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e8a533cbeb
These cases were done with this Coccinelle: @@ expression H; expression L; @@ - (get_random_u32_below(H) + L) + get_random_u32_inclusive(L, H + L - 1) @@ expression H; expression L; expression E; @@ get_random_u32_inclusive(L, H - + E - - E ) @@ expression H; expression L; expression E; @@ get_random_u32_inclusive(L, H - - E - + E ) @@ expression H; expression L; expression E; expression F; @@ get_random_u32_inclusive(L, H - - E + F - + E ) @@ expression H; expression L; expression E; expression F; @@ get_random_u32_inclusive(L, H - + E + F - - E ) And then subsequently cleaned up by hand, with several automatic cases rejected if it didn't make sense contextually. Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> # for infiniband Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
871 lines
24 KiB
C
871 lines
24 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Test cases for KFENCE memory safety error detector. Since the interface with
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* which KFENCE's reports are obtained is via the console, this is the output we
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* should verify. For each test case checks the presence (or absence) of
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* generated reports. Relies on 'console' tracepoint to capture reports as they
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* appear in the kernel log.
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*
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* Copyright (C) 2020, Google LLC.
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* Author: Alexander Potapenko <glider@google.com>
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* Marco Elver <elver@google.com>
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*/
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#include <kunit/test.h>
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#include <linux/jiffies.h>
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#include <linux/kernel.h>
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#include <linux/kfence.h>
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#include <linux/mm.h>
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#include <linux/random.h>
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#include <linux/slab.h>
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#include <linux/spinlock.h>
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#include <linux/string.h>
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#include <linux/tracepoint.h>
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#include <trace/events/printk.h>
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#include <asm/kfence.h>
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#include "kfence.h"
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/* May be overridden by <asm/kfence.h>. */
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#ifndef arch_kfence_test_address
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#define arch_kfence_test_address(addr) (addr)
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#endif
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#define KFENCE_TEST_REQUIRES(test, cond) do { \
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if (!(cond)) \
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kunit_skip((test), "Test requires: " #cond); \
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} while (0)
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/* Report as observed from console. */
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static struct {
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spinlock_t lock;
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int nlines;
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char lines[2][256];
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} observed = {
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.lock = __SPIN_LOCK_UNLOCKED(observed.lock),
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};
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/* Probe for console output: obtains observed lines of interest. */
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static void probe_console(void *ignore, const char *buf, size_t len)
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{
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unsigned long flags;
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int nlines;
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spin_lock_irqsave(&observed.lock, flags);
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nlines = observed.nlines;
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if (strnstr(buf, "BUG: KFENCE: ", len) && strnstr(buf, "test_", len)) {
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/*
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* KFENCE report and related to the test.
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*
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* The provided @buf is not NUL-terminated; copy no more than
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* @len bytes and let strscpy() add the missing NUL-terminator.
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*/
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strscpy(observed.lines[0], buf, min(len + 1, sizeof(observed.lines[0])));
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nlines = 1;
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} else if (nlines == 1 && (strnstr(buf, "at 0x", len) || strnstr(buf, "of 0x", len))) {
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strscpy(observed.lines[nlines++], buf, min(len + 1, sizeof(observed.lines[0])));
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}
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WRITE_ONCE(observed.nlines, nlines); /* Publish new nlines. */
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spin_unlock_irqrestore(&observed.lock, flags);
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}
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/* Check if a report related to the test exists. */
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static bool report_available(void)
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{
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return READ_ONCE(observed.nlines) == ARRAY_SIZE(observed.lines);
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}
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/* Information we expect in a report. */
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struct expect_report {
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enum kfence_error_type type; /* The type or error. */
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void *fn; /* Function pointer to expected function where access occurred. */
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char *addr; /* Address at which the bad access occurred. */
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bool is_write; /* Is access a write. */
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};
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static const char *get_access_type(const struct expect_report *r)
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{
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return r->is_write ? "write" : "read";
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}
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/* Check observed report matches information in @r. */
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static bool report_matches(const struct expect_report *r)
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{
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unsigned long addr = (unsigned long)r->addr;
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bool ret = false;
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unsigned long flags;
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typeof(observed.lines) expect;
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const char *end;
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char *cur;
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/* Doubled-checked locking. */
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if (!report_available())
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return false;
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/* Generate expected report contents. */
