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From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: "Luke Nelson" <luke.r.nels@gmail.com>,
	"Xi Wang" <xi.wang@gmail.com>, "Song Liu" <songliubraving@fb.com>,
	"Björn Töpel" <bjorn.topel@gmail.com>,
	"Palmer Dabbelt" <palmer@sifive.com>,
	"Alexei Starovoitov" <ast@kernel.org>,
	"Sasha Levin" <sashal@kernel.org>,
	netdev@vger.kernel.org, linux-riscv@lists.infradead.org,
	bpf@vger.kernel.org
Subject: [PATCH AUTOSEL 5.1 24/95] bpf, riscv: clear high 32 bits for ALU32 add/sub/neg/lsh/rsh/arsh
Date: Wed, 26 Jun 2019 20:29:09 -0400
Message-ID: <20190627003021.19867-24-sashal@kernel.org> (raw)
In-Reply-To: <20190627003021.19867-1-sashal@kernel.org>

From: Luke Nelson <luke.r.nels@gmail.com>

[ Upstream commit 1e692f09e091bf5c8b38384f297d6dae5dbf0f12 ]

In BPF, 32-bit ALU operations should zero-extend their results into
the 64-bit registers.

The current BPF JIT on RISC-V emits incorrect instructions that perform
sign extension only (e.g., addw, subw) on 32-bit add, sub, lsh, rsh,
arsh, and neg. This behavior diverges from the interpreter and JITs
for other architectures.

This patch fixes the bugs by performing zero extension on the destination
register of 32-bit ALU operations.

Fixes: 2353ecc6f91f ("bpf, riscv: add BPF JIT for RV64G")
Cc: Xi Wang <xi.wang@gmail.com>
Signed-off-by: Luke Nelson <luke.r.nels@gmail.com>
Acked-by: Song Liu <songliubraving@fb.com>
Acked-by: Björn Töpel <bjorn.topel@gmail.com>
Reviewed-by: Palmer Dabbelt <palmer@sifive.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/riscv/net/bpf_jit_comp.c | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/arch/riscv/net/bpf_jit_comp.c b/arch/riscv/net/bpf_jit_comp.c
index e5c8d675bd6e..426d5c33ea90 100644
--- a/arch/riscv/net/bpf_jit_comp.c
+++ b/arch/riscv/net/bpf_jit_comp.c
@@ -751,10 +751,14 @@ static int emit_insn(const struct bpf_insn *insn, struct rv_jit_context *ctx,
 	case BPF_ALU | BPF_ADD | BPF_X:
 	case BPF_ALU64 | BPF_ADD | BPF_X:
 		emit(is64 ? rv_add(rd, rd, rs) : rv_addw(rd, rd, rs), ctx);
+		if (!is64)
+			emit_zext_32(rd, ctx);
 		break;
 	case BPF_ALU | BPF_SUB | BPF_X:
 	case BPF_ALU64 | BPF_SUB | BPF_X:
 		emit(is64 ? rv_sub(rd, rd, rs) : rv_subw(rd, rd, rs), ctx);
+		if (!is64)
+			emit_zext_32(rd, ctx);
 		break;
 	case BPF_ALU | BPF_AND | BPF_X:
 	case BPF_ALU64 | BPF_AND | BPF_X:
@@ -795,14 +799,20 @@ static int emit_insn(const struct bpf_insn *insn, struct rv_jit_context *ctx,
 	case BPF_ALU | BPF_LSH | BPF_X:
 	case BPF_ALU64 | BPF_LSH | BPF_X:
 		emit(is64 ? rv_sll(rd, rd, rs) : rv_sllw(rd, rd, rs), ctx);
+		if (!is64)
+			emit_zext_32(rd, ctx);
 		break;
 	case BPF_ALU | BPF_RSH | BPF_X:
 	case BPF_ALU64 | BPF_RSH | BPF_X:
 		emit(is64 ? rv_srl(rd, rd, rs) : rv_srlw(rd, rd, rs), ctx);
+		if (!is64)
+			emit_zext_32(rd, ctx);
 		break;
 	case BPF_ALU | BPF_ARSH | BPF_X:
 	case BPF_ALU64 | BPF_ARSH | BPF_X:
 		emit(is64 ? rv_sra(rd, rd, rs) : rv_sraw(rd, rd, rs), ctx);
+		if (!is64)
+			emit_zext_32(rd, ctx);
 		break;
 
 	/* dst = -dst */
@@ -810,6 +820,8 @@ static int emit_insn(const struct bpf_insn *insn, struct rv_jit_context *ctx,
 	case BPF_ALU64 | BPF_NEG:
 		emit(is64 ? rv_sub(rd, RV_REG_ZERO, rd) :
 		     rv_subw(rd, RV_REG_ZERO, rd), ctx);
+		if (!is64)
+			emit_zext_32(rd, ctx);
 		break;
 
 	/* dst = BSWAP##imm(dst) */
@@ -964,14 +976,20 @@ static int emit_insn(const struct bpf_insn *insn, struct rv_jit_context *ctx,
 	case BPF_ALU | BPF_LSH | BPF_K:
 	case BPF_ALU64 | BPF_LSH | BPF_K:
 		emit(is64 ? rv_slli(rd, rd, imm) : rv_slliw(rd, rd, imm), ctx);
+		if (!is64)
+			emit_zext_32(rd, ctx);
 		break;
 	case BPF_ALU | BPF_RSH | BPF_K:
 	case BPF_ALU64 | BPF_RSH | BPF_K:
 		emit(is64 ? rv_srli(rd, rd, imm) : rv_srliw(rd, rd, imm), ctx);
+		if (!is64)
+			emit_zext_32(rd, ctx);
 		break;
 	case BPF_ALU | BPF_ARSH | BPF_K:
 	case BPF_ALU64 | BPF_ARSH | BPF_K:
 		emit(is64 ? rv_srai(rd, rd, imm) : rv_sraiw(rd, rd, imm), ctx);
+		if (!is64)
+			emit_zext_32(rd, ctx);
 		break;
 
 	/* JUMP off */
-- 
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 ` [PATCH AUTOSEL 5.1 11/95] bpf, riscv: clear target register high 32-bits for and/or/xor on ALU32 Sasha Levin
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 ` Sasha Levin [this message]
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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