Jann Horn 0da74120c5 selinux: move user accesses in selinuxfs out of locked regions
If a user is accessing a file in selinuxfs with a pointer to a userspace
buffer that is backed by e.g. a userfaultfd, the userspace access can
stall indefinitely, which can block fsi->mutex if it is held.

For sel_read_policy(), remove the locking, since this method doesn't seem
to access anything that requires locking.

For sel_read_bool(), move the user access below the locked region.

For sel_write_bool() and sel_commit_bools_write(), move the user access
up above the locked region.

Cc: [email protected]
Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Signed-off-by: Jann Horn <[email protected]>
Acked-by: Stephen Smalley <[email protected]>
[PM: removed an unused variable in sel_read_policy()]
Signed-off-by: Paul Moore <[email protected]>
2018-06-28 20:39:54 -04:00
2018-01-06 10:59:44 -07:00
2018-04-15 18:24:20 -07:00

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 Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.

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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