diff options
Diffstat (limited to 'kernel/bpf/core.c')
| -rw-r--r-- | kernel/bpf/core.c | 273 |
1 files changed, 119 insertions, 154 deletions
diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index f908b9356025..a7bcb23bee84 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -307,15 +307,16 @@ int bpf_prog_calc_tag(struct bpf_prog *fp) return 0; } -static int bpf_adj_delta_to_imm(struct bpf_insn *insn, u32 pos, u32 delta, - u32 curr, const bool probe_pass) +static int bpf_adj_delta_to_imm(struct bpf_insn *insn, u32 pos, s32 end_old, + s32 end_new, u32 curr, const bool probe_pass) { const s64 imm_min = S32_MIN, imm_max = S32_MAX; + s32 delta = end_new - end_old; s64 imm = insn->imm; - if (curr < pos && curr + imm + 1 > pos) + if (curr < pos && curr + imm + 1 >= end_old) imm += delta; - else if (curr > pos + delta && curr + imm + 1 <= pos + delta) + else if (curr >= end_new && curr + imm + 1 < end_new) imm -= delta; if (imm < imm_min || imm > imm_max) return -ERANGE; @@ -324,15 +325,16 @@ static int bpf_adj_delta_to_imm(struct bpf_insn *insn, u32 pos, u32 delta, return 0; } -static int bpf_adj_delta_to_off(struct bpf_insn *insn, u32 pos, u32 delta, - u32 curr, const bool probe_pass) +static int bpf_adj_delta_to_off(struct bpf_insn *insn, u32 pos, s32 end_old, + s32 end_new, u32 curr, const bool probe_pass) { const s32 off_min = S16_MIN, off_max = S16_MAX; + s32 delta = end_new - end_old; s32 off = insn->off; - if (curr < pos && curr + off + 1 > pos) + if (curr < pos && curr + off + 1 >= end_old) off += delta; - else if (curr > pos + delta && curr + off + 1 <= pos + delta) + else if (curr >= end_new && curr + off + 1 < end_new) off -= delta; if (off < off_min || off > off_max) return -ERANGE; @@ -341,10 +343,10 @@ static int bpf_adj_delta_to_off(struct bpf_insn *insn, u32 pos, u32 delta, return 0; } -static int bpf_adj_branches(struct bpf_prog *prog, u32 pos, u32 delta, - const bool probe_pass) +static int bpf_adj_branches(struct bpf_prog *prog, u32 pos, s32 end_old, + s32 end_new, const bool probe_pass) { - u32 i, insn_cnt = prog->len + (probe_pass ? delta : 0); + u32 i, insn_cnt = prog->len + (probe_pass ? end_new - end_old : 0); struct bpf_insn *insn = prog->insnsi; int ret = 0; @@ -356,22 +358,23 @@ static int bpf_adj_branches(struct bpf_prog *prog, u32 pos, u32 delta, * do any other adjustments. Therefore skip the patchlet. */ if (probe_pass && i == pos) { - i += delta + 1; - insn++; + i = end_new; + insn = prog->insnsi + end_old; } code = insn->code; - if (BPF_CLASS(code) != BPF_JMP || + if ((BPF_CLASS(code) != BPF_JMP && + BPF_CLASS(code) != BPF_JMP32) || BPF_OP(code) == BPF_EXIT) continue; /* Adjust offset of jmps if we cross patch boundaries. */ if (BPF_OP(code) == BPF_CALL) { if (insn->src_reg != BPF_PSEUDO_CALL) continue; - ret = bpf_adj_delta_to_imm(insn, pos, delta, i, - probe_pass); + ret = bpf_adj_delta_to_imm(insn, pos, end_old, + end_new, i, probe_pass); } else { - ret = bpf_adj_delta_to_off(insn, pos, delta, i, - probe_pass); + ret = bpf_adj_delta_to_off(insn, pos, end_old, + end_new, i, probe_pass); } if (ret) break; @@ -421,7 +424,7 @@ struct bpf_prog *bpf_patch_insn_single(struct bpf_prog *prog, u32 off, * we afterwards may not fail anymore. */ if (insn_adj_cnt > cnt_max && - bpf_adj_branches(prog, off, insn_delta, true)) + bpf_adj_branches(prog, off, off + 1, off + len, true)) return NULL; /* Several new instructions need to be inserted. Make room @@ -453,13 +456,25 @@ struct bpf_prog *bpf_patch_insn_single(struct bpf_prog *prog, u32 off, * the ship has sailed to reverse to the original state. An * overflow cannot happen at this point. */ - BUG_ON(bpf_adj_branches(prog_adj, off, insn_delta, false)); + BUG_ON(bpf_adj_branches(prog_adj, off, off + 1, off + len, false)); bpf_adj_linfo(prog_adj, off, insn_delta); return prog_adj; } +int bpf_remove_insns(struct bpf_prog *prog, u32 off, u32 cnt) +{ + /* Branch offsets can't overflow when program is shrinking, no need + * to call bpf_adj_branches(..., true) here + */ + memmove(prog->insnsi + off, prog->insnsi + off + cnt, + sizeof(struct bpf_insn) * (prog->len - off - cnt)); + prog->len -= cnt; + + return WARN_ON_ONCE(bpf_adj_branches(prog, off, off + cnt, off, false)); +} + void bpf_prog_kallsyms_del_subprogs(struct bpf_prog *fp) { int i; @@ -934,6 +949,27 @@ static int bpf_jit_blind_insn(const struct bpf_insn *from, *to++ = BPF_JMP_REG(from->code, from->dst_reg, BPF_REG_AX, off); break; + case BPF_JMP32 | BPF_JEQ | BPF_K: + case BPF_JMP32 | BPF_JNE | BPF_K: + case BPF_JMP32 | BPF_JGT | BPF_K: + case BPF_JMP32 | BPF_JLT | BPF_K: + case BPF_JMP32 | BPF_JGE | BPF_K: + case BPF_JMP32 | BPF_JLE | BPF_K: + case BPF_JMP32 | BPF_JSGT | BPF_K: + case BPF_JMP32 | BPF_JSLT | BPF_K: + case BPF_JMP32 | BPF_JSGE | BPF_K: + case BPF_JMP32 | BPF_JSLE | BPF_K: + case BPF_JMP32 | BPF_JSET | BPF_K: + /* Accommodate for extra offset in case of a backjump. */ + off = from->off; + if (off < 0) + off -= 2; + *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_JMP32_REG(from->code, from->dst_reg, BPF_REG_AX, + off); + break; + case BPF_LD | BPF_IMM | BPF_DW: *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ aux[1].imm); *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); @@ -1130,6 +1166,31 @@ EXPORT_SYMBOL_GPL(__bpf_call_base); INSN_2(JMP, CALL), \ /* Exit instruction. */ \ INSN_2(JMP, EXIT), \ + /* 32-bit Jump instructions. */ \ + /* Register based. */ \ + INSN_3(JMP32, JEQ, X), \ + INSN_3(JMP32, JNE, X), \ + INSN_3(JMP32, JGT, X), \ + INSN_3(JMP32, JLT, X), \ + INSN_3(JMP32, JGE, X), \ + INSN_3(JMP32, JLE, X), \ + INSN_3(JMP32, JSGT, X), \ + INSN_3(JMP32, JSLT, X), \ + INSN_3(JMP32, JSGE, X), \ + INSN_3(JMP32, JSLE, X), \ + INSN_3(JMP32, JSET, X), \ + /* Immediate based. */ \ + INSN_3(JMP32, JEQ, K), \ + INSN_3(JMP32, JNE, K), \ + INSN_3(JMP32, JGT, K), \ + INSN_3(JMP32, JLT, K), \ + INSN_3(JMP32, JGE, K), \ + INSN_3(JMP32, JLE, K), \ + INSN_3(JMP32, JSGT, K), \ + INSN_3(JMP32, JSLT, K), \ + INSN_3(JMP32, JSGE, K), \ + INSN_3(JMP32, JSLE, K), \ + INSN_3(JMP32, JSET, K), \ /* Jump instructions. */ \ /* Register based. */ \ INSN_3(JMP, JEQ, X), \ @@ -1390,145 +1451,49 @@ select_insn: out: CONT; } - /* JMP */ JMP_JA: insn += insn->off; CONT; - JMP_JEQ_X: - if (DST == SRC) { - insn += insn->off; - CONT_JMP; - } - CONT; - JMP_JEQ_K: - if (DST == IMM) { - insn += insn->off; - CONT_JMP; - } - CONT; - JMP_JNE_X: - if (DST != SRC) { - insn += insn->off; - CONT_JMP; - } - CONT; - JMP_JNE_K: - if (DST != IMM) { - insn += insn->off; - CONT_JMP; - } - CONT; - JMP_JGT_X: - if (DST > SRC) { - insn += insn->off; - CONT_JMP; - } - CONT; - JMP_JGT_K: - if (DST > IMM) { - insn += insn->off; - CONT_JMP; - } - CONT; - JMP_JLT_X: - if (DST < SRC) { - insn += insn->off; - CONT_JMP; - } - CONT; - JMP_JLT_K: - if (DST < IMM) { - insn += insn->off; - CONT_JMP; - } - CONT; - JMP_JGE_X: - if (DST >= SRC) { - insn += insn->off; - CONT_JMP; - } - CONT; - JMP_JGE_K: - if (DST >= IMM) { - insn += insn->off; - CONT_JMP; - } - CONT; - JMP_JLE_X: - if (DST <= SRC) { - insn += insn->off; - CONT_JMP; - } - CONT; - JMP_JLE_K: - if (DST <= IMM) { - insn += insn->off; - CONT_JMP; - } - CONT; - JMP_JSGT_X: - if (((s64) DST) > ((s64) SRC)) { - insn += insn->off; - CONT_JMP; - } - CONT; - JMP_JSGT_K: - if (((s64) DST) > ((s64) IMM)) { - insn += insn->off; - CONT_JMP; - } - CONT; - JMP_JSLT_X: - if (((s64) DST) < ((s64) SRC)) { - insn += insn->off; - CONT_JMP; - } - CONT; - JMP_JSLT_K: - if (((s64) DST) < ((s64) IMM)) { - insn += insn->off; - CONT_JMP; - } - CONT; - JMP_JSGE_X: - if (((s64) DST) >= ((s64) SRC)) { - insn += insn->off; - CONT_JMP; - } - CONT; - JMP_JSGE_K: - if (((s64) DST) >= ((s64) IMM)) { - insn += insn->off; - CONT_JMP; - } - CONT; - JMP_JSLE_X: - if (((s64) DST) <= ((s64) SRC)) { - insn += insn->off; - CONT_JMP; - } - CONT; - JMP_JSLE_K: - if (((s64) DST) <= ((s64) IMM)) { - insn += insn->off; - CONT_JMP; - } - CONT; - JMP_JSET_X: - if (DST & SRC) { - insn += insn->off; - CONT_JMP; - } - CONT; - JMP_JSET_K: - if (DST & IMM) { - insn += insn->off; - CONT_JMP; - } - CONT; JMP_EXIT: return BPF_R0; - + /* JMP */ +#define COND_JMP(SIGN, OPCODE, CMP_OP) \ + JMP_##OPCODE##_X: \ + if ((SIGN##64) DST CMP_OP (SIGN##64) SRC) { \ + insn += insn->off; \ + CONT_JMP; \ + } \ + CONT; \ + JMP32_##OPCODE##_X: \ + if ((SIGN##32) DST CMP_OP (SIGN##32) SRC) { \ + insn += insn->off; \ + CONT_JMP; \ + } \ + CONT; \ + JMP_##OPCODE##_K: \ + if ((SIGN##64) DST CMP_OP (SIGN##64) IMM) { \ + insn += insn->off; \ + CONT_JMP; \ + } \ + CONT; \ + JMP32_##OPCODE##_K: \ + if ((SIGN##32) DST CMP_OP (SIGN##32) IMM) { \ + insn += insn->off; \ + CONT_JMP; \ + } \ + CONT; + COND_JMP(u, JEQ, ==) + COND_JMP(u, JNE, !=) + COND_JMP(u, JGT, >) + COND_JMP(u, JLT, <) + COND_JMP(u, JGE, >=) + COND_JMP(u, JLE, <=) + COND_JMP(u, JSET, &) + COND_JMP(s, JSGT, >) + COND_JMP(s, JSLT, <) + COND_JMP(s, JSGE, >=) + COND_JMP(s, JSLE, <=) +#undef COND_JMP /* STX and ST and LDX*/ #define LDST(SIZEOP, SIZE) \ STX_MEM_##SIZEOP: \ |