diff options
| author | Alexei Starovoitov <ast@kernel.org> | 2019-01-26 13:33:03 -0800 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2019-01-26 13:33:03 -0800 |
| commit | ae575c8a9868c2247c6ba287b91f0420e27aad4b (patch) | |
| tree | dae6534e7471ad23e7698aa60ef663fa753d0871 /kernel | |
| parent | dbbd79ae166fbd37ceaef77a96b5a99cce0022c3 (diff) | |
| parent | 3ef84346c56141c72a28efcad2ddf17809533832 (diff) | |
Merge branch 'jmp32-insns'
Jiong Wang says:
====================
v3 -> v4:
- Fixed rebase issue. JMP32 checks were missing in two new functions:
+ kernel/bpf/verifier.c:insn_is_cond_jump
+ drivers/net/ethernet/netronome/nfp/bpf/main.h:is_mbpf_cond_jump
(Daniel)
- Further rebased on top of latest llvm-readelf change.
v2 -> v3:
- Added missed check on JMP32 inside bpf_jit_build_body. (Sandipan)
- Wrap ?: statements in s390 port with brace. They are used by macros
which doesn't guard the operand with brace.
- Fixed the ',' issues test_verifier change.
- Reorder two selftests patches to be near each other.
- Rebased on top of latest bpf-next.
v1 -> v2:
- Updated encoding. Use reserved insn class 0x6 instead of packing with
existing BPF_JMP. (Alexei)
- Updated code comments in s390 port. (Martin)
- Separate JIT function for jeq32_imm in NFP port. (Jakub)
- Re-implemented auto-testing support. (Jakub)
- Moved testcases to test_verifer.c, plus more unit tests. (Jakub)
- Fixed JEQ/JNE range deduction. (Jakub)
- Also supported JSET in this patch set.
- Fixed/Improved range deduction for all the other operations. All C
programs under bpf selftest passed verification now.
- Improved min/max code implementation.
- Fixed bpftool/disassembler.
Current eBPF ISA has 32-bit sub-register and has defined a set of ALU32
instructions.
However, there is no JMP32 instructions, the consequence is code-gen for
32-bit sub-registers is not efficient. For example, explicit sign-extension
from 32-bit to 64-bit is needed for signed comparison.
Adding JMP32 instruction therefore could complete eBPF ISA on 32-bit
sub-register support. This also match those JMP32 instructions in most JIT
backends, for example x64-64 and AArch64. These new eBPF JMP32 instructions
could have one-to-one map on them.
A few verifier ALU32 related bugs has been fixed recently, and JMP32
introduced by this set further improves BPF sub-register ecosystem. Once
this is landed, BPF programs using 32-bit sub-register ISA could get
reasonably good support from verifier and JIT compilers. Users then could
compare the runtime efficiency of one BPF program under both modes, and
could use the one shown better from benchmark result.
From benchmark results on some Cilium BPF programs, for 64-bit arches,
after JMP32 introduced, programs compiled with -mattr=+alu32 (meaning
enable sub-register usage) are smaller in code size and generally smaller
in verifier processed insn number.
Benchmark results
===
Text size in bytes (generated by "size")
---
LLVM code-gen option default alu32 alu32/jmp32 change Vs. change Vs.
alu32 default
bpf_lb-DLB_L3.o: 6456 6280 6160 -1.91% -4.58%
bpf_lb-DLB_L4.o: 7848 7664 7136 -6.89% -9.07%
bpf_lb-DUNKNOWN.o: 2680 2664 2568 -3.60% -4.18%
bpf_lxc.o: 104824 104744 97360 -7.05% -7.12%
bpf_netdev.o: 23456 23576 21632 -8.25% -7.78%
bpf_overlay.o: 16184 16304 14648 -10.16% -9.49%
Processed instruction number
---
LLVM code-gen option default alu32 alu32/jmp32 change Vs. change Vs.
alu32 default
bpf_lb-DLB_L3.o: 1579 1281 1295 +1.09% -17.99%
bpf_lb-DLB_L4.o: 2045 1663 1556 -6.43% -23.91%
bpf_lb-DUNKNOWN.o: 606 513 501 -2.34% -17.33%
bpf_lxc.o: 85381 103218 94435 -8.51% +10.60%
bpf_netdev.o: 5246 5809 5200 -10.48% -0.08%
bpf_overlay.o: 2443 2705 2456 -9.02% -0.53%
It is even better for 32-bit arches like x32, arm32 and nfp etc, as now
some conditional jump will become JMP32 which doesn't require code-gen for
high 32-bit comparison.
