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This reverts commits 6d04fe15f78acdf8e32329e208552e226f7a8ae6 and
a31edb2059ed4e498f9aa8230c734b59d0ad797a.
It turns out the idea to share a single pointer for both kernel and user
space address causes various kinds of problems. So use the slightly less
optimal version that uses an extra bit, but which is guaranteed to be safe
everywhere.
Fixes: 6d04fe15f78a ("net: optimize the sockptr_t for unified kernel/user address spaces")
Reported-by: Eric Dumazet <edumazet@google.com>
Reported-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Make sure not just the pointer itself but the whole range lies in
the user address space. For that pass the length and then use
the access_ok helper to do the check.
Fixes: 6d04fe15f78a ("net: optimize the sockptr_t for unified kernel/user address spaces")
Reported-by: David Laight <David.Laight@ACULAB.COM>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
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For architectures like x86 and arm64 we don't need the separate bit to
indicate that a pointer is a kernel pointer as the address spaces are
unified. That way the sockptr_t can be reduced to a union of two
pointers, which leads to nicer calling conventions.
The only caveat is that we need to check that users don't pass in kernel
address and thus gain access to kernel memory. Thus the USER_SOCKPTR
helper is replaced with a init_user_sockptr function that does this check
and returns an error if it fails.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
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This is mostly to prepare for cleaning up the callers, as bpfilter by
design can't handle kernel pointers.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Instead of relying on the exit_umh cleanup callback use the fact a
struct pid can be tested to see if a process still exists, and that
struct pid has a wait queue that notifies when the process dies.
v1: https://lkml.kernel.org/r/87h7uydlu9.fsf_-_@x220.int.ebiederm.org
v2: https://lkml.kernel.org/r/874kqt4owu.fsf_-_@x220.int.ebiederm.org
Link: https://lkml.kernel.org/r/20200702164140.4468-14-ebiederm@xmission.com
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Tested-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
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Use struct pid instead of user space pid values that are prone to wrap
araound.
In addition track the entire thread group instead of just the first
thread that is started by exec. There are no multi-threaded user mode
drivers today but there is nothing preclucing user drivers from being
multi-threaded, so it is just a good idea to track the entire process.
Take a reference count on the tgid's in question to make it possible
to remove exit_umh in a future change.
As a struct pid is available directly use kill_pid_info.
The prior process signalling code was iffy in using a userspace pid
known to be in the initial pid namespace and then looking up it's task
in whatever the current pid namespace is. It worked only because
kernel threads always run in the initial pid namespace.
As the tgid is now refcounted verify the tgid is NULL at the start of
fork_usermode_driver to avoid the possibility of silent pid leaks.
v1: https://lkml.kernel.org/r/87mu4qdlv2.fsf_-_@x220.int.ebiederm.org
v2: https://lkml.kernel.org/r/a70l4oy8.fsf_-_@x220.int.ebiederm.org
Link: https://lkml.kernel.org/r/20200702164140.4468-12-ebiederm@xmission.com
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Tested-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
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The only thing supplied in the cmdline today is the driver name so
rename the field to clarify the code.
As this value is always supplied stop trying to handle the case of
a NULL cmdline.
Additionally since we now have a name we can count on use the
driver_name any place where the code is looking for a name
of the binary.
v1: https://lkml.kernel.org/r/87imfef0k3.fsf_-_@x220.int.ebiederm.org
v2: https://lkml.kernel.org/r/87366d63os.fsf_-_@x220.int.ebiederm.org
Link: https://lkml.kernel.org/r/20200702164140.4468-7-ebiederm@xmission.com
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Tested-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
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This structure is only used for user mode drivers so change
the prefix from umh to umd to make that clear.
v1: https://lkml.kernel.org/r/87o8p6f0kw.fsf_-_@x220.int.ebiederm.org
v2: https://lkml.kernel.org/r/878sg563po.fsf_-_@x220.int.ebiederm.org
Link: https://lkml.kernel.org/r/20200702164140.4468-6-ebiederm@xmission.com
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Tested-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
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If bpfilter is not available return ENOPROTOOPT to fallback to netfilter.
Function request_module() returns both errors and userspace exit codes.
