[PATCH v2 0/2] usb: gadget: u_ether: fix out-of-bounds read in get_ether_addr

[Liu Chao]

Rework of

  [PATCH] usb: gadget: u_ether: fix out-of-bounds read in get_ether_addr
  https://lore.kernel.org/all/20261023110113.2969708-1-liuc63@xxxxxxxxxxxx/

following Andy's review: 1/2 prepares a parse_mac_pton() helper in
lib/net_utils.c, 2/2 uses it in get_ether_addr().

The two patches belong to different trees: 1/2 touches lib/ and should go
via netdev or -mm, 2/2 is for the USB tree.  2/2 depends on 1/2, so it
can only be applied once 1/2 has reached Linus' tree.

Changes since v1:
  - rework the fix on top of parse_mac_pton() as suggested by Andy
    instead of open coding the bounds checks in get_ether_addr()
  - add the KASAN report and the malformed address example that v1 was
    missing, both collected on a KASAN build by loading g_ether with a
    short and with a non-hex dev_addr
  - select GENERIC_NET_UTILS for USB_U_ETHER
  - drop Cc: stable: 2/2 calls parse_mac_pton(), which 1/2 introduces,
    so it cannot be backported to any stable tree on its own
  - drop the Reviewed-by, the implementation changed completely

One user visible effect worth pointing out: the old loop also accepted a
separator-less string such as "aabbccddeeff" and the Cisco notation
"aabb.ccdd.eeff", both of which parse_mac_pton() rejects, so such input
now falls back to a random address.  Details are in the log of 2/2.

Liu Chao (2):
  lib/net_utils: allow mac_pton() to take a custom delimiter
  usb: gadget: u_ether: fix out-of-bounds read in get_ether_addr

 drivers/usb/gadget/Kconfig            |  1 +
 drivers/usb/gadget/function/u_ether.c | 14 +++-----------
 include/linux/hex.h                   |  7 ++++++-
 lib/net_utils.c                       | 17 ++++++++++++++---
 4 files changed, 24 insertions(+), 15 deletions(-)


base-commit: a5ebb76233b79db01e82e061173cb73c6d2b5c6b
-- 
2.50.1