Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Fix error output of boot instance creation failure

   Currently if a boot instance creation fails, instead of printing out
   the name of the instance that failed, it prints "(null)". That is
   because it prints "cur_str" that had already been processed by
   strsep(). Print the saved name instead.

   While at it, print the error code of the failure.

 - Fix use-after-free for same named historgrams

   Histograms can be named so that they can be used in multiple events.
   But if the named histogram has a variable attached, the second event
   that uses the named histogram which duplicates it and needs to free
   the original after duplication leaves the old variable in place and
   still visible. If another histogram uses than variable, it will use
   the stale one which will try to reference the freed duplicate
   histogram and crash the kernel.

   Free the duplicate variables along with the duplicated histogram
   data.

 - Check return value of kthread_run() in event self test

   The events self tests uses a kthread for testing but does not check
   if it succeeded in creating a kthread. If the kthread creation were
   to fail, the code will still try to call kthread_stop() on the error
   returned.

 - Fix race between reading trace_pipe and updating subbuffer size

   If a user is reading the trace_pipe file at the same time they update
   the ring buffer sub-buffer size, can cause the trace_pipe read to
   read stale data. Add trace_access_lock() around updating the ring
   buffer sub-buffer size.

 - Fix eventfs_inode on failure path in creation of the events directory

   In the creation of the "events" directory, if after allocating the
   eventfs_inode a failure is detected, it calls cleanup_ei() which
   calls free_ei(). The free_ei() will test if eventfs_inode being freed
   has no children. It is a bug if it does. But on the failure case of
   the creation of the "events" directory, the children lists have not
   yet been initialized and the free will trigger a warning because
   list_empty() on an uninitialized list returns false.

   Move the initialization into init_ei() where it makes more sense and
   makes sure that a created eventfs_inode has its lists initialized
   upon creation.

 - Check return value of kthread_run() in ftrace direct sample code

   The sample code that shows how to use the ftrace direct calls does
   not test the return of kthread_run() to see if it succeeds. Return a
   failure if the kthread_run() doesn't succeed.

 - Clear user events state on fork in case of alloc failure

   On fork, the child gets a pointer to the parent's user events state.
   It makes a copy of it then updates the child's pointer to it. But if
   the allocation fails, the duplication function leaves the child with
   a pointer to its parent's descriptor. When the child cleans up its
   data, it will free the parent's descriptor while the parent is still
   using it.

   In the duplication function, set the child's user_event_mm to NULL
   before testing if the allocation succeeded, and when it exits it will
   not free the parent's descriptor.

 - Fix retry exhaustion in simple ring buffer reader swap

   simple_ring_buffer_swap_reader_page() starts with retry set to 8 and
   post-decrements it only after a failed link replacement. On the final
   attempt, a successful replacement leaves retry at zero, while a
   failed replacement leaves it at -1.

   But the check for success expects the retry value to be non-zero and
   exits with an error on zero. This is the opposite result. Fix it.

 - Fail nicely when the remote swap_reader_page() returns an error

   Currently, if the swap_reader_page() of a remote buffer fails, it
   triggers a WARN_ON_ONCE() and continues normally. Instead, have it
   exit with an error and a pr_warn() print instead of a full WARNING.

* tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Stop remote reader update when page swap fails
  tracing: Fix retry exhaustion in simple ring buffer reader swap
  tracing/user_events: Clear copied tracing state before fork duplication
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify
  eventfs: Initialize ei->children and ei->list in init_ei()
  tracing: Fix use-after-free in trace_pipe read on sub-buffer order change
  tracing: Fix crash passing ERR_PTR to kthread_stop()
  tracing: Fix use-after-free with same-name named triggers
  tracing: Fix logged instance name on creation failure

