From c6f7c753f71cccb21d1a7f0c1127ce7804374c5e Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Thu, 3 Sep 2020 16:22:37 +0200 Subject: lkdtm: remove set_fs-based tests Once we can't manipulate the address limit, we also can't test what happens when the manipulation is abused. Signed-off-by: Christoph Hellwig Signed-off-by: Al Viro --- drivers/misc/lkdtm/bugs.c | 10 ---------- drivers/misc/lkdtm/core.c | 2 -- drivers/misc/lkdtm/lkdtm.h | 2 -- drivers/misc/lkdtm/usercopy.c | 15 --------------- 4 files changed, 29 deletions(-) (limited to 'drivers') diff --git a/drivers/misc/lkdtm/bugs.c b/drivers/misc/lkdtm/bugs.c index 4dfbfd51bdf7..a0675d4154d2 100644 --- a/drivers/misc/lkdtm/bugs.c +++ b/drivers/misc/lkdtm/bugs.c @@ -312,16 +312,6 @@ void lkdtm_CORRUPT_LIST_DEL(void) pr_err("list_del() corruption not detected!\n"); } -/* Test if unbalanced set_fs(KERNEL_DS)/set_fs(USER_DS) check exists. */ -void lkdtm_CORRUPT_USER_DS(void) -{ - pr_info("setting bad task size limit\n"); - set_fs(KERNEL_DS); - - /* Make sure we do not keep running with a KERNEL_DS! */ - force_sig(SIGKILL); -} - /* Test that VMAP_STACK is actually allocating with a leading guard page */ void lkdtm_STACK_GUARD_PAGE_LEADING(void) { diff --git a/drivers/misc/lkdtm/core.c b/drivers/misc/lkdtm/core.c index a5e344df9166..97803f213d9d 100644 --- a/drivers/misc/lkdtm/core.c +++ b/drivers/misc/lkdtm/core.c @@ -112,7 +112,6 @@ static const struct crashtype crashtypes[] = { CRASHTYPE(CORRUPT_STACK_STRONG), CRASHTYPE(CORRUPT_LIST_ADD), CRASHTYPE(CORRUPT_LIST_DEL), - CRASHTYPE(CORRUPT_USER_DS), CRASHTYPE(STACK_GUARD_PAGE_LEADING), CRASHTYPE(STACK_GUARD_PAGE_TRAILING), CRASHTYPE(UNSET_SMEP), @@ -172,7 +171,6 @@ static const struct crashtype crashtypes[] = { CRASHTYPE(USERCOPY_STACK_FRAME_FROM), CRASHTYPE(USERCOPY_STACK_BEYOND), CRASHTYPE(USERCOPY_KERNEL), - CRASHTYPE(USERCOPY_KERNEL_DS), CRASHTYPE(STACKLEAK_ERASING), CRASHTYPE(CFI_FORWARD_PROTO), #ifdef CONFIG_X86_32 diff --git a/drivers/misc/lkdtm/lkdtm.h b/drivers/misc/lkdtm/lkdtm.h index 8878538b2c13..6dec4c9b442f 100644 --- a/drivers/misc/lkdtm/lkdtm.h +++ b/drivers/misc/lkdtm/lkdtm.h @@ -27,7 +27,6 @@ void lkdtm_OVERFLOW_UNSIGNED(void); void lkdtm_ARRAY_BOUNDS(void); void lkdtm_CORRUPT_LIST_ADD(void); void lkdtm_CORRUPT_LIST_DEL(void); -void lkdtm_CORRUPT_USER_DS(void); void lkdtm_STACK_GUARD_PAGE_LEADING(void); void lkdtm_STACK_GUARD_PAGE_TRAILING(void); void lkdtm_UNSET_SMEP(void); @@ -96,7 +95,6 @@ void lkdtm_USERCOPY_STACK_FRAME_TO(void); void lkdtm_USERCOPY_STACK_FRAME_FROM(void); void lkdtm_USERCOPY_STACK_BEYOND(void); void lkdtm_USERCOPY_KERNEL(void); -void lkdtm_USERCOPY_KERNEL_DS(void); /* lkdtm_stackleak.c */ void lkdtm_STACKLEAK_ERASING(void); diff --git a/drivers/misc/lkdtm/usercopy.c b/drivers/misc/lkdtm/usercopy.c index b833367a45d0..109e8d4302c1 100644 --- a/drivers/misc/lkdtm/usercopy.c +++ b/drivers/misc/lkdtm/usercopy.c @@ -325,21 +325,6 @@ free_user: vm_munmap(user_addr, PAGE_SIZE); } -void lkdtm_USERCOPY_KERNEL_DS(void) -{ - char __user *user_ptr = - (char __user *)(0xFUL << (sizeof(unsigned long) * 8 - 4)); - mm_segment_t old_fs = get_fs(); - char buf[10] = {0}; - - pr_info("attempting copy_to_user() to noncanonical address: %px\n", - user_ptr); - set_fs(KERNEL_DS); - if (copy_to_user(user_ptr, buf, sizeof(buf)) == 0) - pr_err("copy_to_user() to noncanonical address succeeded!?\n"); - set_fs(old_fs); -} - void __init lkdtm_usercopy_init(void) { /* Prepare cache that lacks SLAB_USERCOPY flag. */ -- cgit