Commit 7058e3a3 authored by Yonghong Song's avatar Yonghong Song Committed by Alexei Starovoitov
Browse files

bpf: Fix jit blinding with new sdiv/smov insns 



Handle new insns properly in bpf_jit_blind_insn() function.

Acked-by: default avatarEduard Zingerman <eddyz87@gmail.com>
Signed-off-by: default avatarYonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/r/20230728011225.3715812-1-yonghong.song@linux.dev


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent ec0e2da9

include/linux/filter.h

+10 −4
Original line number Diff line number Diff line
@@ -93,22 +93,28 @@ struct ctl_table_header; 


/* ALU ops on registers, bpf_add|sub|...: dst_reg += src_reg */



#define BPF_ALU64_REG(OP, DST, SRC)				\

#define BPF_ALU64_REG_OFF(OP, DST, SRC, OFF)			\

	((struct bpf_insn) {					\

		.code  = BPF_ALU64 | BPF_OP(OP) | BPF_X,	\

		.dst_reg = DST,					\

		.src_reg = SRC,					\

		.off   = 0,					\

		.off   = OFF,					\

		.imm   = 0 })



#define BPF_ALU32_REG(OP, DST, SRC)				\

#define BPF_ALU64_REG(OP, DST, SRC)				\

	BPF_ALU64_REG_OFF(OP, DST, SRC, 0)



#define BPF_ALU32_REG_OFF(OP, DST, SRC, OFF)			\

	((struct bpf_insn) {					\

		.code  = BPF_ALU | BPF_OP(OP) | BPF_X,		\

		.dst_reg = DST,					\

		.src_reg = SRC,					\

		.off   = 0,					\

		.off   = OFF,					\

		.imm   = 0 })



#define BPF_ALU32_REG(OP, DST, SRC)				\

	BPF_ALU32_REG_OFF(OP, DST, SRC, 0)



/* ALU ops on immediates, bpf_add|sub|...: dst_reg += imm32 */



#define BPF_ALU64_IMM(OP, DST, IMM)				\

kernel/bpf/core.c

+2 −2
Original line number Diff line number Diff line
@@ -1272,7 +1272,7 @@ static int bpf_jit_blind_insn(const struct bpf_insn *from, 
	case BPF_ALU | BPF_MOD | BPF_K:

		*to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);

		*to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);

		*to++ = BPF_ALU32_REG(from->code, from->dst_reg, BPF_REG_AX);

		*to++ = BPF_ALU32_REG_OFF(from->code, from->dst_reg, BPF_REG_AX, from->off);

		break;



	case BPF_ALU64 | BPF_ADD | BPF_K:
@@ -1286,7 +1286,7 @@ static int bpf_jit_blind_insn(const struct bpf_insn *from, 
	case BPF_ALU64 | BPF_MOD | BPF_K:

		*to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);

		*to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);

		*to++ = BPF_ALU64_REG(from->code, from->dst_reg, BPF_REG_AX);

		*to++ = BPF_ALU64_REG_OFF(from->code, from->dst_reg, BPF_REG_AX, from->off);

		break;



	case BPF_JMP | BPF_JEQ  | BPF_K: