selftests/bpf: Test packet range of pointers sharing an idgrafted

Add tests where two packet pointers share an id and tightening one
pointer's umax from its var_off would put it less than their constant
distance from the other's umax: with an index & 0x38 capped at 50, the
base pointer keeps umax 50, so the pointer 8 bytes further on must keep
umax 58, even though its known bits allow at most 56.

These refused a valid program or accepted an out-of-bounds access before
the fix:

- check the advanced copy, load through the base: valid, was refused;
- check the base, load the byte at base + 1 through a copy advanced by
  8: was accepted;
- check base + 4, load 4 bytes at base + 2 through base + 8: reads two
  bytes past the checked range, was accepted;
- the same as the second with data_meta pointers checked against data:
  was accepted.

These pass with and without the fix and cover nearby paths:

- subtract an unknown scalar from a checked pointer and load below it
  (the range is kept across a new id);
- reach a load through two paths whose checks cover 8 and 7 bytes after
  the loaded pointer; the second path must not be pruned by the first;
- spill a copy of a pointer, check the pointer, fill the copy and load
  one byte past the checked range: the load is refused, and the copy
  has the range of the check.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20261001145255.855630-2-alexei.starovoitov@gmail.com
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>

1 files changed, 242 insertions, 0 deletions

diff --git a/drivers/mtd/maps/physmap-versatile.c b/drivers/mtd/maps/physmap-versatile.c
new file mode 100644
index 000000000..2e779111b
--- /dev/null
+++ b/drivers/mtd/maps/physmap-versatile.c
@@ -0,0 +1,242 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Versatile OF physmap driver add-on
+ *
+ * Copyright (c) 2016, Linaro Limited
+ * Author: Linus Walleij <linus.walleij@linaro.org>
+ */
+#include <linux/export.h>
+#include <linux/io.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/mtd/map.h>
+#include <linux/mfd/syscon.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/bitops.h>
+#include "physmap-versatile.h"
+
+static struct regmap *syscon_regmap;
+
+enum versatile_flashprot {
+	INTEGRATOR_AP_FLASHPROT,
+	INTEGRATOR_CP_FLASHPROT,
+	VERSATILE_FLASHPROT,
+	REALVIEW_FLASHPROT,
+};
+
+static const struct of_device_id syscon_match[] = {
+	{
+		.compatible = "arm,integrator-ap-syscon",
+		.data = (void *)INTEGRATOR_AP_FLASHPROT,
+	},
+	{
+		.compatible = "arm,integrator-cp-syscon",
+		.data = (void *)INTEGRATOR_CP_FLASHPROT,
+	},
+	{
+		.compatible = "arm,core-module-versatile",
+		.data = (void *)VERSATILE_FLASHPROT,
+	},
+	{
+		.compatible = "arm,realview-eb-syscon",
+		.data = (void *)REALVIEW_FLASHPROT,
+	},
+	{
+		.compatible = "arm,realview-pb1176-syscon",
+		.data = (void *)REALVIEW_FLASHPROT,
+	},
+	{
+		.compatible = "arm,realview-pb11mp-syscon",
+		.data = (void *)REALVIEW_FLASHPROT,
+	},
+	{
+		.compatible = "arm,realview-pba8-syscon",
+		.data = (void *)REALVIEW_FLASHPROT,
+	},
+	{
+		.compatible = "arm,realview-pbx-syscon",
+		.data = (void *)REALVIEW_FLASHPROT,
+	},
+	{},
+};
+
+/*
+ * Flash protection handling for the Integrator/AP
+ */
+#define INTEGRATOR_SC_CTRLS_OFFSET	0x08
+#define INTEGRATOR_SC_CTRLC_OFFSET	0x0C
+#define INTEGRATOR_SC_CTRL_FLVPPEN	BIT(1)
+#define INTEGRATOR_SC_CTRL_FLWP		BIT(2)
+
+#define INTEGRATOR_EBI_CSR1_OFFSET	0x04
+/* The manual says bit 2, the code says bit 3, trust the code */
+#define INTEGRATOR_EBI_WRITE_ENABLE	BIT(3)
+#define INTEGRATOR_EBI_LOCK_OFFSET	0x20
+#define INTEGRATOR_EBI_LOCK_VAL		0xA05F
+
+static const struct of_device_id ebi_match[] = {
+	{ .compatible = "arm,external-bus-interface"},
+	{ },
+};
+
+static int ap_flash_init(struct platform_device *pdev)
+{
+	struct device_node *ebi;
+	void __iomem *ebi_base;
+	u32 val;