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/* Title */
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cur = expect[0];
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end = &expect[0][sizeof(expect[0]) - 1];
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switch (r->type) {
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case KFENCE_ERROR_OOB:
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cur += scnprintf(cur, end - cur, "BUG: KFENCE: out-of-bounds %s",
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get_access_type(r));
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break;
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case KFENCE_ERROR_UAF:
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cur += scnprintf(cur, end - cur, "BUG: KFENCE: use-after-free %s",
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get_access_type(r));
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break;
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case KFENCE_ERROR_CORRUPTION:
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cur += scnprintf(cur, end - cur, "BUG: KFENCE: memory corruption");
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break;
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case KFENCE_ERROR_INVALID:
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cur += scnprintf(cur, end - cur, "BUG: KFENCE: invalid %s",
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get_access_type(r));
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break;
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case KFENCE_ERROR_INVALID_FREE:
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cur += scnprintf(cur, end - cur, "BUG: KFENCE: invalid free");
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break;
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}
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scnprintf(cur, end - cur, " in %pS", r->fn);
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/* The exact offset won't match, remove it; also strip module name. */
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cur = strchr(expect[0], '+');
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if (cur)
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*cur = '\0';
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/* Access information */
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cur = expect[1];
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end = &expect[1][sizeof(expect[1]) - 1];
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switch (r->type) {
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case KFENCE_ERROR_OOB:
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cur += scnprintf(cur, end - cur, "Out-of-bounds %s at", get_access_type(r));
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addr = arch_kfence_test_address(addr);
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break;
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case KFENCE_ERROR_UAF:
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cur += scnprintf(cur, end - cur, "Use-after-free %s at", get_access_type(r));
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addr = arch_kfence_test_address(addr);
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break;
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case KFENCE_ERROR_CORRUPTION:
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cur += scnprintf(cur, end - cur, "Corrupted memory at");
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break;
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case KFENCE_ERROR_INVALID:
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cur += scnprintf(cur, end - cur, "Invalid %s at", get_access_type(r));
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addr = arch_kfence_test_address(addr);
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break;
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case KFENCE_ERROR_INVALID_FREE:
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cur += scnprintf(cur, end - cur, "Invalid free of");
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break;
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}
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cur += scnprintf(cur, end - cur, " 0x%p", (void *)addr);
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spin_lock_irqsave(&observed.lock, flags);
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if (!report_available())
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goto out; /* A new report is being captured. */
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/* Finally match expected output to what we actually observed. */
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ret = strstr(observed.lines[0], expect[0]) && strstr(observed.lines[1], expect[1]);
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out:
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spin_unlock_irqrestore(&observed.lock, flags);
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return ret;
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}
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/* ===== Test cases ===== */
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#define TEST_PRIV_WANT_MEMCACHE ((void *)1)
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/* Cache used by tests; if NULL, allocate from kmalloc instead. */
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static struct kmem_cache *test_cache;
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static size_t setup_test_cache(struct kunit *test, size_t size, slab_flags_t flags,
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void (*ctor)(void *))
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{
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if (test->priv != TEST_PRIV_WANT_MEMCACHE)
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return size;
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kunit_info(test, "%s: size=%zu, ctor=%ps\n", __func__, size, ctor);
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/*
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* Use SLAB_NOLEAKTRACE to prevent merging with existing caches. Any
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* other flag in SLAB_NEVER_MERGE also works. Use SLAB_ACCOUNT to
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* allocate via memcg, if enabled.
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*/
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flags |= SLAB_NOLEAKTRACE | SLAB_ACCOUNT;
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test_cache = kmem_cache_create("test", size, 1, flags, ctor);
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KUNIT_ASSERT_TRUE_MSG(test, test_cache, "could not create cache");
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return size;
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}
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static void test_cache_destroy(void)
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{
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if (!test_cache)
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return;
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kmem_cache_destroy(test_cache);
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test_cache = NULL;
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}
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static inline size_t kmalloc_cache_alignment(size_t size)
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{
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return kmalloc_caches[kmalloc_type(GFP_KERNEL)][__kmalloc_index(size, false)]->align;
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}
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/* Must always inline to match stack trace against caller. */
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static __always_inline void test_free(void *ptr)
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{
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if (test_cache)
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kmem_cache_free(test_cache, ptr);
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else
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kfree(ptr);
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}
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/*
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* If this should be a KFENCE allocation, and on which side the allocation and
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* the closest guard page should be.