Just ignore them. Rechecking bpfilter_ops is enough.
Fixes: d2ba09c17a06 ("net: add skeleton of bpfilter kernel module")
Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Signed-off-by: David S. Miller <davem@davemloft.net>
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The Kconfig controlling this code is:
bpfilter/Kconfig:menuconfig BPFILTER
bpfilter/Kconfig: bool "BPF based packet filtering framework (BPFILTER)"
Since it isn't a module, we shouldn't use module_init(). Instead we
use device_initcall() - which is exactly what module_init() defaults
to for non-modular code/builds.
We don't remove <linux/module.h> from the includes since this file does
a request_module() and hence is a valid user of that header file, even
though it is not modular itself.
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
Cc: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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The bpfilter.ko module can be removed while functions of the bpfilter.ko
are executing. so panic can occurred. in order to protect that, locks can
be used. a bpfilter_lock protects routines in the
__bpfilter_process_sockopt() but it's not enough because __exit routine
can be executed concurrently.
Now, the bpfilter_umh can not run in parallel.
So, the module do not removed while it's being used and it do not
double-create UMH process.
The members of the umh_info and the bpfilter_umh_ops are protected by
the bpfilter_umh_ops.lock.
test commands:
while :
do
iptables -I FORWARD -m string --string ap --algo kmp &
modprobe -rv bpfilter &
done
splat looks like:
[ 298.623435] BUG: unable to handle kernel paging request at fffffbfff807440b
[ 298.628512] #PF error: [normal kernel read fault]
[ 298.633018] PGD 124327067 P4D 124327067 PUD 11c1a3067 PMD 119eb2067 PTE 0
[ 298.638859] Oops: 0000 [#1] SMP DEBUG_PAGEALLOC KASAN PTI
[ 298.638859] CPU: 0 PID: 2997 Comm: iptables Not tainted 4.20.0+ #154
[ 298.638859] RIP: 0010:__mutex_lock+0x6b9/0x16a0
[ 298.638859] Code: c0 00 00 e8 89 82 ff ff 80 bd 8f fc ff ff 00 0f 85 d9 05 00 00 48 8b 85 80 fc ff ff 48 bf 00 00 00 00 00 fc ff df 48 c1 e8 03 <80> 3c 38 00 0f 85 1d 0e 00 00 48 8b 85 c8 fc ff ff 49 39 47 58 c6
[ 298.638859] RSP: 0018:ffff88810e7777a0 EFLAGS: 00010202
[ 298.638859] RAX: 1ffffffff807440b RBX: ffff888111bd4d80 RCX: 0000000000000000
[ 298.638859] RDX: 1ffff110235ff806 RSI: ffff888111bd5538 RDI: dffffc0000000000
[ 298.638859] RBP: ffff88810e777b30 R08: 0000000080000002 R09: 0000000000000000
[ 298.638859] R10: 0000000000000000 R11: 0000000000000000 R12: fffffbfff168a42c
[ 298.638859] R13: ffff888111bd4d80 R14: ffff8881040e9a05 R15: ffffffffc03a2000
[ 298.638859] FS: 00007f39e3758700(0000) GS:ffff88811ae00000(0000) knlGS:0000000000000000
[ 298.638859] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 298.638859] CR2: fffffbfff807440b CR3: 000000011243e000 CR4: 00000000001006f0
[ 298.638859] Call Trace:
[ 298.638859] ? mutex_lock_io_nested+0x1560/0x1560
[ 298.638859] ? kasan_kmalloc+0xa0/0xd0
[ 298.638859] ? kmem_cache_alloc+0x1c2/0x260
[ 298.638859] ? __alloc_file+0x92/0x3c0
[ 298.638859] ? alloc_empty_file+0x43/0x120
[ 298.638859] ? alloc_file_pseudo+0x220/0x330
[ 298.638859] ? sock_alloc_file+0x39/0x160
[ 298.638859] ? __sys_socket+0x113/0x1d0
[ 298.638859] ? __x64_sys_socket+0x6f/0xb0
[ 298.638859] ? do_syscall_64+0x138/0x560
[ 298.638859] ? entry_SYSCALL_64_after_hwframe+0x49/0xbe
[ 298.638859] ? __alloc_file+0x92/0x3c0
[ 298.638859] ? init_object+0x6b/0x80
[ 298.638859] ? cyc2ns_read_end+0x10/0x10
[ 298.638859] ? cyc2ns_read_end+0x10/0x10
[ 298.638859] ? hlock_class+0x140/0x140
[ 298.638859] ? sched_clock_local+0xd4/0x140
[ 298.638859] ? sched_clock_local+0xd4/0x140
[ 298.638859] ? check_flags.part.37+0x440/0x440
[ 298.638859] ? __lock_acquire+0x4f90/0x4f90
[ 298.638859] ? set_rq_offline.part.89+0x140/0x140
[ ... ]
Fixes: d2ba09c17a06 ("net: add skeleton of bpfilter kernel module")
Signed-off-by: Taehee Yoo <ap420073@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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The bpfilter_umh will be stopped via __stop_umh() when the bpfilter
error occurred.