+	int ret;
+
+	/* Look up the EBI */
+	ebi = of_find_matching_node(NULL, ebi_match);
+	if (!ebi) {
+		return -ENODEV;
+	}
+	ebi_base = of_iomap(ebi, 0);
+	of_node_put(ebi);
+	if (!ebi_base)
+		return -ENODEV;
+
+	/* Clear VPP and write protection bits */
+	ret = regmap_write(syscon_regmap,
+		INTEGRATOR_SC_CTRLC_OFFSET,
+		INTEGRATOR_SC_CTRL_FLVPPEN | INTEGRATOR_SC_CTRL_FLWP);
+	if (ret)
+		dev_err(&pdev->dev, "error clearing Integrator VPP/WP\n");
+
+	/* Unlock the EBI */
+	writel(INTEGRATOR_EBI_LOCK_VAL, ebi_base + INTEGRATOR_EBI_LOCK_OFFSET);
+
+	/* Enable write cycles on the EBI, CSR1 (flash) */
+	val = readl(ebi_base + INTEGRATOR_EBI_CSR1_OFFSET);
+	val |= INTEGRATOR_EBI_WRITE_ENABLE;
+	writel(val, ebi_base + INTEGRATOR_EBI_CSR1_OFFSET);
+
+	/* Lock the EBI again */
+	writel(0, ebi_base + INTEGRATOR_EBI_LOCK_OFFSET);
+	iounmap(ebi_base);
+
+	return 0;
+}
+
+static void ap_flash_set_vpp(struct map_info *map, int on)
+{
+	int ret;
+
+	if (on) {
+		ret = regmap_write(syscon_regmap,
+			INTEGRATOR_SC_CTRLS_OFFSET,
+			INTEGRATOR_SC_CTRL_FLVPPEN | INTEGRATOR_SC_CTRL_FLWP);
+		if (ret)
+			pr_err("error enabling AP VPP\n");
+	} else {
+		ret = regmap_write(syscon_regmap,
+			INTEGRATOR_SC_CTRLC_OFFSET,
+			INTEGRATOR_SC_CTRL_FLVPPEN | INTEGRATOR_SC_CTRL_FLWP);
+		if (ret)
+			pr_err("error disabling AP VPP\n");
+	}
+}
+
+/*
+ * Flash protection handling for the Integrator/CP
+ */
+
+#define INTCP_FLASHPROG_OFFSET		0x04
+#define CINTEGRATOR_FLVPPEN		BIT(0)
+#define CINTEGRATOR_FLWREN		BIT(1)
+#define CINTEGRATOR_FLMASK		BIT(0)|BIT(1)
+
+static void cp_flash_set_vpp(struct map_info *map, int on)
+{
+	int ret;
+
+	if (on) {
+		ret = regmap_update_bits(syscon_regmap,
+				INTCP_FLASHPROG_OFFSET,
+				CINTEGRATOR_FLMASK,
+				CINTEGRATOR_FLVPPEN | CINTEGRATOR_FLWREN);
+		if (ret)
+			pr_err("error setting CP VPP\n");
+	} else {
+		ret = regmap_update_bits(syscon_regmap,
+				INTCP_FLASHPROG_OFFSET,
+				CINTEGRATOR_FLMASK,
+				0);
+		if (ret)
+			pr_err("error setting CP VPP\n");
+	}
+}
+
+/*
+ * Flash protection handling for the Versatiles and RealViews
+ */
+
+#define VERSATILE_SYS_FLASH_OFFSET            0x4C
+
+static void versatile_flash_set_vpp(struct map_info *map, int on)
+{
+	int ret;
+
+	ret = regmap_update_bits(syscon_regmap, VERSATILE_SYS_FLASH_OFFSET,
+				 0x01, !!on);
+	if (ret)
+		pr_err("error setting Versatile VPP\n");
+}
+
+int of_flash_probe_versatile(struct platform_device *pdev,
+			     struct device_node *np,
+			     struct map_info *map)
+{
+	struct device_node *sysnp;
+	const struct of_device_id *devid;
+	struct regmap *rmap;
+	static enum versatile_flashprot versatile_flashprot;
+	int ret;
+
+	/* Not all flash chips use this protection line */
+	if (!of_device_is_compatible(np, "arm,versatile-flash"))
+		return 0;
+
+	/* For first chip probed, look up the syscon regmap */
+	if (!syscon_regmap) {
+		sysnp = of_find_matching_node_and_match(NULL,
+							syscon_match,
+							&devid);
+		if (!sysnp)
+			return -ENODEV;
+
+		versatile_flashprot = (uintptr_t)devid->data;
+		rmap = syscon_node_to_regmap(sysnp);
+		of_node_put(sysnp);
+		if (IS_ERR(rmap))
+			return PTR_ERR(rmap);
+
+		syscon_regmap = rmap;
+	}
+
+	switch (versatile_flashprot) {
+	case INTEGRATOR_AP_FLASHPROT:
+		ret = ap_flash_init(pdev);
+		if (ret)
+			return ret;
+		map->set_vpp = ap_flash_set_vpp;
+		dev_info(&pdev->dev, "Integrator/AP flash protection\n");
+		break;
+	case INTEGRATOR_CP_FLASHPROT:
+		map->set_vpp = cp_flash_set_vpp;
+		dev_info(&pdev->dev, "Integrator/CP flash protection\n");
+		break;
+	case VERSATILE_FLASHPROT:
+	case REALVIEW_FLASHPROT:
+		map->set_vpp = versatile_flash_set_vpp;
+		dev_info(&pdev->dev, "versatile/realview flash protection\n");
+		break;
+	default:
+		dev_info(&pdev->dev, "device marked as Versatile flash "
+			 "but no system controller was found\n");
+		break;
+	}
+
+	return 0;
+}