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*/
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enum allocation_policy {
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ALLOCATE_ANY, /* KFENCE, any side. */
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ALLOCATE_LEFT, /* KFENCE, left side of page. */
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ALLOCATE_RIGHT, /* KFENCE, right side of page. */
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ALLOCATE_NONE, /* No KFENCE allocation. */
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};
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/*
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* Try to get a guarded allocation from KFENCE. Uses either kmalloc() or the
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* current test_cache if set up.
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*/
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static void *test_alloc(struct kunit *test, size_t size, gfp_t gfp, enum allocation_policy policy)
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{
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void *alloc;
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unsigned long timeout, resched_after;
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const char *policy_name;
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switch (policy) {
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case ALLOCATE_ANY:
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policy_name = "any";
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break;
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case ALLOCATE_LEFT:
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policy_name = "left";
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break;
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case ALLOCATE_RIGHT:
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policy_name = "right";
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break;
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case ALLOCATE_NONE:
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policy_name = "none";
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break;
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}
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kunit_info(test, "%s: size=%zu, gfp=%x, policy=%s, cache=%i\n", __func__, size, gfp,
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policy_name, !!test_cache);
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/*
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* 100x the sample interval should be more than enough to ensure we get
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* a KFENCE allocation eventually.
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*/
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timeout = jiffies + msecs_to_jiffies(100 * kfence_sample_interval);
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/*
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* Especially for non-preemption kernels, ensure the allocation-gate
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* timer can catch up: after @resched_after, every failed allocation
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* attempt yields, to ensure the allocation-gate timer is scheduled.
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*/
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resched_after = jiffies + msecs_to_jiffies(kfence_sample_interval);
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do {
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if (test_cache)
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alloc = kmem_cache_alloc(test_cache, gfp);
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else
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alloc = kmalloc(size, gfp);
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if (is_kfence_address(alloc)) {
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struct slab *slab = virt_to_slab(alloc);
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struct kmem_cache *s = test_cache ?:
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kmalloc_caches[kmalloc_type(GFP_KERNEL)][__kmalloc_index(size, false)];
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/*
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* Verify that various helpers return the right values
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* even for KFENCE objects; these are required so that
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* memcg accounting works correctly.
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*/
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KUNIT_EXPECT_EQ(test, obj_to_index(s, slab, alloc), 0U);
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KUNIT_EXPECT_EQ(test, objs_per_slab(s, slab), 1);
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if (policy == ALLOCATE_ANY)
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return alloc;
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if (policy == ALLOCATE_LEFT && PAGE_ALIGNED(alloc))
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return alloc;
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if (policy == ALLOCATE_RIGHT && !PAGE_ALIGNED(alloc))
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return alloc;
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} else if (policy == ALLOCATE_NONE)
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return alloc;
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test_free(alloc);
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if (time_after(jiffies, resched_after))
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cond_resched();
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} while (time_before(jiffies, timeout));
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KUNIT_ASSERT_TRUE_MSG(test, false, "failed to allocate from KFENCE");
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return NULL; /* Unreachable. */
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}
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static void test_out_of_bounds_read(struct kunit *test)
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{
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size_t size = 32;
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struct expect_report expect = {
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.type = KFENCE_ERROR_OOB,
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.fn = test_out_of_bounds_read,
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.is_write = false,
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};
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char *buf;
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setup_test_cache(test, size, 0, NULL);
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/*
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* If we don't have our own cache, adjust based on alignment, so that we
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* actually access guard pages on either side.
