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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 <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Christoph Hellwig 2020-09-03 16:22:37 +02:00 committed by Al Viro
parent 81b1e242b8
commit c6f7c753f7
5 changed files with 0 additions and 31 deletions
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10
drivers/misc/lkdtm/bugs.c
View File

@ -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)
{

2
drivers/misc/lkdtm/core.c
View File

@ -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

2
drivers/misc/lkdtm/lkdtm.h
View File

@ -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);

15
drivers/misc/lkdtm/usercopy.c
View File

@ -325,21 +325,6 @@ void lkdtm_USERCOPY_KERNEL(void)
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. */

2
tools/testing/selftests/lkdtm/tests.txt
View File

@ -9,7 +9,6 @@ EXCEPTION
#CORRUPT_STACK_STRONG Crashes entire system on success
CORRUPT_LIST_ADD list_add corruption
CORRUPT_LIST_DEL list_del corruption
CORRUPT_USER_DS Invalid address limit on user-mode return
STACK_GUARD_PAGE_LEADING
STACK_GUARD_PAGE_TRAILING
UNSET_SMEP CR4 bits went missing
@ -67,6 +66,5 @@ USERCOPY_STACK_FRAME_TO
USERCOPY_STACK_FRAME_FROM
USERCOPY_STACK_BEYOND
USERCOPY_KERNEL
USERCOPY_KERNEL_DS
STACKLEAK_ERASING OK: the rest of the thread stack is properly erased
CFI_FORWARD_PROTO