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5f1bc39979
The GSS Message Integrity Check data for krb5i may lie partially in the XDR
reply buffer's pages and tail. If so, we try to copy the entire MIC into
free space in the tail. But as the estimations of the slack space required
for authentication and verification have improved there may be less free
space in the tail to complete this copy -- see commit 2c94b8eca1
("SUNRPC: Use au_rslack when computing reply buffer size"). In fact, there
may only be room in the tail for a single copy of the MIC, and not part of
the MIC and then another complete copy.
The real world failure reported is that `ls` of a directory on NFS may
sometimes return -EIO, which can be traced back to xdr_buf_read_netobj()
failing to find available free space in the tail to copy the MIC.
Fix this by checking for the case of the MIC crossing the boundaries of
head, pages, and tail. If so, shift the buffer until the MIC is contained
completely within the pages or tail. This allows the remainder of the
function to create a sub buffer that directly address the complete MIC.
Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
Cc: stable@vger.kernel.org # v5.1
Reviewed-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
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.