Commit Graph

17 Commits

Author SHA1 Message Date
Heiko Carstens
3af57f78c3 s390/bpf,jit: fix 32 bit divisions, use unsigned divide instructions
The s390 bpf jit compiler emits the signed divide instructions "dr" and "d"
for unsigned divisions.
This can cause problems: the dividend will be zero extended to a 64 bit value
and the divisor is the 32 bit signed value as specified A or X accumulator,
even though A and X are supposed to be treated as unsigned values.

The divide instrunctions will generate an exception if the result cannot be
expressed with a 32 bit signed value.
This is the case if e.g. the dividend is 0xffffffff and the divisor either 1
or also 0xffffffff (signed: -1).

To avoid all these issues simply use unsigned divide instructions.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2014-01-17 18:54:49 -08:00
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
Martin Schwidefsky
6cef30034c s390/bpf,jit: fix prolog oddity
The prolog of functions generated by the bpf jit compiler uses an
instruction sequence with an "ahi" instruction to create stack space
instead of using an "aghi" instruction. Using the 32-bit "ahi" is not
wrong as the stack we are operating on is an order-4 allocation which
is always aligned to 16KB. But it is more consistent to use an "aghi"
as the stack pointer is a 64-bit value.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2013-10-24 17:16:59 +02:00
Heiko Carstens
0f20822a69 s390/dis: move disassembler function prototypes to proper header file
Now that the in-kernel disassembler has an own header file move the
disassembler related function prototypes to that header file.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2013-10-24 17:16:48 +02:00
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
Heiko Carstens
4784955a52 s390/bpf,jit: fix address randomization
Add misssing braces to hole calculation. This resulted in an addition
instead of an substraction. Which in turn means that the jit compiler
could try to write out of bounds of the allocated piece of memory.

This bug was introduced with aa2d2c73 "s390/bpf,jit: address randomize
and write protect jit code".

Fixes this one:

[   37.320956] Unable to handle kernel pointer dereference at virtual kernel address 000003ff80231000
[   37.320984] Oops: 0011 [#1] PREEMPT SMP DEBUG_PAGEALLOC
[   37.320993] Modules linked in: dm_multipath scsi_dh eadm_sch dm_mod ctcm fsm autofs4
[   37.321007] CPU: 28 PID: 6443 Comm: multipathd Not tainted 3.10.9-61.x.20130829-s390xdefault #1
[   37.321011] task: 0000004ada778000 ti: 0000004ae3304000 task.ti: 0000004ae3304000
[   37.321014] Krnl PSW : 0704c00180000000 000000000012d1de (bpf_jit_compile+0x198e/0x23d0)
[   37.321022]            R:0 T:1 IO:1 EX:1 Key:0 M:1 W:0 P:0 AS:3 CC:0 PM:0 EA:3
               Krnl GPRS: 000000004350207d 0000004a00000001 0000000000000007 000003ff80231002
[   37.321029]            0000000000000007 000003ff80230ffe 00000000a7740000 000003ff80230f76
[   37.321032]            000003ffffffffff 000003ff00000000 000003ff0000007d 000000000071e820
[   37.321035]            0000004adbe99950 000000000071ea18 0000004af3d9e7c0 0000004ae3307b80
[   37.321046] Krnl Code: 000000000012d1d0: 41305004            la      %r3,4(%r5)
                          000000000012d1d4: e330f0f80021        clg     %r3,248(%r15)
                         #000000000012d1da: a7240009            brc     2,12d1ec
                         >000000000012d1de: 50805000            st      %r8,0(%r5)
                          000000000012d1e2: e330f0f00004        lg      %r3,240(%r15)
                          000000000012d1e8: 41303004            la      %r3,4(%r3)
                          000000000012d1ec: e380f0e00004        lg      %r8,224(%r15)
                          000000000012d1f2: e330f0f00024        stg     %r3,240(%r15)
[   37.321074] Call Trace:
[   37.321077] ([<000000000012da78>] bpf_jit_compile+0x2228/0x23d0)
[   37.321083]  [<00000000006007c2>] sk_attach_filter+0xfe/0x214
[   37.321090]  [<00000000005d2d92>] sock_setsockopt+0x926/0xbdc
[   37.321097]  [<00000000005cbfb6>] SyS_setsockopt+0x8a/0xe8
[   37.321101]  [<00000000005ccaa8>] SyS_socketcall+0x264/0x364
[   37.321106]  [<0000000000713f1c>] sysc_nr_ok+0x22/0x28
[   37.321113]  [<000003fffce10ea8>] 0x3fffce10ea8
[   37.321118] INFO: lockdep is turned off.
[   37.321121] Last Breaking-Event-Address:
[   37.321124]  [<000000000012d192>] bpf_jit_compile+0x1942/0x23d0
[   37.321132]
[   37.321135] Kernel panic - not syncing: Fatal exception: panic_on_oops