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*/
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if (!test_cache)
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size = kmalloc_cache_alignment(size);
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/* Test both sides. */
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buf = test_alloc(test, size, GFP_KERNEL, ALLOCATE_LEFT);
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expect.addr = buf - 1;
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READ_ONCE(*expect.addr);
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KUNIT_EXPECT_TRUE(test, report_matches(&expect));
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test_free(buf);
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buf = test_alloc(test, size, GFP_KERNEL, ALLOCATE_RIGHT);
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expect.addr = buf + size;
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READ_ONCE(*expect.addr);
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KUNIT_EXPECT_TRUE(test, report_matches(&expect));
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test_free(buf);
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}
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static void test_out_of_bounds_write(struct kunit *test)
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{
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size_t size = 32;
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struct expect_report expect = {
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.type = KFENCE_ERROR_OOB,
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.fn = test_out_of_bounds_write,
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.is_write = true,
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};
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char *buf;
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setup_test_cache(test, size, 0, NULL);
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buf = test_alloc(test, size, GFP_KERNEL, ALLOCATE_LEFT);
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expect.addr = buf - 1;
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WRITE_ONCE(*expect.addr, 42);
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KUNIT_EXPECT_TRUE(test, report_matches(&expect));
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test_free(buf);
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}
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static void test_use_after_free_read(struct kunit *test)
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{
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const size_t size = 32;
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struct expect_report expect = {
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.type = KFENCE_ERROR_UAF,
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.fn = test_use_after_free_read,
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.is_write = false,
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};
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setup_test_cache(test, size, 0, NULL);
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expect.addr = test_alloc(test, size, GFP_KERNEL, ALLOCATE_ANY);
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test_free(expect.addr);
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READ_ONCE(*expect.addr);
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KUNIT_EXPECT_TRUE(test, report_matches(&expect));
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}
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static void test_double_free(struct kunit *test)
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{
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const size_t size = 32;
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struct expect_report expect = {
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.type = KFENCE_ERROR_INVALID_FREE,
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.fn = test_double_free,
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};
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setup_test_cache(test, size, 0, NULL);
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expect.addr = test_alloc(test, size, GFP_KERNEL, ALLOCATE_ANY);
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test_free(expect.addr);
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test_free(expect.addr); /* Double-free. */
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KUNIT_EXPECT_TRUE(test, report_matches(&expect));
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}
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static void test_invalid_addr_free(struct kunit *test)
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{
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const size_t size = 32;
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struct expect_report expect = {
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.type = KFENCE_ERROR_INVALID_FREE,
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.fn = test_invalid_addr_free,
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};
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char *buf;
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setup_test_cache(test, size, 0, NULL);
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buf = test_alloc(test, size, GFP_KERNEL, ALLOCATE_ANY);
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expect.addr = buf + 1; /* Free on invalid address. */
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test_free(expect.addr); /* Invalid address free. */
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test_free(buf); /* No error. */
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KUNIT_EXPECT_TRUE(test, report_matches(&expect));
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}
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static void test_corruption(struct kunit *test)
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{
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size_t size = 32;
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struct expect_report expect = {
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.type = KFENCE_ERROR_CORRUPTION,
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.fn = test_corruption,
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};
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char *buf;
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setup_test_cache(test, size, 0, NULL);
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/* Test both sides. */
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buf = test_alloc(test, size, GFP_KERNEL, ALLOCATE_LEFT);
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expect.addr = buf + size;
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WRITE_ONCE(*expect.addr, 42);
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test_free(buf);
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KUNIT_EXPECT_TRUE(test, report_matches(&expect));
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buf = test_alloc(test, size, GFP_KERNEL, ALLOCATE_RIGHT);
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expect.addr = buf - 1;
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WRITE_ONCE(*expect.addr, 42);
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test_free(buf);
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KUNIT_EXPECT_TRUE(test, report_matches(&expect));
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}
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/*
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* KFENCE is unable to detect an OOB if the allocation's alignment requirements
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* leave a gap between the object and the guard page. Specifically, an
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* allocation of e.g. 73 bytes is aligned on 8 and 128 bytes for SLUB or SLAB
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* respectively. Therefore it is impossible for the allocated object to
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* contiguously line up with the right guard page.
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*
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* However, we test that an access to memory beyond the gap results in KFENCE
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* detecting an OOB access.
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*/
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static void test_kmalloc_aligned_oob_read(struct kunit *test)
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{
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const size_t size = 73;
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const size_t align = kmalloc_cache_alignment(size);
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struct expect_report expect = {
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.type = KFENCE_ERROR_OOB,
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.fn = test_kmalloc_aligned_oob_read,
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.is_write = false,
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};
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char *buf;
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buf = test_alloc(test, size, GFP_KERNEL, ALLOCATE_RIGHT);
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/*
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* The object is offset to the right, so there won't be an OOB to the
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* left of it.
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*/
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READ_ONCE(*(buf - 1));
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KUNIT_EXPECT_FALSE(test, report_available());
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/*
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* @buf must be aligned on @align, therefore buf + size belongs to the
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* same page -> no OOB.
