lkdtm updates and new tests

- Check NULL dereferences (Christophe Leroy)
 - Print real addresses for debugging (Christophe Leroy)
 - Drop CONFIG_BLOCK dependency
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 Comment: Kees Cook <kees@outflux.net>
 
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Merge tag 'lkdtm-next' of https://git.kernel.org/pub/scm/linux/kernel/git/kees/linux into char-misc-next

Kees writes:

lkdtm updates and new tests

- Check NULL dereferences (Christophe Leroy)
- Print real addresses for debugging (Christophe Leroy)
- Drop CONFIG_BLOCK dependency

* tag 'lkdtm-next' of https://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  lkdtm: Add tests for NULL pointer dereference
  lkdtm: Print real addresses
  lkdtm: Do not depend on BLOCK and clean up headers

drivers/misc/lkdtm/core.c

@@ -37,16 +37,9 @@
 #include <linux/kprobes.h>
 #include <linux/list.h>
 #include <linux/init.h>
-#include <linux/interrupt.h>
-#include <linux/hrtimer.h>
 #include <linux/slab.h>
-#include <scsi/scsi_cmnd.h>
 #include <linux/debugfs.h>
 
-#ifdef CONFIG_IDE
-#include <linux/ide.h>
-#endif
-
 #define DEFAULT_COUNT 10
 
 static int lkdtm_debugfs_open(struct inode *inode, struct file *file);
@@ -102,9 +95,7 @@ static struct crashpoint crashpoints[] = {
 	CRASHPOINT("MEM_SWAPOUT",	 "shrink_inactive_list"),
 	CRASHPOINT("TIMERADD",		 "hrtimer_start"),
 	CRASHPOINT("SCSI_DISPATCH_CMD",	 "scsi_dispatch_cmd"),
-# ifdef CONFIG_IDE
 	CRASHPOINT("IDE_CORE_CP",	 "generic_ide_ioctl"),
-# endif
 #endif
 };
 
@@ -152,7 +143,9 @@ static const struct crashtype crashtypes[] = {
 	CRASHTYPE(EXEC_VMALLOC),
 	CRASHTYPE(EXEC_RODATA),
 	CRASHTYPE(EXEC_USERSPACE),
+	CRASHTYPE(EXEC_NULL),
 	CRASHTYPE(ACCESS_USERSPACE),
+	CRASHTYPE(ACCESS_NULL),
 	CRASHTYPE(WRITE_RO),
 	CRASHTYPE(WRITE_RO_AFTER_INIT),
 	CRASHTYPE(WRITE_KERN),

drivers/misc/lkdtm/lkdtm.h

@@ -45,7 +45,9 @@ void lkdtm_EXEC_KMALLOC(void);
 void lkdtm_EXEC_VMALLOC(void);
 void lkdtm_EXEC_RODATA(void);
 void lkdtm_EXEC_USERSPACE(void);
+void lkdtm_EXEC_NULL(void);
 void lkdtm_ACCESS_USERSPACE(void);
+void lkdtm_ACCESS_NULL(void);
 
 /* lkdtm_refcount.c */
 void lkdtm_REFCOUNT_INC_OVERFLOW(void);

drivers/misc/lkdtm/perms.c

@@ -47,7 +47,7 @@ static noinline void execute_location(void *dst, bool write)
 {
 	void (*func)(void) = dst;
 
-	pr_info("attempting ok execution at %p\n", do_nothing);
+	pr_info("attempting ok execution at %px\n", do_nothing);
 	do_nothing();
 
 	if (write == CODE_WRITE) {
@@ -55,7 +55,7 @@ static noinline void execute_location(void *dst, bool write)
 		flush_icache_range((unsigned long)dst,
 				   (unsigned long)dst + EXEC_SIZE);
 	}
-	pr_info("attempting bad execution at %p\n", func);
+	pr_info("attempting bad execution at %px\n", func);
 	func();
 }
 