Encoding
===
The new JMP32 instructions are using new BPF_JMP32 class which is using
the reserved eBPF class number 0x6. And BPF_JA/CALL/EXIT only exist for
BPF_JMP, they are reserved opcode for BPF_JMP32.
LLVM support
===
A couple of unit tests has been added and included in this set. Also LLVM
code-gen for JMP32 has been added, so you could just compile any BPF C
program with both -mcpu=probe and -mattr=+alu32 specified. If you are
compiling on a machine with kernel patched by this set, LLVM will select
the ISA automatically based on host probe results. Otherwise specify
-mcpu=v3 and -mattr=+alu32 could also force use JMP32 ISA.
LLVM support could be found at:
https://github.com/Netronome/llvm/tree/jmp32-v2
(clang driver also taught about the new "v3" processor, will send out
merge request for both clang and llvm once kernel set landed.)
JIT backends support
===
A couple of JIT backends has been supported in this set except SPARC and
MIPS. It shouldn't be a big issue for these two ports as LLVM default won't
generate JMP32 insns, it will only generate them when host machine is
probed to be with the support.
Thanks.
====================
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/bpf/core.c | 221 | ||||
| -rw-r--r-- | kernel/bpf/disasm.c | 34 | ||||
| -rw-r--r-- | kernel/bpf/verifier.c | 365 |
3 files changed, 370 insertions, 250 deletions
diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index 2a81b8af3748..a7bcb23bee84 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -362,7 +362,8 @@ static int bpf_adj_branches(struct bpf_prog *prog, u32 pos, s32 end_old, 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. */ @@ -948,6 +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); @@ -1144,6 +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), \ @@ -1404,145 +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: \ diff --git a/kernel/bpf/disasm.c b/kernel/bpf/disasm.c index d6b76377cb6e..de73f55e42fd 100644 --- a/kernel/bpf/disasm.c +++ b/kernel/bpf/disasm.c @@ -67,7 +67,7 @@ const char *const bpf_class_string[8] = { [BPF_STX] = "stx", [BPF_ALU] = "alu", [BPF_JMP] = "jmp", - [BPF_RET] = "BUG", + [BPF_JMP32] = "jmp32", [BPF_ALU64] = "alu64", }; @@ -136,23 +136,22 @@ void print_bpf_insn(const struct bpf_insn_cbs *cbs, else print_bpf_end_insn(verbose, cbs->private_data, insn); } else if (BPF_OP(insn->code) == BPF_NEG) { - verbose(cbs->private_data, "(%02x) r%d = %s-r%d\n", - insn->code, insn->dst_reg, - class == BPF_ALU ? "(u32) " : "", + verbose(cbs->private_data, "(%02x) %c%d = -%c%d\n", + insn->code, class == BPF_ALU ? 'w' : 'r', + insn->dst_reg, class == BPF_ALU ? 'w' : 'r', insn->dst_reg); } else if (BPF_SRC(insn->code) == BPF_X) { - verbose(cbs->private_data, "(%02x) %sr%d %s %sr%d\n", - insn->code, class == BPF_ALU ? "(u32) " : "", + verbose(cbs->private_data, "(%02x) %c%d %s %c%d\n", + insn->code, class == BPF_ALU ? 'w' : 'r', insn->dst_reg, bpf_alu_string[BPF_OP(insn->code) >> 4], - class == BPF_ALU ? "(u32) " : "", + class == BPF_ALU ? 'w' : 'r', insn->src_reg); } else { - verbose(cbs->private_data, "(%02x) %sr%d %s %s%d\n", - insn->code, class == BPF_ALU ? "(u32) " : "", + verbose(cbs->private_data, "(%02x) %c%d %s %d\n", + insn->code, class == BPF_ALU ? 