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-rw-r--r--drivers/misc/lkdtm.c107
1 files changed, 91 insertions, 16 deletions
diff --git a/drivers/misc/lkdtm.c b/drivers/misc/lkdtm.c
index 2fc0586..a2edb2e 100644
--- a/drivers/misc/lkdtm.c
+++ b/drivers/misc/lkdtm.c
@@ -44,13 +44,25 @@
#include <scsi/scsi_cmnd.h>
#include <linux/debugfs.h>
#include <linux/vmalloc.h>
+#include <linux/mman.h>
#ifdef CONFIG_IDE
#include <linux/ide.h>
#endif
+/*
+ * 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 (CONFIG_FRAME_WARN / 2)
+#else
+#define REC_STACK_SIZE (THREAD_SIZE / 8)
+#endif
+#define REC_NUM_DEFAULT ((THREAD_SIZE / REC_STACK_SIZE) * 2)
+
#define DEFAULT_COUNT 10
-#define REC_NUM_DEFAULT 10
#define EXEC_SIZE 64
enum cname {
@@ -86,6 +98,9 @@ enum ctype {
CT_EXEC_STACK,
CT_EXEC_KMALLOC,
CT_EXEC_VMALLOC,
+ CT_EXEC_USERSPACE,
+ CT_ACCESS_USERSPACE,
+ CT_WRITE_RO,
};
static char* cp_name[] = {
@@ -119,6 +134,9 @@ static char* cp_type[] = {
"EXEC_STACK",
"EXEC_KMALLOC",
"EXEC_VMALLOC",
+ "EXEC_USERSPACE",
+ "ACCESS_USERSPACE",
+ "WRITE_RO",
};
static struct jprobe lkdtm;
@@ -139,9 +157,10 @@ static DEFINE_SPINLOCK(lock_me_up);
static u8 data_area[EXEC_SIZE];
+static const unsigned long rodata = 0xAA55AA55;
+
module_param(recur_count, int, 0644);
-MODULE_PARM_DESC(recur_count, " Recursion level for the stack overflow test, "\
- "default is 10");
+MODULE_PARM_DESC(recur_count, " Recursion level for the stack overflow test");
module_param(cpoint_name, charp, 0444);
MODULE_PARM_DESC(cpoint_name, " Crash Point, where kernel is to be crashed");
module_param(cpoint_type, charp, 0444);
@@ -280,16 +299,16 @@ static int lkdtm_parse_commandline(void)
return -EINVAL;
}
-static int recursive_loop(int a)
+static int recursive_loop(int remaining)
{
- char buf[1024];
+ char buf[REC_STACK_SIZE];
- memset(buf,0xFF,1024);
- recur_count--;
- if (!recur_count)
+ /* Make sure compiler does not optimize this away. */
+ memset(buf, (remaining & 0xff) | 0x1, REC_STACK_SIZE);
+ if (!remaining)
return 0;
else
- return recursive_loop(a);
+ return recursive_loop(remaining - 1);
}
static void do_nothing(void)
@@ -297,6 +316,14 @@ static void do_nothing(void)
return;
}
+static noinline void corrupt_stack(void)
+{
+ /* Use default char array length that triggers stack protection. */
+ char data[8];
+
+ memset((void *)data, 0, 64);
+}
+
static void execute_location(void *dst)
{
void (*func)(void) = dst;
@@ -305,6 +332,15 @@ static void execute_location(void *dst)
func();
}
+static void execute_user_location(void *dst)
+{
+ void (*func)(void) = dst;
+
+ if (copy_to_user(dst, do_nothing, EXEC_SIZE))
+ return;
+ func();
+}
+
static void lkdtm_do_action(enum ctype which)
{
switch (which) {
@@ -325,15 +361,11 @@ static void lkdtm_do_action(enum ctype which)
;
break;
case CT_OVERFLOW:
- (void) recursive_loop(0);
+ (void) recursive_loop(recur_count);
break;
- case CT_CORRUPT_STACK: {
- /* Make sure the compiler creates and uses an 8 char array. */
- volatile char data[8];
-
- memset((void *)data, 0, 64);
+ case CT_CORRUPT_STACK:
+ corrupt_stack();
break;
- }
case CT_UNALIGNED_LOAD_STORE_WRITE: {
static u8 data[5] __attribute__((aligned(4))) = {1, 2,
3, 4, 5};
@@ -401,6 +433,49 @@ static void lkdtm_do_action(enum ctype which)
vfree(vmalloc_area);
break;
}
+ case CT_EXEC_USERSPACE: {
+ 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);
+ break;
+ }
+ case CT_ACCESS_USERSPACE: {
+ unsigned long user_addr, tmp;
+ 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;
+ }
+
+ ptr = (unsigned long *)user_addr;
+ tmp = *ptr;
+ tmp += 0xc0dec0de;
+ *ptr = tmp;
+
+ vm_munmap(user_addr, PAGE_SIZE);
+
+ break;
+ }
+ case CT_WRITE_RO: {
+ unsigned long *ptr;
+
+ ptr = (unsigned long *)&rodata;
+ *ptr ^= 0xabcd1234;
+
+ break;
+ }
case CT_NONE:
default:
break;
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