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John Fastabend d468e4775c bpf: Sockmap/tls, tls_sw can create a plaintext buf > encrypt buf
It is possible to build a plaintext buffer using push helper that is larger
than the allocated encrypt buffer. When this record is pushed to crypto
layers this can result in a NULL pointer dereference because the crypto
API expects the encrypt buffer is large enough to fit the plaintext
buffer. Kernel splat below.

To resolve catch the cases this can happen and split the buffer into two
records to send individually. Unfortunately, there is still one case to
handle where the split creates a zero sized buffer. In this case we merge
the buffers and unmark the split. This happens when apply is zero and user
pushed data beyond encrypt buffer. This fixes the original case as well
because the split allocated an encrypt buffer larger than the plaintext
buffer and the merge simply moves the pointers around so we now have
a reference to the new (larger) encrypt buffer.

Perhaps its not ideal but it seems the best solution for a fixes branch
and avoids handling these two cases, (a) apply that needs split and (b)
non apply case. The are edge cases anyways so optimizing them seems not
necessary unless someone wants later in next branches.

[  306.719107] BUG: kernel NULL pointer dereference, address: 0000000000000008
[...]
[  306.747260] RIP: 0010:scatterwalk_copychunks+0x12f/0x1b0
[...]
[  306.770350] Call Trace:
[  306.770956]  scatterwalk_map_and_copy+0x6c/0x80
[  306.772026]  gcm_enc_copy_hash+0x4b/0x50
[  306.772925]  gcm_hash_crypt_remain_continue+0xef/0x110
[  306.774138]  gcm_hash_crypt_continue+0xa1/0xb0
[  306.775103]  ? gcm_hash_crypt_continue+0xa1/0xb0
[  306.776103]  gcm_hash_assoc_remain_continue+0x94/0xa0
[  306.777170]  gcm_hash_assoc_continue+0x9d/0xb0
[  306.778239]  gcm_hash_init_continue+0x8f/0xa0
[  306.779121]  gcm_hash+0x73/0x80
[  306.779762]  gcm_encrypt_continue+0x6d/0x80
[  306.780582]  crypto_gcm_encrypt+0xcb/0xe0
[  306.781474]  crypto_aead_encrypt+0x1f/0x30
[  306.782353]  tls_push_record+0x3b9/0xb20 [tls]
[  306.783314]  ? sk_psock_msg_verdict+0x199/0x300
[  306.784287]  bpf_exec_tx_verdict+0x3f2/0x680 [tls]
[  306.785357]  tls_sw_sendmsg+0x4a3/0x6a0 [tls]

test_sockmap test signature to trigger bug,

[TEST]: (1, 1, 1, sendmsg, pass,redir,start 1,end 2,pop (1,2),ktls,):

Fixes: d3b18ad31f ("tls: add bpf support to sk_msg handling")
Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Jonathan Lemon <jonathan.lemon@gmail.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/bpf/20200111061206.8028-7-john.fastabend@gmail.com
2020-01-15 23:26:13 +01:00
Documentation doc/net: Update git https URLs in netdev-FAQ documentation 2020-01-03 12:33:54 -08:00
LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
arch riscv: export flush_icache_all to modules 2019-12-27 21:51:01 -08:00
block compat_ioctl: block: handle Persistent Reservations 2019-12-21 07:26:56 -07:00
certs certs: Add wrapper function to check blacklisted binary hash 2019-11-12 12:25:50 +11:00
crypto tpmdd fixes for Linux v5.5-rc3 2019-12-18 17:17:36 -08:00
drivers net: stmmac: Fixed link does not need MDIO Bus 2020-01-07 13:40:29 -08:00
fs File locking fix for v5.5 2019-12-29 09:50:57 -08:00
include bpf: Sockmap/tls, push write_space updates through ulp updates 2020-01-15 23:26:13 +01:00
init early init: fix error handling when opening /dev/console 2019-12-17 13:10:11 -08:00
ipc treewide: Use sizeof_field() macro 2019-12-09 10:36:44 -08:00
kernel bpf: Fix incorrect verifier simulation of ARSH under ALU32 2020-01-15 13:39:59 -08:00
lib Merge branch 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2019-12-22 17:00:04 -08:00
mm mm: vmscan: protect shrinker idr replace with CONFIG_MEMCG 2019-12-17 20:59:59 -08:00
net bpf: Sockmap/tls, tls_sw can create a plaintext buf > encrypt buf 2020-01-15 23:26:13 +01:00
samples Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2019-12-22 09:54:33 -08:00
scripts Kbuild fixes for v5.5 2019-12-21 10:49:47 -08:00
security Two bugfix patches for 5.5. 2019-12-31 10:51:27 -08:00
sound sound fixes for 5.5-rc3 2019-12-18 08:54:15 -08:00
tools bpftool: Fix printing incorrect pointer in btf_dump_ptr 2020-01-11 19:08:21 -08:00
usr kbuild: fix 'No such file or directory' warning when cleaning 2019-12-09 10:08:21 +09:00
virt PPC KVM fix for 5.5 2019-12-22 13:18:15 +01:00
.clang-format clang-format: Update with the latest for_each macro list 2019-08-31 10:00:51 +02:00
.cocciconfig
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore modpost: dump missing namespaces into a single modules.nsdeps file 2019-11-11 20:10:01 +09:00
.mailmap Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2019-12-22 09:54:33 -08:00
COPYING COPYING: use the new text with points to the license files 2018-03-23 12:41:45 -06:00
CREDITS Linux 5.4-rc4 2019-10-29 04:43:29 -06:00
Kbuild kbuild: do not descend to ./Kbuild when cleaning 2019-08-21 21:03:58 +09:00
Kconfig docs: kbuild: convert docs to ReST and rename to *.rst 2019-06-14 14:21:21 -06:00
MAINTAINERS MAINTAINERS: Drop obsolete entries from Samsung sxgbe ethernet driver 2020-01-05 14:49:31 -08:00
Makefile Linux 5.5-rc4 2019-12-29 15:29:16 -08:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

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.