'w' : 'r', insn->dst_reg, bpf_alu_string[BPF_OP(insn->code) >> 4], - class == BPF_ALU ? "(u32) " : "", insn->imm); } } else if (class == BPF_STX) { @@ -220,7 +219,7 @@ void print_bpf_insn(const struct bpf_insn_cbs *cbs, verbose(cbs->private_data, "BUG_ld_%02x\n", insn->code); return; } - } else if (class == BPF_JMP) { + } else if (class == BPF_JMP32 || class == BPF_JMP) { u8 opcode = BPF_OP(insn->code); if (opcode == BPF_CALL) { @@ -244,13 +243,18 @@ void print_bpf_insn(const struct bpf_insn_cbs *cbs, } else if (insn->code == (BPF_JMP | BPF_EXIT)) { verbose(cbs->private_data, "(%02x) exit\n", insn->code); } else if (BPF_SRC(insn->code) == BPF_X) { - verbose(cbs->private_data, "(%02x) if r%d %s r%d goto pc%+d\n", - insn->code, insn->dst_reg, + verbose(cbs->private_data, + "(%02x) if %c%d %s %c%d goto pc%+d\n", + insn->code, class == BPF_JMP32 ? 'w' : 'r', + insn->dst_reg, bpf_jmp_string[BPF_OP(insn->code) >> 4], + class == BPF_JMP32 ? 'w' : 'r', insn->src_reg, insn->off); } else { - verbose(cbs->private_data, "(%02x) if r%d %s 0x%x goto pc%+d\n", - insn->code, insn->dst_reg, + verbose(cbs->private_data, + "(%02x) if %c%d %s 0x%x goto pc%+d\n", + insn->code, class == BPF_JMP32 ? 'w' : 'r', + insn->dst_reg, bpf_jmp_string[BPF_OP(insn->code) >> 4], insn->imm, insn->off); } diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 8cfe39ef770f..8c1c21cd50b4 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -1095,7 +1095,7 @@ static int check_subprogs(struct bpf_verifier_env *env) for (i = 0; i < insn_cnt; i++) { u8 code = insn[i].code; - if (BPF_CLASS(code) != BPF_JMP) + if (BPF_CLASS(code) != BPF_JMP && BPF_CLASS(code) != BPF_JMP32) goto next; if (BPF_OP(code) == BPF_EXIT || BPF_OP(code) == BPF_CALL) goto next; @@ -4031,11 +4031,50 @@ static void find_good_pkt_pointers(struct bpf_verifier_state *vstate, * 0 - branch will not be taken and fall-through to next insn * -1 - unknown. Example: "if (reg < 5)" is unknown when register value range [0,10] */ -static int is_branch_taken(struct bpf_reg_state *reg, u64 val, u8 opcode) +static int is_branch_taken(struct bpf_reg_state *reg, u64 val, u8 opcode, + bool is_jmp32) { + struct bpf_reg_state reg_lo; + s64 sval; + if (__is_pointer_value(false, reg)) return -1; + if (is_jmp32) { + reg_lo = *reg; + reg = ®_lo; + /* For JMP32, only low 32 bits are compared, coerce_reg_to_size + * could truncate high bits and update umin/umax according to + * information of low bits. + */ + coerce_reg_to_size(reg, 4); + /* smin/smax need special handling. For example, after coerce, + * if smin_value is 0x00000000ffffffffLL, the value is -1 when + * used as operand to JMP32. It is a negative number from s32's + * point of view, while it is a positive number when seen as + * s64. The smin/smax are kept as s64, therefore, when used with + * JMP32, they need to be transformed into s32, then sign + * extended back to s64. + * + * Also, smin/smax were copied from umin/umax. If umin/umax has + * different sign bit, then min/max relationship doesn't + * maintain after casting into s32, for this case, set smin/smax + * to safest range. + */ + if ((reg->umax_value ^ reg->umin_value) & + (1ULL << 31)) { + reg->smin_value = S32_MIN; + reg->smax_value = S32_MAX; + } + reg->smin_value = (s64)(s32)reg->smin_value; + reg->smax_value = (s64)(s32)reg->smax_value; + + val = (u32)val; + sval = (s64)(s32)val; + } else { + sval = (s64)val; + } + switch (opcode) { case BPF_JEQ: if (tnum_is_const(reg->var_off)) @@ -4058,9 +4097,9 @@ static int is_branch_taken(struct bpf_reg_state *reg, u64 val, u8 opcode) return 0; break; case BPF_JSGT: - if (reg->smin_value > (s64)val) + if (reg->smin_value > sval) return 1; - else if (reg->smax_value < (s64)val) + else if (reg->smax_value < sval) return 0; break; case BPF_JLT: @@ -4070,9 +4109,9 @@ static int is_branch_taken(struct bpf_reg_state *reg, u64 val, u8 opcode) return 0; break; case BPF_JSLT: - if (reg->smax_value < (s64)val) + if (reg->smax_value < sval) return 1; - else if (reg->smin_value >= (s64)val) + else if (reg->smin_value >= sval) return 0; break; case BPF_JGE: @@ -4082,9 +4121,9 @@ static int is_branch_taken(struct bpf_reg_state *reg, u64 val, u8 opcode) return 0; break; case BPF_JSGE: - if (reg->smin_value >= (s64)val) + if (reg->smin_value >= sval) return 1; - else if (reg->smax_value < (s64)val) + else if (reg->smax_value < sval) return 0; break; case BPF_JLE: @@ -4094,9 +4133,9 @@ static int is_branch_taken(struct bpf_reg_state *reg, u64 val, u8 opcode) return 0; break; case BPF_JSLE: - if (reg->smax_value <= (s64)val) + if (reg->smax_value <= sval) return 1; - else if (reg->smin_value > (s64)val) + else if (reg->smin_value > sval) return 0; break; } @@ -4104,6 +4143,29 @@ static int is_branch_taken(struct bpf_reg_state *reg, u64 val, u8 opcode) return -1; } +/* Generate min value of the high 32-bit from TNUM info. */ +static u64 gen_hi_min(struct tnum var) +{ + return var.value & ~0xffffffffULL; +} + +/* Generate max value of the high 32-bit from TNUM info. */ +static u64 gen_hi_max(struct tnum var) +{ + return (var.value | var.mask) & ~0xffffffffULL; +} + +/* Return true if VAL is compared with a s64 sign extended from s32, and they + * are with the same signedness. + */ +static bool cmp_val_with_extended_s64(s64 sval, struct bpf_reg_state *reg) +{ + return ((s32)sval >= 0 && + reg->smin_value >= 0 && reg->smax_value <= S32_MAX) || + ((s32)sval < 0 && + reg->smax_value <= 0 && reg->smin_value >= S32_MIN); +} + /* Adjusts the register min/max values in the case that the dst_reg is the * variable register that we are working on, and src_reg is a constant or we're * simply doing a BPF_K check. @@ -4111,8 +4173,10 @@ static int is_branch_taken(struct bpf_reg_state *reg, u64 val, u8 opcode) */ static void reg_set_min_max(struct bpf_reg_state *true_reg, struct bpf_reg_state *false_reg, u64 val, - u8 opcode) + u8 opcode, bool is_jmp32) { + s64 sval; + /* If the dst_reg is a pointer, we can't learn anything about its * variable offset from the compare (unless src_reg were a pointer into * the same object, but we don't bother with that. @@ -4122,19 +4186,31 @@ static void reg_set_min_max(struct bpf_reg_state *true_reg, if (__is_pointer_value(false, false_reg)) return; + val = is_jmp32 ? (u32)val : val; + sval = is_jmp32 ? (s64)(s32)val : (s64)val; + switch (opcode) { case BPF_JEQ: - /* If this is false then we know nothing Jon Snow, but if it is - * true then we know for sure. - */ - __mark_reg_known(true_reg, val); - break; case BPF_JNE: - /* If this is