Cc: stable@vger.kernel.org # v3.11
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
2013-09-04 17:18:55 +02:00
Heiko Carstens
c9a7afa380 s390/bpf,jit: add pkt_type support
s390 version of 3b58908a "x86: bpf_jit_comp: add pkt_type support".

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
2013-07-18 12:44:38 +02:00
Heiko Carstens
aa2d2c73c2 s390/bpf,jit: address randomize and write protect jit code
This is the s390 variant of 314beb9b "x86: bpf_jit_comp: secure bpf
jit against spraying attacks".
With this change the whole jit code and literal pool will be write
protected after creation. In addition the start address of the jit
code won't be always on a page boundary anymore.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2013-07-18 12:44:37 +02:00
Heiko Carstens
fee1b5488d s390/bpf,jit: use generic jit dumper
This is the s390 backend of 79617801 "filter: bpf_jit_comp: refactor
and unify BPF JIT image dump output".

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2013-07-18 12:44:35 +02:00
Heiko Carstens
1eeb74782d s390/bpf,jit: call module_free() from any context
The workqueue workaround is no longer needed. Same as 5199dfe531
"sparc: bpf_jit_comp: can call module_free() from any context".

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2013-07-18 12:44:34 +02:00
Stelian Nirlu
3d04fea5e7 s390/bpf,jit: use kcalloc instead of kmalloc and memset
Signed-off-by: Stelian Nirlu <steliannirlu@gmail.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2013-04-17 14:07:27 +02:00
Heiko Carstens
5303a0fe8c s390/bpf,jit: add vlan tag support
s390 version of 855ddb56 "x86: bpf_jit_comp: add vlan tag support".

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2013-02-14 15:55:20 +01:00
Heiko Carstens
916908df24 s390/bpf,jit: add support for XOR instruction
Add support for XOR instruction for use with X/K.

s390 JIT support for the new BPF_S_ALU_XOR_* instructions introduced
with 9e49e889 "filter: add XOR instruction for use with X/K".

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2012-12-03 10:44:05 -05:00
Heiko Carstens
3247274536 s390/bpf,jit: add support MOD instruction
Add support for MOD operation for s390's JIT.

Same as 280050cc "x86 bpf_jit: support MOD operation" for x86 which
adds JIT support for the generic new MOD operation introduced with
b6069a9570 "filter: add MOD operation".

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2012-12-03 10:44:02 -05:00
Heiko Carstens
c59eed111b s390/bpf,jit: add support for BPF_S_ANC_ALU_XOR_X instruction
Add support for new BPF_S_ANC_ALU_XOR_X instruction which got added
with ffe06c17 "filter: add XOR operation".

s390 version of 4bfaddf1 "x86 bpf_jit: support BPF_S_ANC_ALU_XOR_X instruction".

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2012-09-26 15:45:28 +02:00
Heiko Carstens
68d9884dbc s390/bpf,jit: improve code generation
Make use of new immediate instructions that came with the
extended immediate and general instruction extension facilities.

Reviewed-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2012-09-26 15:44:49 +02:00
Martin Schwidefsky
c10302efe5 s390/bpf,jit: BPF Just In Time compiler for s390
The s390 implementation of the JIT compiler for packet filter speedup.

Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2012-09-26 15:44:49 +02:00