bpf: Test_verifier, #65 error message updates for trunc of boundary-cross
After changes to add update_reg_bounds after ALU ops and 32-bit bounds tracking truncation of boundary crossing range will fail earlier and with a different error message. Now the test error trace is the following 11: (17) r1 -= 2147483584 12: R0_w=map_value(id=0,off=0,ks=8,vs=8,imm=0) R1_w=invP(id=0,smin_value=-2147483584,smax_value=63) R10=fp0 fp-8_w=mmmmmmmm 12: (17) r1 -= 2147483584 13: R0_w=map_value(id=0,off=0,ks=8,vs=8,imm=0) R1_w=invP(id=0, umin_value=18446744069414584448,umax_value=18446744071562068095, var_off=(0xffffffff00000000; 0xffffffff)) R10=fp0 fp-8_w=mmmmmmmm 13: (77) r1 >>= 8 14: R0_w=map_value(id=0,off=0,ks=8,vs=8,imm=0) R1_w=invP(id=0, umin_value=72057594021150720,umax_value=72057594029539328, var_off=(0xffffffff000000; 0xffffff), s32_min_value=-16777216,s32_max_value=-1, u32_min_value=-16777216) R10=fp0 fp-8_w=mmmmmmmm 14: (0f) r0 += r1 value 72057594021150720 makes map_value pointer be out of bounds Because we have 'umin_value == umax_value' instead of previously where 'umin_value != umax_value' we can now fail earlier noting that pointer addition is out of bounds. Signed-off-by: John Fastabend <john.fastabend@gmail.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/158560428103.10843.6316594510312781186.stgit@john-Precision-5820-Tower
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@ -257,17 +257,15 @@
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* [0x00ff'ffff'ff00'0000, 0x00ff'ffff'ffff'ffff]
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*/
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BPF_ALU64_IMM(BPF_RSH, BPF_REG_1, 8),
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/* no-op or OOB pointer computation */
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/* error on OOB pointer computation */
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BPF_ALU64_REG(BPF_ADD, BPF_REG_0, BPF_REG_1),
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/* potentially OOB access */
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BPF_LDX_MEM(BPF_B, BPF_REG_0, BPF_REG_0, 0),
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/* exit */
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BPF_MOV64_IMM(BPF_REG_0, 0),
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BPF_EXIT_INSN(),
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},
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.fixup_map_hash_8b = { 3 },
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/* not actually fully unbounded, but the bound is very high */
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.errstr = "R0 unbounded memory access",
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.errstr = "value 72057594021150720 makes map_value pointer be out of bounds",
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.result = REJECT
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},
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{
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@ -299,17 +297,15 @@
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* [0x00ff'ffff'ff00'0000, 0x00ff'ffff'ffff'ffff]
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*/
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BPF_ALU64_IMM(BPF_RSH, BPF_REG_1, 8),
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/* no-op or OOB pointer computation */
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/* error on OOB pointer computation */
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BPF_ALU64_REG(BPF_ADD, BPF_REG_0, BPF_REG_1),
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/* potentially OOB access */
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BPF_LDX_MEM(BPF_B, BPF_REG_0, BPF_REG_0, 0),
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/* exit */
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BPF_MOV64_IMM(BPF_REG_0, 0),
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BPF_EXIT_INSN(),
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},
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.fixup_map_hash_8b = { 3 },
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/* not actually fully unbounded, but the bound is very high */
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.errstr = "R0 unbounded memory access",
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.errstr = "value 72057594021150720 makes map_value pointer be out of bounds",
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.result = REJECT
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},
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{
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