Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 672 insertions, 0 deletions

diff --git a/drivers/misc/lkdtm/bugs.c b/drivers/misc/lkdtm/bugs.c
new file mode 100644
index 000000000..c66cc05a6
--- /dev/null
+++ b/drivers/misc/lkdtm/bugs.c
@@ -0,0 +1,672 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * This is for all the tests related to logic bugs (e.g. bad dereferences,
+ * bad alignment, bad loops, bad locking, bad scheduling, deep stacks, and
+ * lockups) along with other things that don't fit well into existing LKDTM
+ * test source files.
+ */
+#include "lkdtm.h"
+#include <linux/list.h>
+#include <linux/sched.h>
+#include <linux/sched/signal.h>
+#include <linux/sched/task_stack.h>
+#include <linux/uaccess.h>
+#include <linux/slab.h>
+
+#if IS_ENABLED(CONFIG_X86_32) && !IS_ENABLED(CONFIG_UML)
+#include <asm/desc.h>
+#endif
+
+struct lkdtm_list {
+	struct list_head node;
+};
+
+/*
+ * Make sure our attempts to over run the kernel stack doesn't trigger
+ * a compiler warning when CONFIG_FRAME_WARN is set. Then make sure we
+ * recurse past the end of THREAD_SIZE by default.
+ */
+#if defined(CONFIG_FRAME_WARN) && (CONFIG_FRAME_WARN > 0)
+#define REC_STACK_SIZE (_AC(CONFIG_FRAME_WARN, UL) / 2)
+#else
+#define REC_STACK_SIZE (THREAD_SIZE / 8UL)
+#endif
+#define REC_NUM_DEFAULT ((THREAD_SIZE / REC_STACK_SIZE) * 2)
+
+static int recur_count = REC_NUM_DEFAULT;
+
+static DEFINE_SPINLOCK(lock_me_up);
+
+/*
+ * Make sure compiler does not optimize this function or stack frame away:
+ * - function marked noinline
+ * - stack variables are marked volatile
+ * - stack variables are written (memset()) and read (buf[..] passed as arg)
+ * - function may have external effects (memzero_explicit())
+ * - no tail recursion possible
+ */
+static int noinline recursive_loop(int remaining)
+{
+	volatile char buf[REC_STACK_SIZE];
+	volatile int ret;
+
+	memset((void *)buf, remaining & 0xFF, sizeof(buf));
+	if (!remaining)
+		ret = 0;
+	else
+		ret = recursive_loop((int)buf[remaining % sizeof(buf)] - 1);
+	memzero_explicit((void *)buf, sizeof(buf));
+	return ret;
+}
+
+/* If the depth is negative, use the default, otherwise keep parameter. */
+void __init lkdtm_bugs_init(int *recur_param)
+{
+	if (*recur_param < 0)
+		*recur_param = recur_count;
+	else
+		recur_count = *recur_param;
+}
+
+static void lkdtm_PANIC(void)
+{
+	panic("dumptest");
+}
+
+static void lkdtm_BUG(void)
+{
+	BUG();
+}
+
+static int warn_counter;
+
+static void lkdtm_WARNING(void)
+{
+	WARN_ON(++warn_counter);
+}
+
+static void lkdtm_WARNING_MESSAGE(void)
+{
+	WARN(1, "Warning message trigger count: %d\n", ++warn_counter);
+}
+
+static void lkdtm_EXCEPTION(void)
+{
+	*((volatile int *) 0) = 0;
+}
+
+static void lkdtm_LOOP(void)
+{
+	for (;;)
+		;
+}
+
+static void lkdtm_EXHAUST_STACK(void)
+{
+	pr_info("Calling function with %lu frame size to depth %d ...\n",
+		REC_STACK_SIZE, recur_count);
+	recursive_loop(recur_count);
+	pr_info("FAIL: survived without exhausting stack?!\n");