1 files changed, 306 insertions, 0 deletions

diff --git a/drivers/misc/lkdtm/perms.c b/drivers/misc/lkdtm/perms.c
new file mode 100644
index 000000000..e1f5e9abb
--- /dev/null
+++ b/drivers/misc/lkdtm/perms.c
@@ -0,0 +1,306 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * This is for all the tests related to validating kernel memory
+ * permissions: non-executable regions, non-writable regions, and
+ * even non-readable regions.
+ */
+#include "lkdtm.h"
+#include <linux/slab.h>
+#include <linux/vmalloc.h>
+#include <linux/mman.h>
+#include <linux/uaccess.h>
+#include <linux/objtool.h>
+#include <asm/cacheflush.h>
+#include <asm/sections.h>
+
+/* Whether or not to fill the target memory area with do_nothing(). */
+#define CODE_WRITE	true
+#define CODE_AS_IS	false
+
+/* How many bytes to copy to be sure we've copied enough of do_nothing(). */
+#define EXEC_SIZE 64
+
+/* This is non-const, so it will end up in the .data section. */
+static u8 data_area[EXEC_SIZE];
+
+/* This is const, so it will end up in the .rodata section. */
+static const unsigned long rodata = 0xAA55AA55;
+
+/* This is marked __ro_after_init, so it should ultimately be .rodata. */
+static unsigned long ro_after_init __ro_after_init = 0x55AA5500;
+
+/*
+ * This is a pointer to do_nothing() which is initialized at runtime rather
+ * than build time to avoid objtool IBT validation warnings caused by an
+ * inlined unrolled memcpy() in execute_location().
+ */
+static void __ro_after_init *do_nothing_ptr;
+
+/*
+ * This just returns to the caller. It is designed to be copied into
+ * non-executable memory regions.
+ */
+static noinline void do_nothing(void)
+{
+	return;
+}
+
+/* Must immediately follow do_nothing for size calculuations to work out. */
+static noinline void do_overwritten(void)
+{
+	pr_info("do_overwritten wasn't overwritten!\n");
+	return;
+}
+
+static noinline void do_almost_nothing(void)
+{
+	pr_info("do_nothing was hijacked!\n");
+}
+
+static void *setup_function_descriptor(func_desc_t *fdesc, void *dst)
+{
+	if (!have_function_descriptors())
+		return dst;
+
+	memcpy(fdesc, do_nothing, sizeof(*fdesc));
+	fdesc->addr = (unsigned long)dst;
+	barrier();
+
+	return fdesc;
+}
+
+static noinline __nocfi void execute_location(void *dst, bool write)
+{
+	void (*func)(void);
+	func_desc_t fdesc;
+
+	pr_info("attempting ok execution at %px\n", do_nothing_ptr);
+	do_nothing();
+
+	if (write == CODE_WRITE) {
+		memcpy(dst, do_nothing_ptr, EXEC_SIZE);
+		flush_icache_range((unsigned long)dst,
+				   (unsigned long)dst + EXEC_SIZE);
+	}
+	pr_info("attempting bad execution at %px\n", dst);
+	func = setup_function_descriptor(&fdesc, dst);
+	func();
+	pr_err("FAIL: func returned\n");
+}
+/*
+ * Explicitly doing the wrong thing for testing.
+ */
+ANNOTATE_NOCFI_SYM(execute_location);
+
+static void execute_user_location(void *dst)
+{
+	int copied;
+
+	/* Intentionally crossing kernel/user memory boundary. */
+	void (*func)(void);
+	func_desc_t fdesc;
+	void *do_nothing_text = dereference_function_descriptor(do_nothing);
+
+	pr_info("attempting ok execution at %px\n", do_nothing_text);
+	do_nothing();
+
+	copied = access_process_vm(current, (unsigned long)dst, do_nothing_text,
+				   EXEC_SIZE, FOLL_WRITE);
+	if (copied < EXEC_SIZE)
+		return;
+	pr_info("attempting bad execution at %px\n", dst);
+	func = setup_function_descriptor(&fdesc, dst);
+	func();
+	pr_err("FAIL: func returned\n");
+}
+
+static void lkdtm_WRITE_RO(void)
+{
+	/* Explicitly cast away "const" for the test and make volatile. */
+	volatile unsigned long *ptr = (unsigned long *)&rodata;
+
+	pr_info("attempting bad rodata write at %px\n", ptr);
+	*ptr ^= 0xabcd1234;
+	pr_err("FAIL: survived bad write\n");
+}
+
+static void lkdtm_WRITE_RO_AFTER_INIT(void)
+{
+	volatile unsigned long *ptr = &ro_after_init;
+
+	/*
+	 * Verify we were written to during init. Since an Oops
+	 * is considered a "success", a failure is to just skip the
+	 * real test.
+	 */
+	if ((*ptr & 0xAA) != 0xAA) {
+		pr_info("%p was NOT written during init!?\n", ptr);
+		return;
+	}
+
