607706027c
[ Upstream commit f654fae47e83e56b454fbbfd0af0a4f232e356d6 ]
Fix broken Tx ring validation for AF_XDP. The commit under the Fixes
tag, fixed an off-by-one error in the validation but introduced
another error. Descriptors are now let through even if they straddle a
chunk boundary which they are not allowed to do in aligned mode. Worse
is that they are let through even if they straddle the end of the umem
itself, tricking the kernel to read data outside the allowed umem
region which might or might not be mapped at all.
Fix this by reintroducing the old code, but subtract the length by one
to fix the off-by-one error that the original patch was
addressing. The test chunk != chunk_end makes sure packets do not
straddle chunk boundraries. Note that packets of zero length are
allowed in the interface, therefore the test if the length is
non-zero.
Fixes: ac31565c2193 ("xsk: Fix for xp_aligned_validate_desc() when len == chunk_size")
Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Acked-by: Björn Töpel <bjorn@kernel.org>
Link: https://lore.kernel.org/bpf/20210618075805.14412-1-magnus.karlsson@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
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.