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Filename Latest commit message Latest commit date
Lorenz Bauer 7842c7b30d bpf, sockmap: Check update requirements after locking
commit 85b8ac01a421791d66c3a458a7f83cfd173fe3fa upstream.

It's currently possible to insert sockets in unexpected states into
a sockmap, due to a TOCTTOU when updating the map from a syscall.
sock_map_update_elem checks that sk->sk_state == TCP_ESTABLISHED,
locks the socket and then calls sock_map_update_common. At this
point, the socket may have transitioned into another state, and
the earlier assumptions don't hold anymore. Crucially, it's
conceivable (though very unlikely) that a socket has become unhashed.
This breaks the sockmap's assumption that it will get a callback
via sk->sk_prot->unhash.

Fix this by checking the (fixed) sk_type and sk_protocol without the
lock, followed by a locked check of sk_state.

Unfortunately it's not possible to push the check down into
sock_(map|hash)_update_common, since BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB
run before the socket has transitioned from TCP_SYN_RECV into
TCP_ESTABLISHED.

Fixes: 604326b41a ("bpf, sockmap: convert to generic sk_msg interface")
Signed-off-by: Lorenz Bauer <lmb@cloudflare.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Jakub Sitnicki <jakub@cloudflare.com>
Link: https://lore.kernel.org/bpf/20200207103713.28175-1-lmb@cloudflare.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-02-14 16:34:10 -05:00
arch powerpc/kuap: Fix set direction in allow/prevent_user_access() 2020-02-11 04:35:55 -08:00
block
certs
crypto crypto: api - Fix race condition in crypto_spawn_alg 2020-02-11 04:35:31 -08:00
Documentation PM / devfreq: Add new name attribute for sysfs 2020-02-05 21:22:40 +00:00
drivers iwlwifi: mvm: avoid use after free for pmsr request 2020-02-14 16:34:09 -05:00
fs cifs: fail i/o on soft mounts if sessionsetup errors out 2020-02-11 04:35:54 -08:00
include RDMA/uverbs: Verify MR access flags 2020-02-14 16:34:08 -05:00
init Revert "um: Enable CONFIG_CONSTRUCTORS" 2020-02-01 09:34:53 +00:00
ipc ipc/msg.c: consolidate all xxxctl_down() functions 2020-02-11 04:35:07 -08:00
kernel perf/core: Fix mlock accounting in perf_mmap() 2020-02-11 04:35:54 -08:00
lib lib/test_kasan.c: fix memory leak in kmalloc_oob_krealloc_more() 2020-02-11 04:35:14 -08:00
LICENSES
mm mm/mmu_gather: invalidate TLB correctly on batch allocation failure and flush 2020-02-11 04:35:42 -08:00
net bpf, sockmap: Check update requirements after locking 2020-02-14 16:34:10 -05:00
samples samples/bpf: Xdp_redirect_cpu fix missing tracepoint attach 2020-02-11 04:35:29 -08:00
scripts scripts/find-unused-docs: Fix massive false positives 2020-02-11 04:35:23 -08:00
security broken ping to ipv6 linklocal addresses on debian buster 2020-02-11 04:35:43 -08:00
sound ASoC: pcm: update FE/BE trigger order based on the command 2020-02-14 16:34:07 -05:00
tools selftests/bpf: Test freeing sockmap/sockhash with a socket in it 2020-02-14 16:34:09 -05:00
usr
virt KVM: Play nice with read-only memslots when querying host page size 2020-02-11 04:35:54 -08:00
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS MAINTAINERS: correct entries for ISDN/mISDN section 2020-02-11 04:35:06 -08:00
Makefile Linux 5.4.19 2020-02-11 04:35:55 -08:00
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.