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authorAndrey Ignatov <rdna@fb.com>2019-04-03 23:22:38 -0700
committerDaniel Borkmann <daniel@iogearbox.net>2019-04-05 16:50:07 +0200
commitf68a5b44647bce6c34b10d5560c5b2c0aff31afc (patch)
tree0170d9696f79fbc5363e971bc8550673d89724a1 /tools/testing/selftests/bpf/verifier
parentbpf: Reject indirect var_off stack access in raw mode (diff)
downloadlinux-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/selftests/bpf/verifier')
-rw-r--r--tools/testing/selftests/bpf/verifier/var_off.c27
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. */