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*/
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READ_ONCE(*(buf + size));
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KUNIT_EXPECT_FALSE(test, report_available());
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/* Overflowing by @align bytes will result in an OOB. */
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expect.addr = buf + size + align;
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READ_ONCE(*expect.addr);
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KUNIT_EXPECT_TRUE(test, report_matches(&expect));
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|
|
test_free(buf);
|
|
}
|
|
|
|
static void test_kmalloc_aligned_oob_write(struct kunit *test)
|
|
{
|
|
const size_t size = 73;
|
|
struct expect_report expect = {
|
|
.type = KFENCE_ERROR_CORRUPTION,
|
|
.fn = test_kmalloc_aligned_oob_write,
|
|
};
|
|
char *buf;
|
|
|
|
buf = test_alloc(test, size, GFP_KERNEL, ALLOCATE_RIGHT);
|
|
/*
|
|
* The object is offset to the right, so we won't get a page
|
|
* fault immediately after it.
|
|
*/
|
|
expect.addr = buf + size;
|
|
WRITE_ONCE(*expect.addr, READ_ONCE(*expect.addr) + 1);
|
|
KUNIT_EXPECT_FALSE(test, report_available());
|
|
test_free(buf);
|
|
KUNIT_EXPECT_TRUE(test, report_matches(&expect));
|
|
}
|
|
|
|
/* Test cache shrinking and destroying with KFENCE. */
|
|
static void test_shrink_memcache(struct kunit *test)
|
|
{
|
|
const size_t size = 32;
|
|
void *buf;
|
|
|
|
setup_test_cache(test, size, 0, NULL);
|
|
KUNIT_EXPECT_TRUE(test, test_cache);
|
|
buf = test_alloc(test, size, GFP_KERNEL, ALLOCATE_ANY);
|
|
kmem_cache_shrink(test_cache);
|
|
test_free(buf);
|
|
|
|
KUNIT_EXPECT_FALSE(test, report_available());
|
|
}
|
|
|
|
static void ctor_set_x(void *obj)
|
|
{
|
|
/* Every object has at least 8 bytes. */
|
|
memset(obj, 'x', 8);
|
|
}
|
|
|
|
/* Ensure that SL*B does not modify KFENCE objects on bulk free. */
|
|
static void test_free_bulk(struct kunit *test)
|
|
{
|
|
int iter;
|
|
|
|
for (iter = 0; iter < 5; iter++) {
|
|
const size_t size = setup_test_cache(test, get_random_u32_inclusive(8, 307),
|
|
0, (iter & 1) ? ctor_set_x : NULL);
|
|
void *objects[] = {
|
|
test_alloc(test, size, GFP_KERNEL, ALLOCATE_RIGHT),
|
|
test_alloc(test, size, GFP_KERNEL, ALLOCATE_NONE),
|
|
test_alloc(test, size, GFP_KERNEL, ALLOCATE_LEFT),
|
|
test_alloc(test, size, GFP_KERNEL, ALLOCATE_NONE),
|
|
test_alloc(test, size, GFP_KERNEL, ALLOCATE_NONE),
|
|
};
|
|
|
|
kmem_cache_free_bulk(test_cache, ARRAY_SIZE(objects), objects);
|
|
KUNIT_ASSERT_FALSE(test, report_available());
|
|
test_cache_destroy();
|
|
}
|
|
}
|
|
|
|
/* Test init-on-free works. */
|
|
static void test_init_on_free(struct kunit *test)
|
|
{
|
|
const size_t size = 32;
|
|
struct expect_report expect = {
|
|
.type = KFENCE_ERROR_UAF,
|
|
.fn = test_init_on_free,
|
|
.is_write = false,
|
|
};
|
|
int i;
|
|
|
|
KFENCE_TEST_REQUIRES(test, IS_ENABLED(CONFIG_INIT_ON_FREE_DEFAULT_ON));
|
|
/* Assume it hasn't been disabled on command line. */
|
|
|
|
setup_test_cache(test, size, 0, NULL);
|
|
expect.addr = test_alloc(test, size, GFP_KERNEL, ALLOCATE_ANY);
|
|
for (i = 0; i < size; i++)
|
|
expect.addr[i] = i + 1;
|
|
test_free(expect.addr);
|
|
|
|
for (i = 0; i < size; i++) {
|
|
/*
|
|
* This may fail if the page was recycled by KFENCE and then
|
|
* written to again -- this however, is near impossible with a
|
|
* default config.
