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, 437 insertions, 0 deletions

diff --git a/drivers/mtd/tests/subpagetest.c b/drivers/mtd/tests/subpagetest.c
new file mode 100644
index 000000000..f34bbf033
--- /dev/null
+++ b/drivers/mtd/tests/subpagetest.c
@@ -0,0 +1,437 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2006-2007 Nokia Corporation
+ *
+ * Test sub-page read and write on MTD device.
+ * Author: Adrian Hunter <ext-adrian.hunter@nokia.com>
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/err.h>
+#include <linux/mtd/mtd.h>
+#include <linux/slab.h>
+#include <linux/sched.h>
+#include <linux/prandom.h>
+
+#include "mtd_test.h"
+
+static int dev = -EINVAL;
+module_param(dev, int, S_IRUGO);
+MODULE_PARM_DESC(dev, "MTD device number to use");
+
+static struct mtd_info *mtd;
+static unsigned char *writebuf;
+static unsigned char *readbuf;
+static unsigned char *bbt;
+
+static int subpgsize;
+static int bufsize;
+static int ebcnt;
+static int pgcnt;
+static int errcnt;
+static struct rnd_state rnd_state;
+
+static inline void clear_data(unsigned char *buf, size_t len)
+{
+	memset(buf, 0, len);
+}
+
+static int write_eraseblock(int ebnum)
+{
+	size_t written;
+	int err = 0;
+	loff_t addr = (loff_t)ebnum * mtd->erasesize;
+
+	prandom_bytes_state(&rnd_state, writebuf, subpgsize);
+	err = mtd_write(mtd, addr, subpgsize, &written, writebuf);
+	if (unlikely(err || written != subpgsize)) {
+		pr_err("error: write failed at %#llx\n",
+		       (long long)addr);
+		if (written != subpgsize) {
+			pr_err("  write size: %#x\n", subpgsize);
+			pr_err("  written: %#zx\n", written);
+		}
+		return err ? err : -1;
+	}
+
+	addr += subpgsize;
+
+	prandom_bytes_state(&rnd_state, writebuf, subpgsize);
+	err = mtd_write(mtd, addr, subpgsize, &written, writebuf);
+	if (unlikely(err || written != subpgsize)) {
+		pr_err("error: write failed at %#llx\n",
+		       (long long)addr);
+		if (written != subpgsize) {
+			pr_err("  write size: %#x\n", subpgsize);
+			pr_err("  written: %#zx\n", written);
+		}
+		return err ? err : -1;
+	}
+
+	return err;
+}
+
+static int write_eraseblock2(int ebnum)
+{
+	size_t written;
+	int err = 0, k;
+	loff_t addr = (loff_t)ebnum * mtd->erasesize;
+
+	for (k = 1; k < 33; ++k) {
+		if (addr + (subpgsize * k) > (loff_t)(ebnum + 1) * mtd->erasesize)
+			break;
+		prandom_bytes_state(&rnd_state, writebuf, subpgsize * k);
+		err = mtd_write(mtd, addr, subpgsize * k, &written, writebuf);
+		if (unlikely(err || written != subpgsize * k)) {
+			pr_err("error: write failed at %#llx\n",
+			       (long long)addr);
+			if (written != subpgsize * k) {
+				pr_err("  write size: %#x\n",
+				       subpgsize * k);
+				pr_err("  written: %#08zx\n",
+				       written);
+			}
+			return err ? err : -1;
+		}
+		addr += subpgsize * k;
+	}
+
+	return err;
+}
+
+static void print_subpage(unsigned char *p)
+{
+	int i, j;
+
+	for (i = 0; i < subpgsize; ) {
+		for (j = 0; i < subpgsize && j < 32; ++i, ++j)
+			printk("%02x", *p++);
+		printk("\n");
+	}
+}
+
+static int verify_eraseblock(int ebnum)
+{
+	size_t read;
+	int err = 0;
+	loff_t addr = (loff_t)ebnum * mtd->erasesize;
+
+	prandom_bytes_state(&rnd_state, writebuf, subpgsize);
+	clear_data(readbuf, subpgsize);
+	err = mtd_read(mtd, addr, subpgsize, &read, readbuf);
+	if (unlikely(err || read != subpgsize)) {
+		if (mtd_is_bitflip(err) && read == subpgsize) {
+			pr_info("ECC correction at %#llx\n",
+			       (long long)addr);
+			err = 0;
+		} else {
+			pr_err("error: read failed at %#llx\n",
+			       (long long)addr);
+			return err ? err : -1;
+		}
+	}
+	if (unlikely(memcmp(readbuf, writebuf, subpgsize))) {
+		pr_err("error: verify failed at %#llx\n",
+		       (long long)addr);
+		pr_info("------------- written----------------\n");
+		print_subpage(writebuf);
+		pr_info("------------- read ------------------\n");
+		print_subpage(readbuf);
+		pr_info("-------------------------------------\n");
+		errcnt += 1;
+	}
+
+	addr += subpgsize;
+
+	prandom_bytes_state(&rnd_state, writebuf, subpgsize);
+	clear_data(readbuf, subpgsize);
+	err = mtd_read(mtd, addr, subpgsize, &read, readbuf);
+	if (unlikely(err || read != subpgsize)) {
+		if (mtd_is_bitflip(err) && read == subpgsize) {
+			pr_info("ECC correction at %#llx\n",
+			       (long long)addr);
+			err = 0;
+		} else {
+			pr_err("error: read failed at %#llx\n",
+			       (long long)addr);
+			return err ? err : -1;
+		}
+	}
+	if (unlikely(memcmp(readbuf, writebuf, subpgsize))) {
+		pr_info("error: verify failed at %#llx\n",
+		       (long long)addr);
+		pr_info("------------- written----------------\n");
+		print_subpage(writebuf);
+		pr_info("------------- read ------------------\n");
+		print_subpage(readbuf);
+		pr_info("-------------------------------------\n");
+		errcnt += 1;
+	}
+
+	return err;
+}
+
+static int verify_eraseblock2(int ebnum)
+{
+	size_t read;
+	int err = 0, k;
+	loff_t addr = (loff_t)ebnum * mtd->erasesize;
+
+	for (k = 1; k < 33; ++k) {
+		if (addr + (subpgsize * k) > (loff_t)(ebnum + 1) * mtd->erasesize)
+			break;
+		prandom_bytes_state(&rnd_state, writebuf, subpgsize * k);
+		clear_data(readbuf, subpgsize * k);
+		err = mtd_read(mtd, addr, subpgsize * k, &read, readbuf);
+		if (unlikely(err || read != subpgsize * k)) {
+			if (mtd_is_bitflip(err) && read == subpgsize * k) {
+				pr_info("ECC correction at %#llx\n",
+				       (long long)addr);
+				err = 0;
+			} else {
+				pr_err("error: read failed at "
+				       "%#llx\n", (long long)addr);
+				return err ? err : -1;
+			}
+		}
+		if (unlikely(memcmp(readbuf, writebuf, subpgsize * k))) {
+			pr_err("error: verify failed at %#llx\n",
+			       (long long)addr);
+			errcnt += 1;
+		}
+		addr += subpgsize * k;
+	}
+
+	return err;
+}
+
+static int verify_eraseblock_ff(int ebnum)
+{
+	uint32_t j;
+	size_t read;
+	int err = 0;
+	loff_t addr = (loff_t)ebnum * mtd->erasesize;
+
+	memset(writebuf, 0xff, subpgsize);
+	for (j = 0; j < mtd->erasesize / subpgsize; ++j) {
+		clear_data(readbuf, subpgsize);
+		err = mtd_read(mtd, addr, subpgsize, &read, readbuf);
+		if (unlikely(err || read != subpgsize)) {
+			if (mtd_is_bitflip(err) && read == subpgsize) {
+				pr_info("ECC correction at %#llx\n",
+				       (long long)addr);
+				err = 0;
+			} else {
+				pr_err("error: read failed at "
+				       "%#llx\n", (long long)addr);
+				return err ? err : -1;
+			}
+		}
+		if (unlikely(memcmp(readbuf, writebuf, subpgsize))) {
+			pr_err("error: verify 0xff failed at "
+			       "%#llx\n", (long long)addr);
+			errcnt += 1;
+		}
+		addr += subpgsize;
+	}
+
+	return err;
+}
+
+static int verify_all_eraseblocks_ff(void)
+{
+	int err;
+	unsigned int i;
+
+	pr_info("verifying all eraseblocks for 0xff\n");
+	for (i = 0; i < ebcnt; ++i) {
+		if (bbt[i])
+			continue;
+		err = verify_eraseblock_ff(i);
+		if (err)
+			return err;
+		if (i % 256 == 0)
+			pr_info("verified up to eraseblock %u\n", i);
+
+		err = mtdtest_relax();
+		if (err)
+			return err;
+	}
+	pr_info("verified %u eraseblocks\n", i);
+	return 0;
+}
+
+static int __init mtd_subpagetest_init(void)
+{
+	int err = 0;
+	uint32_t i;
+	uint64_t tmp;
+
+	printk(KERN_INFO "\n");
+	printk(KERN_INFO "=================================================\n");
+
+	if (dev < 0) {
+		pr_info("Please specify a valid mtd-device via module parameter\n");
