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From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: "Björn Töpel" <bjorn.topel@gmail.com>,
	"Jiong Wang" <jiong.wang@netronome.com>,
	"Daniel Borkmann" <daniel@iogearbox.net>,
	"Sasha Levin" <sashal@kernel.org>,
	netdev@vger.kernel.org, bpf@vger.kernel.org,
	linux-riscv@lists.infradead.org
Subject: [PATCH AUTOSEL 5.1 11/95] bpf, riscv: clear target register high 32-bits for and/or/xor on ALU32
Date: Wed, 26 Jun 2019 20:28:56 -0400
Message-ID: <20190627003021.19867-11-sashal@kernel.org> (raw)
In-Reply-To: <20190627003021.19867-1-sashal@kernel.org>

From: Björn Töpel <bjorn.topel@gmail.com>

[ Upstream commit fe121ee531d1362810bfd30f38a1b88b1d3d376c ]

When using 32-bit subregisters (ALU32), the RISC-V JIT would not clear
the high 32-bits of the target register and therefore generate
incorrect code.

E.g., in the following code:

  $ cat test.c
  unsigned int f(unsigned long long a,
  	       unsigned int b)
  {
  	return (unsigned int)a & b;
  }

  $ clang-9 -target bpf -O2 -emit-llvm -S test.c -o - | \
  	llc-9 -mattr=+alu32 -mcpu=v3
  	.text
  	.file	"test.c"
  	.globl	f
  	.p2align	3
  	.type	f,@function
  f:
  	r0 = r1
  	w0 &= w2
  	exit
  .Lfunc_end0:
  	.size	f, .Lfunc_end0-f

The JIT would not clear the high 32-bits of r0 after the
and-operation, which in this case might give an incorrect return
value.

After this patch, that is not the case, and the upper 32-bits are
cleared.

Reported-by: Jiong Wang <jiong.wang@netronome.com>
Fixes: 2353ecc6f91f ("bpf, riscv: add BPF JIT for RV64G")
Signed-off-by: Björn Töpel <bjorn.topel@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/riscv/net/bpf_jit_comp.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/arch/riscv/net/bpf_jit_comp.c b/arch/riscv/net/bpf_jit_comp.c
index 80b12aa5e10d..e5c8d675bd6e 100644
--- a/arch/riscv/net/bpf_jit_comp.c
+++ b/arch/riscv/net/bpf_jit_comp.c
@@ -759,14 +759,20 @@ static int emit_insn(const struct bpf_insn *insn, struct rv_jit_context *ctx,
 	case BPF_ALU | BPF_AND | BPF_X:
 	case BPF_ALU64 | BPF_AND | BPF_X:
 		emit(rv_and(rd, rd, rs), ctx);
+		if (!is64)
+			emit_zext_32(rd, ctx);
 		break;
 	case BPF_ALU | BPF_OR | BPF_X:
 	case BPF_ALU64 | BPF_OR | BPF_X:
 		emit(rv_or(rd, rd, rs), ctx);
+		if (!is64)
+			emit_zext_32(rd, ctx);
 		break;
 	case BPF_ALU | BPF_XOR | BPF_X:
 	case BPF_ALU64 | BPF_XOR | BPF_X:
 		emit(rv_xor(rd, rd, rs), ctx);
+		if (!is64)
+			emit_zext_32(rd, ctx);
 		break;
 	case BPF_ALU | BPF_MUL | BPF_X:
 	case BPF_ALU64 | BPF_MUL | BPF_X:
-- 
2.20.1