|
|
*/
|
|
KUNIT_EXPECT_EQ(test, expect.addr[i], (char)0);
|
|
|
|
if (!i) /* Only check first access to not fail test if page is ever re-protected. */
|
|
KUNIT_EXPECT_TRUE(test, report_matches(&expect));
|
|
}
|
|
}
|
|
|
|
/* Ensure that constructors work properly. */
|
|
static void test_memcache_ctor(struct kunit *test)
|
|
{
|
|
const size_t size = 32;
|
|
char *buf;
|
|
int i;
|
|
|
|
setup_test_cache(test, size, 0, ctor_set_x);
|
|
buf = test_alloc(test, size, GFP_KERNEL, ALLOCATE_ANY);
|
|
|
|
for (i = 0; i < 8; i++)
|
|
KUNIT_EXPECT_EQ(test, buf[i], (char)'x');
|
|
|
|
test_free(buf);
|
|
|
|
KUNIT_EXPECT_FALSE(test, report_available());
|
|
}
|
|
|
|
/* Test that memory is zeroed if requested. */
|
|
static void test_gfpzero(struct kunit *test)
|
|
{
|
|
const size_t size = PAGE_SIZE; /* PAGE_SIZE so we can use ALLOCATE_ANY. */
|
|
char *buf1, *buf2;
|
|
int i;
|
|
|
|
/* Skip if we think it'd take too long. */
|
|
KFENCE_TEST_REQUIRES(test, kfence_sample_interval <= 100);
|
|
|
|
setup_test_cache(test, size, 0, NULL);
|
|
buf1 = test_alloc(test, size, GFP_KERNEL, ALLOCATE_ANY);
|
|
for (i = 0; i < size; i++)
|
|
buf1[i] = i + 1;
|
|
test_free(buf1);
|
|
|
|
/* Try to get same address again -- this can take a while. */
|
|
for (i = 0;; i++) {
|
|
buf2 = test_alloc(test, size, GFP_KERNEL | __GFP_ZERO, ALLOCATE_ANY);
|
|
if (buf1 == buf2)
|
|
break;
|
|
test_free(buf2);
|
|
|
|
if (kthread_should_stop() || (i == CONFIG_KFENCE_NUM_OBJECTS)) {
|
|
kunit_warn(test, "giving up ... cannot get same object back\n");
|
|
return;
|
|
}
|
|
cond_resched();
|
|
}
|
|
|
|
for (i = 0; i < size; i++)
|
|
KUNIT_EXPECT_EQ(test, buf2[i], (char)0);
|
|
|
|
test_free(buf2);
|
|
|
|
KUNIT_EXPECT_FALSE(test, report_available());
|
|
}
|
|
|
|
static void test_invalid_access(struct kunit *test)
|
|
{
|
|
const struct expect_report expect = {
|
|
.type = KFENCE_ERROR_INVALID,
|
|
.fn = test_invalid_access,
|
|
.addr = &__kfence_pool[10],
|
|
.is_write = false,
|
|
};
|
|
|
|
READ_ONCE(__kfence_pool[10]);
|
|
KUNIT_EXPECT_TRUE(test, report_matches(&expect));
|
|
}
|
|
|
|
/* Test SLAB_TYPESAFE_BY_RCU works. */
|
|
static void test_memcache_typesafe_by_rcu(struct kunit *test)
|
|
{
|
|
const size_t size = 32;
|
|
struct expect_report expect = {
|
|
.type = KFENCE_ERROR_UAF,
|
|
.fn = test_memcache_typesafe_by_rcu,
|
|
.is_write = false,
|
|
};
|
|
|
|
setup_test_cache(test, size, SLAB_TYPESAFE_BY_RCU, NULL);
|
|
KUNIT_EXPECT_TRUE(test, test_cache); /* Want memcache. */
|
|
|
|
expect.addr = test_alloc(test, size, GFP_KERNEL, ALLOCATE_ANY);
|
|
*expect.addr = 42;
|
|
|
|
rcu_read_lock();
|
|
test_free(expect.addr);
|
|
KUNIT_EXPECT_EQ(test, *expect.addr, (char)42);
|
|
/*
|
|
* Up to this point, memory should not have been freed yet, and
|
|
* therefore there should be no KFENCE report from the above access.
|
|
*/
|
|
rcu_read_unlock();
|
|
|
|
/* Above access to @expect.addr should not have generated a report! */
|
|
KUNIT_EXPECT_FALSE(test, report_available());
|
|
|
|
/* Only after rcu_barrier() is the memory guaranteed to be freed. */
|
|
rcu_barrier();
|
|
|
|
/* Expect use-after-free. */
|
|
KUNIT_EXPECT_EQ(test, *expect.addr, (char)42);
|
|
KUNIT_EXPECT_TRUE(test, report_matches(&expect));
|
|
}
|
|
|
|
/* Test krealloc(). */
|
|
static void test_krealloc(struct kunit *test)
|
|
{
|
|
const size_t size = 32;
|
|
const struct expect_report expect = {
|
|
.type = KFENCE_ERROR_UAF,
|
|
.fn = test_krealloc,
|
|
.addr = test_alloc(test, size, GFP_KERNEL, ALLOCATE_ANY),
|
|
.is_write = false,
|
|
};
|
|
char *buf = expect.addr;
|
|
int i;
|
|
|
|
KUNIT_EXPECT_FALSE(test, test_cache);
|
|
KUNIT_EXPECT_EQ(test, ksize(buf), size); /* Precise size match after KFENCE alloc. */
|
|
for (i = 0; i < size; i++)
|
|
buf[i] = i + 1;
|
|
|
|
/* Check that we successfully change the size. */
|
|
buf = krealloc(buf, size * 3, GFP_KERNEL); /* Grow. */
|
|
/* Note: Might no longer be a KFENCE alloc. */
|
|
KUNIT_EXPECT_GE(test, ksize(buf), size * 3);
|
|
for (i = 0; i < size; i++)
|
|
KUNIT_EXPECT_EQ(test, buf[i], (char)(i + 1));
|
|
for (; i < size * 3; i++) /* Fill to extra bytes. */
|
|
buf[i] = i + 1;
|
|
|
|
buf = krealloc(buf, size * 2, GFP_KERNEL); /* Shrink. */
|
|
KUNIT_EXPECT_GE(test, ksize(buf), size * 2);
|
|
for (i = 0; i < size * 2; i++)
|
|
KUNIT_EXPECT_EQ(test, buf[i], (char)(i + 1));
|
|
|
|
buf = krealloc(buf, 0, GFP_KERNEL); /* Free. */
|
|
KUNIT_EXPECT_EQ(test, (unsigned long)buf, (unsigned long)ZERO_SIZE_PTR);
|
|
KUNIT_ASSERT_FALSE(test, report_available()); /* No reports yet! */
|
|
|
|
READ_ONCE(*expect.addr); /* Ensure krealloc() actually freed earlier KFENCE object. */
|
|
KUNIT_ASSERT_TRUE(test, report_matches(&expect));
|
|
}
|
|
|
|
/* Test that some objects from a bulk allocation belong to KFENCE pool. */
|
|
static void test_memcache_alloc_bulk(struct kunit *test)
|
|
{
|
|
const size_t size = 32;
|
|
bool pass = false;
|
|
unsigned long timeout;
|
|
|
|
setup_test_cache(test, size, 0, NULL);
|
|
KUNIT_EXPECT_TRUE(test, test_cache); /* Want memcache. */
|
|
/*
|
|
* 100x the sample interval should be more than enough to ensure we get
|
|
* a KFENCE allocation eventually.
|
|
*/
|
|
timeout = jiffies + msecs_to_jiffies(100 * kfence_sample_interval);
|
|
do {
|
|
void *objects[100];
|
|
int i, num = kmem_cache_alloc_bulk(test_cache, GFP_ATOMIC, ARRAY_SIZE(objects),
|
|
objects);
|
|
if (!num)
|
|
continue;
|
|
for (i = 0; i < ARRAY_SIZE(objects); i++) {
|
|
if (is_kfence_address(objects[i])) {
|
|
pass = true;
|
|
break;
|
|
}
|
|
}
|
|
kmem_cache_free_bulk(test_cache, num, objects);
|
|
/*
|
|
* kmem_cache_alloc_bulk() disables interrupts, and calling it
|
|
* in a tight loop may not give KFENCE a chance to switch the
|
|
* static branch. Call cond_resched() to let KFENCE chime in.
|
|
*/
|
|
cond_resched();
|
|
} while (!pass && time_before(jiffies, timeout));
|
|
|
|
KUNIT_EXPECT_TRUE(test, pass);
|
|
KUNIT_EXPECT_FALSE(test, report_available());
|
|
}
|
|
|
|
/*
|
|
* KUnit does not provide a way to provide arguments to tests, and we encode
|
|
* additional info in the name. Set up 2 tests per test case, one using the
|
|
* default allocator, and another using a custom memcache (suffix '-memcache').
