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bpf: Fix jit blinding with new sdiv/smov insns

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Handle new insns properly in bpf_jit_blind_insn() function.

Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/r/20230728011225.3715812-1-yonghong.song@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Yonghong Song 2023-07-27 18:12:25 -07:00 committed by Alexei Starovoitov
parent ec0e2da95f
commit 7058e3a31e
2 changed files with 12 additions and 6 deletions
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14
include/linux/filter.h
View File

@ -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) \

4
kernel/bpf/core.c
View File

@ -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: