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| author |   Andrey Ignatov <rdna@fb.com> | 2019-04-03 23:22:38 -0700 |
|---|---|---|
| committer |   Daniel Borkmann <daniel@iogearbox.net> | 2019-04-05 16:50:07 +0200 |
| commit | f68a5b44647bce6c34b10d5560c5b2c0aff31afc (patch) | |
| tree | 0170d9696f79fbc5363e971bc8550673d89724a1 /tools/testing | |
| parent | bpf: Reject indirect var_off stack access in raw mode (diff) | |
| download | linux-dev-f68a5b44647bce6c34b10d5560c5b2c0aff31afc.tar.xz linux-dev-f68a5b44647bce6c34b10d5560c5b2c0aff31afc.zip | |
selftests/bpf: Test indirect var_off stack access in raw mode
Test that verifier rejects indirect access to uninitialized stack with
variable offset.
Example of output:
# ./test_verifier
...
#859/p indirect variable-offset stack access, uninitialized OK
Signed-off-by: Andrey Ignatov <rdna@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Diffstat (limited to 'tools/testing')
| -rw-r--r-- | tools/testing/selftests/bpf/verifier/var_off.c | 27 |
1 files changed, 27 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/verifier/var_off.c b/tools/testing/selftests/bpf/verifier/var_off.c index c4ebd0bb0781..3840bd16e173 100644 --- a/tools/testing/selftests/bpf/verifier/var_off.c +++ b/tools/testing/selftests/bpf/verifier/var_off.c @@ -115,6 +115,33 @@ .prog_type = BPF_PROG_TYPE_LWT_IN, }, { + "indirect variable-offset stack access, uninitialized", + .insns = { + BPF_MOV64_IMM(BPF_REG_2, 6), + BPF_MOV64_IMM(BPF_REG_3, 28), + /* Fill the top 16 bytes of the stack. */ + BPF_ST_MEM(BPF_W, BPF_REG_10, -16, 0), + BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0), + /* Get an unknown value. */ + BPF_LDX_MEM(BPF_W, BPF_REG_4, BPF_REG_1, 0), + /* Make it small and 4-byte aligned. */ + BPF_ALU64_IMM(BPF_AND, BPF_REG_4, 4), + BPF_ALU64_IMM(BPF_SUB, BPF_REG_4, 16), + /* Add it to fp. We now have either fp-12 or fp-16, we don't know + * which, but either way it points to initialized stack. + */ + BPF_ALU64_REG(BPF_ADD, BPF_REG_4, BPF_REG_10), + BPF_MOV64_IMM(BPF_REG_5, 8), + /* Dereference it indirectly. */ + BPF_EMIT_CALL(BPF_FUNC_getsockopt), + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_EXIT_INSN(), + }, + .errstr = "invalid indirect read from stack var_off", + .result = REJECT, + .prog_type = BPF_PROG_TYPE_SOCK_OPS, +}, +{ "indirect variable-offset stack access, ok", .insns = { /* Fill the top 16 bytes of the stack. */ |