The bpfilter_umh() couldn't start again because there is no restart
routine.
The section of the bpfilter_umh_{start/end} is no longer .init.rodata
because these area should be reused in the restart routine. hence
the section name is changed to .bpfilter_umh.
The bpfilter_ops->start() is restart callback. it will be called when
bpfilter_umh is stopped.
The stop bit means bpfilter_umh is stopped. this bit is set by both
start and stop routine.
Before this patch,
Test commands:
$ iptables -vnL
$ kill -9 <pid of bpfilter_umh>
$ iptables -vnL
[ 480.045136] bpfilter: write fail -32
$ iptables -vnL
All iptables commands will fail.
After this patch,
Test commands:
$ iptables -vnL
$ kill -9 <pid of bpfilter_umh>
$ iptables -vnL
$ iptables -vnL
Now, all iptables commands will work.
Fixes: d2ba09c17a06 ("net: add skeleton of bpfilter kernel module")
Signed-off-by: Taehee Yoo <ap420073@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Now, UMH process is killed, do_exit() calls the umh_info->cleanup callback
to release members of the umh_info.
This patch makes bpfilter_umh's cleanup routine to use the
umh_info->cleanup callback.
Signed-off-by: Taehee Yoo <ap420073@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Fixes the following sparse warnings:
net/ipv4/bpfilter/sockopt.c:13:5: warning:
symbol 'bpfilter_mbox_request' was not declared. Should it be static?
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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bpfilter.ko consists of bpfilter_kern.c (normal kernel module code)
and user mode helper code that is embedded into bpfilter.ko
The steps to build bpfilter.ko are the following:
- main.c is compiled by HOSTCC into the bpfilter_umh elf executable file
- with quite a bit of objcopy and Makefile magic the bpfilter_umh elf file
is converted into bpfilter_umh.o object file
with _binary_net_bpfilter_bpfilter_umh_start and _end symbols
Example:
$ nm ./bld_x64/net/bpfilter/bpfilter_umh.o
0000000000004cf8 T _binary_net_bpfilter_bpfilter_umh_end
0000000000004cf8 A _binary_net_bpfilter_bpfilter_umh_size
0000000000000000 T _binary_net_bpfilter_bpfilter_umh_start
- bpfilter_umh.o and bpfilter_kern.o are linked together into bpfilter.ko
bpfilter_kern.c is a normal kernel module code that calls
the fork_usermode_blob() helper to execute part of its own data
as a user mode process.
Notice that _binary_net_bpfilter_bpfilter_umh_start - end
is placed into .init.rodata section, so it's freed as soon as __init
function of bpfilter.ko is finished.
As part of __init the bpfilter.ko does first request/reply action
via two unix pipe provided by fork_usermode_blob() helper to
make sure that umh is healthy. If not it will kill it via pid.
Later bpfilter_process_sockopt() will be called from bpfilter hooks
in get/setsockopt() to pass iptable commands into umh via bpfilter.ko
If admin does 'rmmod bpfilter' the __exit code bpfilter.ko will
kill umh as well.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Christoph Hellwig
Eric W. Biederman
Konstantin Khlebnikov
Paul Gortmaker
Taehee Yoo
Wei Yongjun
Alexei Starovoitov