  parent reply index

Thread overview: 52+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20190627003021.19867-1-sashal@kernel.org>
2019-06-27  0:28 ` [PATCH AUTOSEL 5.1 08/95] bpf: fix out-of-bounds read in __bpf_skc_lookup Sasha Levin
2019-06-27  0:28 ` [PATCH AUTOSEL 5.1 09/95] samples, bpf: fix to change the buffer size for read() Sasha Levin
2019-06-27  0:28 ` [PATCH AUTOSEL 5.1 10/95] samples, bpf: suppress compiler warning Sasha Levin
2019-06-27  0:28 ` Sasha Levin [this message]
2019-06-27  0:28 ` [PATCH AUTOSEL 5.1 12/95] bpf: sockmap, restore sk_write_space when psock gets dropped Sasha Levin
2019-06-27  0:28 ` [PATCH AUTOSEL 5.1 13/95] mac80211: fix rate reporting inside cfg80211_calculate_bitrate_he() Sasha Levin
2019-06-27  0:28 ` [PATCH AUTOSEL 5.1 14/95] bpf: sockmap, fix use after free from sleep in psock backlog workqueue Sasha Levin
2019-06-27  0:29 ` [PATCH AUTOSEL 5.1 19/95] mac80211: mesh: fix RCU warning Sasha Levin
2019-06-27  0:29 ` [PATCH AUTOSEL 5.1 20/95] mac80211: free peer keys before vif down in mesh Sasha Levin
2019-06-27  0:29 ` [PATCH AUTOSEL 5.1 22/95] mwifiex: Fix possible buffer overflows at parsing bss descriptor Sasha Levin
2019-06-27  0:29 ` [PATCH AUTOSEL 5.1 23/95] mwifiex: Abort at too short BSS descriptor element Sasha Levin
2019-06-27  0:29 ` [PATCH AUTOSEL 5.1 24/95] bpf, riscv: clear high 32 bits for ALU32 add/sub/neg/lsh/rsh/arsh Sasha Levin
2019-06-27  0:29 ` [PATCH AUTOSEL 5.1 25/95] iwlwifi: fix load in rfkill flow for unified firmware Sasha Levin
2019-06-27  0:29 ` [PATCH AUTOSEL 5.1 26/95] iwlwifi: clear persistence bit according to device family Sasha Levin
2019-06-27  0:29 ` [PATCH AUTOSEL 5.1 27/95] iwlwifi: fix AX201 killer sku loading firmware issue Sasha Levin
2019-06-27  0:29 ` [PATCH AUTOSEL 5.1 28/95] iwlwifi: Fix double-free problems in iwl_req_fw_callback() Sasha Levin
2019-06-27  0:29 ` [PATCH AUTOSEL 5.1 29/95] mwifiex: Fix heap overflow in mwifiex_uap_parse_tail_ies() Sasha Levin
2019-06-27  0:29 ` [PATCH AUTOSEL 5.1 30/95] bpf: udp: ipv6: Avoid running reuseport's bpf_prog from __udp6_lib_err Sasha Levin
2019-06-27  0:29 ` [PATCH AUTOSEL 5.1 31/95] bpf: udp: Avoid calling reuseport's bpf_prog from udp_gro Sasha Levin
2019-06-27  0:29 ` [PATCH AUTOSEL 5.1 32/95] netfilter: ipv6: nf_defrag: fix leakage of unqueued fragments Sasha Levin
2019-06-27  0:29 ` [PATCH AUTOSEL 5.1 33/95] tools: bpftool: Fix JSON output when lookup fails Sasha Levin
2019-06-27  0:29 ` [PATCH AUTOSEL 5.1 36/95] netfilter: ipv6: nf_defrag: accept duplicate fragments again Sasha Levin
2019-06-27  0:29 ` [PATCH AUTOSEL 5.1 37/95] dt-bindings: can: mcp251x: add mcp25625 support Sasha Levin
2019-06-27  0:29 ` [PATCH AUTOSEL 5.1 38/95] can: mcp251x: add support for mcp25625 Sasha Levin
2019-06-27  0:29 ` [PATCH AUTOSEL 5.1 39/95] can: m_can: implement errata "Needless activation of MRAF irq" Sasha Levin
2019-06-27  0:29 ` [PATCH AUTOSEL 5.1 40/95] can: af_can: Fix error path of can_init() Sasha Levin
