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Richard Yao c38367c73f Eliminate runtime function pointer mods in autotools checks
PaX/GrSecurity patched kernels implement a dialect of C that relies on a
GCC plugin for enforcement. A basic idea in this dialect is that
function pointers in structures should not change during runtime.
This causes code that modifies function pointers at runtime to fail to
compile in many instances. The autotools checks rely on whether or
not small test cases compile against a given kernel. Some
autotools checks assume some default case if other cases fail. When one
of these autotools checks tests a PaX/GrSecurity patched kernel by
modifying a function pointer at runtime, the default case will be used.

Early detection of such situations is possible by relying on compiler
warnings, which are compiler errors when --enable-debug is used.
Unfortunately, very few people build ZFS with --enable-debug. The more
common situation is that these issues manifest themselves as runtime
failures in the form of NULL pointer exceptions.

Previous patches that addressed such issues with PaX/GrSecurity
compatibility largely relied on rewriting autotools checks to avoid
runtime function pointer modification or the addition of PaX/GrSecurity
specific checks. This patch takes the previous work to its logical
conclusion by eliminating the use of runtime function pointer
modification. This permits the removal of PaX-specific autotools checks
in favor of ones that work across all supported kernels.

This should resolve issues that were reported to occur with
PaX/GrSecurity-patched Linux 3.7.5 kernels on Gentoo Linux.

https://bugs.gentoo.org/show_bug.cgi?id=457176

We should be able to prevent future regressions in PaX/GrSecurity
compatibility by ensuring that all changes to ZFSOnLinux avoid runtime
function pointer modification. At the same time, this does not solve the
issue of silent failures triggering default cases in the autotools
check, which is what permitted these regressions to become runtime
failures in the first place. This will need to be addressed in a future
patch.

Reported-by: Marcin Mirosław <bug@mejor.pl>
Signed-off-by: Richard Yao <ryao@cs.stonybrook.edu>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #1300
2013-03-04 08:49:17 -08:00
cmd Fix hot spares 2013-03-01 13:31:02 -08:00
config Eliminate runtime function pointer mods in autotools checks 2013-03-04 08:49:17 -08:00
dracut Retire zpool_id infrastructure 2013-01-29 12:23:17 -08:00
etc Retire zpool_id infrastructure 2013-01-29 12:23:17 -08:00
include Fix hot spares 2013-03-01 13:31:02 -08:00
lib Remove unused machelf.h header 2013-02-05 15:34:50 -08:00
man -x shouldn't warn about old on-disk format or unavailable features 2013-02-28 09:17:09 -08:00
module Fix hot spares 2013-03-01 13:31:02 -08:00
patches Adding grub2 mkconfig support patch 2012-07-30 16:17:23 -07:00
scripts Retire zpool_id infrastructure 2013-01-29 12:23:17 -08:00
udev Retire zpool_id infrastructure 2013-01-29 12:23:17 -08:00
.gitignore Remove autotools products 2012-09-11 10:15:13 -07:00
AUTHORS Refresh AUTHORS 2012-12-19 09:47:25 -08:00
autogen.sh Remove autotools products 2012-08-27 11:47:44 -07:00
configure.ac Retire zpool_id infrastructure 2013-01-29 12:23:17 -08:00
copy-builtin Consistent menuconfig name 2012-08-26 13:49:37 -07:00
COPYING Relocate COPYING+COPYRIGHT, remove README cruft 2008-12-01 15:34:53 -08:00
COPYRIGHT Update COPYRIGHT to reference zpios CDDL exceptions. 2010-05-18 14:25:28 -07:00
DISCLAIMER Update COPYRIGHT and DISCLAIMER. 2010-05-18 10:32:23 -07:00
dkms.conf.in Support building a zfs-modules-dkms sub package 2012-08-08 15:21:01 -07:00
dkms.postinst Support building a zfs-modules-dkms sub package 2012-08-08 15:21:01 -07:00
Makefile.am Do not use KERNEL_DIR env var in Makefile.am 2012-12-17 09:45:47 -08:00
META ZFS 0.6.0-rc14 2013-02-01 11:26:55 -08:00
OPENSOLARIS.LICENSE Add CDDL license file 2008-12-01 14:49:34 -08:00
PKGBUILD-zfs-modules.in Add make rule for building Arch Linux packages 2011-12-14 19:14:23 -08:00
PKGBUILD-zfs.in Retire zpool_id infrastructure 2013-01-29 12:23:17 -08:00
README.markdown Add script for builtin module building. 2012-07-26 13:45:09 -07:00
zfs-modules.spec.in Cleanly remove zfs-modules-devel headers 2012-08-13 16:35:26 -07:00
zfs-script-config.sh.in Retire zpool_id infrastructure 2013-01-29 12:23:17 -08:00
ZFS.RELEASE Update to onnv_147 2010-08-26 14:24:34 -07:00
zfs.release.in Move zfs.release generation to configure step 2012-07-12 12:22:51 -07:00
zfs.spec.in Fix broken RPATH in spec file 2013-02-12 13:59:09 -08:00

Native ZFS for Linux! ZFS is an advanced file system and volume manager which was originally developed for Solaris. It has been successfully ported to FreeBSD and now there is a functional Linux ZFS kernel port too. The port currently includes a fully functional and stable SPA, DMU, and ZVOL with a ZFS Posix Layer (ZPL) on the way!

$ ./configure
$ make pkg

To copy the kernel code inside your kernel source tree for builtin compilation:

$ ./configure --enable-linux-builtin --with-linux=/usr/src/linux-...
$ ./copy-builtin /usr/src/linux-...

Full documentation for building, configuring, and using ZFS can be found at: http://zfsonlinux.org