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authorLinus Torvalds <torvalds@linux-foundation.org>2022-06-03 11:36:34 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2022-06-03 11:36:34 -0700
commit6f9b5ed8caddfbc94af8307c557ed57a8ec5c65c (patch)
treedda90fb07a35fc07cf0cedc22f0f6be61b29cf53 /drivers/misc/lkdtm/usercopy.c
parent54c2cc79194c961a213c1d375fe3aa4165664cc4 (diff)
parent90de6805267f8c79cd2b1a36805071e257c39b5c (diff)
Merge tag 'char-misc-5.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc
Pull char / misc / other smaller driver subsystem updates from Greg KH: "Here is the large set of char, misc, and other driver subsystem updates for 5.19-rc1. The merge request for this has been delayed as I wanted to get lots of linux-next testing due to some late arrivals of changes for the habannalabs driver. Highlights of this merge are: - habanalabs driver updates for new hardware types and fixes and other updates - IIO driver tree merge which includes loads of new IIO drivers and cleanups and additions - PHY driver tree merge with new drivers and small updates to existing ones - interconnect driver tree merge with fixes and updates - soundwire driver tree merge with some small fixes - coresight driver tree merge with small fixes and updates - mhi bus driver tree merge with lots of updates and new device support - firmware driver updates - fpga driver updates - lkdtm driver updates (with a merge conflict, more on that below) - extcon driver tree merge with small updates - lots of other tiny driver updates and fixes and cleanups, full details in the shortlog. All of these have been in linux-next for almost 2 weeks with no reported problems" * tag 'char-misc-5.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: (387 commits) habanalabs: use separate structure info for each error collect data habanalabs: fix missing handle shift during mmap habanalabs: remove hdev from hl_ctx_get args habanalabs: do MMU prefetch as deferred work habanalabs: order memory manager messages habanalabs: return -EFAULT on copy_to_user error habanalabs: use NULL for eventfd habanalabs: update firmware header habanalabs: add support for notification via eventfd habanalabs: add topic to memory manager buffer habanalabs: handle race in driver fini habanalabs: add device memory scrub ability through debugfs habanalabs: use unified memory manager for CB flow habanalabs: unified memory manager new code for CB flow habanalabs/gaudi: set arbitration timeout to a high value habanalabs: add put by handle method to memory manager habanalabs: hide memory manager page shift habanalabs: Add separate poll interval value for protocol habanalabs: use get_task_pid() to take PID habanalabs: add prefetch flag to the MAP operation ...
Diffstat (limited to 'drivers/misc/lkdtm/usercopy.c')
-rw-r--r--drivers/misc/lkdtm/usercopy.c146
1 files changed, 128 insertions, 18 deletions
diff --git a/drivers/misc/lkdtm/usercopy.c b/drivers/misc/lkdtm/usercopy.c
index 9161ce7ed47a..6215ec995cd3 100644
--- a/drivers/misc/lkdtm/usercopy.c
+++ b/drivers/misc/lkdtm/usercopy.c
@@ -5,6 +5,7 @@
*/
#include "lkdtm.h"
#include <linux/slab.h>
+#include <linux/highmem.h>
#include <linux/vmalloc.h>
#include <linux/sched/task_stack.h>
#include <linux/mman.h>
@@ -30,12 +31,12 @@ static const unsigned char test_text[] = "This is a test.\n";
*/
static noinline unsigned char *trick_compiler(unsigned char *stack)
{
- return stack + 0;
+ return stack + unconst;
}
static noinline unsigned char *do_usercopy_stack_callee(int value)
{
- unsigned char buf[32];
+ unsigned char buf[128];
int i;
/* Exercise stack to avoid everything living in registers. */
@@ -43,7 +44,12 @@ static noinline unsigned char *do_usercopy_stack_callee(int value)
buf[i] = value & 0xff;
}
- return trick_compiler(buf);
+ /*
+ * Put the target buffer in the middle of stack allocation
+ * so that we don't step on future stack users regardless
+ * of stack growth direction.
+ */
+ return trick_compiler(&buf[(128/2)-32]);
}
static noinline void do_usercopy_stack(bool to_user, bool bad_frame)
@@ -66,6 +72,12 @@ static noinline void do_usercopy_stack(bool to_user, bool bad_frame)
bad_stack -= sizeof(unsigned long);
}
+#ifdef ARCH_HAS_CURRENT_STACK_POINTER
+ pr_info("stack : %px\n", (void *)current_stack_pointer);
+#endif
+ pr_info("good_stack: %px-%px\n", good_stack, good_stack + sizeof(good_stack));
+ pr_info("bad_stack : %px-%px\n", bad_stack, bad_stack + sizeof(good_stack));
+
user_addr = vm_mmap(NULL, 0, PAGE_SIZE,
PROT_READ | PROT_WRITE | PROT_EXEC,
MAP_ANONYMOUS | MAP_PRIVATE, 0);
@@ -119,7 +131,7 @@ free_user:
* This checks for whole-object size validation with hardened usercopy,
* with or without usercopy whitelisting.
