mirror_zfs/config
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
..
.gitignore Remove autotools products 2012-08-27 11:47:44 -07:00
always-no-unused-but-set-variable.m4 In autoconf v2.68, AC_LANG_PROGRAM must be quoted 2011-11-28 11:16:33 -08:00
arch.am Don't build packages that haven't been selected. 2012-07-26 13:39:37 -07:00
config.awk Add build system 2010-08-31 13:41:27 -07:00
deb.am Don't build packages that haven't been selected. 2012-07-26 13:39:37 -07:00
kernel-automount.m4 Fix snapshot automounting with GrSecurity constify plugin. 2012-08-24 08:56:38 -07:00
kernel-bdev-block-device-operations.m4 Eliminate runtime function pointer mods in autotools checks 2013-03-04 08:49:17 -08:00
kernel-bdev-logical-size.m4 Only use gcc -Wunused-but-set-variable when available 2013-01-10 16:09:39 -08:00
kernel-bdev-physical-size.m4 Only use gcc -Wunused-but-set-variable when available 2013-01-10 16:09:39 -08:00
kernel-bdi-setup-and-register.m4 When checking for symbol exports, try compiling. 2012-07-26 13:42:57 -07:00
kernel-bdi.m4 Add backing_device_info per-filesystem 2011-08-04 13:37:38 -07:00
kernel-bio-end-io-t-args.m4 Eliminate runtime function pointer mods in autotools checks 2013-03-04 08:49:17 -08:00
kernel-bio-failfast.m4 Fix gcc configure warnings 2011-04-19 10:10:47 -07:00
kernel-bio-rw-syncio.m4 Fix gcc configure warnings 2011-04-19 10:10:47 -07:00
kernel-blk-end-request.m4 Only use gcc -Wunused-but-set-variable when available 2013-01-10 16:09:39 -08:00
kernel-blk-fetch-request.m4 Only use gcc -Wunused-but-set-variable when available 2013-01-10 16:09:39 -08:00
kernel-blk-queue-discard.m4 Only use gcc -Wunused-but-set-variable when available 2013-01-10 16:09:39 -08:00
kernel-blk-queue-flush.m4 Only use gcc -Wunused-but-set-variable when available 2013-01-10 16:09:39 -08:00
kernel-blk-queue-io-opt.m4 Only use gcc -Wunused-but-set-variable when available 2013-01-10 16:09:39 -08:00
kernel-blk-queue-max-hw-sectors.m4 Only use gcc -Wunused-but-set-variable when available 2013-01-10 16:09:39 -08:00
kernel-blk-queue-max-segments.m4 Only use gcc -Wunused-but-set-variable when available 2013-01-10 16:09:39 -08:00
kernel-blk-queue-nonrot.m4 Only use gcc -Wunused-but-set-variable when available 2013-01-10 16:09:39 -08:00
kernel-blk-queue-physical-block-size.m4 Only use gcc -Wunused-but-set-variable when available 2013-01-10 16:09:39 -08:00
kernel-blk-requeue-request.m4 Only use gcc -Wunused-but-set-variable when available 2013-01-10 16:09:39 -08:00
kernel-blk-rq-bytes.m4 Only use gcc -Wunused-but-set-variable when available 2013-01-10 16:09:39 -08:00
kernel-blk-rq-pos.m4 Only use gcc -Wunused-but-set-variable when available 2013-01-10 16:09:39 -08:00
kernel-blk-rq-sectors.m4 Only use gcc -Wunused-but-set-variable when available 2013-01-10 16:09:39 -08:00
kernel-blkdev-get-by-path.m4 When checking for symbol exports, try compiling. 2012-07-26 13:42:57 -07:00
kernel-blkdev-get.m4 Move partition scanning from userspace to module. 2012-07-17 09:17:31 -07:00
kernel-check-disk-size-change.m4 When checking for symbol exports, try compiling. 2012-07-26 13:42:57 -07:00
kernel-clear-inode.m4 When checking for symbol exports, try compiling. 2012-07-26 13:42:57 -07:00
kernel-commit-metadata.m4 Implement .commit_metadata hook for NFS export 2012-10-03 10:49:45 -07:00
kernel-create-nameidata.m4 Eliminate runtime function pointer mods in autotools checks 2013-03-04 08:49:17 -08:00
kernel-d-make-root.m4 When checking for symbol exports, try compiling. 2012-07-26 13:42:57 -07:00
kernel-d-obtain-alias.m4 When checking for symbol exports, try compiling. 2012-07-26 13:42:57 -07:00
kernel-dentry-operations.m4 Eliminate runtime function pointer mods in autotools checks 2013-03-04 08:49:17 -08:00
kernel-dirty-inode.m4 Eliminate runtime function pointer mods in autotools checks 2013-03-04 08:49:17 -08:00
