selftests/bpf: Check that JMP32 pointer vs zero jumps are not predictedgrafted

Add jmp32_ptr_vs_zero_jne: the fall-through of the 32-bit compare, which
the verifier used to skip, contains an out of bounds map value access,
hence w/o the previous patch the program is accepted. See previous patch
for detailed description.

Reported-by: Nicholas Carlini <npc@anthropic.com>
Suggested-by: Nicholas Carlini <npc@anthropic.com>
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/bpf/20260904083325.2083493-6-eddyz87@gmail.com
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>

1 files changed, 173 insertions, 0 deletions

diff --git a/drivers/misc/ibmasm/command.c b/drivers/misc/ibmasm/command.c
new file mode 100644
index 000000000..6b037675f
--- /dev/null
+++ b/drivers/misc/ibmasm/command.c
@@ -0,0 +1,173 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+/*
+ * IBM ASM Service Processor Device Driver
+ *
+ * Copyright (C) IBM Corporation, 2004
+ *
+ * Author: Max Asböck <amax@us.ibm.com>
+ */
+
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include "ibmasm.h"
+#include "lowlevel.h"
+
+static void exec_next_command(struct service_processor *sp);
+
+static atomic_t command_count = ATOMIC_INIT(0);
+
+struct command *ibmasm_new_command(struct service_processor *sp, size_t buffer_size)
+{
+	struct command *cmd;
+
+	if (buffer_size > IBMASM_CMD_MAX_BUFFER_SIZE)
+		return NULL;
+
+	cmd = kzalloc_obj(struct command);
+	if (cmd == NULL)
+		return NULL;
+
+
+	cmd->buffer = kzalloc(buffer_size, GFP_KERNEL);
+	if (cmd->buffer == NULL) {
+		kfree(cmd);
+		return NULL;
+	}
+	cmd->buffer_size = buffer_size;
+
+	kref_init(&cmd->kref);
+	cmd->lock = &sp->lock;
+
+	cmd->status = IBMASM_CMD_PENDING;
+	init_waitqueue_head(&cmd->wait);
+	INIT_LIST_HEAD(&cmd->queue_node);
+
+	atomic_inc(&command_count);
+	dbg("command count: %d\n", atomic_read(&command_count));
+
+	return cmd;
+}
+
+void ibmasm_free_command(struct kref *kref)
+{
+	struct command *cmd = to_command(kref);
+
+	list_del(&cmd->queue_node);
+	atomic_dec(&command_count);
+	dbg("command count: %d\n", atomic_read(&command_count));
+	kfree(cmd->buffer);
+	kfree(cmd);
+}
+
+static void enqueue_command(struct service_processor *sp, struct command *cmd)
+{
+	list_add_tail(&cmd->queue_node, &sp->command_queue);
+}
+
+static struct command *dequeue_command(struct service_processor *sp)
+{
+	struct command *cmd;
+	struct list_head *next;
+
+	if (list_empty(&sp->command_queue))
+		return NULL;
+
+	next = sp->command_queue.next;
+	list_del_init(next);
+	cmd = list_entry(next, struct command, queue_node);
+
+	return cmd;
+}
+
+static inline void do_exec_command(struct service_processor *sp)
+{
+	char tsbuf[32];
+
+	dbg("%s:%d at %s\n", __func__, __LINE__, get_timestamp(tsbuf));
+
+	if (ibmasm_send_i2o_message(sp)) {
+		sp->current_command->status = IBMASM_CMD_FAILED;
+		wake_up(&sp->current_command->wait);
+		command_put(sp->current_command);
+		exec_next_command(sp);
+	}
+}
+
+/*
+ * exec_command
+ * send a command to a service processor
+ * Commands are executed sequentially. One command (sp->current_command)
+ * is sent to the service processor. Once the interrupt handler gets a
+ * message of type command_response, the message is copied into
+ * the current commands buffer,
+ */
+void ibmasm_exec_command(struct service_processor *sp, struct command *cmd)
+{
+	unsigned long flags;
+	char tsbuf[32];
+
+	dbg("%s:%d at %s\n", __func__, __LINE__, get_timestamp(tsbuf));
+
+	spin_lock_irqsave(&sp->lock, flags);
+
+	if (!sp->current_command) {
+		sp->current_command = cmd;
+		command_get(sp->current_command);
+		spin_unlock_irqrestore(&sp->lock, flags);
+		do_exec_command(sp);
+	} else {
+		enqueue_command(sp, cmd);
+		spin_unlock_irqrestore(&sp->lock, flags);
+	}
+}
+
+static void exec_next_command(struct service_processor *sp)
+{
+	unsigned long flags;
+	char tsbuf[32];
+
+	dbg("%s:%d at %s\n", __func__, __LINE__, get_timestamp(tsbuf));
+
+	spin_lock_irqsave(&sp->lock, flags);
+	sp->current_command = dequeue_command(sp);
+	if (sp->current_command) {
+		command_get(sp->current_command);
+		spin_unlock_irqrestore(&sp->lock, flags);
+		do_exec_command(sp);
+	} else {
+		spin_unlock_irqrestore(&sp->lock, flags);
+	}
+}
+
+/*
+ * Sleep until a command has failed or a response has been received
+ * and the command status been updated by the interrupt handler.
+ * (see receive_response).
+ */
+void ibmasm_wait_for_response(struct command *cmd, int timeout)
+{
+	wait_event_interruptible_timeout(cmd->wait,
+				cmd->status == IBMASM_CMD_COMPLETE ||
+				cmd->status == IBMASM_CMD_FAILED,
+				timeout * HZ);
+}
+
+/*
+ * receive_command_response
+ * called by the interrupt handler when a dot command of type command_response
+ * was received.
+ */
+void ibmasm_receive_command_response(struct service_processor *sp, void *response, size_t size)
+{
+	struct command *cmd = sp->current_command;
+
+	if (!sp->current_command)
+		return;
+
+	memcpy_fromio(cmd->buffer, response, min(size, cmd->buffer_size));
+	cmd->status = IBMASM_CMD_COMPLETE;
+	wake_up(&sp->current_command->wait);
+	command_put(sp->current_command);
+	exec_next_command(sp);
+}