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Feng Liu dae64749db virtio_net: Introduce skb_vnet_common_hdr to avoid typecasting
The virtio_net driver currently deals with different versions and types
of virtio net headers, such as virtio_net_hdr_mrg_rxbuf,
virtio_net_hdr_v1_hash, etc. Due to these variations, the code relies
on multiple type casts to convert memory between different structures,
potentially leading to bugs when there are changes in these structures.

Introduces the "struct skb_vnet_common_hdr" as a unifying header
structure using a union. With this approach, various virtio net header
structures can be converted by accessing different members of this
structure, thus eliminating the need for type casting and reducing the
risk of potential bugs.

For example following code:
static struct sk_buff *page_to_skb(struct virtnet_info *vi,
		struct receive_queue *rq,
		struct page *page, unsigned int offset,
		unsigned int len, unsigned int truesize,
		unsigned int headroom)
{
[...]
	struct virtio_net_hdr_mrg_rxbuf *hdr;
[...]
	hdr_len = vi->hdr_len;
[...]
ok:
	hdr = skb_vnet_hdr(skb);
	memcpy(hdr, hdr_p, hdr_len);
[...]
}

When VIRTIO_NET_F_HASH_REPORT feature is enabled, hdr_len = 20
But the sizeof(*hdr) is 12,
memcpy(hdr, hdr_p, hdr_len); will copy 20 bytes to the hdr,
which make a potential risk of bug. And this risk can be avoided by
introducing struct skb_vnet_common_hdr.

Change log
v1->v2
feedback from Willem de Bruijn <willemdebruijn.kernel@gmail.com>
feedback from Simon Horman <horms@kernel.org>
1. change to use net-next tree.
2. move skb_vnet_common_hdr inside kernel file instead of the UAPI header.

v2->v3
feedback from Willem de Bruijn <willemdebruijn.kernel@gmail.com>
1. fix typo in commit message.
2. add original struct virtio_net_hdr into union
3. remove virtio_net_hdr_mrg_rxbuf variable in receive_buf;

Signed-off-by: Feng Liu <feliu@nvidia.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2023-08-23 09:40:18 +01:00
Documentation mptcp: add a new sysctl scheduler 2023-08-22 17:31:18 -07:00
LICENSES LICENSES: Add the copyleft-next-0.3.1 license 2022-11-08 15:44:01 +01:00
arch Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2023-08-18 12:44:56 -07:00
block block-6.5-2023-08-11 2023-08-11 12:14:08 -07:00
certs KEYS: Add missing function documentation 2023-04-24 16:15:52 +03:00
crypto crypto: algif_hash - Fix race between MORE and non-MORE sends 2023-07-08 22:48:42 +10:00
drivers virtio_net: Introduce skb_vnet_common_hdr to avoid typecasting 2023-08-23 09:40:18 +01:00
fs three smb client fixes, all for stable 2023-08-15 20:00:40 +00:00
include mlx4: Delete custom device management logic 2023-08-23 08:25:28 +01:00
init Kbuild updates for v6.5 2023-07-01 09:24:31 -07:00
io_uring io_uring/parisc: Adjust pgoff in io_uring mmap() for parisc 2023-08-08 12:37:01 -06:00
ipc Merge branch 'work.namespace' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2023-02-24 19:20:07 -08:00
kernel Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2023-08-18 12:44:56 -07:00
lib Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2023-08-18 12:44:56 -07:00
mm Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2023-08-18 12:44:56 -07:00
net nf-next pull request 2023-08-22 2023-08-22 18:47:35 -07:00
rust rust: fix bindgen build error with UBSAN_BOUNDS_STRICT 2023-08-04 17:10:50 +02:00
samples samples/bpf: README: Update build dependencies required 2023-07-18 17:29:43 -07:00
scripts Kbuild fixes for v6.5 (2nd) 2023-08-13 08:56:24 -07:00
security Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2023-08-10 14:10:53 -07:00
sound ASoC: Fixes for v6.5 2023-07-27 14:54:23 +02:00
tools selftests: fib_test: add a test case for IPv6 source address delete 2023-08-20 15:27:22 +01:00
usr initramfs: Encode dependency on KBUILD_BUILD_TIMESTAMP 2023-06-06 17:54:49 +09:00
virt KVM: Grab a reference to KVM for VM and vCPU stats file descriptors 2023-07-29 11:05:28 -04:00
.clang-format iommu: Add for_each_group_device() 2023-05-23 08:15:51 +02:00
.cocciconfig
.get_maintainer.ignore get_maintainer: add Alan to .get_maintainer.ignore 2022-08-20 15:17:44 -07:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore Revert ".gitignore: ignore *.cover and *.mbx" 2023-07-04 15:05:12 -07:00
.mailmap mailmap: add entries for Simon Horman 2023-08-16 09:53:10 +01:00
.rustfmt.toml rust: add `.rustfmt.toml` 2022-09-28 09:02:20 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS - Address -Wmissing-prototype warnings 2023-06-26 16:43:54 -07:00
Kbuild Kbuild updates for v6.1 2022-10-10 12:00:45 -07:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2023-08-18 12:44:56 -07:00
Makefile Linux 6.5-rc6 2023-08-13 11:29:55 -07:00
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.