Chuck Lever 18d1bb4973 SUNRPC: Fix ("SUNRPC: Add "@len" parameter to gss_unwrap()")
[ Upstream commit 986a4b63d3bc5f2c0eb4083b05aff2bf883b7b2f ]

Braino when converting "buf->len -=" to "buf->len = len -".

The result is under-estimation of the ralign and rslack values. On
krb5p mounts, this has caused READDIR to fail with EIO, and KASAN
splats when decoding READLINK replies.

As a result of fixing this oversight, the gss_unwrap method now
returns a buf->len that can be shorter than priv_len for small
RPC messages. The additional adjustment done in unwrap_priv_data()
can underflow buf->len. This causes the nfsd_request_too_large
check to fail during some NFSv3 operations.

Reported-by: Marian Rainer-Harbach
Reported-by: Pierre Sauter <pierre.sauter@stwm.de>
BugLink: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1886277
Fixes: 31c9590ae468 ("SUNRPC: Add "@len" parameter to gss_unwrap()")
Reviewed-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-08-19 08:16:21 +02:00
..
2019-07-18 14:32:33 -07:00
2018-12-19 13:52:46 -05:00
2019-07-06 14:54:52 -04:00