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Florian Westphal 1d305ba40e netfilter: nf_tables: fix infinite loop when expr is not available
nft will loop forever if the kernel doesn't support an expression:

1. nft_expr_type_get() appends the family specific name to the module list.
2. -EAGAIN is returned to nfnetlink, nfnetlink calls abort path.
3. abort path sets ->done to true and calls request_module for the
   expression.
4. nfnetlink replays the batch, we end up in nft_expr_type_get() again.
5. nft_expr_type_get attempts to append family-specific name. This
   one already exists on the list, so we continue
6. nft_expr_type_get adds the generic expression name to the module
   list. -EAGAIN is returned, nfnetlink calls abort path.
7. abort path encounters the family-specific expression which
   has 'done' set, so it gets removed.
8. abort path requests the generic expression name, sets done to true.
9. batch is replayed.

If the expression could not be loaded, then we will end up back at 1),
because the family-specific name got removed and the cycle starts again.

Note that userspace can SIGKILL the nft process to stop the cycle, but
the desired behaviour is to return an error after the generic expr name
fails to load the expression.

Fixes: eb014de4fd ("netfilter: nf_tables: autoload modules from the abort path")
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2020-03-05 12:56:33 +01:00
arch Revert "KVM: x86: enable -Werror" 2020-02-26 09:59:58 -08:00
block block-5.6-2020-02-05 2020-02-06 06:15:23 +00:00
certs certs: Add wrapper function to check blacklisted binary hash 2019-11-12 12:25:50 +11:00
crypto Merge branch 'next-integrity' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity 2020-02-20 15:15:16 -08:00
Documentation docs: networking: net_failover: Fix a few typos 2020-03-03 16:07:02 -08:00
drivers team: add missing attribute validation for array index 2020-03-03 13:28:48 -08:00
fs for-5.6-rc2-tag 2020-02-23 09:43:50 -08:00
include fib: add missing attribute validation for tun_id 2020-03-03 13:28:48 -08:00
init Tracing updates: 2020-02-26 10:34:42 -08:00
ipc Revert "ipc,sem: remove uneeded sem_undo_list lock usage in exit_sem()" 2020-02-21 11:22:15 -08:00
kernel audit/stable-5.6 PR 20200226 2020-02-27 11:01:22 -08:00
lib Tracing updates: 2020-02-26 10:34:42 -08:00
LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
mm Merge branch 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-02-24 11:32:15 -08:00
net netfilter: nf_tables: fix infinite loop when expr is not available 2020-03-05 12:56:33 +01:00
samples Kbuild updates for v5.6 (2nd) 2020-02-09 16:05:50 -08:00
scripts kbuild: remove unneeded semicolon at the end of cmd_dtb_check 2020-02-27 02:24:34 +09:00
security Merge branch 'next-integrity' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity 2020-02-20 15:15:16 -08:00
sound ASoC: Fixes for v5.6 2020-02-18 13:33:39 +01:00
tools selftests/net/fib_tests: update addr_metric_test for peer route testing 2020-03-03 14:43:16 -08:00
usr Kbuild updates for v5.6 (2nd) 2020-02-09 16:05:50 -08:00
virt KVM: Disable preemption in kvm_get_running_vcpu() 2020-02-12 12:19:35 +01:00
.clang-format clang-format: Update with the latest for_each macro list 2019-08-31 10:00:51 +02:00
.cocciconfig
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore selftest/lkdtm: Don't pollute 'git status' 2020-02-20 08:55:06 -07:00
.mailmap A handful of small documentation fixes that wandered in. 2020-02-07 13:03:10 -08:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Hand MIPS over to Thomas 2020-02-24 22:43:18 -08:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig docs: kbuild: convert docs to ReST and rename to *.rst 2019-06-14 14:21:21 -06:00
MAINTAINERS Merge branch 'mips-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/mips/linux 2020-02-25 10:09:41 -08:00
Makefile kbuild: add dt_binding_check to PHONY in a correct place 2020-02-27 02:28:15 +09:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

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.

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.