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@xxxxxx>
---
drivers/misc/lkdtm/bugs.c | 10 ----------
drivers/misc/lkdtm/core.c | 2 --
drivers/misc/lkdtm/lkdtm.h | 2 --
drivers/misc/lkdtm/usercopy.c | 15 ---------------
tools/testing/selftests/lkdtm/tests.txt | 2 --
5 files changed, 31 deletions(-)
diff --git a/drivers/misc/lkdtm/bugs.c b/drivers/misc/lkdtm/bugs.c
index 4dfbfd51bdf774..a0675d4154d2fd 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 a5e344df916632..97803f213d9d45 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 8878538b2c1322..6dec4c9b442ff3 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 b833367a45d053..109e8d4302c113 100644
--- a/drivers/misc/lkdtm/usercopy.c
+++ b/drivers/misc/lkdtm/usercopy.c
@@ -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. */
diff --git a/tools/testing/selftests/lkdtm/tests.txt b/tools/testing/selftests/lkdtm/tests.txt
index 9d266e79c6a270..74a8d329a72c80 100644
--- a/tools/testing/selftests/lkdtm/tests.txt
+++ b/tools/testing/selftests/lkdtm/tests.txt
@@ -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
--
2.28.0
