Commit Graph

13 Commits

Author SHA1 Message Date
Daniel Borkmann f8bbbfc3b9 net: filter: add jited flag to indicate jit compiled filters
This patch adds a jited flag into sk_filter struct in order to indicate
whether a filter is currently jited or not. The size of sk_filter is
not being expanded as the 32 bit 'len' member allows upper bits to be
reused since a filter can currently only grow as large as BPF_MAXINSNS.

Therefore, there's enough room also for other in future needed flags to
reuse 'len' field if necessary. The jited flag also allows for having
alternative interpreter functions running as currently, we can only
detect jit compiled filters by testing fp->bpf_func to not equal the
address of sk_run_filter().

Joint work with Alexei Starovoitov.

Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Cc: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2014-03-31 00:45:08 -04:00
Tom Herbert 61b905da33 net: Rename skb->rxhash to skb->hash
The packet hash can be considered a property of the packet, not just
on RX path.

This patch changes name of rxhash and l4_rxhash skbuff fields to be
hash and l4_hash respectively. This includes changing uses of the
field in the code which don't call the access functions.

Signed-off-by: Tom Herbert <therbert@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Mahesh Bandewar <maheshb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2014-03-26 15:58:20 -04:00
Eric Dumazet aee636c480 bpf: do not use reciprocal divide
At first Jakub Zawadzki noticed that some divisions by reciprocal_divide
were not correct. (off by one in some cases)
http://www.wireshark.org/~darkjames/reciprocal-buggy.c

He could also show this with BPF:
http://www.wireshark.org/~darkjames/set-and-dump-filter-k-bug.c

The reciprocal divide in linux kernel is not generic enough,
lets remove its use in BPF, as it is not worth the pain with
current cpus.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Jakub Zawadzki <darkjames-ws@darkjames.pl>
Cc: Mircea Gherzan <mgherzan@gmail.com>
Cc: Daniel Borkmann <dxchgb@gmail.com>
Cc: Hannes Frederic Sowa <hannes@stressinduktion.org>
Cc: Matt Evans <matt@ozlabs.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2014-01-15 17:02:08 -08:00
Alexei Starovoitov d45ed4a4e3 net: fix unsafe set_memory_rw from softirq
on x86 system with net.core.bpf_jit_enable = 1

sudo tcpdump -i eth1 'tcp port 22'

causes the warning:
[   56.766097]  Possible unsafe locking scenario:
[   56.766097]
[   56.780146]        CPU0
[   56.786807]        ----
[   56.793188]   lock(&(&vb->lock)->rlock);
[   56.799593]   <Interrupt>
[   56.805889]     lock(&(&vb->lock)->rlock);
[   56.812266]
[   56.812266]  *** DEADLOCK ***
[   56.812266]
[   56.830670] 1 lock held by ksoftirqd/1/13:
[   56.836838]  #0:  (rcu_read_lock){.+.+..}, at: [<ffffffff8118f44c>] vm_unmap_aliases+0x8c/0x380
[   56.849757]
[   56.849757] stack backtrace:
[   56.862194] CPU: 1 PID: 13 Comm: ksoftirqd/1 Not tainted 3.12.0-rc3+ #45
[   56.868721] Hardware name: System manufacturer System Product Name/P8Z77 WS, BIOS 3007 07/26/2012
[   56.882004]  ffffffff821944c0 ffff88080bbdb8c8 ffffffff8175a145 0000000000000007
[   56.895630]  ffff88080bbd5f40 ffff88080bbdb928 ffffffff81755b14 0000000000000001
[   56.909313]  ffff880800000001 ffff880800000000 ffffffff8101178f 0000000000000001
[   56.923006] Call Trace:
[   56.929532]  [<ffffffff8175a145>] dump_stack+0x55/0x76
[   56.936067]  [<ffffffff81755b14>] print_usage_bug+0x1f7/0x208
[   56.942445]  [<ffffffff8101178f>] ? save_stack_trace+0x2f/0x50
[   56.948932]  [<ffffffff810cc0a0>] ? check_usage_backwards+0x150/0x150
[   56.955470]  [<ffffffff810ccb52>] mark_lock+0x282/0x2c0
[   56.961945]  [<ffffffff810ccfed>] __lock_acquire+0x45d/0x1d50
[   56.968474]  [<ffffffff810cce6e>] ? __lock_acquire+0x2de/0x1d50
[   56.975140]  [<ffffffff81393bf5>] ? cpumask_next_and+0x55/0x90
[   56.981942]  [<ffffffff810cef72>] lock_acquire+0x92/0x1d0
[   56.988745]  [<ffffffff8118f52a>] ? vm_unmap_aliases+0x16a/0x380
[   56.995619]  [<ffffffff817628f1>] _raw_spin_lock+0x41/0x50
[   57.002493]  [<ffffffff8118f52a>] ? vm_unmap_aliases+0x16a/0x380
[   57.009447]  [<ffffffff8118f52a>] vm_unmap_aliases+0x16a/0x380
[   57.016477]  [<ffffffff8118f44c>] ? vm_unmap_aliases+0x8c/0x380
[   57.023607]  [<ffffffff810436b0>] change_page_attr_set_clr+0xc0/0x460
[   57.030818]  [<ffffffff810cfb8d>] ? trace_hardirqs_on+0xd/0x10
[   57.037896]  [<ffffffff811a8330>] ? kmem_cache_free+0xb0/0x2b0
[   57.044789]  [<ffffffff811b59c3>] ? free_object_rcu+0x93/0xa0
[   57.051720]  [<ffffffff81043d9f>] set_memory_rw+0x2f/0x40
[   57.058727]  [<ffffffff8104e17c>] bpf_jit_free+0x2c/0x40
[   57.065577]  [<ffffffff81642cba>] sk_filter_release_rcu+0x1a/0x30
[   57.072338]  [<ffffffff811108e2>] rcu_process_callbacks+0x202/0x7c0
[   57.078962]  [<ffffffff81057f17>] __do_softirq+0xf7/0x3f0
[   57.085373]  [<ffffffff81058245>] run_ksoftirqd+0x35/0x70

