From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Ilya Leoshkevich <iii@linux.ibm.com>,
Yauheni Kaliuta <yauheni.kaliuta@redhat.com>,
Vasily Gorbik <gor@linux.ibm.com>,
Daniel Borkmann <daniel@iogearbox.net>,
Sasha Levin <sashal@kernel.org>,
netdev@vger.kernel.org, bpf@vger.kernel.org,
linux-s390@vger.kernel.org
Subject: [PATCH AUTOSEL 5.2 17/94] s390/bpf: use 32-bit index for tail calls
Date: Wed, 4 Sep 2019 11:56:22 -0400 [thread overview]
Message-ID: <20190904155739.2816-17-sashal@kernel.org> (raw)
In-Reply-To: <20190904155739.2816-1-sashal@kernel.org>
From: Ilya Leoshkevich <iii@linux.ibm.com>
[ Upstream commit 91b4db5313a2c793aabc2143efb8ed0cf0fdd097 ]
"p runtime/jit: pass > 32bit index to tail_call" fails when
bpf_jit_enable=1, because the tail call is not executed.
This in turn is because the generated code assumes index is 64-bit,
while it must be 32-bit, and as a result prog array bounds check fails,
while it should pass. Even if bounds check would have passed, the code
that follows uses 64-bit index to compute prog array offset.
Fix by using clrj instead of clgrj for comparing index with array size,
and also by using llgfr for truncating index to 32 bits before using it
to compute prog array offset.
Fixes: 6651ee070b31 ("s390/bpf: implement bpf_tail_call() helper")
Reported-by: Yauheni Kaliuta <yauheni.kaliuta@redhat.com>
Acked-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/s390/net/bpf_jit_comp.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)
diff --git a/arch/s390/net/bpf_jit_comp.c b/arch/s390/net/bpf_jit_comp.c
index 9a711472cbdc0..fd9844f947f79 100644
--- a/arch/s390/net/bpf_jit_comp.c
+++ b/arch/s390/net/bpf_jit_comp.c
@@ -1027,8 +1027,8 @@ static noinline int bpf_jit_insn(struct bpf_jit *jit, struct bpf_prog *fp, int i
/* llgf %w1,map.max_entries(%b2) */
EMIT6_DISP_LH(0xe3000000, 0x0016, REG_W1, REG_0, BPF_REG_2,
offsetof(struct bpf_array, map.max_entries));
- /* clgrj %b3,%w1,0xa,label0: if %b3 >= %w1 goto out */
- EMIT6_PCREL_LABEL(0xec000000, 0x0065, BPF_REG_3,
+ /* clrj %b3,%w1,0xa,label0: if (u32)%b3 >= (u32)%w1 goto out */
+ EMIT6_PCREL_LABEL(0xec000000, 0x0077, BPF_REG_3,
REG_W1, 0, 0xa);
/*
@@ -1054,8 +1054,10 @@ static noinline int bpf_jit_insn(struct bpf_jit *jit, struct bpf_prog *fp, int i
* goto out;
*/
- /* sllg %r1,%b3,3: %r1 = index * 8 */
- EMIT6_DISP_LH(0xeb000000, 0x000d, REG_1, BPF_REG_3, REG_0, 3);
+ /* llgfr %r1,%b3: %r1 = (u32) index */
+ EMIT4(0xb9160000, REG_1, BPF_REG_3);
+ /* sllg %r1,%r1,3: %r1 *= 8 */
+ EMIT6_DISP_LH(0xeb000000, 0x000d, REG_1, REG_1, REG_0, 3);
/* lg %r1,prog(%b2,%r1) */
EMIT6_DISP_LH(0xe3000000, 0x0004, REG_1, BPF_REG_2,
REG_1, offsetof(struct bpf_array, ptrs));
--
2.20.1
next prev parent reply other threads:[~2019-09-04 16:20 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-04 15:56 [PATCH AUTOSEL 5.2 01/94] ieee802154: hwsim: Fix error handle path in hwsim_init_module Sasha Levin
2019-09-04 15:56 ` [PATCH AUTOSEL 5.2 10/94] s390/bpf: fix lcgr instruction encoding Sasha Levin
2019-09-04 15:56 ` Sasha Levin [this message]
2019-09-04 15:56 ` [PATCH AUTOSEL 5.2 19/94] selftests/bpf: fix "bind{4, 6} deny specific IP & port" on s390 Sasha Levin
2019-09-04 15:56 ` [PATCH AUTOSEL 5.2 20/94] tools: bpftool: close prog FD before exit on showing a single program Sasha Levin
2019-09-04 15:56 ` [PATCH AUTOSEL 5.2 30/94] xdp: unpin xdp umem pages in error path Sasha Levin
2019-09-04 15:56 ` [PATCH AUTOSEL 5.2 31/94] selftests/bpf: fix test_cgroup_storage on s390 Sasha Levin
2019-09-04 15:56 ` [PATCH AUTOSEL 5.2 32/94] selftests/bpf: add config fragment BPF_JIT Sasha Levin
2019-09-04 15:56 ` [PATCH AUTOSEL 5.2 33/94] selftests/bpf: install files test_xdp_vlan.sh Sasha Levin
2019-09-04 15:56 ` [PATCH AUTOSEL 5.2 40/94] flow_dissector: Fix potential use-after-free on BPF_PROG_DETACH Sasha Levin
2019-09-04 15:56 ` [PATCH AUTOSEL 5.2 41/94] bpf: fix use after free in prog symbol exposure Sasha Levin
2019-09-04 15:56 ` [PATCH AUTOSEL 5.2 42/94] bpf: allow narrow loads of some sk_reuseport_md fields with offset > 0 Sasha Levin
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