From c4b1be928ea05add0e0f9334e5bc44932395782e Mon Sep 17 00:00:00 2001 From: Eduard Zingerman Date: Thu, 26 Jun 2025 18:55:39 -0700 Subject: [PATCH] selftests/bpf: bpf_rdonly_cast u{8,16,32,64} access tests Tests with aligned and misaligned memory access of different sizes via pointer returned by bpf_rdonly_cast(). Suggested-by: Andrii Nakryiko Signed-off-by: Eduard Zingerman Link: https://lore.kernel.org/r/20250627015539.1439656-1-eddyz87@gmail.com Signed-off-by: Alexei Starovoitov --- .../bpf/progs/mem_rdonly_untrusted.c | 41 +++++++++++++++++++ 1 file changed, 41 insertions(+) diff --git a/tools/testing/selftests/bpf/progs/mem_rdonly_untrusted.c b/tools/testing/selftests/bpf/progs/mem_rdonly_untrusted.c index 00604755e6987..b0486af36f550 100644 --- a/tools/testing/selftests/bpf/progs/mem_rdonly_untrusted.c +++ b/tools/testing/selftests/bpf/progs/mem_rdonly_untrusted.c @@ -133,4 +133,45 @@ int mixed_mem_type(void *ctx) return *p; } +__attribute__((__aligned__(8))) +u8 global[] = { + 0x11, 0x22, 0x33, 0x44, + 0x55, 0x66, 0x77, 0x88, + 0x99 +}; + +__always_inline +static u64 combine(void *p) +{ + u64 acc; + + acc = 0; +#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__ + acc |= (*(u64 *)p >> 56) << 24; + acc |= (*(u32 *)p >> 24) << 16; + acc |= (*(u16 *)p >> 8) << 8; + acc |= *(u8 *)p; +#else + acc |= (*(u64 *)p & 0xff) << 24; + acc |= (*(u32 *)p & 0xff) << 16; + acc |= (*(u16 *)p & 0xff) << 8; + acc |= *(u8 *)p; +#endif + return acc; +} + +SEC("socket") +__retval(0x88442211) +int diff_size_access(void *ctx) +{ + return combine(bpf_rdonly_cast(&global, 0)); +} + +SEC("socket") +__retval(0x99553322) +int misaligned_access(void *ctx) +{ + return combine(bpf_rdonly_cast(&global, 0) + 1); +} + char _license[] SEC("license") = "GPL"; -- 2.47.2