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Jouni K. Seppänen d73f7e7575 net: cdc_ncm: correct overhead in delayed_ndp_size
[ Upstream commit 7a68d725e4 ]

Aligning to tx_ndp_modulus is not sufficient because the next align
call can be cdc_ncm_align_tail, which can add up to ctx->tx_modulus +
ctx->tx_remainder - 1 bytes. This used to lead to occasional crashes
on a Huawei 909s-120 LTE module as follows:

- the condition marked /* if there is a remaining skb [...] */ is true
  so the swaps happen
- skb_out is set from ctx->tx_curr_skb
- skb_out->len is exactly 0x3f52
- ctx->tx_curr_size is 0x4000 and delayed_ndp_size is 0xac
  (note that the sum of skb_out->len and delayed_ndp_size is 0x3ffe)
- the for loop over n is executed once
- the cdc_ncm_align_tail call marked /* align beginning of next frame */
  increases skb_out->len to 0x3f56 (the sum is now 0x4002)
- the condition marked /* check if we had enough room left [...] */ is
  false so we break out of the loop
- the condition marked /* If requested, put NDP at end of frame. */ is
  true so the NDP is written into skb_out
- now skb_out->len is 0x4002, so padding_count is minus two interpreted
  as an unsigned number, which is used as the length argument to memset,
  leading to a crash with various symptoms but usually including

> Call Trace:
>  <IRQ>
>  cdc_ncm_fill_tx_frame+0x83a/0x970 [cdc_ncm]
>  cdc_mbim_tx_fixup+0x1d9/0x240 [cdc_mbim]
>  usbnet_start_xmit+0x5d/0x720 [usbnet]

The cdc_ncm_align_tail call first aligns on a ctx->tx_modulus
boundary (adding at most ctx->tx_modulus-1 bytes), then adds
ctx->tx_remainder bytes. Alternatively, the next alignment call can
occur in cdc_ncm_ndp16 or cdc_ncm_ndp32, in which case at most
ctx->tx_ndp_modulus-1 bytes are added.

A similar problem has occurred before, and the code is nontrivial to
reason about, so add a guard before the crashing call. By that time it
is too late to prevent any memory corruption (we'll have written past
the end of the buffer already) but we can at least try to get a warning
written into an on-disk log by avoiding the hard crash caused by padding
past the buffer with a huge number of zeros.

Signed-off-by: Jouni K. Seppänen <jks@iki.fi>
Fixes: 4a0e3e989d ("cdc_ncm: Add support for moving NDP to end of NCM frame")
Link: https://bugzilla.kernel.org/show_bug.cgi?id=209407
Reported-by: kernel test robot <lkp@intel.com>
Reviewed-by: Bjørn Mork <bjorn@mork.no>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-01-17 14:05:31 +01:00
Documentation x86/CPU/AMD: Save AMD NodeId as cpu_die_id 2020-12-30 11:51:47 +01:00
LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
arch x86/asm/32: Add ENDs to some functions and relabel with SYM_CODE_* 2021-01-17 14:05:30 +01:00
block scsi: block: Fix a race in the runtime power management code 2021-01-06 14:48:37 +01:00
certs PKCS#7: Refactor verify_pkcs7_signature() 2019-08-05 18:40:18 -04:00
crypto crypto: asym_tpm: correct zero out potential secrets 2021-01-12 20:16:17 +01:00
drivers net: cdc_ncm: correct overhead in delayed_ndp_size 2021-01-17 14:05:31 +01:00
fs btrfs: send: fix wrong file path when there is an inode with a pending rmdir 2021-01-12 20:16:23 +01:00
include vfio iommu: Add dma available capability 2021-01-17 14:05:30 +01:00
init exec: Transform exec_update_mutex into a rw_semaphore 2021-01-09 13:44:55 +01:00
ipc ipc/util.c: sysvipc_find_ipc() incorrectly updates position index 2020-05-20 08:20:16 +02:00
kernel workqueue: Kick a worker based on the actual activation of delayed works 2021-01-12 20:16:09 +01:00
lib lib/genalloc: fix the overflow when size is too big 2021-01-12 20:16:10 +01:00
mm mm: don't wake kswapd prematurely when watermark boosting is disabled 2020-12-30 11:51:27 +01:00
net netfilter: nft_dynset: report EOPNOTSUPP on missing set feature 2021-01-12 20:16:24 +01:00
samples samples: bpf: Fix lwt_len_hist reusing previous BPF map 2020-12-30 11:51:12 +01:00
scripts depmod: handle the case of /sbin/depmod without /sbin in PATH 2021-01-12 20:16:10 +01:00
security ima: Don't modify file descriptor mode on the fly 2020-12-30 11:51:39 +01:00
sound ALSA: hda/realtek: Add two "Intel Reference board" SSID in the ALC256. 2021-01-12 20:16:23 +01:00
tools tools headers UAPI: Sync linux/const.h with the kernel headers 2021-01-06 14:48:37 +01:00
usr initramfs: restore default compression behavior 2020-04-08 09:08:38 +02:00
virt kvm: check tlbs_dirty directly 2021-01-12 20:16:22 +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: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore Modules updates for v5.4 2019-09-22 10:34:46 -07:00
.mailmap ARM: SoC fixes 2019-11-10 13:41:59 -08:00
COPYING COPYING: use the new text with points to the license files 2018-03-23 12:41:45 -06:00
CREDITS MAINTAINERS: Remove Simon as Renesas SoC Co-Maintainer 2019-10-10 08:12:51 -07:00
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 Documentation/llvm: add documentation on building w/ Clang/LLVM 2020-08-26 10:40:46 +02:00
Makefile Linux 5.4.89 2021-01-12 20:16:25 +01:00
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.