26350535c2
The convention with xattrs is to not store the termination with string data, given that it returns the length. This is how setfattr/getfattr operate. Most of ceph's virtual xattr routines use snprintf to plop the string directly into the destination buffer, but snprintf always NULL terminates the string. This means that if we send the kernel a buffer that is the exact length needed to hold the string, it'll end up truncated. Add a ceph_fmt_xattr helper function to format the string into an on-stack buffer that should always be large enough to hold the whole thing and then memcpy the result into the destination buffer. If it does turn out that the formatted string won't fit in the on-stack buffer, then return -E2BIG and do a WARN_ONCE(). Change over most of the virtual xattr routines to use the new helper. A couple of the xattrs are sourced from strings however, and it's difficult to know how long they'll be. Just have those memcpy the result in place after verifying the length. Signed-off-by: Jeff Layton <jlayton@kernel.org> Reviewed-by: "Yan, Zheng" <zyan@redhat.com> Acked-by: Ilya Dryomov <idryomov@gmail.com> Signed-off-by: Ilya Dryomov <idryomov@gmail.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.