2019-06-27  0:29 ` [PATCH AUTOSEL 5.1 41/95] can: flexcan: Remove unneeded registration message Sasha Levin
2019-06-27  0:29 ` [PATCH AUTOSEL 5.1 42/95] net: phy: rename Asix Electronics PHY driver Sasha Levin
2019-06-27  0:29 ` [PATCH AUTOSEL 5.1 43/95] ibmvnic: Do not close unopened driver during reset Sasha Levin
2019-06-27  0:29 ` [PATCH AUTOSEL 5.1 44/95] ibmvnic: Refresh device multicast list after reset Sasha Levin
2019-06-27  0:29 ` [PATCH AUTOSEL 5.1 45/95] ibmvnic: Fix unchecked return codes of memory allocations Sasha Levin
2019-06-27  0:29 ` [PATCH AUTOSEL 5.1 48/95] bpf: lpm_trie: check left child of last leftmost node for NULL Sasha Levin
2019-06-27  0:29 ` [PATCH AUTOSEL 5.1 54/95] xdp: check device pointer before clearing Sasha Levin
2019-06-27  0:29 ` [PATCH AUTOSEL 5.1 56/95] mlxsw: spectrum: Disallow prio-tagged packets when PVID is removed Sasha Levin
2019-06-27  0:29 ` [PATCH AUTOSEL 5.1 58/95] bpf: fix div64 overflow tests to properly detect errors Sasha Levin
2019-06-27  0:29 ` [PATCH AUTOSEL 5.1 64/95] mac80211: only warn once on chanctx_conf being NULL Sasha Levin
2019-06-27  0:29 ` [PATCH AUTOSEL 5.1 65/95] mac80211: do not start any work during reconfigure flow Sasha Levin
2019-06-27  0:29 ` [PATCH AUTOSEL 5.1 66/95] cfg80211: util: fix bit count off by one Sasha Levin
2019-06-27  0:29 ` [PATCH AUTOSEL 5.1 67/95] cfg80211: report measurement start TSF correctly Sasha Levin
2019-06-27  0:29 ` [PATCH AUTOSEL 5.1 68/95] bpf, devmap: Fix premature entry free on destroying map Sasha Levin
2019-06-27  0:29 ` [PATCH AUTOSEL 5.1 69/95] bpf, devmap: Add missing bulk queue free Sasha Levin
2019-06-27  0:29 ` [PATCH AUTOSEL 5.1 70/95] bpf, devmap: Add missing RCU read lock on flush Sasha Levin
2019-06-27  0:29 ` [PATCH AUTOSEL 5.1 71/95] bpf, x64: fix stack layout of JITed bpf code Sasha Levin
2019-06-27  0:29 ` [PATCH AUTOSEL 5.1 72/95] qmi_wwan: add support for QMAP padding in the RX path Sasha Levin
2019-06-27  0:29 ` [PATCH AUTOSEL 5.1 73/95] qmi_wwan: avoid RCU stalls on device disconnect when in QMAP mode Sasha Levin
2019-06-27  0:29 ` [PATCH AUTOSEL 5.1 74/95] qmi_wwan: extend permitted QMAP mux_id value range Sasha Levin
2019-06-27  0:30 ` [PATCH AUTOSEL 5.1 75/95] bpf: fix nested bpf tracepoints with per-cpu data Sasha Levin
2019-06-27  0:30 ` [PATCH AUTOSEL 5.1 84/95] bnx2x: Check if transceiver implements DDM before access Sasha Levin
2019-06-27  0:30 ` [PATCH AUTOSEL 5.1 86/95] ip6_tunnel: allow not to count pkts on tstats by passing dev as NULL Sasha Levin
2019-06-27  0:30 ` [PATCH AUTOSEL 5.1 87/95] net: lio_core: fix potential sign-extension overflow on large shift Sasha Levin
2019-06-27  0:30 ` [PATCH AUTOSEL 5.1 92/95] net: dsa: mv88e6xxx: fix shift of FID bits in mv88e6185_g1_vtu_loadpurge() Sasha Levin
2019-06-27  0:30 ` [PATCH AUTOSEL 5.1 95/95] net :sunrpc :clnt :Fix xps refcount imbalance on the error path Sasha Levin

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