From: Benjamin Tissoires <bentiss@kernel.org>
To: Jiri Kosina <jikos@kernel.org>, Shuah Khan <shuah@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>
Cc: linux-input@vger.kernel.org, linux-kernel@vger.kernel.org,
bpf@vger.kernel.org, linux-kselftest@vger.kernel.org,
Benjamin Tissoires <bentiss@kernel.org>
Subject: [PATCH v2 2/3] selftests/hid: Add a test to ensure we can write fields in hid_device
Date: Tue, 25 Aug 2026 11:55:12 +0200 [thread overview]
Message-ID: <20260825-wip-bpf-safe-v2-2-d044355c09d8@kernel.org> (raw)
In-Reply-To: <20260825-wip-bpf-safe-v2-0-d044355c09d8@kernel.org>
hid_device->{name,uniq,phys} are all writeable fields, we need to have
tests for them in case the verifier becomes too much strict.
Signed-off-by: Benjamin Tissoires <bentiss@kernel.org>
---
changes in v2:
- sashiko fixes:
- iterate the for loop up to 5, to account for dev_id >= 1000
- properly undef the correct macro
---
tools/testing/selftests/hid/hid_bpf.c | 26 ++++++++++++++++++++++
tools/testing/selftests/hid/progs/hid.c | 26 ++++++++++++++++++++++
.../testing/selftests/hid/progs/hid_bpf_helpers.h | 3 +++
3 files changed, 55 insertions(+)
diff --git a/tools/testing/selftests/hid/hid_bpf.c b/tools/testing/selftests/hid/hid_bpf.c
index b851339308c2..069ebdbb4d1c 100644
--- a/tools/testing/selftests/hid/hid_bpf.c
+++ b/tools/testing/selftests/hid/hid_bpf.c
@@ -909,6 +909,32 @@ TEST_F(hid_bpf, test_rdesc_fixup_get_data_overflow)
ASSERT_EQ(self->skel->bss->get_data_overflow_check, 1);
}
+TEST_F(hid_bpf, test_rdesc_fixup_change_uniq_name_phys)
+{
+ const struct test_program progs[] = {
+ { .name = "hid_rdesc_fixup_change_uniq_name_phys" },
+ };
+ char expected[256], buf[256] = {};
+ int err;
+
+ LOAD_PROGRAMS(progs);
+
+ err = ioctl(self->hidraw_fd, HIDIOCGRAWNAME(sizeof(buf)), buf);
+ ASSERT_GE(err, 0) TH_LOG("HIDIOCGRAWNAME");
+ ASSERT_STREQ("name coming from bpf", buf);
+
+ snprintf(expected, sizeof(expected), "%d phys:coming:from:bpf", self->hid.dev_id);
+
+ err = ioctl(self->hidraw_fd, HIDIOCGRAWPHYS(sizeof(buf)), buf);
+ ASSERT_GE(err, 0) TH_LOG("HIDIOCGRAWPHYS");
+ ASSERT_STREQ(expected, buf);
+
+ err = ioctl(self->hidraw_fd, HIDIOCGRAWUNIQ(sizeof(buf)), buf);
+ ASSERT_GE(err, 0) TH_LOG("HIDIOCGRAWUNIQ");
+ ASSERT_STREQ("uniq:coming:from:bpf", buf);
+
+}
+
static int libbpf_print_fn(enum libbpf_print_level level,
const char *format, va_list args)
{
diff --git a/tools/testing/selftests/hid/progs/hid.c b/tools/testing/selftests/hid/progs/hid.c
index b21fbb13c926..361dc7eaad22 100644
--- a/tools/testing/selftests/hid/progs/hid.c
+++ b/tools/testing/selftests/hid/progs/hid.c
@@ -255,6 +255,32 @@ struct hid_bpf_ops rdesc_fixup_get_data_overflow = {
.hid_rdesc_fixup = (void *)hid_rdesc_fixup_get_data_overflow,
};
+SEC("?struct_ops.s/hid_rdesc_fixup")
+int BPF_PROG(hid_rdesc_fixup_change_uniq_name_phys, struct hid_bpf_ctx *hid_ctx)
+{
+#define HID_BPF_MEMCPY(target, str) \
+ __builtin_memcpy(target, str, sizeof(str))
+
+ HID_BPF_MEMCPY(hid_ctx->hid->name, "name coming from bpf");
+ HID_BPF_MEMCPY(hid_ctx->hid->uniq, "uniq:coming:from:bpf");
+ /* hid_bpf relies on a phys being a rand % 1024 */
+ for (int i = 0; i < 5; i++) {
+ if (!hid_ctx->hid->phys[i]) {
+ HID_BPF_MEMCPY(hid_ctx->hid->phys + i, " phys:coming:from:bpf");
+ break;
+ }
+ }
+
+#undef HID_BPF_MEMCPY
+
+ return 0;
+}
+
+SEC(".struct_ops.link")
+struct hid_bpf_ops rdesc_fixup_change_uniq_name_phys = {
+ .hid_rdesc_fixup = (void *)hid_rdesc_fixup_change_uniq_name_phys,
+};
+
SEC("?struct_ops/hid_device_event")
int BPF_PROG(hid_test_insert1, struct hid_bpf_ctx *hid_ctx, enum hid_report_type type)
{
diff --git a/tools/testing/selftests/hid/progs/hid_bpf_helpers.h b/tools/testing/selftests/hid/progs/hid_bpf_helpers.h
index cdca912f3afd..05698793762a 100644
--- a/tools/testing/selftests/hid/progs/hid_bpf_helpers.h
+++ b/tools/testing/selftests/hid/progs/hid_bpf_helpers.h
@@ -61,6 +61,9 @@ enum hid_report_type {
struct hid_device {
unsigned int id;
+ char name[128];
+ char phys[64];
+ char uniq[64];
} __attribute__((preserve_access_index));
struct bpf_wq {
--
2.55.0
next prev parent reply other threads:[~2026-08-25 9:55 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-08-25 9:55 [PATCH v2 0/3] HID: bpf: fix 7.3-rc0 bpf breakage Benjamin Tissoires
2026-08-25 9:55 ` [PATCH v2 1/3] HID: bpf: mark struct hid_device as safe BPF pointer Benjamin Tissoires
2026-08-25 9:55 ` Benjamin Tissoires [this message]
2026-08-25 9:55 ` [PATCH v2 3/3] selftests/hid: prepare test_rdesc_fixup_get_data_overflow for the new verifier Benjamin Tissoires
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