@@ -66,14 +66,14 @@ static void execute_user_location(void *dst)
 	/* Intentionally crossing kernel/user memory boundary. */
 	void (*func)(void) = dst;
 
-	pr_info("attempting ok execution at %p\n", do_nothing);
+	pr_info("attempting ok execution at %px\n", do_nothing);
 	do_nothing();
 
 	copied = access_process_vm(current, (unsigned long)dst, do_nothing,
 				   EXEC_SIZE, FOLL_WRITE);
 	if (copied < EXEC_SIZE)
 		return;
-	pr_info("attempting bad execution at %p\n", func);
+	pr_info("attempting bad execution at %px\n", func);
 	func();
 }
 
@@ -82,7 +82,7 @@ void lkdtm_WRITE_RO(void)
 	/* Explicitly cast away "const" for the test. */
 	unsigned long *ptr = (unsigned long *)&rodata;
 
-	pr_info("attempting bad rodata write at %p\n", ptr);
+	pr_info("attempting bad rodata write at %px\n", ptr);
 	*ptr ^= 0xabcd1234;
 }
 
@@ -100,7 +100,7 @@ void lkdtm_WRITE_RO_AFTER_INIT(void)
 		return;
 	}
 
-	pr_info("attempting bad ro_after_init write at %p\n", ptr);
+	pr_info("attempting bad ro_after_init write at %px\n", ptr);
 	*ptr ^= 0xabcd1234;
 }
 
@@ -112,7 +112,7 @@ void lkdtm_WRITE_KERN(void)
 	size = (unsigned long)do_overwritten - (unsigned long)do_nothing;
 	ptr = (unsigned char *)do_overwritten;
 
-	pr_info("attempting bad %zu byte write at %p\n", size, ptr);
+	pr_info("attempting bad %zu byte write at %px\n", size, ptr);
 	memcpy(ptr, (unsigned char *)do_nothing, size);
 	flush_icache_range((unsigned long)ptr, (unsigned long)(ptr + size));
 
@@ -164,6 +164,11 @@ void lkdtm_EXEC_USERSPACE(void)
 	vm_munmap(user_addr, PAGE_SIZE);
 }
 
+void lkdtm_EXEC_NULL(void)
+{
+	execute_location(NULL, CODE_AS_IS);
+}
+
 void lkdtm_ACCESS_USERSPACE(void)
 {
 	unsigned long user_addr, tmp = 0;
@@ -185,16 +190,29 @@ void lkdtm_ACCESS_USERSPACE(void)
 
 	ptr = (unsigned long *)user_addr;
 
-	pr_info("attempting bad read at %p\n", ptr);
+	pr_info("attempting bad read at %px\n", ptr);
 	tmp = *ptr;
 	tmp += 0xc0dec0de;
 
-	pr_info("attempting bad write at %p\n", ptr);
+	pr_info("attempting bad write at %px\n", ptr);
 	*ptr = tmp;
 
 	vm_munmap(user_addr, PAGE_SIZE);
 }
 
+void lkdtm_ACCESS_NULL(void)
+{
+	unsigned long tmp;
+	unsigned long *ptr = (unsigned long *)NULL;
+
+	pr_info("attempting bad read at %px\n", ptr);
+	tmp = *ptr;
+	tmp += 0xc0dec0de;
+
+	pr_info("attempting bad write at %px\n", ptr);
+	*ptr = tmp;
+}
+
 void __init lkdtm_perms_init(void)
 {
 	/* Make sure we can write to __ro_after_init values during __init */

lib/Kconfig.debug

@@ -1700,7 +1700,6 @@ if RUNTIME_TESTING_MENU
 config LKDTM
 	tristate "Linux Kernel Dump Test Tool Module"
 	depends on DEBUG_FS
-	depends on BLOCK
 	help
 	This module enables testing of the different dumping mechanisms by
 	inducing system failures at predefined crash points.