+}
+
+static noinline void __lkdtm_CORRUPT_STACK(void *stack)
+{
+	memset(stack, '\xff', 64);
+}
+
+/* This should trip the stack canary, not corrupt the return address. */
+static noinline void lkdtm_CORRUPT_STACK(void)
+{
+	/* Use default char array length that triggers stack protection. */
+	char data[8] __aligned(sizeof(void *));
+
+	pr_info("Corrupting stack containing char array ...\n");
+	__lkdtm_CORRUPT_STACK((void *)&data);
+}
+
+/* Same as above but will only get a canary with -fstack-protector-strong */
+static noinline void lkdtm_CORRUPT_STACK_STRONG(void)
+{
+	union {
+		unsigned short shorts[4];
+		unsigned long *ptr;
+	} data __aligned(sizeof(void *));
+
+	pr_info("Corrupting stack containing union ...\n");
+	__lkdtm_CORRUPT_STACK((void *)&data);
+}
+
+static pid_t stack_pid;
+static unsigned long stack_addr;
+
+static void lkdtm_REPORT_STACK(void)
+{
+	volatile uintptr_t magic;
+	pid_t pid = task_pid_nr(current);
+
+	if (pid != stack_pid) {
+		pr_info("Starting stack offset tracking for pid %d\n", pid);
+		stack_pid = pid;
+		stack_addr = (uintptr_t)&magic;
+	}
+
+	pr_info("Stack offset: %d\n", (int)(stack_addr - (uintptr_t)&magic));
+}
+
+static pid_t stack_canary_pid;
+static unsigned long stack_canary;
+static unsigned long stack_canary_offset;
+
+static noinline void __lkdtm_REPORT_STACK_CANARY(void *stack)
+{
+	int i = 0;
+	pid_t pid = task_pid_nr(current);
+	unsigned long *canary = (unsigned long *)stack;
+	unsigned long current_offset = 0, init_offset = 0;
+
+	/* Do our best to find the canary in a 16 word window ... */
+	for (i = 1; i < 16; i++) {
+		canary = (unsigned long *)stack + i;
+#ifdef CONFIG_STACKPROTECTOR
+		if (*canary == current->stack_canary)
+			current_offset = i;
+		if (*canary == init_task.stack_canary)
+			init_offset = i;
+#endif
+	}
+
+	if (current_offset == 0) {
+		/*
+		 * If the canary doesn't match what's in the task_struct,
+		 * we're either using a global canary or the stack frame
+		 * layout changed.
+		 */
+		if (init_offset != 0) {
+			pr_err("FAIL: global stack canary found at offset %ld (canary for pid %d matches init_task's)!\n",
+			       init_offset, pid);
+		} else {
+			pr_warn("FAIL: did not correctly locate stack canary :(\n");
+			pr_expected_config(CONFIG_STACKPROTECTOR);
+		}
+
+		return;
+	} else if (init_offset != 0) {
+		pr_warn("WARNING: found both current and init_task canaries nearby?!\n");
+	}
+
+	canary = (unsigned long *)stack + current_offset;
+	if (stack_canary_pid == 0) {
+		stack_canary = *canary;
+		stack_canary_pid = pid;
+		stack_canary_offset = current_offset;
+		pr_info("Recorded stack canary for pid %d at offset %ld\n",
+			stack_canary_pid, stack_canary_offset);
+	} else if (pid == stack_canary_pid) {
+		pr_warn("ERROR: saw pid %d again -- please use a new pid\n", pid);
+	} else {
+		if (current_offset != stack_canary_offset) {
+			pr_warn("ERROR: canary offset changed from %ld to %ld!?\n",
