup(sockmap_link->map);
				   mutex_unlock(&sockmap_mutex);
   

Fix it by adding a NULL pointer check. In this specific case, it makes
no sense to update a link which is being released.

Reported-by: Ruan Bonan 
Fixes: 699c23f02c65 ("bpf: Add bpf_link support for sk_msg and sk_skb progs")
Cc: Yonghong Song 
Cc: John Fastabend 
Cc: Jakub Sitnicki 
Signed-off-by: Cong Wang 
Link: https://lore.kernel.org/r/20241026185522.338562-1-xiyou.wangcong@gmail.com
Signed-off-by: Martin KaFai Lau

bpf, sockmap: SK_DROP on attempted redirects of unsupported af_vsock

2024-10-17T11:02:54+00:00

Don't mislead the callers of bpf_{sk,msg}_redirect_{map,hash}(): make sure
to immediately and visibly fail the forwarding of unsupported af_vsock
packets.

Fixes: 634f1a7110b4 ("vsock: support sockmap")
Signed-off-by: Michal Luczaj 
Signed-off-by: Daniel Borkmann 
Acked-by: John Fastabend 
Link: https://lore.kernel.org/bpf/20241013-vsock-fixes-for-redir-v2-1-d6577bbfe742@rbox.co

Merge tag 'bpf-next-6.12-struct-fd' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next

2024-09-24T21:54:26+00:00

Pull bpf 'struct fd' updates from Alexei Starovoitov:
 "This includes struct_fd BPF changes from Al and Andrii"

* tag 'bpf-next-6.12-struct-fd' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next:
  bpf: convert bpf_token_create() to CLASS(fd, ...)
  security,bpf: constify struct path in bpf_token_create() LSM hook
  bpf: more trivial fdget() conversions
  bpf: trivial conversions for fdget()
  bpf: switch maps to CLASS(fd, ...)
  bpf: factor out fetching bpf_map from FD and adding it to used_maps list
  bpf: switch fdget_raw() uses to CLASS(fd_raw, ...)
  bpf: convert __bpf_prog_get() to CLASS(fd, ...)

sock_map: Add a cond_resched() in sock_hash_free()

2024-09-11T20:16:04+00:00

Several syzbot soft lockup reports all have in common sock_hash_free()

If a map with a large number of buckets is destroyed, we need to yield
the cpu when needed.

Fixes: 75e68e5bf2c7 ("bpf, sockhash: Synchronize delete from bucket list on map free")
Reported-by: syzbot 
Signed-off-by: Eric Dumazet 
Signed-off-by: Daniel Borkmann 
Acked-by: Martin KaFai Lau 
Acked-by: John Fastabend 
Link: https://lore.kernel.org/bpf/20240906154449.3742932-1-edumazet@google.com

bpf: switch maps to CLASS(fd, ...)

2024-08-13T22:58:17+00:00

        Calling conventions for __bpf_map_get() would be more convenient
if it left fpdut() on failure to callers.  Makes for simpler logics
in the callers.

	Among other things, the proof of memory safety no longer has to
rely upon file->private_data never being ERR_PTR(...) for bpffs files.
Original calling conventions made it impossible for the caller to tell
whether __bpf_map_get() has returned ERR_PTR(-EINVAL) because it has found
the file not be a bpf map one (in which case it would've done fdput())
or because it found that ERR_PTR(-EINVAL) in file->private_data of a
bpf map file (in which case fdput() would _not_ have been done).

Signed-off-by: Al Viro 
Reviewed-by: Christian Brauner 
Signed-off-by: Andrii Nakryiko

sock_map: avoid race between sock_map_close and sk_psock_put

2024-05-28T10:05:19+00:00

sk_psock_get will return NULL if the refcount of psock has gone to 0, which
will happen when the last call of sk_psock_put is done. However,
sk_psock_drop may not have finished yet, so the close callback will still
point to sock_map_close despite psock being NULL.

