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Filename Latest commit message Latest commit date
A Sun 5567384fec media: mceusb: fix out of bounds read in MCE receiver buffer
commit e43148645d18efc3072b1ba45afaa3f385299e55 upstream.

Fix multiple cases of out of bounds (OOB) read associated with
MCE device receive/input data handling.

In reference for the OOB cases below, the incoming/read (byte) data
format when the MCE device responds to a command is:
    { cmd_prefix, subcmd, data0, data1, ... }
where cmd_prefix are:
    MCE_CMD_PORT_SYS
    MCE_CMD_PORT_IR
and subcmd examples are:
    MCE_RSP_GETPORTSTATUS
    MCE_RSP_EQIRNUMPORTS
    ...
Response size dynamically depends on cmd_prefix and subcmd.
So data0, data1, ... may or may not be present on input.
Multiple responses may return in a single receiver buffer.

The trigger condition for OOB read is typically random or
corrupt input data that fills the mceusb receiver buffer.

Case 1:

mceusb_handle_command() reads data0 (var hi) and data1 (var lo)
regardless of whether the response includes such data.
If { cmd_prefix, subcmd } is at the end of the receiver buffer,
read past end of buffer occurs.

This case was reported by
KASAN: slab-out-of-bounds Read in mceusb_dev_recv
https://syzkaller.appspot.com/bug?extid=c7fdb6cb36e65f2fe8c9

Fix: In mceusb_handle_command(), change variable hi and lo to
pointers, and dereference only when required.

Case 2:

If response with data is truncated at end of buffer after
{ cmd_prefix, subcmd }, mceusb_handle_command() reads past
end of buffer for data0, data1, ...

Fix: In mceusb_process_ir_data(), check response size with
remaining buffer size before invoking mceusb_handle_command().
+    if (i + ir->rem < buf_len)
            mceusb_handle_command(ir, &ir->buf_in[i - 1]);

Case 3:

mceusb_handle_command() handles invalid/bad response such as
{ 0x??, MCE_RSP_GETPORTSTATUS } of length 2 as a response
{ MCE_CMD_PORT_SYS, MCE_RSP_GETPORTSTATUS, data0, ... }
of length 7. Read OOB occurs for non-existent data0, data1, ...
Cause is mceusb_handle_command() does not check cmd_prefix value.

Fix: mceusb_handle_command() must test both cmd_prefix and subcmd.

Case 4:

mceusb_process_ir_data() receiver parser state SUBCMD is
possible at start (i=0) of receiver buffer resulting in buffer
offset=-1 passed to mceusb_dev_printdata().
Bad offset results in OOB read before start of buffer.

[1214218.580308] mceusb 1-1.3:1.0: rx data[0]: 00 80 (length=2)
[1214218.580323] mceusb 1-1.3:1.0: Unknown command 0x00 0x80
...
[1214218.580406] mceusb 1-1.3:1.0: rx data[14]: 7f 7f (length=2)
[1214218.679311] mceusb 1-1.3:1.0: rx data[-1]: 80 90 (length=2)
[1214218.679325] mceusb 1-1.3:1.0: End of raw IR data
[1214218.679340] mceusb 1-1.3:1.0: rx data[1]: 7f 7f (length=2)

Fix: If parser_state is SUBCMD after processing receiver buffer,
reset parser_state to CMD_HEADER.
In effect, discard cmd_prefix at end of receiver buffer.
In mceusb_dev_printdata(), abort if buffer offset is out of bounds.

Case 5:

If response with data is truncated at end of buffer after
{ cmd_prefix, subcmd }, mceusb_dev_printdata() reads past
end of buffer for data0, data1, ...
while decoding the response to print out.

Fix: In mceusb_dev_printdata(), remove unneeded buffer offset
adjustments (var start and var skip) associated with MCE gen1 header.
Test for truncated MCE cmd response (compare offset+len with buf_len)
and skip decoding of incomplete response.
Move IR data tracing to execute before the truncation test.

Signed-off-by: A Sun <as1033x@comcast.net>
Signed-off-by: Sean Young <sean@mess.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-11-29 10:10:18 +01:00
arch x86/entry/32: Fix FIXUP_ESPFIX_STACK with user CR3 2019-11-29 10:10:00 +01:00
block iocost: check active_list of all the ancestors in iocg_activate() 2019-11-14 13:56:54 -07:00
certs PKCS#7: Refactor verify_pkcs7_signature() 2019-08-05 18:40:18 -04:00
crypto Merge branch 'next-lockdown' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security 2019-09-28 08:14:15 -07:00
Documentation x86/speculation: Fix incorrect MDS/TAA mitigation status 2019-11-29 10:09:46 +01:00
drivers media: mceusb: fix out of bounds read in MCE receiver buffer 2019-11-29 10:10:18 +01:00
fs exit/exec: Seperate mm_release() 2019-11-29 10:10:10 +01:00
include futex: Add mutex around futex exit 2019-11-29 10:10:13 +01:00
init Merge branch 'next-lockdown' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security 2019-09-28 08:14:15 -07:00
ipc ipc/sem.c: convert to use built-in RCU list checking 2019-09-25 17:51:41 -07:00
kernel futex: Prevent exit livelock 2019-11-29 10:10:14 +01:00
lib lib/xz: fix XZ_DYNALLOC to avoid useless memory reallocations 2019-11-15 18:34:00 -08:00
LICENSES
mm mm/ksm.c: don't WARN if page is still mapped in remove_stable_node() 2019-11-22 09:11:18 -08:00
net udp: drop skb extensions before marking skb stateless 2019-11-22 09:28:46 -08:00
samples samples/bpf: fix build by setting HAVE_ATTR_TEST to zero 2019-10-31 21:39:15 +01:00
scripts arm64 fix for -rc8 / final 2019-11-15 09:14:23 -08:00
security efi/efi_test: Lock down /dev/efi_test and require CAP_SYS_ADMIN 2019-10-31 09:40:21 +01:00
sound ALSA: usb-audio: Fix Scarlett 6i6 Gen 2 port data 2019-11-29 10:10:02 +01:00
tools selftests/x86/sigreturn/32: Invalidate DS and ES when abusing the kernel 2019-11-29 10:09:59 +01:00
usr kbuild: update compile-test header list for v5.4-rc2 2019-10-05 15:29:49 +09:00
virt KVM: Add a comment describing the /dev/kvm no_compat handling 2019-11-15 10:14:04 +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
.gitattributes
.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
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 Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2019-11-22 14:28:14 -08:00
Makefile Linux 5.4 2019-11-24 16:32:01 -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.