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authorGreg Kroah-Hartman2019-05-24 20:30:04 +0200
committerGreg Kroah-Hartman2019-05-24 20:30:04 +0200
commit02bd610e858d764fb32ebfa123083fdbadd88a08 (patch)
tree468f5319ab0dc0ef517b1adaedf7866b578ce88d
parent6660a04feb7ef648e50c792e19084d675fa6f3a2 (diff)
parent24cccab42c4199c6daa0a6981e6f6a1ffb0b5a09 (diff)
Merge tag 'lkdtm-next' of https://git.kernel.org/pub/scm/linux/kernel/git/kees/linux into char-misc-linus
Kees writes: lkdtm: various fixes - Move KERNEL_DS test to non-canonical range - Make stack exhaustion test more robust * tag 'lkdtm-next' of https://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: lkdtm/bugs: Adjust recursion test to avoid elision lkdtm/usercopy: Moves the KERNEL_DS test to non-canonical
-rw-r--r--drivers/misc/lkdtm/bugs.c23
-rw-r--r--drivers/misc/lkdtm/core.c6
-rw-r--r--drivers/misc/lkdtm/lkdtm.h2
-rw-r--r--drivers/misc/lkdtm/usercopy.c10
4 files changed, 27 insertions, 14 deletions
diff --git a/drivers/misc/lkdtm/bugs.c b/drivers/misc/lkdtm/bugs.c
index 7eebbdfbcacd..17f839dee976 100644
--- a/drivers/misc/lkdtm/bugs.c
+++ b/drivers/misc/lkdtm/bugs.c
@@ -32,12 +32,20 @@ static int recur_count = REC_NUM_DEFAULT;
static DEFINE_SPINLOCK(lock_me_up);
-static int recursive_loop(int remaining)
+/*
+ * Make sure compiler does not optimize this function or stack frame away:
+ * - function marked noinline
+ * - stack variables are marked volatile
+ * - stack variables are written (memset()) and read (pr_info())
+ * - function has external effects (pr_info())
+ * */
+static int noinline recursive_loop(int remaining)
{
- char buf[REC_STACK_SIZE];
+ volatile char buf[REC_STACK_SIZE];
- /* Make sure compiler does not optimize this away. */
- memset(buf, (remaining & 0xff) | 0x1, REC_STACK_SIZE);
+ memset((void *)buf, remaining & 0xFF, sizeof(buf));
+ pr_info("loop %d/%d ...\n", (int)buf[remaining % sizeof(buf)],
+ recur_count);
if (!remaining)
return 0;
else
@@ -81,9 +89,12 @@ void lkdtm_LOOP(void)
;
}
-void lkdtm_OVERFLOW(void)
+void lkdtm_EXHAUST_STACK(void)
{
- (void) recursive_loop(recur_count);
+ pr_info("Calling function with %d frame size to depth %d ...\n",
+ REC_STACK_SIZE, recur_count);
+ recursive_loop(recur_count);
+ pr_info("FAIL: survived without exhausting stack?!\n");
}
static noinline void __lkdtm_CORRUPT_STACK(void *stack)
diff --git a/drivers/misc/lkdtm/core.c b/drivers/misc/lkdtm/core.c
index b51cf182b031..4f3a6e1cd331 100644
--- a/drivers/misc/lkdtm/core.c
+++ b/drivers/misc/lkdtm/core.c
@@ -119,12 +119,12 @@ static const struct crashtype crashtypes[] = {
CRASHTYPE(WARNING),
CRASHTYPE(EXCEPTION),
CRASHTYPE(LOOP),
- CRASHTYPE(OVERFLOW),
+ CRASHTYPE(EXHAUST_STACK),
+ CRASHTYPE(CORRUPT_STACK),
+ CRASHTYPE(CORRUPT_STACK_STRONG),
CRASHTYPE(CORRUPT_LIST_ADD),
CRASHTYPE(CORRUPT_LIST_DEL),
CRASHTYPE(CORRUPT_USER_DS),
- CRASHTYPE(CORRUPT_STACK),
- CRASHTYPE(CORRUPT_STACK_STRONG),
CRASHTYPE(STACK_GUARD_PAGE_LEADING),
CRASHTYPE(STACK_GUARD_PAGE_TRAILING),
CRASHTYPE(UNALIGNED_LOAD_STORE_WRITE),
diff --git a/drivers/misc/lkdtm/lkdtm.h b/drivers/misc/lkdtm/lkdtm.h
index b69ee004a3f7..23dc565b4307 100644
--- a/drivers/misc/lkdtm/lkdtm.h
+++ b/drivers/misc/lkdtm/lkdtm.h
@@ -13,7 +13,7 @@ void lkdtm_BUG(void);
void lkdtm_WARNING(void);
void lkdtm_EXCEPTION(void);
void lkdtm_LOOP(void);
-void lkdtm_OVERFLOW(void);
+void lkdtm_EXHAUST_STACK(void);
void lkdtm_CORRUPT_STACK(void);
void lkdtm_CORRUPT_STACK_STRONG(void);
void lkdtm_UNALIGNED_LOAD_STORE_WRITE(void);
diff --git a/drivers/misc/lkdtm/usercopy.c b/drivers/misc/lkdtm/usercopy.c
index d5a0e7f1813b..e172719dd86d 100644
--- a/drivers/misc/lkdtm/usercopy.c
+++ b/drivers/misc/lkdtm/usercopy.c
@@ -324,14 +324,16 @@ free_user:
void lkdtm_USERCOPY_KERNEL_DS(void)
{
- char __user *user_ptr = (char __user *)ERR_PTR(-EINVAL);
+ 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 on unmapped kernel address\n");
+ 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)))
- pr_info("copy_to_user un unmapped kernel address failed\n");
+ if (copy_to_user(user_ptr, buf, sizeof(buf)) == 0)
+ pr_err("copy_to_user() to noncanonical address succeeded!?\n");
set_fs(old_fs);
}