|
|
*/
|
|
#define KFENCE_KUNIT_CASE(test_name) \
|
|
{ .run_case = test_name, .name = #test_name }, \
|
|
{ .run_case = test_name, .name = #test_name "-memcache" }
|
|
|
|
static struct kunit_case kfence_test_cases[] = {
|
|
KFENCE_KUNIT_CASE(test_out_of_bounds_read),
|
|
KFENCE_KUNIT_CASE(test_out_of_bounds_write),
|
|
KFENCE_KUNIT_CASE(test_use_after_free_read),
|
|
KFENCE_KUNIT_CASE(test_double_free),
|
|
KFENCE_KUNIT_CASE(test_invalid_addr_free),
|
|
KFENCE_KUNIT_CASE(test_corruption),
|
|
KFENCE_KUNIT_CASE(test_free_bulk),
|
|
KFENCE_KUNIT_CASE(test_init_on_free),
|
|
KUNIT_CASE(test_kmalloc_aligned_oob_read),
|
|
KUNIT_CASE(test_kmalloc_aligned_oob_write),
|
|
KUNIT_CASE(test_shrink_memcache),
|
|
KUNIT_CASE(test_memcache_ctor),
|
|
KUNIT_CASE(test_invalid_access),
|
|
KUNIT_CASE(test_gfpzero),
|
|
KUNIT_CASE(test_memcache_typesafe_by_rcu),
|
|
KUNIT_CASE(test_krealloc),
|
|
KUNIT_CASE(test_memcache_alloc_bulk),
|
|
{},
|
|
};
|
|
|
|
/* ===== End test cases ===== */
|
|
|
|
static int test_init(struct kunit *test)
|
|
{
|
|
unsigned long flags;
|
|
int i;
|
|
|
|
if (!__kfence_pool)
|
|
return -EINVAL;
|
|
|
|
spin_lock_irqsave(&observed.lock, flags);
|
|
for (i = 0; i < ARRAY_SIZE(observed.lines); i++)
|
|
observed.lines[i][0] = '\0';
|
|
observed.nlines = 0;
|
|
spin_unlock_irqrestore(&observed.lock, flags);
|
|
|
|
/* Any test with 'memcache' in its name will want a memcache. */
|
|
if (strstr(test->name, "memcache"))
|
|
test->priv = TEST_PRIV_WANT_MEMCACHE;
|
|
else
|
|
test->priv = NULL;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void test_exit(struct kunit *test)
|
|
{
|
|
test_cache_destroy();
|
|
}
|
|
|
|
static void register_tracepoints(struct tracepoint *tp, void *ignore)
|
|
{
|
|
check_trace_callback_type_console(probe_console);
|
|
if (!strcmp(tp->name, "console"))
|
|
WARN_ON(tracepoint_probe_register(tp, probe_console, NULL));
|
|
}
|
|
|
|
static void unregister_tracepoints(struct tracepoint *tp, void *ignore)
|
|
{
|
|
if (!strcmp(tp->name, "console"))
|
|
tracepoint_probe_unregister(tp, probe_console, NULL);
|
|
}
|
|
|
|
static int kfence_suite_init(struct kunit_suite *suite)
|
|
{
|
|
/*
|
|
* Because we want to be able to build the test as a module, we need to
|
|
* iterate through all known tracepoints, since the static registration
|
|
* won't work here.
|
|
*/
|
|
for_each_kernel_tracepoint(register_tracepoints, NULL);
|
|
return 0;
|
|
}
|
|
|
|
static void kfence_suite_exit(struct kunit_suite *suite)
|
|
{
|
|
for_each_kernel_tracepoint(unregister_tracepoints, NULL);
|
|
tracepoint_synchronize_unregister();
|
|
}
|
|
|
|
static struct kunit_suite kfence_test_suite = {
|
|
.name = "kfence",
|
|
.test_cases = kfence_test_cases,
|
|
.init = test_init,
|
|
.exit = test_exit,
|
|
.suite_init = kfence_suite_init,
|
|
.suite_exit = kfence_suite_exit,
|
|
};
|
|
|
|
kunit_test_suites(&kfence_test_suite);
|
|
|
|
MODULE_LICENSE("GPL v2");
|
|
MODULE_AUTHOR("Alexander Potapenko <glider@google.com>, Marco Elver <elver@google.com>");
|