This can be reproduced with a thread deleting an element from the sock map,
while the second one creates a socket, adds it to the map and closes it.

That will trigger the WARN_ON_ONCE:

------------[ cut here ]------------
WARNING: CPU: 1 PID: 7220 at net/core/sock_map.c:1701 sock_map_close+0x2a2/0x2d0 net/core/sock_map.c:1701
Modules linked in:
CPU: 1 PID: 7220 Comm: syz-executor380 Not tainted 6.9.0-syzkaller-07726-g3c999d1ae3c7 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024
RIP: 0010:sock_map_close+0x2a2/0x2d0 net/core/sock_map.c:1701
Code: df e8 92 29 88 f8 48 8b 1b 48 89 d8 48 c1 e8 03 42 80 3c 20 00 74 08 48 89 df e8 79 29 88 f8 4c 8b 23 eb 89 e8 4f 15 23 f8 90 <0f> 0b 90 48 83 c4 08 5b 41 5c 41 5d 41 5e 41 5f 5d e9 13 26 3d 02
RSP: 0018:ffffc9000441fda8 EFLAGS: 00010293
RAX: ffffffff89731ae1 RBX: ffffffff94b87540 RCX: ffff888029470000
RDX: 0000000000000000 RSI: ffffffff8bcab5c0 RDI: ffffffff8c1faba0
RBP: 0000000000000000 R08: ffffffff92f9b61f R09: 1ffffffff25f36c3
R10: dffffc0000000000 R11: fffffbfff25f36c4 R12: ffffffff89731840
R13: ffff88804b587000 R14: ffff88804b587000 R15: ffffffff89731870
FS:  000055555e080380(0000) GS:ffff8880b9500000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 00000000207d4000 CR4: 0000000000350ef0
Call Trace:
 
 unix_release+0x87/0xc0 net/unix/af_unix.c:1048
 __sock_release net/socket.c:659 [inline]
 sock_close+0xbe/0x240 net/socket.c:1421
 __fput+0x42b/0x8a0 fs/file_table.c:422
 __do_sys_close fs/open.c:1556 [inline]
 __se_sys_close fs/open.c:1541 [inline]
 __x64_sys_close+0x7f/0x110 fs/open.c:1541
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf5/0x240 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fb37d618070
Code: 00 00 48 c7 c2 b8 ff ff ff f7 d8 64 89 02 b8 ff ff ff ff eb d4 e8 10 2c 00 00 80 3d 31 f0 07 00 00 74 17 b8 03 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 48 c3 0f 1f 80 00 00 00 00 48 83 ec 18 89 7c
RSP: 002b:00007ffcd4a525d8 EFLAGS: 00000202 ORIG_RAX: 0000000000000003
RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 00007fb37d618070
RDX: 0000000000000010 RSI: 00000000200001c0 RDI: 0000000000000004
RBP: 0000000000000000 R08: 0000000100000000 R09: 0000000100000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 

Use sk_psock, which will only check that the pointer is not been set to
NULL yet, which should only happen after the callbacks are restored. If,
then, a reference can still be gotten, we may call sk_psock_stop and cancel
psock->work.

As suggested by Paolo Abeni, reorder the condition so the control flow is
less convoluted.

After that change, the reproducer does not trigger the WARN_ON_ONCE
anymore.

Suggested-by: Paolo Abeni 
Reported-by: syzbot+07a2e4a1a57118ef7355@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=07a2e4a1a57118ef7355
Fixes: aadb2bb83ff7 ("sock_map: Fix a potential use-after-free in sock_map_close()")
Fixes: 5b4a79ba65a1 ("bpf, sockmap: Don't let sock_map_{close,destroy,unhash} call itself")
Cc: stable@vger.kernel.org
Signed-off-by: Thadeu Lima de Souza Cascardo 
Acked-by: Jakub Sitnicki 
Link: https://lore.kernel.org/r/20240524144702.1178377-1-cascardo@igalia.com
Signed-off-by: Paolo Abeni

Revert "bpf, sockmap: Prevent lock inversion deadlock in map delete elem"

2024-05-27T17:34:25+00:00

This reverts commit ff91059932401894e6c86341915615c5eb0eca48.

