bpf: mark a NULL kfunc argument precisegrafted

check_kfunc_arg() allows bpf_register_is_null() for nullable arguments
w/o marking the underlying scalar register precise. Hence a checkpoint
created on such a path would prune against arbitrary scalar value.

Fixes: 3bda08b63670 ("bpf: Allow NULL buffers in bpf_dynptr_slice(_rw)")
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20260904-register-is-null-precise-fixes-v1-5-0f5a360ff15d@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

1 files changed, 103 insertions, 0 deletions

diff --git a/drivers/bus/fsl-mc/obj-api.c b/drivers/bus/fsl-mc/obj-api.c
new file mode 100644
index 000000000..06c1dd84e
--- /dev/null
+++ b/drivers/bus/fsl-mc/obj-api.c
@@ -0,0 +1,103 @@
+// SPDX-License-Identifier: (GPL-2.0+ OR BSD-3-Clause)
+/*
+ * Copyright 2021 NXP
+ *
+ */
+#include <linux/kernel.h>
+#include <linux/fsl/mc.h>
+
+#include "fsl-mc-private.h"
+
+static int fsl_mc_get_open_cmd_id(const char *type)
+{
+	static const struct {
+		int cmd_id;
+		const char *type;
+	} dev_ids[] = {
+		{ DPRTC_CMDID_OPEN, "dprtc" },
+		{ DPRC_CMDID_OPEN, "dprc" },
+		{ DPNI_CMDID_OPEN, "dpni" },
+		{ DPIO_CMDID_OPEN, "dpio" },
+		{ DPSW_CMDID_OPEN, "dpsw" },
+		{ DPBP_CMDID_OPEN, "dpbp" },
+		{ DPCON_CMDID_OPEN, "dpcon" },
+		{ DPMCP_CMDID_OPEN, "dpmcp" },
+		{ DPMAC_CMDID_OPEN, "dpmac" },
+		{ DPSECI_CMDID_OPEN, "dpseci" },
+		{ DPDMUX_CMDID_OPEN, "dpdmux" },
+		{ DPDCEI_CMDID_OPEN, "dpdcei" },
+		{ DPAIOP_CMDID_OPEN, "dpaiop" },
+		{ DPCI_CMDID_OPEN, "dpci" },
+		{ DPDMAI_CMDID_OPEN, "dpdmai" },
+		{ DPDBG_CMDID_OPEN, "dpdbg" },
+		{ 0, NULL }
+	};
+	int i;
+
+	for (i = 0; dev_ids[i].type; i++)
+		if (!strcmp(dev_ids[i].type, type))
+			return dev_ids[i].cmd_id;
+
+	return -1;
+}
+
+int fsl_mc_obj_open(struct fsl_mc_io *mc_io,
+		    u32 cmd_flags,
+		    int obj_id,
+		    char *obj_type,
+		    u16 *token)
+{
+	struct fsl_mc_command cmd = { 0 };
+	struct fsl_mc_obj_cmd_open *cmd_params;
+	int err = 0;
+	int cmd_id = fsl_mc_get_open_cmd_id(obj_type);
+
+	if (cmd_id == -1)
+		return -ENODEV;
+
+	/* prepare command */
+	cmd.header = mc_encode_cmd_header(cmd_id, cmd_flags, 0);
+	cmd_params = (struct fsl_mc_obj_cmd_open *)cmd.params;
+	cmd_params->obj_id = cpu_to_le32(obj_id);
+
+	/* send command to mc*/
+	err = mc_send_command(mc_io, &cmd);
+	if (err)
+		return err;
+
+	/* retrieve response parameters */
+	*token = mc_cmd_hdr_read_token(&cmd);
+
+	return err;
+}
+EXPORT_SYMBOL_GPL(fsl_mc_obj_open);
+
+int fsl_mc_obj_close(struct fsl_mc_io *mc_io,
+		     u32 cmd_flags,
+		     u16 token)
+{
+	struct fsl_mc_command cmd = { 0 };
+
+	/* prepare command */
+	cmd.header = mc_encode_cmd_header(OBJ_CMDID_CLOSE, cmd_flags,
+					  token);
+
+	/* send command to mc*/
+	return mc_send_command(mc_io, &cmd);
+}
+EXPORT_SYMBOL_GPL(fsl_mc_obj_close);
+
+int fsl_mc_obj_reset(struct fsl_mc_io *mc_io,
+		     u32 cmd_flags,
+		     u16 token)
+{
+	struct fsl_mc_command cmd = { 0 };
+
+	/* prepare command */
+	cmd.header = mc_encode_cmd_header(OBJ_CMDID_RESET, cmd_flags,
+					  token);
+
+	/* send command to mc*/
+	return mc_send_command(mc_io, &cmd);
+}
+EXPORT_SYMBOL_GPL(fsl_mc_obj_reset);