selftests/bpf: Add return value checks for failed tests

The return ranges of some bpf lsm test progs can not be deduced by
the verifier accurately. To avoid erroneous rejections, add explicit
return value checks for these progs.

Signed-off-by: Xu Kuohai <xukuohai@huawei.com>
Link: https://lore.kernel.org/r/20240719110059.797546-8-xukuohai@huaweicloud.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>

diff --git a/tools/testing/selftests/bpf/progs/err.h b/tools/testing/selftests/bpf/progs/err.h
index d66d283d9e59a4b556180223f2d227f9f53ee6f0..38529779a2363d4db862f1739b5e55af70dfa138 100644 (file)
--- a/tools/testing/selftests/bpf/progs/err.h
+++ b/tools/testing/selftests/bpf/progs/err.h
@@ -5,6 +5,16 @@
 #define MAX_ERRNO 4095
 #define IS_ERR_VALUE(x) (unsigned long)(void *)(x) >= (unsigned long)-MAX_ERRNO
 
+#define __STR(x) #x
+
+#define set_if_not_errno_or_zero(x, y)                 \
+({                                                     \
+       asm volatile ("if %0 s< -4095 goto +1\n"        \
+                     "if %0 s<= 0 goto +1\n"           \
+                     "%0 = " __STR(y) "\n"             \
+                     : "+r"(x));                       \
+})
+
 static inline int IS_ERR_OR_NULL(const void *ptr)
 {
        return !ptr || IS_ERR_VALUE((unsigned long)ptr);

diff --git a/tools/testing/selftests/bpf/progs/test_sig_in_xattr.c b/tools/testing/selftests/bpf/progs/test_sig_in_xattr.c
index 2f0eb1334d65a36130c887b16002c06e39b10759..8ef6b39335b678224e4591887286c9fccb78d0b9 100644 (file)
--- a/tools/testing/selftests/bpf/progs/test_sig_in_xattr.c
+++ b/tools/testing/selftests/bpf/progs/test_sig_in_xattr.c
@@ -6,6 +6,7 @@
 #include <bpf/bpf_helpers.h>
 #include <bpf/bpf_tracing.h>
 #include "bpf_kfuncs.h"
+#include "err.h"
 
 char _license[] SEC("license") = "GPL";
 
@@ -79,5 +80,8 @@ int BPF_PROG(test_file_open, struct file *f)
        ret = bpf_verify_pkcs7_signature(&digest_ptr, &sig_ptr, trusted_keyring);
 
        bpf_key_put(trusted_keyring);
+
+       set_if_not_errno_or_zero(ret, -EFAULT);
+
        return ret;
 }

diff --git a/tools/testing/selftests/bpf/progs/test_verify_pkcs7_sig.c b/tools/testing/selftests/bpf/progs/test_verify_pkcs7_sig.c
index f42e9f3831a126f1536d4e7a19902f16f9b49284..12034a73ee2d237966db0b3f4ec1ef60374359bc 100644 (file)
--- a/tools/testing/selftests/bpf/progs/test_verify_pkcs7_sig.c
+++ b/tools/testing/selftests/bpf/progs/test_verify_pkcs7_sig.c
@@ -11,6 +11,7 @@
 #include <bpf/bpf_helpers.h>
 #include <bpf/bpf_tracing.h>
 #include "bpf_kfuncs.h"
+#include "err.h"
 
 #define MAX_DATA_SIZE (1024 * 1024)
 #define MAX_SIG_SIZE 1024
@@ -55,12 +56,12 @@ int BPF_PROG(bpf, int cmd, union bpf_attr *attr, unsigned int size)
 
        ret = bpf_probe_read_kernel(&value, sizeof(value), &attr->value);
        if (ret)
-               return ret;
+               goto out;
 
        ret = bpf_copy_from_user(data_val, sizeof(struct data),
                                 (void *)(unsigned long)value);
        if (ret)
-               return ret;
+               goto out;
 
        if (data_val->data_len > sizeof(data_val->data))
                return -EINVAL;
@@ -84,5 +85,8 @@ int BPF_PROG(bpf, int cmd, union bpf_attr *attr, unsigned int size)
 
        bpf_key_put(trusted_keyring);
 
+out:
+       set_if_not_errno_or_zero(ret, -EFAULT);
+
        return ret;
 }

diff --git a/tools/testing/selftests/bpf/progs/verifier_global_subprogs.c b/tools/testing/selftests/bpf/progs/verifier_global_subprogs.c
index a9fc30ed4d732b3935730bc2d30024bb0bd9bc85..20904cd2baa2fcbae5badc82877973992c2acb26 100644 (file)
--- a/tools/testing/selftests/bpf/progs/verifier_global_subprogs.c
+++ b/tools/testing/selftests/bpf/progs/verifier_global_subprogs.c
@@ -7,6 +7,7 @@
 #include "bpf_misc.h"
 #include "xdp_metadata.h"
 #include "bpf_kfuncs.h"
+#include "err.h"
 
 /* The compiler may be able to detect the access to uninitialized
    memory in the routines performing out of bound memory accesses and
@@ -331,7 +332,11 @@ SEC("?lsm/bpf")
 __success __log_level(2)
 int BPF_PROG(arg_tag_ctx_lsm)
 {
-       return tracing_subprog_void(ctx) + tracing_subprog_u64(ctx);
+       int ret;
+
+       ret = tracing_subprog_void(ctx) + tracing_subprog_u64(ctx);
+       set_if_not_errno_or_zero(ret, -1);
+       return ret;
 }
 
 SEC("?struct_ops/test_1")