This check is no longer needed. BPF programs attached to tracepoints are
now rejected by the verifier when they attempt to delete from a
sockmap/sockhash maps.

Signed-off-by: Jakub Sitnicki 
Signed-off-by: Daniel Borkmann 
Acked-by: John Fastabend 
Link: https://lore.kernel.org/bpf/20240527-sockmap-verify-deletes-v1-2-944b372f2101@cloudflare.com

Merge tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next

2024-04-29T20:12:19+00:00

Daniel Borkmann says:

====================
pull-request: bpf-next 2024-04-29

We've added 147 non-merge commits during the last 32 day(s) which contain
a total of 158 files changed, 9400 insertions(+), 2213 deletions(-).

The main changes are:

1) Add an internal-only BPF per-CPU instruction for resolving per-CPU
   memory addresses and implement support in x86 BPF JIT. This allows
   inlining per-CPU array and hashmap lookups
   and the bpf_get_smp_processor_id() helper, from Andrii Nakryiko.

2) Add BPF link support for sk_msg and sk_skb programs, from Yonghong Song.

3) Optimize x86 BPF JIT's emit_mov_imm64, and add support for various
   atomics in bpf_arena which can be JITed as a single x86 instruction,
   from Alexei Starovoitov.

4) Add support for passing mark with bpf_fib_lookup helper,
   from Anton Protopopov.

5) Add a new bpf_wq API for deferring events and refactor sleepable
   bpf_timer code to keep common code where possible,
   from Benjamin Tissoires.

6) Fix BPF_PROG_TEST_RUN infra with regards to bpf_dummy_struct_ops programs
   to check when NULL is passed for non-NULLable parameters,
   from Eduard Zingerman.

7) Harden the BPF verifier's and/or/xor value tracking,
   from Harishankar Vishwanathan.

8) Introduce crypto kfuncs to make BPF programs able to utilize the kernel
   crypto subsystem, from Vadim Fedorenko.

9) Various improvements to the BPF instruction set standardization doc,
   from Dave Thaler.

10) Extend libbpf APIs to partially consume items from the BPF ringbuffer,
    from Andrea Righi.

11) Bigger batch of BPF selftests refactoring to use common network helpers
    and to drop duplicate code, from Geliang Tang.

12) Support bpf_tail_call_static() helper for BPF programs with GCC 13,
    from Jose E. Marchesi.

13) Add bpf_preempt_{disable,enable}() kfuncs in order to allow a BPF
    program to have code sections where preemption is disabled,
    from Kumar Kartikeya Dwivedi.

14) Allow invoking BPF kfuncs from BPF_PROG_TYPE_SYSCALL programs,
    from David Vernet.

15) Extend the BPF verifier to allow different input maps for a given
    bpf_for_each_map_elem() helper call in a BPF program, from Philo Lu.

16) Add support for PROBE_MEM32 and bpf_addr_space_cast instructions
    for riscv64 and arm64 JITs to enable BPF Arena, from Puranjay Mohan.

17) Shut up a false-positive KMSAN splat in interpreter mode by unpoison
    the stack memory, from Martin KaFai Lau.

18) Improve xsk selftest coverage with new tests on maximum and minimum
    hardware ring size configurations, from Tushar Vyavahare.

19) Various ReST man pages fixes as well as documentation and bash completion
    improvements for bpftool, from Rameez Rehman & Quentin Monnet.

20) Fix libbpf with regards to dumping subsequent char arrays,
    from Quentin Deslandes.

* tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (147 commits)
  bpf, docs: Clarify PC use in instruction-set.rst
  bpf_helpers.h: Define bpf_tail_call_static when building with GCC
  bpf, docs: Add introduction for use in the ISA Internet Draft
  selftests/bpf: extend BPF_SOCK_OPS_RTT_CB test for srtt and mrtt_us
  bpf: add mrtt and srtt as BPF_SOCK_OPS_RTT_CB args
  selftests/bpf: dummy_st_ops should reject 0 for non-nullable params
  bpf: check bpf_dummy_struct_ops program params for test runs
  selftests/bpf: do not pass NULL for non-nullable params in dummy_st_ops
  selftests/bpf: adjust dummy_st_ops_success to detect additional error
  bpf: mark bpf_dummy_struct_ops.test_1 parameter as nullable
  selftests/bpf: Add ring_buffer__consume_n test.
  bpf: Add bpf_guard_preempt() convenience macro
  selftests: bpf: crypto: add benchmark for crypto functions
  selftests: bpf: crypto skcipher algo selftests
  bpf: crypto: add skcipher to bpf crypto
  bpf: make common crypto API for TC/XDP programs
  bpf: update the comment for BTF_FIELDS_MAX
  selftests/bpf: Fix wq test.
  selftests/bpf: Use make_sockaddr in test_sock_addr
  selftests/bpf: Use connect_to_addr in test_sock_addr
  ...
====================

Link: https://lore.kernel.org/r/20240429131657.19423-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski

bpf: Add bpf_link support for sk_msg and sk_skb progs

2024-04-11T02:52:25+00:00

Add bpf_link support for sk_msg and sk_skb programs. We have an
internal request to support bpf_link for sk_msg programs so user
space can have a uniform handling with bpf_link based libbpf
APIs. Using bpf_link based libbpf API also has a benefit which
makes system robust by decoupling prog life cycle and
attachment life cycle.

Reviewed-by: John Fastabend 
Signed-off-by: Yonghong Song 
Link: https://lore.kernel.org/r/20240410043527.3737160-1-yonghong.song@linux.dev
Signed-off-by: Alexei Starovoitov

bpf, sockmap: Prevent lock inversion deadlock in map delete elem

2024-04-02T14:31:05+00:00

syzkaller started using corpuses where a BPF tracing program deletes
elements from a sockmap/sockhash map. Because BPF tracing programs can be
invoked from any interrupt context, locks taken during a map_delete_elem
operation must be hardirq-safe. Otherwise a deadlock due to lock inversion
is possible, as reported by lockdep:

       CPU0                    CPU1
       ----                    ----
  lock(&htab->buckets[i].lock);
                               local_irq_disable();
                               lock(&host->lock);
                               lock(&htab->buckets[i].lock);
  
    lock(&host->lock);

Locks in sockmap are hardirq-unsafe by design. We expects elements to be
deleted from sockmap/sockhash only in task (normal) context with interrupts
enabled, or in softirq context.

Detect when map_delete_elem operation is invoked from a context which is
_not_ hardirq-unsafe, that is interrupts are disabled, and bail out with an
error.

Note that map updates are not affected by this issue. BPF verifier does not
allow updating sockmap/sockhash from a BPF tracing program today.

Fixes: 604326b41a6f ("bpf, sockmap: convert to generic sk_msg interface")
Reported-by: xingwei lee 
Reported-by: yue sun 
Reported-by: syzbot+bc922f476bd65abbd466@syzkaller.appspotmail.com
Reported-by: syzbot+d4066896495db380182e@syzkaller.appspotmail.com
Signed-off-by: Jakub Sitnicki 
Signed-off-by: Daniel Borkmann 
Tested-by: syzbot+d4066896495db380182e@syzkaller.appspotmail.com
Acked-by: John Fastabend 
Closes: https://syzkaller.appspot.com/bug?extid=d4066896495db380182e
Closes: https://syzkaller.appspot.com/bug?extid=bc922f476bd65abbd466
Link: https://lore.kernel.org/bpf/20240402104621.1050319-1-jakub@cloudflare.com