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Filename Latest commit message Latest commit date
Harshit Mogalapalli f15eca9513 VMCI: Fix memcpy() run-time warning in dg_dispatch_as_host()
[ Upstream commit 19b070fefd0d024af3daa7329cbc0d00de5302ec ]

Syzkaller hit 'WARNING in dg_dispatch_as_host' bug.

memcpy: detected field-spanning write (size 56) of single field "&dg_info->msg"
at drivers/misc/vmw_vmci/vmci_datagram.c:237 (size 24)

WARNING: CPU: 0 PID: 1555 at drivers/misc/vmw_vmci/vmci_datagram.c:237
dg_dispatch_as_host+0x88e/0xa60 drivers/misc/vmw_vmci/vmci_datagram.c:237

Some code commentry, based on my understanding:

544 #define VMCI_DG_SIZE(_dg) (VMCI_DG_HEADERSIZE + (size_t)(_dg)->payload_size)
/// This is 24 + payload_size

memcpy(&dg_info->msg, dg, dg_size);
	Destination = dg_info->msg ---> this is a 24 byte
					structure(struct vmci_datagram)
	Source = dg --> this is a 24 byte structure (struct vmci_datagram)
	Size = dg_size = 24 + payload_size

{payload_size = 56-24 =32} -- Syzkaller managed to set payload_size to 32.

 35 struct delayed_datagram_info {
 36         struct datagram_entry *entry;
 37         struct work_struct work;
 38         bool in_dg_host_queue;
 39         /* msg and msg_payload must be together. */
 40         struct vmci_datagram msg;
 41         u8 msg_payload[];
 42 };

So those extra bytes of payload are copied into msg_payload[], a run time
warning is seen while fuzzing with Syzkaller.

One possible way to fix the warning is to split the memcpy() into
two parts -- one -- direct assignment of msg and second taking care of payload.

Gustavo quoted:
"Under FORTIFY_SOURCE we should not copy data across multiple members
in a structure."

Reported-by: syzkaller <syzkaller@googlegroups.com>
Suggested-by: Vegard Nossum <vegard.nossum@oracle.com>
Suggested-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: Harshit Mogalapalli <harshit.m.mogalapalli@oracle.com>
Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Dan Carpenter <dan.carpenter@linaro.org>
Link: https://lore.kernel.org/r/20240105164001.2129796-2-harshit.m.mogalapalli@oracle.com
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-04-13 12:51:37 +02:00
arch s390/entry: align system call table on 8 bytes 2024-04-13 12:51:37 +02:00
block block: sed-opal: handle empty atoms when parsing response 2024-03-26 18:22:12 -04:00
certs
crypto crypto: api - Disallow identical driver names 2024-02-23 08:24:48 +01:00
Documentation x86/cpu: Enable STIBP on AMD if Automatic IBRS is enabled 2024-04-13 12:51:32 +02:00
drivers VMCI: Fix memcpy() run-time warning in dg_dispatch_as_host() 2024-04-13 12:51:37 +02:00
fs fs: add a vfs_fchmod helper 2024-04-13 12:51:35 +02:00
include erspan: Add type I version 0 support. 2024-04-13 12:51:36 +02:00
init init: open /initrd.image with O_LARGEFILE 2024-04-13 12:51:36 +02:00
ipc ipc/sem: Fix dangling sem_array access in semtimedop race 2022-12-08 11:23:06 +01:00
kernel bounds: support non-power-of-two CONFIG_NR_CPUS 2024-04-13 12:51:31 +02:00
lib net: blackhole_dev: fix build warning for ethh set but not used 2024-03-26 18:22:15 -04:00
LICENSES
mm mm, vmscan: prevent infinite loop for costly GFP_NOIO | __GFP_RETRY_MAYFAIL allocations 2024-04-13 12:51:34 +02:00
net erspan: make sure erspan_base_hdr is present in skb->head 2024-04-13 12:51:36 +02:00
samples media: rename VFL_TYPE_GRABBER to _VIDEO 2024-03-26 18:22:22 -04:00
scripts kbuild: Move -Wenum-{compare-conditional,enum-conversion} into W=1 2024-04-13 12:51:26 +02:00
security smack: Handle SMACK64TRANSMUTE in smack_inode_setsecurity() 2024-04-13 12:51:22 +02:00
sound ALSA: hda/realtek: Update Panasonic CF-SZ6 quirk to support headset with microphone 2024-04-13 12:51:36 +02:00
tools selftests: reuseaddr_conflict: add missing new line at the end of the output 2024-04-13 12:51:35 +02:00
usr
virt KVM: Always flush async #PF workqueue when vCPU is being destroyed 2024-04-13 12:51:22 +02:00
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS iio: stx104: Move to addac subdirectory 2023-08-30 16:27:12 +02:00
Makefile Linux 5.4.273 2024-03-26 18:23:12 -04:00
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.