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Filename Latest commit message Latest commit date
Liu Jian 5f0bfe21c8 tcp_bpf: Fix one concurrency problem in the tcp_bpf_send_verdict function
commit cd9733f5d75c94a32544d6ce5be47e14194cf137 upstream.

With two Msgs, msgA and msgB and a user doing nonblocking sendmsg calls (or
multiple cores) on a single socket 'sk' we could get the following flow.

 msgA, sk                               msgB, sk
 -----------                            ---------------
 tcp_bpf_sendmsg()
 lock(sk)
 psock = sk->psock
                                        tcp_bpf_sendmsg()
                                        lock(sk) ... blocking
tcp_bpf_send_verdict
if (psock->eval == NONE)
   psock->eval = sk_psock_msg_verdict
 ..
 < handle SK_REDIRECT case >
   release_sock(sk)                     < lock dropped so grab here >
   ret = tcp_bpf_sendmsg_redir
                                        psock = sk->psock
                                        tcp_bpf_send_verdict
 lock_sock(sk) ... blocking on B
                                        if (psock->eval == NONE) <- boom.
                                         psock->eval will have msgA state

The problem here is we dropped the lock on msgA and grabbed it with msgB.
Now we have old state in psock and importantly psock->eval has not been
cleared. So msgB will run whatever action was done on A and the verdict
program may never see it.

Fixes: 604326b41a ("bpf, sockmap: convert to generic sk_msg interface")
Signed-off-by: Liu Jian <liujian56@huawei.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20211012052019.184398-1-liujian56@huawei.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-11-02 19:46:13 +01:00
arch powerpc/bpf: Fix BPF_MOD when imm == 1 2021-11-02 19:46:11 +01:00
block Revert "block, bfq: honor already-setup queue merges" 2021-10-06 15:42:34 +02:00
certs certs: Trigger creation of RSA module signing key if it's not an RSA key 2021-09-15 09:47:29 +02:00
crypto crypto: shash - avoid comparing pointers to exported functions under CFI 2021-07-14 16:53:13 +02:00
Documentation dt-bindings: mtd: gpmc: Fix the ECC bytes vs. OOB bytes equation 2021-09-22 12:26:43 +02:00
drivers drm/ttm: fix memleak in ttm_transfered_destroy 2021-11-02 19:46:13 +01:00
fs btrfs: deal with errors when checking if a dir entry exists during log replay 2021-10-27 09:54:29 +02:00
include net/tls: Fix flipped sign in tls_err_abort() calls 2021-11-02 19:46:12 +01:00
init kbuild: add CONFIG_LD_IS_LLD 2021-06-30 08:47:44 -04:00
ipc
kernel tracing: Have all levels of checks prevent recursion 2021-10-27 09:54:29 +02:00
lib Kconfig.debug: drop selecting non-existing HARDLOCKUP_DETECTOR_ARCH 2021-09-26 14:07:10 +02:00
LICENSES
mm mm, slub: fix potential memoryleak in kmem_cache_open() 2021-10-27 09:54:28 +02:00
net tcp_bpf: Fix one concurrency problem in the tcp_bpf_send_verdict function 2021-11-02 19:46:13 +01:00
samples samples: bpf: Fix tracex7 error raised on the missing argument 2021-09-22 12:26:30 +02:00
scripts gcc-plugins/structleak: add makefile var for disabling structleak 2021-10-27 09:54:28 +02:00
security apparmor: remove duplicate macro list_entry_is_head() 2021-09-26 14:07:06 +02:00
sound ALSA: hda: avoid write to STATESTS if controller is in reset 2021-10-27 09:54:29 +02:00
tools selftests: netfilter: remove stray bash debug line 2021-10-27 09:54:28 +02:00
usr
virt KVM: do not shrink halt_poll_ns below grow_start 2021-10-09 14:39:50 +02:00
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS
Makefile Linux 5.4.156 2021-10-27 09:54:30 +02:00
README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.