diff options
Diffstat (limited to 'drivers/misc/lkdtm.c')
| -rw-r--r-- | drivers/misc/lkdtm.c | 107 |
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; |