+				stack_canary_offset, current_offset);
+			return;
+		}
+
+		if (*canary == stack_canary) {
+			pr_warn("FAIL: canary identical for pid %d and pid %d at offset %ld!\n",
+				stack_canary_pid, pid, current_offset);
+		} else {
+			pr_info("ok: stack canaries differ between pid %d and pid %d at offset %ld.\n",
+				stack_canary_pid, pid, current_offset);
+			/* Reset the test. */
+			stack_canary_pid = 0;
+		}
+	}
+}
+
+static void lkdtm_REPORT_STACK_CANARY(void)
+{
+	/* Use default char array length that triggers stack protection. */
+	char data[8] __aligned(sizeof(void *)) = { };
+
+	__lkdtm_REPORT_STACK_CANARY((void *)&data);
+}
+
+static void lkdtm_UNALIGNED_LOAD_STORE_WRITE(void)
+{
+	static u8 data[5] __attribute__((aligned(4))) = {1, 2, 3, 4, 5};
+	u32 *p;
+	u32 val = 0x12345678;
+
+	p = (u32 *)(data + 1);
+	if (*p == 0)
+		val = 0x87654321;
+	*p = val;
+
+	if (IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS))
+		pr_err("XFAIL: arch has CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS\n");
+}
+
+static void lkdtm_SOFTLOCKUP(void)
+{
+	preempt_disable();
+	for (;;)
+		cpu_relax();
+}
+
+static void lkdtm_HARDLOCKUP(void)
+{
+	local_irq_disable();
+	for (;;)
+		cpu_relax();
+}
+
+static void lkdtm_SPINLOCKUP(void)
+{
+	/* Must be called twice to trigger. */
+	spin_lock(&lock_me_up);
+	/* Let sparse know we intended to exit holding the lock. */
+	__release(&lock_me_up);
+}
+
+static void lkdtm_HUNG_TASK(void)
+{
+	set_current_state(TASK_UNINTERRUPTIBLE);
+	schedule();
+}
+
+static volatile unsigned int huge = INT_MAX - 2;
+static volatile unsigned int ignored;
+
+static void lkdtm_OVERFLOW_SIGNED(void)
+{
+	int value;
+
+	value = huge;
+	pr_info("Normal signed addition ...\n");
+	value += 1;
+	ignored = value;
+
+	pr_info("Overflowing signed addition ...\n");
+	value += 4;
+	ignored = value;
+}
+
+
+static void lkdtm_OVERFLOW_UNSIGNED(void)
+{
+	unsigned int value;
+
+	value = huge;
+	pr_info("Normal unsigned addition ...\n");
+	value += 1;
+	ignored = value;
+
+	pr_info("Overflowing unsigned addition ...\n");
+	value += 4;
+	ignored = value;
+}
+
+/* Intentionally using unannotated flex array definition. */
+struct array_bounds_flex_array {
+	int one;
+	int two;
+	char data[];
+};
+
+struct array_bounds {
+	int one;
+	int two;
+	char data[8];
+	int three;
+};
+
+static void lkdtm_ARRAY_BOUNDS(void)
+{
+	struct array_bounds_flex_array *not_checked;
+	struct array_bounds *checked;
+	volatile int i;
+
+	not_checked = kmalloc(sizeof(*not_checked) * 2, GFP_KERNEL);
+	checked = kmalloc(sizeof(*checked) * 2, GFP_KERNEL);
+	if (!not_checked || !checked) {
+		kfree(not_checked);
+		kfree(checked);
+		return;
+	}
+
+	pr_info("Array access within bounds ...\n");
+	/* For both, touch all bytes in the actual member size. */
+	for (i = 0; i < sizeof(checked->data); i++)
+		checked->data[i] = 'A';
+	/*
+	 * For the uninstrumented flex array member, also touch 1 byte
+	 * beyond to verify it is correctly uninstrumented.
