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| author | John Fastabend <john.fastabend@gmail.com> | 2020-03-30 23:38:01 +0200 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2020-03-31 00:00:30 +0200 |
| commit | 32f13a5add87caf11e9dd262372b4a2b79c57aa5 (patch) | |
| tree | d8870787d8c8eaa35b92abdf0a43a85d60eea292 | |
| parent | bpf: Test_verifier, bpf_get_stack return value add <0 (diff) | |
| download | linux-32f13a5add87caf11e9dd262372b4a2b79c57aa5.tar.xz linux-32f13a5add87caf11e9dd262372b4a2b79c57aa5.zip | |
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
| -rw-r--r-- | tools/testing/selftests/bpf/verifier/bounds.c | 12 |
1 files changed, 4 insertions, 8 deletions
diff --git a/tools/testing/selftests/bpf/verifier/bounds.c b/tools/testing/selftests/bpf/verifier/bounds.c index 7c9b659095e9..cf72fcc5ced0 100644 --- a/tools/testing/selftests/bpf/verifier/bounds.c +++ b/tools/testing/selftests/bpf/verifier/bounds.c @@ -257,17 +257,15 @@ * [0x00ff'ffff'ff00'0000, 0x00ff'ffff'ffff'ffff] */ BPF_ALU64_IMM(BPF_RSH, BPF_REG_1, 8), - /* no-op or OOB pointer computation */ + /* error on OOB pointer computation */ BPF_ALU64_REG(BPF_ADD, BPF_REG_0, BPF_REG_1), - /* potentially OOB access */ - BPF_LDX_MEM(BPF_B, BPF_REG_0, BPF_REG_0, 0), /* exit */ BPF_MOV64_IMM(BPF_REG_0, 0), BPF_EXIT_INSN(), }, .fixup_map_hash_8b = { 3 }, /* not actually fully unbounded, but the bound is very high */ - .errstr = "R0 unbounded memory access", + .errstr = "value 72057594021150720 makes map_value pointer be out of bounds", .result = REJECT }, { @@ -299,17 +297,15 @@ * [0x00ff'ffff'ff00'0000, 0x00ff'ffff'ffff'ffff] */ BPF_ALU64_IMM(BPF_RSH, BPF_REG_1, 8), - /* no-op or OOB pointer computation */ + /* error on OOB pointer computation */ BPF_ALU64_REG(BPF_ADD, BPF_REG_0, BPF_REG_1), - /* potentially OOB access */ - BPF_LDX_MEM(BPF_B, BPF_REG_0, BPF_REG_0, 0), /* exit */ BPF_MOV64_IMM(BPF_REG_0, 0), BPF_EXIT_INSN(), }, .fixup_map_hash_8b = { 3 }, /* not actually fully unbounded, but the bound is very high */ - .errstr = "R0 unbounded memory access", + .errstr = "value 72057594021150720 makes map_value pointer be out of bounds", .result = REJECT }, { |