cannot reuse jited filter memory, since it's readonly,
so use original bpf insns memory to hold work_struct

defer kfree of sk_filter until jit completed freeing

tested on x86_64 and i386

Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2013-10-07 15:16:45 -04:00
Eric Dumazet 5199dfe531 sparc: bpf_jit_comp: can call module_free() from any context
module_free()/vfree() takes care of details, we no longer need a wrapper
and a work_struct.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2013-05-17 18:27:52 -07:00
Daniel Borkmann 79617801ea filter: bpf_jit_comp: refactor and unify BPF JIT image dump output
If bpf_jit_enable > 1, then we dump the emitted JIT compiled image
after creation. Currently, only SPARC and PowerPC has similar output
as in the reference implementation on x86_64. Make a small helper
function in order to reduce duplicated code and make the dump output
uniform across architectures x86_64, SPARC, PPC, ARM (e.g. on ARM
flen, pass and proglen are currently not shown, but would be
interesting to know as well), also for future BPF JIT implementations
on other archs.

Cc: Mircea Gherzan <mgherzan@gmail.com>
Cc: Matt Evans <matt@ozlabs.org>
Cc: Eric Dumazet <eric.dumazet@google.com>
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2013-03-21 17:25:56 -04:00
Daniel Borkmann 54e7e2df3e sparc: bpf_jit_comp: add VLAN instructions for BPF JIT
This patch is a follow-up for patch "net: filter: add vlan tag access"
to support the new VLAN_TAG/VLAN_TAG_PRESENT accessors in BPF JIT.

Signed-off-by: Daniel Borkmann <daniel.borkmann@tik.ee.ethz.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
2012-11-06 17:41:42 -05:00
Daniel Borkmann aa99521eed sparc: bpf_jit_comp: add XOR instruction for BPF JIT JIT
This patch is a follow-up for patch "filter: add XOR instruction for use
with X/K" that implements BPF SPARC JIT parts for the BPF XOR operation.

Signed-off-by: Daniel Borkmann <daniel.borkmann@tik.ee.ethz.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
2012-09-27 18:04:35 -04:00
David S. Miller d7ce8a5f63 sparc bpf_jit: support BPF_S_ANC_ALU_XOR_X instruction
Signed-off-by: David S. Miller <davem@davemloft.net>
2012-06-06 10:20:21 -07:00
Eric Dumazet 85bba52de1 net: filter: remove unused cpu_off in sparc JIT
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2012-04-17 22:55:59 -04:00
David S. Miller 584c5e2ad3 net: filter: Fix some more small issues in sparc JIT.
Fix mixed space and tabs.

Put bpf_jit_load_*[] externs into bpf_jit.h

"while(0)" --> "while (0)"
"COND (X)" --> "COND(X)"
Document branch offset calculations, and bpf_error's return
sequence.

Document the reason we need to emit three nops between the
%y register write and the divide instruction.

Remove erroneous trailing semicolons from emit_read_y() and
emit_write_y().

Based upon feedback from Sam Ravnborg.

Signed-off-by: David S. Miller <davem@davemloft.net>
2012-04-17 16:43:46 -04:00
David S. Miller 7b56f76edf net: filter: Fix some minor issues in sparc JIT.
Correct conventions comments.  %o4 and %o5 were swapped,
%g3 was not documented.

Use r_TMP instead of r_SKB_DATA + r_OFF where possible in
assembler stubs.

Correct discussion of %o4 and %o5 in one of bpf_jit_compile()'s
comments.

Based upon feedback from Richard Mortimer.

Signed-off-by: David S. Miller <davem@davemloft.net>
2012-04-17 16:08:29 -04:00
David S. Miller 2809a2087c net: filter: Just In Time compiler for sparc
Signed-off-by: David S. Miller <davem@davemloft.net>
2012-04-16 23:15:14 -04:00