+	 */
+	for (i = 0; i < 2; i++)
+		not_checked->data[i] = 'A';
+
+	pr_info("Array access beyond bounds ...\n");
+	for (i = 0; i < sizeof(checked->data) + 1; i++)
+		checked->data[i] = 'B';
+
+	kfree(not_checked);
+	kfree(checked);
+	pr_err("FAIL: survived array bounds overflow!\n");
+	if (IS_ENABLED(CONFIG_UBSAN_BOUNDS))
+		pr_expected_config(CONFIG_UBSAN_TRAP);
+	else
+		pr_expected_config(CONFIG_UBSAN_BOUNDS);
+}
+
+struct lkdtm_annotated {
+	unsigned long flags;
+	int count;
+	int array[] __counted_by(count);
+};
+
+static volatile int fam_count = 4;
+
+static void lkdtm_FAM_BOUNDS(void)
+{
+	struct lkdtm_annotated *inst;
+
+	inst = kzalloc(struct_size(inst, array, fam_count + 1), GFP_KERNEL);
+	if (!inst) {
+		pr_err("FAIL: could not allocate test struct!\n");
+		return;
+	}
+
+	inst->count = fam_count;
+	pr_info("Array access within bounds ...\n");
+	inst->array[1] = fam_count;
+	ignored = inst->array[1];
+
+	pr_info("Array access beyond bounds ...\n");
+	inst->array[fam_count] = fam_count;
+	ignored = inst->array[fam_count];
+
+	kfree(inst);
+
+	pr_err("FAIL: survived access of invalid flexible array member index!\n");
+
+	if (!__has_attribute(__counted_by__))
+		pr_warn("This is expected since this %s was built a compiler supporting __counted_by\n",
+			lkdtm_kernel_info);
+	else if (IS_ENABLED(CONFIG_UBSAN_BOUNDS))
+		pr_expected_config(CONFIG_UBSAN_TRAP);
+	else
+		pr_expected_config(CONFIG_UBSAN_BOUNDS);
+}
+
+static void lkdtm_CORRUPT_LIST_ADD(void)
+{
+	/*
+	 * Initially, an empty list via LIST_HEAD:
+	 *	test_head.next = &test_head
+	 *	test_head.prev = &test_head
+	 */
+	LIST_HEAD(test_head);
+	struct lkdtm_list good, bad;
+	void *target[2] = { };
+	void *redirection = &target;
+
+	pr_info("attempting good list addition\n");
+
+	/*
+	 * Adding to the list performs these actions:
+	 *	test_head.next->prev = &good.node
+	 *	good.node.next = test_head.next
+	 *	good.node.prev = test_head
+	 *	test_head.next = good.node
+	 */
+	list_add(&good.node, &test_head);
+
+	pr_info("attempting corrupted list addition\n");
+	/*
+	 * In simulating this "write what where" primitive, the "what" is
+	 * the address of &bad.node, and the "where" is the address held
+	 * by "redirection".
+	 */
+	test_head.next = redirection;
+	list_add(&bad.node, &test_head);
+
+	if (target[0] == NULL && target[1] == NULL)
+		pr_err("Overwrite did not happen, but no BUG?!\n");
+	else {
+		pr_err("list_add() corruption not detected!\n");
+		pr_expected_config(CONFIG_LIST_HARDENED);
+	}
+}
+
+static void lkdtm_CORRUPT_LIST_DEL(void)
+{
+	LIST_HEAD(test_head);
+	struct lkdtm_list item;
+	void *target[2] = { };
+	void *redirection = &target;
+
+	list_add(&item.node, &test_head);
+
+	pr_info("attempting good list removal\n");
+	list_del(&item.node);
+
+	pr_info("attempting corrupted list removal\n");
+	list_add(&item.node, &test_head);
+
+	/* As with the list_add() test above, this corrupts "next". */
+	item.node.next = redirection;
+	list_del(&item.node);
+
+	if (target[0] == NULL && target[1] == NULL)
+		pr_err("Overwrite did not happen, but no BUG?!\n");
+	else {
+		pr_err("list_del() corruption not detected!\n");
+		pr_expected_config(CONFIG_LIST_HARDENED);
+	}
+}
+
+/* Test that VMAP_STACK is actually allocating with a leading guard page */
+static void lkdtm_STACK_GUARD_PAGE_LEADING(void)
+{
