From b33ceb6a3d2ee07fdd836373383a6d4783581324 Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Tue, 5 Dec 2023 10:42:43 -0800 Subject: selftests/bpf: validate STACK_ZERO is preserved on subreg spill Add tests validating that STACK_ZERO slots are preserved when slot is partially overwritten with subregister spill. Acked-by: Eduard Zingerman Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/r/20231205184248.1502704-6-andrii@kernel.org Signed-off-by: Alexei Starovoitov --- .../selftests/bpf/progs/verifier_spill_fill.c | 40 ++++++++++++++++++++++ 1 file changed, 40 insertions(+) (limited to 'tools/testing/selftests/bpf/progs') diff --git a/tools/testing/selftests/bpf/progs/verifier_spill_fill.c b/tools/testing/selftests/bpf/progs/verifier_spill_fill.c index 6115520154e3..d9dabae81176 100644 --- a/tools/testing/selftests/bpf/progs/verifier_spill_fill.c +++ b/tools/testing/selftests/bpf/progs/verifier_spill_fill.c @@ -4,6 +4,7 @@ #include #include #include "bpf_misc.h" +#include <../../../tools/include/linux/filter.h> struct { __uint(type, BPF_MAP_TYPE_RINGBUF); @@ -450,4 +451,43 @@ l0_%=: r1 >>= 16; \ : __clobber_all); } +SEC("raw_tp") +__log_level(2) +__success +__msg("fp-8=0m??mmmm") +__msg("fp-16=00mm??mm") +__msg("fp-24=00mm???m") +__naked void spill_subregs_preserve_stack_zero(void) +{ + asm volatile ( + "call %[bpf_get_prandom_u32];" + + /* 32-bit subreg spill with ZERO, MISC, and INVALID */ + ".8byte %[fp1_u8_st_zero];" /* ZERO, LLVM-18+: *(u8 *)(r10 -1) = 0; */ + "*(u8 *)(r10 -2) = r0;" /* MISC */ + /* fp-3 and fp-4 stay INVALID */ + "*(u32 *)(r10 -8) = r0;" + + /* 16-bit subreg spill with ZERO, MISC, and INVALID */ + ".8byte %[fp10_u16_st_zero];" /* ZERO, LLVM-18+: *(u16 *)(r10 -10) = 0; */ + "*(u16 *)(r10 -12) = r0;" /* MISC */ + /* fp-13 and fp-14 stay INVALID */ + "*(u16 *)(r10 -16) = r0;" + + /* 8-bit subreg spill with ZERO, MISC, and INVALID */ + ".8byte %[fp18_u16_st_zero];" /* ZERO, LLVM-18+: *(u16 *)(r18 -10) = 0; */ + "*(u16 *)(r10 -20) = r0;" /* MISC */ + /* fp-21, fp-22, and fp-23 stay INVALID */ + "*(u8 *)(r10 -24) = r0;" + + "r0 = 0;" + "exit;" + : + : __imm(bpf_get_prandom_u32), + __imm_insn(fp1_u8_st_zero, BPF_ST_MEM(BPF_B, BPF_REG_FP, -1, 0)), + __imm_insn(fp10_u16_st_zero, BPF_ST_MEM(BPF_H, BPF_REG_FP, -10, 0)), + __imm_insn(fp18_u16_st_zero, BPF_ST_MEM(BPF_H, BPF_REG_FP, -18, 0)) + : __clobber_all); +} + char _license[] SEC("license") = "GPL"; -- cgit