+	pr_info("attempting bad ro_after_init write at %px\n", ptr);
+	*ptr ^= 0xabcd1234;
+	pr_err("FAIL: survived bad write\n");
+}
+
+static void lkdtm_WRITE_KERN(void)
+{
+	size_t size;
+	volatile unsigned char *ptr;
+
+	size = (unsigned long)dereference_function_descriptor(do_overwritten) -
+	       (unsigned long)dereference_function_descriptor(do_nothing);
+	ptr = dereference_function_descriptor(do_overwritten);
+
+	pr_info("attempting bad %zu byte write at %px\n", size, ptr);
+	memcpy((void *)ptr, (unsigned char *)do_nothing, size);
+	flush_icache_range((unsigned long)ptr, (unsigned long)(ptr + size));
+	pr_err("FAIL: survived bad write\n");
+
+	do_overwritten();
+}
+
+static void lkdtm_WRITE_OPD(void)
+{
+	size_t size = sizeof(func_desc_t);
+	void (*func)(void) = do_nothing;
+
+	if (!have_function_descriptors()) {
+		pr_info("XFAIL: Platform doesn't use function descriptors.\n");
+		return;
+	}
+	pr_info("attempting bad %zu bytes write at %px\n", size, do_nothing);
+	memcpy(do_nothing, do_almost_nothing, size);
+	pr_err("FAIL: survived bad write\n");
+
+	asm("" : "=m"(func));
+	func();
+}
+
+static void lkdtm_EXEC_DATA(void)
+{
+	execute_location(data_area, CODE_WRITE);
+}
+
+static void lkdtm_EXEC_STACK(void)
+{
+	u8 stack_area[EXEC_SIZE];
+	execute_location(stack_area, CODE_WRITE);
+}
+
+static void lkdtm_EXEC_KMALLOC(void)
+{
+	u32 *kmalloc_area = kmalloc(EXEC_SIZE, GFP_KERNEL);
+	execute_location(kmalloc_area, CODE_WRITE);
+	kfree(kmalloc_area);
+}
+
+static void lkdtm_EXEC_VMALLOC(void)
+{
+	u32 *vmalloc_area = vmalloc(EXEC_SIZE);
+	execute_location(vmalloc_area, CODE_WRITE);
+	vfree(vmalloc_area);
+}
+
+static void lkdtm_EXEC_RODATA(void)
+{
+	execute_location(dereference_function_descriptor(lkdtm_rodata_do_nothing),
+			 CODE_AS_IS);
+}
+
+static void lkdtm_EXEC_USERSPACE(void)
+{
+	unsigned long user_addr;
+
+	user_addr = vm_mmap(NULL, 0, PAGE_SIZE,
+			    PROT_READ | PROT_WRITE | PROT_EXEC,
+			    MAP_ANONYMOUS | MAP_PRIVATE, 0);
+	if (user_addr >= TASK_SIZE) {
+		pr_warn("Failed to allocate user memory\n");
+		return;
+	}
+	execute_user_location((void *)user_addr);
+	vm_munmap(user_addr, PAGE_SIZE);
+}
+
+static void lkdtm_EXEC_NULL(void)
+{
+	execute_location(NULL, CODE_AS_IS);
+}
+
+static void lkdtm_ACCESS_USERSPACE(void)
+{
+	unsigned long user_addr, tmp = 0;
+	unsigned long *ptr;
+
+	user_addr = vm_mmap(NULL, 0, PAGE_SIZE,
+			    PROT_READ | PROT_WRITE | PROT_EXEC,
+			    MAP_ANONYMOUS | MAP_PRIVATE, 0);
+	if (user_addr >= TASK_SIZE) {
+		pr_warn("Failed to allocate user memory\n");
+		return;
+	}
+
+	if (copy_to_user((void __user *)user_addr, &tmp, sizeof(tmp))) {
+		pr_warn("copy_to_user failed\n");
+		vm_munmap(user_addr, PAGE_SIZE);
+		return;
+	}
+
+	ptr = (unsigned long *)user_addr;
+
+	pr_info("attempting bad read at %px\n", ptr);
+	tmp = *ptr;
+	tmp += 0xc0dec0de;
+	pr_err("FAIL: survived bad read\n");
+
+	pr_info("attempting bad write at %px\n", ptr);
+	*ptr = tmp;
+	pr_err("FAIL: survived bad write\n");
+
+	vm_munmap(user_addr, PAGE_SIZE);
+}
+
+static void lkdtm_ACCESS_NULL(void)
+{
+	unsigned long tmp;
+	volatile unsigned long *ptr = (unsigned long *)NULL;
+
+	pr_info("attempting bad read at %px\n", ptr);
+	tmp = *ptr;
+	tmp += 0xc0dec0de;
+	pr_err("FAIL: survived bad read\n");
+
+	pr_info("attempting bad write at %px\n", ptr);
+	*ptr = tmp;
+	pr_err("FAIL: survived bad write\n");
+}
+
+void __init lkdtm_perms_init(void)
+{
+	do_nothing_ptr = dereference_function_descriptor(do_nothing);
+
+	/* Make sure we can write to __ro_after_init values during __init */
+	ro_after_init |= 0xAA;
+}
+
+static struct crashtype crashtypes[] = {
+	CRASHTYPE(WRITE_RO),
+	CRASHTYPE(WRITE_RO_AFTER_INIT),
+	CRASHTYPE(WRITE_KERN),
+	CRASHTYPE(WRITE_OPD),
+	CRASHTYPE(EXEC_DATA),
+	CRASHTYPE(EXEC_STACK),
+	CRASHTYPE(EXEC_KMALLOC),
+	CRASHTYPE(EXEC_VMALLOC),
+	CRASHTYPE(EXEC_RODATA),
+	CRASHTYPE(EXEC_USERSPACE),
+	CRASHTYPE(EXEC_NULL),
+	CRASHTYPE(ACCESS_USERSPACE),
+	CRASHTYPE(ACCESS_NULL),
+};
+
+struct crashtype_category perms_crashtypes = {
+	.crashtypes = crashtypes,
+	.len	    = ARRAY_SIZE(crashtypes),
+};