+	const unsigned char *stack = task_stack_page(current);
+	const unsigned char *ptr = stack - 1;
+	volatile unsigned char byte;
+
+	pr_info("attempting bad read from page below current stack\n");
+
+	byte = *ptr;
+
+	pr_err("FAIL: accessed page before stack! (byte: %x)\n", byte);
+}
+
+/* Test that VMAP_STACK is actually allocating with a trailing guard page */
+static void lkdtm_STACK_GUARD_PAGE_TRAILING(void)
+{
+	const unsigned char *stack = task_stack_page(current);
+	const unsigned char *ptr = stack + THREAD_SIZE;
+	volatile unsigned char byte;
+
+	pr_info("attempting bad read from page above current stack\n");
+
+	byte = *ptr;
+
+	pr_err("FAIL: accessed page after stack! (byte: %x)\n", byte);
+}
+
+static void lkdtm_UNSET_SMEP(void)
+{
+#if IS_ENABLED(CONFIG_X86_64) && !IS_ENABLED(CONFIG_UML)
+#define MOV_CR4_DEPTH	64
+	void (*direct_write_cr4)(unsigned long val);
+	unsigned char *insn;
+	unsigned long cr4;
+	int i;
+
+	cr4 = native_read_cr4();
+
+	if ((cr4 & X86_CR4_SMEP) != X86_CR4_SMEP) {
+		pr_err("FAIL: SMEP not in use\n");
+		return;
+	}
+	cr4 &= ~(X86_CR4_SMEP);
+
+	pr_info("trying to clear SMEP normally\n");
+	native_write_cr4(cr4);
+	if (cr4 == native_read_cr4()) {
+		pr_err("FAIL: pinning SMEP failed!\n");
+		cr4 |= X86_CR4_SMEP;
+		pr_info("restoring SMEP\n");
+		native_write_cr4(cr4);
+		return;
+	}
+	pr_info("ok: SMEP did not get cleared\n");
+
+	/*
+	 * To test the post-write pinning verification we need to call
+	 * directly into the middle of native_write_cr4() where the
+	 * cr4 write happens, skipping any pinning. This searches for
+	 * the cr4 writing instruction.
+	 */
+	insn = (unsigned char *)native_write_cr4;
+	OPTIMIZER_HIDE_VAR(insn);
+	for (i = 0; i < MOV_CR4_DEPTH; i++) {
+		/* mov %rdi, %cr4 */
+		if (insn[i] == 0x0f && insn[i+1] == 0x22 && insn[i+2] == 0xe7)
+			break;
+		/* mov %rdi,%rax; mov %rax, %cr4 */
+		if (insn[i]   == 0x48 && insn[i+1] == 0x89 &&
+		    insn[i+2] == 0xf8 && insn[i+3] == 0x0f &&
+		    insn[i+4] == 0x22 && insn[i+5] == 0xe0)
+			break;
+	}
+	if (i >= MOV_CR4_DEPTH) {
+		pr_info("ok: cannot locate cr4 writing call gadget\n");
+		return;
+	}
+	direct_write_cr4 = (void *)(insn + i);
+
+	pr_info("trying to clear SMEP with call gadget\n");
+	direct_write_cr4(cr4);
+	if (native_read_cr4() & X86_CR4_SMEP) {
+		pr_info("ok: SMEP removal was reverted\n");
+	} else {
+		pr_err("FAIL: cleared SMEP not detected!\n");
+		cr4 |= X86_CR4_SMEP;
+		pr_info("restoring SMEP\n");
+		native_write_cr4(cr4);
+	}
+#else
+	pr_err("XFAIL: this test is x86_64-only\n");
+#endif
+}
+
+static void lkdtm_DOUBLE_FAULT(void)
+{
+#if IS_ENABLED(CONFIG_X86_32) && !IS_ENABLED(CONFIG_UML)
+	/*
+	 * Trigger #DF by setting the stack limit to zero.  This clobbers
+	 * a GDT TLS slot, which is okay because the current task will die
+	 * anyway due to the double fault.
+	 */
+	struct desc_struct d = {
+		.type = 3,	/* expand-up, writable, accessed data */
+		.p = 1,		/* present */
+		.d = 1,		/* 32-bit */
+		.g = 0,		/* limit in bytes */
+		.s = 1,		/* not system */
+	};
+
+	local_irq_disable();
+	write_gdt_entry(get_cpu_gdt_rw(smp_processor_id()),
+			GDT_ENTRY_TLS_MIN, &d, DESCTYPE_S);
+
+	/*
+	 * Put our zero-limit segment in SS and then trigger a fault.  The
+	 * 4-byte access to (%esp) will fault with #SS, and the attempt to
+	 * deliver the fault will recursively cause #SS and result in #DF.
