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| author |   Eduard Zingerman <eddyz87@gmail.com> | 2025-07-04 16:03:49 -0700 |
|---|---|---|
| committer |   Alexei Starovoitov <ast@kernel.org> | 2025-07-07 08:25:06 -0700 |
| commit | f1f5d6f25d098e21b0a53237cfd055fc28787c46 (patch) | |
| tree | 11e699fbf5777708c73a16c003f657083138f308 | |
| parent | bpf: rdonly_untrusted_mem for btf id walk pointer leafs (diff) | |
| download | wireguard-linux-f1f5d6f25d098e21b0a53237cfd055fc28787c46.tar.xz wireguard-linux-f1f5d6f25d098e21b0a53237cfd055fc28787c46.zip | |
selftests/bpf: ptr_to_btf_id struct walk ending with primitive pointer
Validate that reading a PTR_TO_BTF_ID field produces a value of type
PTR_TO_MEM|MEM_RDONLY|PTR_UNTRUSTED, if field is a pointer to a
primitive type.
Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20250704230354.1323244-4-eddyz87@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
| -rw-r--r-- | tools/testing/selftests/bpf/progs/mem_rdonly_untrusted.c | 31 |
1 files changed, 31 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/progs/mem_rdonly_untrusted.c b/tools/testing/selftests/bpf/progs/mem_rdonly_untrusted.c index 8185130ede95..4f94c971ae86 100644 --- a/tools/testing/selftests/bpf/progs/mem_rdonly_untrusted.c +++ b/tools/testing/selftests/bpf/progs/mem_rdonly_untrusted.c @@ -5,6 +5,37 @@ #include "bpf_misc.h" #include "../test_kmods/bpf_testmod_kfunc.h" +SEC("tp_btf/sys_enter") +__success +__log_level(2) +__msg("r8 = *(u64 *)(r7 +0) ; R7_w=ptr_nameidata(off={{[0-9]+}}) R8_w=rdonly_untrusted_mem(sz=0)") +__msg("r9 = *(u8 *)(r8 +0) ; R8_w=rdonly_untrusted_mem(sz=0) R9_w=scalar") +int btf_id_to_ptr_mem(void *ctx) +{ + struct task_struct *task; + struct nameidata *idata; + u64 ret, off; + + task = bpf_get_current_task_btf(); + idata = task->nameidata; + off = bpf_core_field_offset(struct nameidata, pathname); + /* + * asm block to have reliable match target for __msg, equivalent of: + * ret = task->nameidata->pathname[0]; + */ + asm volatile ( + "r7 = %[idata];" + "r7 += %[off];" + "r8 = *(u64 *)(r7 + 0);" + "r9 = *(u8 *)(r8 + 0);" + "%[ret] = r9;" + : [ret]"=r"(ret) + : [idata]"r"(idata), + [off]"r"(off) + : "r7", "r8", "r9"); + return ret; +} + SEC("socket") __success __retval(0) |