From 1f9a1ea821ff25353a0e80d971e7958cd55b47a3 Mon Sep 17 00:00:00 2001 From: Yonghong Song Date: Thu, 27 Jul 2023 18:11:56 -0700 Subject: bpf: Support new sign-extension load insns Add interpreter/jit support for new sign-extension load insns which adds a new mode (BPF_MEMSX). Also add verifier support to recognize these insns and to do proper verification with new insns. In verifier, besides to deduce proper bounds for the dst_reg, probed memory access is also properly handled. Acked-by: Eduard Zingerman Signed-off-by: Yonghong Song Link: https://lore.kernel.org/r/20230728011156.3711870-1-yonghong.song@linux.dev Signed-off-by: Alexei Starovoitov --- include/linux/filter.h | 3 +++ 1 file changed, 3 insertions(+) (limited to 'include/linux') diff --git a/include/linux/filter.h b/include/linux/filter.h index f69114083ec7..a93242b5516b 100644 --- a/include/linux/filter.h +++ b/include/linux/filter.h @@ -69,6 +69,9 @@ struct ctl_table_header; /* unused opcode to mark special load instruction. Same as BPF_ABS */ #define BPF_PROBE_MEM 0x20 +/* unused opcode to mark special ldsx instruction. Same as BPF_IND */ +#define BPF_PROBE_MEMSX 0x40 + /* unused opcode to mark call to interpreter with arguments */ #define BPF_CALL_ARGS 0xe0 -- cgit v1.2.3 From 7058e3a31ee4b9240cccab5bc13c1afbfa3d16a0 Mon Sep 17 00:00:00 2001 From: Yonghong Song Date: Thu, 27 Jul 2023 18:12:25 -0700 Subject: bpf: Fix jit blinding with new sdiv/smov insns Handle new insns properly in bpf_jit_blind_insn() function. Acked-by: Eduard Zingerman Signed-off-by: Yonghong Song Link: https://lore.kernel.org/r/20230728011225.3715812-1-yonghong.song@linux.dev Signed-off-by: Alexei Starovoitov --- include/linux/filter.h | 14 ++++++++++---- kernel/bpf/core.c | 4 ++-- 2 files changed, 12 insertions(+), 6 deletions(-) (limited to 'include/linux') diff --git a/include/linux/filter.h b/include/linux/filter.h index a93242b5516b..f5eabe3fa5e8 100644 --- a/include/linux/filter.h +++ b/include/linux/filter.h @@ -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) \ diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index 3fe895199f6e..646d2fe537be 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -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: -- cgit v1.2.3