kernel-discard-granularity.m4 Set zvol discard_granularity to the volblocksize. 2012-08-07 14:55:31 -07:00
kernel-elevator-change.m4 Only use gcc -Wunused-but-set-variable when available 2013-01-10 16:09:39 -08:00
kernel-encode-fh-inode.m4 Linux 3.5 compat, eops->encode_fh() takes inodes 2012-07-23 12:29:23 -07:00
kernel-evict-inode.m4 Fix build failures on PaX/GRSecurity patched kernels 2012-07-17 09:22:43 -07:00
kernel-fallocate.m4 Eliminate runtime function pointer mods in autotools checks 2013-03-04 08:49:17 -08:00
kernel-fmode-t.m4 Fix gcc configure warnings 2011-04-19 10:10:47 -07:00
kernel-fsync.m4 Eliminate runtime function pointer mods in autotools checks 2013-03-04 08:49:17 -08:00
kernel-get-disk-ro.m4 Only use gcc -Wunused-but-set-variable when available 2013-01-10 16:09:39 -08:00
kernel-get-gendisk.m4 When checking for symbol exports, try compiling. 2012-07-26 13:42:57 -07:00
kernel-insert-inode-locked.m4 When checking for symbol exports, try compiling. 2012-07-26 13:42:57 -07:00
kernel-invalidate-bdev-args.m4 Fix gcc configure warnings 2011-04-19 10:10:47 -07:00
kernel-kobj-name-len.m4 Fix gcc configure warnings 2011-04-19 10:10:47 -07:00
kernel-lookup-bdev.m4 Linux 2.6.26 compat, lookup_bdev() 2013-01-28 15:35:00 -08:00
kernel-lookup-nameidata.m4 Eliminate runtime function pointer mods in autotools checks 2013-03-04 08:49:17 -08:00
kernel-mkdir-umode-t.m4 Eliminate runtime function pointer mods in autotools checks 2013-03-04 08:49:17 -08:00
kernel-mount-nodev.m4 When checking for symbol exports, try compiling. 2012-07-26 13:42:57 -07:00
kernel-open-bdev-exclusive.m4 When checking for symbol exports, try compiling. 2012-07-26 13:42:57 -07:00
kernel-rq-for-each_segment.m4 Only use gcc -Wunused-but-set-variable when available 2013-01-10 16:09:39 -08:00
kernel-rq-is_sync.m4 Only use gcc -Wunused-but-set-variable when available 2013-01-10 16:09:39 -08:00
kernel-security-inode-init.m4 Use -Werror for all kernel configure tests. 2013-02-24 10:20:28 -08:00
kernel-set-nlink.m4 Linux 3.2 compat: set_nlink() 2011-12-16 20:02:52 -08:00
kernel-sget-args.m4 Linux 3.6 compat, sget() 2012-10-14 13:06:48 -07:00
kernel-show-options.m4 Fix NULL pointer dereference on PaX/GRSecurity patched Linux 3.3 and later kernels 2012-07-20 12:31:45 -07:00
kernel-shrink.m4 Eliminate runtime function pointer mods in autotools checks 2013-03-04 08:49:17 -08:00
kernel-truncate-range.m4 Linux 3.5 compat, iops->truncate_range() removed 2012-07-23 12:29:32 -07:00
kernel-truncate-setsize.m4 When checking for symbol exports, try compiling. 2012-07-26 13:42:57 -07:00
kernel-xattr-handler.m4 Fix gcc configure warnings 2011-04-19 10:10:47 -07:00
kernel.m4 Remove the bio_empty_barrier() check. 2013-02-24 10:22:34 -08:00
rpm.am Support building a zfs-modules-dkms sub package 2012-08-08 15:21:01 -07:00
Rules.am Check for -Wno-unused-but-set-variable gcc support 2011-06-14 14:43:22 -07:00
suppressed-warnings.txt Suppress packaging warning 2011-11-08 11:32:04 -08:00
tgz.am Don't build packages that haven't been selected. 2012-07-26 13:39:37 -07:00
user-arch.m4 Add build system 2010-08-31 13:41:27 -07:00
user-frame-larger-than.m4 In autoconf v2.68, AC_LANG_PROGRAM must be quoted 2011-11-28 11:16:33 -08:00
user-ioctl.m4 Add build system 2010-08-31 13:41:27 -07:00
user-libblkid.m4 In autoconf v2.68, AC_LANG_PROGRAM must be quoted 2011-11-28 11:16:33 -08:00
user-libuuid.m4 Add build system 2010-08-31 13:41:27 -07:00
user-selinux.m4 Autoconf selinux support 2011-01-28 12:45:19 -08:00
user-udev.m4 Move udev rules from /etc/udev to /lib/udev 2011-08-08 16:21:10 -07:00
user-zlib.m4 Add build system 2010-08-31 13:41:27 -07:00
user.m4 Remove NPTL_GUARD_WITHIN_STACK 2013-01-29 10:58:20 -08:00
zfs-build.m4 Make configure builtin-aware. 2012-07-26 13:40:18 -07:00
zfs-meta.m4 Add build system 2010-08-31 13:41:27 -07:00