[PATCH] HID: bpf: One function call less in call_hid_bpf_rdesc_fixup() after error detection

[Markus Elfring]

From: Markus Elfring <elfring@xxxxxxxxxxxxxxxxxxxxx>
Date: Tue, 26 Dec 2023 19:13:25 +0100

The kfree() function was called in one case by the
call_hid_bpf_rdesc_fixup() function during error handling
even if the passed data structure member contained a null pointer.
This issue was detected by using the Coccinelle software.

Thus adjust jump targets.

Signed-off-by: Markus Elfring <elfring@xxxxxxxxxxxxxxxxxxxxx>
---
 drivers/hid/bpf/hid_bpf_dispatch.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/hid/bpf/hid_bpf_dispatch.c b/drivers/hid/bpf/hid_bpf_dispatch.c
index d9ef45fcaeab..c84fe55be5ed 100644
--- a/drivers/hid/bpf/hid_bpf_dispatch.c
+++ b/drivers/hid/bpf/hid_bpf_dispatch.c
@@ -118,17 +118,17 @@ u8 *call_hid_bpf_rdesc_fixup(struct hid_device *hdev, u8 *rdesc, unsigned int *s

 	ctx_kern.data = kzalloc(ctx_kern.ctx.allocated_size, GFP_KERNEL);
 	if (!ctx_kern.data)
-		goto ignore_bpf;
+		goto dup_mem;

 	memcpy(ctx_kern.data, rdesc, min_t(unsigned int, *size, HID_MAX_DESCRIPTOR_SIZE));

 	ret = hid_bpf_prog_run(hdev, HID_BPF_PROG_TYPE_RDESC_FIXUP, &ctx_kern);
 	if (ret < 0)
-		goto ignore_bpf;
+		goto free_data;

 	if (ret) {
 		if (ret > ctx_kern.ctx.allocated_size)
-			goto ignore_bpf;
+			goto free_data;

 		*size = ret;
 	}
@@ -137,8 +137,9 @@ u8 *call_hid_bpf_rdesc_fixup(struct hid_device *hdev, u8 *rdesc, unsigned int *s

 	return rdesc;

- ignore_bpf:
+free_data:
 	kfree(ctx_kern.data);
+dup_mem:
 	return kmemdup(rdesc, *size, GFP_KERNEL);
 }
 EXPORT_SYMBOL_GPL(call_hid_bpf_rdesc_fixup);
--
2.43.0