+		pr_crit("CAREFUL: This test wipes all data on the specified MTD device!\n");
+		return -EINVAL;
+	}
+
+	pr_info("MTD device: %d\n", dev);
+
+	mtd = get_mtd_device(NULL, dev);
+	if (IS_ERR(mtd)) {
+		err = PTR_ERR(mtd);
+		pr_err("error: cannot get MTD device\n");
+		return err;
+	}
+
+	if (!mtd_type_is_nand(mtd)) {
+		pr_info("this test requires NAND flash\n");
+		goto out;
+	}
+
+	subpgsize = mtd->writesize >> mtd->subpage_sft;
+	tmp = mtd->size;
+	do_div(tmp, mtd->erasesize);
+	ebcnt = tmp;
+	pgcnt = mtd->erasesize / mtd->writesize;
+
+	pr_info("MTD device size %llu, eraseblock size %u, "
+	       "page size %u, subpage size %u, count of eraseblocks %u, "
+	       "pages per eraseblock %u, OOB size %u\n",
+	       (unsigned long long)mtd->size, mtd->erasesize,
+	       mtd->writesize, subpgsize, ebcnt, pgcnt, mtd->oobsize);
+
+	err = -ENOMEM;
+	bufsize = subpgsize * 32;
+	writebuf = kmalloc(bufsize, GFP_KERNEL);
+	if (!writebuf)
+		goto out;
+	readbuf = kmalloc(bufsize, GFP_KERNEL);
+	if (!readbuf)
+		goto out;
+	bbt = kzalloc(ebcnt, GFP_KERNEL);
+	if (!bbt)
+		goto out;
+
+	err = mtdtest_scan_for_bad_eraseblocks(mtd, bbt, 0, ebcnt);
+	if (err)
+		goto out;
+
+	err = mtdtest_erase_good_eraseblocks(mtd, bbt, 0, ebcnt);
+	if (err)
+		goto out;
+
+	pr_info("writing whole device\n");
+	prandom_seed_state(&rnd_state, 1);
+	for (i = 0; i < ebcnt; ++i) {
+		if (bbt[i])
+			continue;
+		err = write_eraseblock(i);
+		if (unlikely(err))
+			goto out;
+		if (i % 256 == 0)
+			pr_info("written up to eraseblock %u\n", i);
+
+		err = mtdtest_relax();
+		if (err)
+			goto out;
+	}
+	pr_info("written %u eraseblocks\n", i);
+
+	prandom_seed_state(&rnd_state, 1);
+	pr_info("verifying all eraseblocks\n");
+	for (i = 0; i < ebcnt; ++i) {
+		if (bbt[i])
+			continue;
+		err = verify_eraseblock(i);
+		if (unlikely(err))
+			goto out;
+		if (i % 256 == 0)
+			pr_info("verified up to eraseblock %u\n", i);
+
+		err = mtdtest_relax();
+		if (err)
+			goto out;
+	}
+	pr_info("verified %u eraseblocks\n", i);
+
+	err = mtdtest_erase_good_eraseblocks(mtd, bbt, 0, ebcnt);
+	if (err)
+		goto out;
+
+	err = verify_all_eraseblocks_ff();
+	if (err)
+		goto out;
+
+	/* Write all eraseblocks */
+	prandom_seed_state(&rnd_state, 3);
+	pr_info("writing whole device\n");
+	for (i = 0; i < ebcnt; ++i) {
+		if (bbt[i])
+			continue;
+		err = write_eraseblock2(i);
+		if (unlikely(err))
+			goto out;
+		if (i % 256 == 0)
+			pr_info("written up to eraseblock %u\n", i);
+
+		err = mtdtest_relax();
+		if (err)
+			goto out;
+	}
+	pr_info("written %u eraseblocks\n", i);
+
+	/* Check all eraseblocks */
+	prandom_seed_state(&rnd_state, 3);
+	pr_info("verifying all eraseblocks\n");
+	for (i = 0; i < ebcnt; ++i) {
+		if (bbt[i])
+			continue;
+		err = verify_eraseblock2(i);
+		if (unlikely(err))
+			goto out;
+		if (i % 256 == 0)
+			pr_info("verified up to eraseblock %u\n", i);
+
+		err = mtdtest_relax();
+		if (err)
+			goto out;
+	}
+	pr_info("verified %u eraseblocks\n", i);
+
+	err = mtdtest_erase_good_eraseblocks(mtd, bbt, 0, ebcnt);
+	if (err)
+		goto out;
+
+	err = verify_all_eraseblocks_ff();
+	if (err)
+		goto out;
+
+	pr_info("finished with %d errors\n", errcnt);
+
+out:
+	kfree(bbt);
+	kfree(readbuf);
+	kfree(writebuf);
+	put_mtd_device(mtd);
+	if (err)
+		pr_info("error %d occurred\n", err);
+	printk(KERN_INFO "=================================================\n");
+	return err;
+}
+module_init(mtd_subpagetest_init);
+
+static void __exit mtd_subpagetest_exit(void)
+{
+	return;
+}
+module_exit(mtd_subpagetest_exit);
+
+MODULE_DESCRIPTION("Subpage test module");
+MODULE_AUTHOR("Adrian Hunter");
+MODULE_LICENSE("GPL");