Pierre Riteau 071ed42cff net/sched: cls_api: fix error handling causing NULL dereference
tcf_exts_miss_cookie_base_alloc() calls xa_alloc_cyclic() which can
return 1 if the allocation succeeded after wrapping. This was treated as
an error, with value 1 returned to caller tcf_exts_init_ex() which sets
exts->actions to NULL and returns 1 to caller fl_change().

fl_change() treats err == 1 as success, calling tcf_exts_validate_ex()
which calls tcf_action_init() with exts->actions as argument, where it
is dereferenced.

Example trace:

BUG: kernel NULL pointer dereference, address: 0000000000000000
CPU: 114 PID: 16151 Comm: handler114 Kdump: loaded Not tainted 5.14.0-503.16.1.el9_5.x86_64 #1
RIP: 0010:tcf_action_init+0x1f8/0x2c0
Call Trace:
 tcf_action_init+0x1f8/0x2c0
 tcf_exts_validate_ex+0x175/0x190
 fl_change+0x537/0x1120 [cls_flower]

Fixes: 80cd22c35c ("net/sched: cls_api: Support hardware miss to tc action")
Signed-off-by: Pierre Riteau <pierre@stackhpc.com>
Reviewed-by: Michal Swiatkowski <michal.swiatkowski@linux.intel.com>
Link: https://patch.msgid.link/20250213223610.320278-1-pierre@stackhpc.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-02-15 09:07:09 -08:00
2024-09-01 20:43:24 -07:00
2025-02-04 11:27:45 -05:00
2022-09-28 09:02:20 +02:00
2025-02-14 13:33:11 -08:00
2025-02-09 12:45:03 -08:00
2024-03-18 03:36:32 -06:00

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 reStructuredText 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.
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