true we know nothing Jon Snow, but if it is false - * we know the value for sure; + { + struct bpf_reg_state *reg = + opcode == BPF_JEQ ? true_reg : false_reg; + + /* For BPF_JEQ, if this is false we know nothing Jon Snow, but + * if it is true we know the value for sure. Likewise for + * BPF_JNE. */ - __mark_reg_known(false_reg, val); + if (is_jmp32) { + u64 old_v = reg->var_off.value; + u64 hi_mask = ~0xffffffffULL; + + reg->var_off.value = (old_v & hi_mask) | val; + reg->var_off.mask &= hi_mask; + } else { + __mark_reg_known(reg, val); + } break; + } case BPF_JSET: false_reg->var_off = tnum_and(false_reg->var_off, tnum_const(~val)); @@ -4142,38 +4218,61 @@ static void reg_set_min_max(struct bpf_reg_state *true_reg, true_reg->var_off = tnum_or(true_reg->var_off, tnum_const(val)); break; - case BPF_JGT: - false_reg->umax_value = min(false_reg->umax_value, val); - true_reg->umin_value = max(true_reg->umin_value, val + 1); - break; - case BPF_JSGT: - false_reg->smax_value = min_t(s64, false_reg->smax_value, val); - true_reg->smin_value = max_t(s64, true_reg->smin_value, val + 1); - break; - case BPF_JLT: - false_reg->umin_value = max(false_reg->umin_value, val); - true_reg->umax_value = min(true_reg->umax_value, val - 1); - break; - case BPF_JSLT: - false_reg->smin_value = max_t(s64, false_reg->smin_value, val); - true_reg->smax_value = min_t(s64, true_reg->smax_value, val - 1); - break; case BPF_JGE: - false_reg->umax_value = min(false_reg->umax_value, val - 1); - true_reg->umin_value = max(true_reg->umin_value, val); + case BPF_JGT: + { + u64 false_umax = opcode == BPF_JGT ? val : val - 1; + u64 true_umin = opcode == BPF_JGT ? val + 1 : val; + + if (is_jmp32) { + false_umax += gen_hi_max(false_reg->var_off); + true_umin += gen_hi_min(true_reg->var_off); + } + false_reg->umax_value = min(false_reg->umax_value, false_umax); + true_reg->umin_value = max(true_reg->umin_value, true_umin); break; + } case BPF_JSGE: - false_reg->smax_value = min_t(s64, false_reg->smax_value, val - 1); - true_reg->smin_value = max_t(s64, true_reg->smin_value, val); + case BPF_JSGT: + { + s64 false_smax = opcode == BPF_JSGT ? sval : sval - 1; + s64 true_smin = opcode == BPF_JSGT ? sval + 1 : sval; + + /* If the full s64 was not sign-extended from s32 then don't + * deduct further info. + */ + if (is_jmp32 && !cmp_val_with_extended_s64(sval, false_reg)) + break; + false_reg->smax_value = min(false_reg->smax_value, false_smax); + true_reg->smin_value = max(true_reg->smin_value, true_smin); break; + } case BPF_JLE: - false_reg->umin_value = max(false_reg->umin_value, val + 1); - true_reg->umax_value = min(true_reg->umax_value, val); + case BPF_JLT: + { + u64 false_umin = opcode == BPF_JLT ? val : val + 1; + u64 true_umax = opcode == BPF_JLT ? val - 1 : val; + + if (is_jmp32) { + false_umin += gen_hi_min(false_reg->var_off); + true_umax += gen_hi_max(true_reg->var_off); + } + false_reg->umin_value = max(false_reg->umin_value, false_umin); + true_reg->umax_value = min(true_reg->umax_value, true_umax); break; + } case BPF_JSLE: - false_reg->smin_value = max_t(s64, false_reg->smin_value, val + 1); - true_reg->smax_value = min_t(s64, true_reg->smax_value, val); + case BPF_JSLT: + { + s64 false_smin = opcode == BPF_JSLT ? sval : sval + 1; + s64 true_smax = opcode == BPF_JSLT ? sval - 1 : sval; + + if (is_jmp32 && !cmp_val_with_extended_s64(sval, false_reg)) + break; + false_reg->smin_value = max(false_reg->smin_value, false_smin); + true_reg->smax_value = min(true_reg->smax_value, true_smax); break; + } default: break; } @@ -4196,24 +4295,34 @@ static void reg_set_min_max(struct bpf_reg_state *true_reg, */ static void reg_set_min_max_inv(struct bpf_reg_state *true_reg, struct bpf_reg_state *false_reg, u64 val, - u8 opcode) + u8 opcode, bool is_jmp32) { + s64 sval; + if (__is_pointer_value(false, false_reg)) return; + val = is_jmp32 ? (u32)val : val; + sval = is_jmp32 ? (s64)(s32)val : (s64)val; + switch (opcode) { case BPF_JEQ: - /* If this is false then we know nothing Jon Snow, but if it is - * true then we know for sure. - */ - __mark_reg_known(true_reg, val); - break; case BPF_JNE: - /* If this is true we know nothing Jon Snow, but if it is false - * we know the value for sure; - */ - __mark_reg_known(false_reg, val); + { + struct bpf_reg_state *reg = + opcode == BPF_JEQ ? true_reg : false_reg; + + if (is_jmp32) { + u64 old_v = reg->var_off.value; + u64 hi_mask = ~0xffffffffULL; + + reg->var_off.value = (old_v & hi_mask) | val; + reg->var_off.mask &= hi_mask; + } else { + __mark_reg_known(reg, val); + } break; + } case BPF_JSET: false_reg->var_off = tnum_and(false_reg->var_off, tnum_const(~val)); @@ -4221,38 +4330,58 @@ static void reg_set_min_max_inv(struct bpf_reg_state *true_reg, true_reg->var_off = tnum_or(true_reg->var_off, tnum_const(val)); break; - case BPF_JGT: - true_reg->umax_value = min(true_reg->umax_value, val - 1); - false_reg->umin_value = max(false_reg->umin_value, val); - break; - case BPF_JSGT: - true_reg->smax_value = min_t(s64, true_reg->smax_value, val - 1); - false_reg->smin_value = max_t(s64, false_reg->smin_value, val); - break; - case BPF_JLT: - true_reg->umin_value = max(true_reg->umin_value, val + 1); - false_reg->umax_value = min(false_reg->umax_value, val); - break; - case BPF_JSLT: - true_reg->smin_value = max_t(s64, true_reg->smin_value, val + 1); - false_reg->smax_value = min_t(s64, false_reg->smax_value, val); - break; case BPF_JGE: - true_reg->umax_value = min(true_reg->umax_value, val); - false_reg->umin_value = max(false_reg->umin_value, val + 1); + case BPF_JGT: + { + u64 false_umin = opcode == BPF_JGT ? val : val + 1; + u64 true_umax = opcode == BPF_JGT ? val - 1 : val; + + if (is_jmp32) { + false_umin += gen_hi_min(false_reg->var_off); + true_umax += gen_hi_max(true_reg->var_off); + } + false_reg->umin_value = max(false_reg->umin_value, false_umin); + true_reg->umax_value = min(true_reg->umax_value, true_umax); break; + } case BPF_JSGE: - true_reg->smax_value = min_t(s64, true_reg->smax_value, val); - false_reg->smin_value = max_t(s64, false_reg->smin_value, val + 1); + case BPF_JSGT: + { + s64 false_smin = opcode == BPF_JSGT ? sval : sval + 1; + s64 true_smax = opcode == BPF_JSGT ? sval - 1 : sval; + + if (is_jmp32 && !cmp_val_with_extended_s64(sval, false_reg)) + break; + false_reg->smin_value = max(false_reg->smin_value, false_smin); + true_reg->smax_value = min(true_reg->smax_value, true_smax); break; + } case BPF_JLE: - true_reg->umin_value = max(true_reg->umin_value, val); - false_reg->umax_value = min(false_reg->umax_value, val - 1); + case BPF_JLT: + { + u64 false_umax = opcode == BPF_JLT ? val : val - 1; + u64 true_umin = opcode == BPF_JLT ? val + 1 : val; + + if (is_jmp32) { + false_umax += gen_hi_max(false_reg->var_off); + true_umin += gen_hi_min(true_reg->var_off); + } + false_reg->umax_value = min(false_reg->umax_value, false_umax); + true_reg->umin_value = max(true_reg->umin_value, true_umin); break; + } case BPF_JSLE: - true_reg->smin_value = max_t(s64, true_reg->smin_value, val); - false_reg->smax_value = min_t(s64, false_reg->smax_value, val - 1); + case BPF_JSLT: + { + s64 false_smax = opcode == BPF_JSLT ? sval : sval - 1; + s64 true_smin = opcode == BPF_JSLT ? sval + 1 : sval; + + if (is_jmp32 && !cmp_val_with_extended_s64(sval, false_reg)) + break; + false_reg->smax_value = min(false_reg->smax_value, false_smax); + true_reg->smin_value = max(true_reg->smin_value, true_smin); break; + } default: break; } @@ -4390,6 +4519,10 @@ static bool try_match_pkt_pointers(const struct bpf_insn *insn, if (BPF_SRC(insn->code) != BPF_X) return false; + /* Pointers are always 64-bit. */ + if (BPF_CLASS(insn->code) == BPF_JMP32) + return false; + switch (BPF_OP(insn->code)) { case BPF_JGT: if ((dst_reg->type == PTR_TO_PACKET && @@ -4482,16 +4615,18 @@ static int check_cond_jmp_op(struct bpf_verifier_env *env, struct bpf_reg_state *regs = this_branch->frame[this_branch->curframe]->regs; struct bpf_reg_state *dst_reg, *other_branch_regs; u8 opcode = BPF_OP(insn->code); + bool is_jmp32; int err; - if (opcode > BPF_JSLE) { - verbose(env, "invalid BPF_JMP opcode %x\n", opcode); + /* Only conditional jumps are expected to reach here. */ + if (opcode == BPF_JA || opcode > BPF_JSLE) { + verbose(env, "invalid BPF_JMP/JMP32 opcode %x\n", opcode); return -EINVAL; } if (BPF_SRC(insn->code) == BPF_X) { if (insn->imm != 0) { - verbose(env, "BPF_JMP uses reserved fields\n"); + verbose(env, "BPF_JMP/JMP32 uses reserved fields\n"); return -EINVAL; } @@ -4507,7 +4642,7 @@ static int check_cond_jmp_op(struct bpf_verifier_env *env, } } else { if (insn->src_reg != BPF_REG_0) { - verbose(env, "BPF_JMP uses reserved fields\n"); + verbose(env, "BPF_JMP/JMP32 uses reserved fields\n"); return -EINVAL; } } @@ -4518,9 +4653,11 @@ static int check_cond_jmp_op(struct bpf_verifier_env *env, return err; dst_reg = ®s[insn->dst_reg]; + is_jmp32 = BPF_CLASS(insn->code) == BPF_JMP32; if (BPF_SRC(insn->code) == BPF_K) { - int pred = is_branch_taken(dst_reg, insn->imm, opcode); + int pred = is_branch_taken(dst_reg, insn->imm, opcode, + is_jmp32); if (pred == 1) { /* only follow the goto, ignore fall-through */ @@ -4548,30 +4685,51 @@ static int check_cond_jmp_op(struct bpf_verifier_env *env, * comparable. */ if (BPF_SRC(insn->code) == BPF_X) { + struct bpf_reg_state *src_reg = ®s[insn->src_reg]; + struct bpf_reg_state lo_reg0 = *dst_reg; + struct bpf_reg_state lo_reg1 = *src_reg; + struct bpf_reg_state *src_lo, *dst_lo; + + dst_lo = &lo_reg0; + src_lo = &lo_reg1; + coerce_reg_to_size(dst_lo, 4); + coerce_reg_to_size(src_lo, 4); + if (dst_reg->type == SCALAR_VALUE && - regs[insn->src_reg].type == SCALAR_VALUE) { - if (tnum_is_const(regs[insn->src_reg].var_off)) + src_reg->type == SCALAR_VALUE) { + if (tnum_is_const(src_reg->var_off) || + (is_jmp32 && tnum_is_const(src_lo->var_off))) reg_set_min_max(&other_branch_regs[insn->dst_reg], - dst_reg, regs[insn->src_reg].var_off.value, - opcode); - else if (tnum_is_const(dst_reg->var_off)) + dst_reg, + is_jmp32 + ? src_lo->var_off.value + : src_reg->var_off.value, + opcode, is_jmp32); + else if (tnum_is_const(dst_reg->var_off) || + (is_jmp32 && tnum_is_const(dst_lo->var_off))) reg_set_min_max_inv(&other_branch_regs[insn->src_reg], - ®s[insn->src_reg], - dst_reg->var_off.value, opcode); - else if (opcode == BPF_JEQ || opcode == BPF_JNE) + src_reg, + is_jmp32 + ? dst_lo->var_off.value + : dst_reg->var_off.value, + opcode, is_jmp32); + else if (!is_jmp32 && + (opcode == BPF_JEQ || opcode == BPF_JNE)) /* Comparing for equality, we can combine knowledge */ reg_combine_min_max(&other_branch_regs[insn->src_reg], &other_branch_regs[insn->dst_reg], - ®s[insn->src_reg], - ®s[insn->dst_reg], opcode); + src_reg, dst_reg, opcode); } } else if (dst_reg->type == SCALAR_VALUE) { reg_set_min_max(&other_branch_regs[insn->dst_reg], - dst_reg, insn->imm, opcode); + dst_reg, insn->imm, opcode, is_jmp32); } - /* detect if R == 0 where R is returned from bpf_map_lookup_elem() */ - if (BPF_SRC(insn->code) == BPF_K && + /* detect if R == 0 where R is returned from bpf_map_lookup_elem(). + * NOTE: these optimizations below are related with pointer comparison + * which will never be JMP32. + */ + if (!is_jmp32 && BPF_SRC(insn->code) == BPF_K && insn->imm == 0 && (opcode == BPF_JEQ || opcode == BPF_JNE) && reg_type_may_be_null(dst_reg->type)) { /* Mark all identical registers in each branch as either @@ -4900,7 +5058,8 @@ peek_stack: goto check_state; t = insn_stack[cur_stack - 1]; - if (BPF_CLASS(insns[t].code) == BPF_JMP) { + if (BPF_CLASS(insns[t].code) == BPF_JMP || + BPF_CLASS(insns[t].code) == BPF_JMP32) { u8 opcode = BPF_OP(insns[t].code); if (opcode == BPF_EXIT) { @@ -6056,7 +6215,7 @@ static int do_check(struct bpf_verifier_env *env) if (err) return err; - } else if (class == BPF_JMP) { + } else if (class == BPF_JMP || class == BPF_JMP32) { u8 opcode = BPF_OP(insn->code); if (opcode == BPF_CALL) { @@ -6064,7 +6223,8 @@ static int do_check(struct bpf_verifier_env *env) insn->off != 0 || (insn->src_reg != BPF_REG_0 && insn->src_reg != BPF_PSEUDO_CALL) || - insn->dst_reg != BPF_REG_0) { + insn->dst_reg != BPF_REG_0 || + class == BPF_JMP32) { verbose(env, "BPF_CALL uses reserved fields\n"); return -EINVAL; } @@ -6080,7 +6240,8 @@ static int do_check(struct bpf_verifier_env *env) if (BPF_SRC(insn->code) != BPF_K || insn->imm != 0 || insn->src_reg != BPF_REG_0 || - insn->dst_reg != BPF_REG_0) { + insn->dst_reg != BPF_REG_0 || + class == BPF_JMP32) { verbose(env, "BPF_JA uses reserved fields\n"); return -EINVAL; } @@ -6092,7 +6253,8 @@ static int do_check(struct bpf_verifier_env *env) if (BPF_SRC(insn->code) != BPF_K || insn->imm != 0 || insn->src_reg != BPF_REG_0 || - insn->dst_reg != BPF_REG_0) { + insn->dst_reg != BPF_REG_0 || + class == BPF_JMP32) { verbose(env, "BPF_EXIT uses reserved fields\n"); return -EINVAL; } @@ -6609,6 +6771,9 @@ static bool insn_is_cond_jump(u8 code) { u8 op; + if (BPF_CLASS(code) == BPF_JMP32) + return true; + if (BPF_CLASS(code) != BPF_JMP) return false; |