+	 * This whole process happens while NMIs and MCEs are blocked by the
+	 * MOV SS window.  This is nice because an NMI with an invalid SS
+	 * would also double-fault, resulting in the NMI or MCE being lost.
+	 */
+	asm volatile ("movw %0, %%ss; addl $0, (%%esp)" ::
+		      "r" ((unsigned short)(GDT_ENTRY_TLS_MIN << 3)));
+
+	pr_err("FAIL: tried to double fault but didn't die\n");
+#else
+	pr_err("XFAIL: this test is ia32-only\n");
+#endif
+}
+
+#ifdef CONFIG_ARM64
+static noinline void change_pac_parameters(void)
+{
+	if (IS_ENABLED(CONFIG_ARM64_PTR_AUTH_KERNEL)) {
+		/* Reset the keys of current task */
+		ptrauth_thread_init_kernel(current);
+		ptrauth_thread_switch_kernel(current);
+	}
+}
+#endif
+
+static noinline void lkdtm_CORRUPT_PAC(void)
+{
+#ifdef CONFIG_ARM64
+#define CORRUPT_PAC_ITERATE	10
+	int i;
+
+	if (!IS_ENABLED(CONFIG_ARM64_PTR_AUTH_KERNEL))
+		pr_err("FAIL: kernel not built with CONFIG_ARM64_PTR_AUTH_KERNEL\n");
+
+	if (!system_supports_address_auth()) {
+		pr_err("FAIL: CPU lacks pointer authentication feature\n");
+		return;
+	}
+
+	pr_info("changing PAC parameters to force function return failure...\n");
+	/*
+	 * PAC is a hash value computed from input keys, return address and
+	 * stack pointer. As pac has fewer bits so there is a chance of
+	 * collision, so iterate few times to reduce the collision probability.
+	 */
+	for (i = 0; i < CORRUPT_PAC_ITERATE; i++)
+		change_pac_parameters();
+
+	pr_err("FAIL: survived PAC changes! Kernel may be unstable from here\n");
+#else
+	pr_err("XFAIL: this test is arm64-only\n");
+#endif
+}
+
+static struct crashtype crashtypes[] = {
+	CRASHTYPE(PANIC),
+	CRASHTYPE(BUG),
+	CRASHTYPE(WARNING),
+	CRASHTYPE(WARNING_MESSAGE),
+	CRASHTYPE(EXCEPTION),
+	CRASHTYPE(LOOP),
+	CRASHTYPE(EXHAUST_STACK),
+	CRASHTYPE(CORRUPT_STACK),
+	CRASHTYPE(CORRUPT_STACK_STRONG),
+	CRASHTYPE(REPORT_STACK),
+	CRASHTYPE(REPORT_STACK_CANARY),
+	CRASHTYPE(UNALIGNED_LOAD_STORE_WRITE),
+	CRASHTYPE(SOFTLOCKUP),
+	CRASHTYPE(HARDLOCKUP),
+	CRASHTYPE(SPINLOCKUP),
+	CRASHTYPE(HUNG_TASK),
+	CRASHTYPE(OVERFLOW_SIGNED),
+	CRASHTYPE(OVERFLOW_UNSIGNED),
+	CRASHTYPE(ARRAY_BOUNDS),
+	CRASHTYPE(FAM_BOUNDS),
+	CRASHTYPE(CORRUPT_LIST_ADD),
+	CRASHTYPE(CORRUPT_LIST_DEL),
+	CRASHTYPE(STACK_GUARD_PAGE_LEADING),
+	CRASHTYPE(STACK_GUARD_PAGE_TRAILING),
+	CRASHTYPE(UNSET_SMEP),
+	CRASHTYPE(DOUBLE_FAULT),
+	CRASHTYPE(CORRUPT_PAC),
+};
+
+struct crashtype_category bugs_crashtypes = {
+	.crashtypes = crashtypes,
+	.len	    = ARRAY_SIZE(crashtypes),
+};