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lkdtm: flush icache and report actions

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Some CPUs explicitly need to have their icache flushed after making
executable code copies for the memory region execution tests.
Additionally, report the specific address targets being used so that
debugging non-crash failures is easier.

Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Kees Cook 2014-02-09 13:48:47 -08:00 committed by Greg Kroah-Hartman
parent feac6e2146
commit aac416fc38
1 changed files with 16 additions and 0 deletions
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16
drivers/misc/lkdtm.c
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@ -329,7 +329,12 @@ static void execute_location(void *dst)
{
void (*func)(void) = dst;
pr_info("attempting ok execution at %p\n", do_nothing);
do_nothing();
memcpy(dst, do_nothing, EXEC_SIZE);
flush_icache_range((unsigned long)dst, (unsigned long)dst + EXEC_SIZE);
pr_info("attempting bad execution at %p\n", func);
func();
}
@ -338,8 +343,13 @@ 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);
do_nothing();
if (copy_to_user((void __user *)dst, do_nothing, EXEC_SIZE))
return;
flush_icache_range((unsigned long)dst, (unsigned long)dst + EXEC_SIZE);
pr_info("attempting bad execution at %p\n", func);
func();
}
@ -464,8 +474,12 @@ static void lkdtm_do_action(enum ctype which)
}
ptr = (unsigned long *)user_addr;
pr_info("attempting bad read at %p\n", ptr);
tmp = *ptr;
tmp += 0xc0dec0de;
pr_info("attempting bad write at %p\n", ptr);
*ptr = tmp;
vm_munmap(user_addr, PAGE_SIZE);
@ -476,6 +490,8 @@ static void lkdtm_do_action(enum ctype which)
unsigned long *ptr;
ptr = (unsigned long *)&rodata;
pr_info("attempting bad write at %p\n", ptr);
*ptr ^= 0xabcd1234;
break;