*/
-static void do_usercopy_heap_size(bool to_user)
+static void do_usercopy_slab_size(bool to_user)
{
unsigned long user_addr;
unsigned char *one, *two;
@@ -185,9 +197,9 @@ free_kernel:
/*
* This checks for the specific whitelist window within an object. If this
- * test passes, then do_usercopy_heap_size() tests will pass too.
+ * test passes, then do_usercopy_slab_size() tests will pass too.
*/
-static void do_usercopy_heap_whitelist(bool to_user)
+static void do_usercopy_slab_whitelist(bool to_user)
{
unsigned long user_alloc;
unsigned char *buf = NULL;
@@ -261,42 +273,42 @@ free_alloc:
}
/* Callable tests. */
-void lkdtm_USERCOPY_HEAP_SIZE_TO(void)
+static void lkdtm_USERCOPY_SLAB_SIZE_TO(void)
{
- do_usercopy_heap_size(true);
+ do_usercopy_slab_size(true);
}
-void lkdtm_USERCOPY_HEAP_SIZE_FROM(void)
+static void lkdtm_USERCOPY_SLAB_SIZE_FROM(void)
{
- do_usercopy_heap_size(false);
+ do_usercopy_slab_size(false);
}
-void lkdtm_USERCOPY_HEAP_WHITELIST_TO(void)
+static void lkdtm_USERCOPY_SLAB_WHITELIST_TO(void)
{
- do_usercopy_heap_whitelist(true);
+ do_usercopy_slab_whitelist(true);
}
-void lkdtm_USERCOPY_HEAP_WHITELIST_FROM(void)
+static void lkdtm_USERCOPY_SLAB_WHITELIST_FROM(void)
{
- do_usercopy_heap_whitelist(false);
+ do_usercopy_slab_whitelist(false);
}
-void lkdtm_USERCOPY_STACK_FRAME_TO(void)
+static void lkdtm_USERCOPY_STACK_FRAME_TO(void)
{
do_usercopy_stack(true, true);
}
-void lkdtm_USERCOPY_STACK_FRAME_FROM(void)
+static void lkdtm_USERCOPY_STACK_FRAME_FROM(void)
{
do_usercopy_stack(false, true);
}
-void lkdtm_USERCOPY_STACK_BEYOND(void)
+static void lkdtm_USERCOPY_STACK_BEYOND(void)
{
do_usercopy_stack(true, false);
}
-void lkdtm_USERCOPY_KERNEL(void)
+static void lkdtm_USERCOPY_KERNEL(void)
{
unsigned long user_addr;
@@ -330,6 +342,86 @@ free_user:
vm_munmap(user_addr, PAGE_SIZE);
}
+/*
+ * This expects "kaddr" to point to a PAGE_SIZE allocation, which means
+ * a more complete test that would include copy_from_user() would risk
+ * memory corruption. Just test copy_to_user() here, as that exercises
+ * almost exactly the same code paths.
+ */
+static void do_usercopy_page_span(const char *name, void *kaddr)
+{
+ unsigned long uaddr;
+
+ uaddr = vm_mmap(NULL, 0, PAGE_SIZE, PROT_READ | PROT_WRITE,
+ MAP_ANONYMOUS | MAP_PRIVATE, 0);
+ if (uaddr >= TASK_SIZE) {
+ pr_warn("Failed to allocate user memory\n");
+ return;
+ }
+
+ /* Initialize contents. */
+ memset(kaddr, 0xAA, PAGE_SIZE);
+
+ /* Bump the kaddr forward to detect a page-spanning overflow. */
+ kaddr += PAGE_SIZE / 2;
+
+ pr_info("attempting good copy_to_user() from kernel %s: %px\n",
+ name, kaddr);
+ if (copy_to_user((void __user *)uaddr, kaddr,
+ unconst + (PAGE_SIZE / 2))) {
+ pr_err("copy_to_user() failed unexpectedly?!\n");
+ goto free_user;
+ }
+
+ pr_info("attempting bad copy_to_user() from kernel %s: %px\n",
+ name, kaddr);
+ if (copy_to_user((void __user *)uaddr, kaddr, unconst + PAGE_SIZE)) {
+ pr_warn("Good, copy_to_user() failed, but lacked Oops(?!)\n");
+ goto free_user;
+ }
+
+ pr_err("FAIL: bad copy_to_user() not detected!\n");
+ pr_expected_config_param(CONFIG_HARDENED_USERCOPY, "hardened_usercopy");
+
+free_user:
+ vm_munmap(uaddr, PAGE_SIZE);
+}
+
+static void lkdtm_USERCOPY_VMALLOC(void)
+{
+ void *addr;
+
+ addr = vmalloc(PAGE_SIZE);
+ if (!addr) {
+ pr_err("vmalloc() failed!?\n");
+ return;
+ }
+ do_usercopy_page_span("vmalloc", addr);
+ vfree(addr);
+}
+
+static void lkdtm_USERCOPY_FOLIO(void)
+{
+ struct folio *folio;
+ void *addr;
+
+ /*
+ * FIXME: Folio checking currently misses 0-order allocations, so
+ * allocate and bump forward to the last page.
+ */
+ folio = folio_alloc(GFP_KERNEL | __GFP_ZERO, 1);
+ if (!folio) {
+ pr_err("folio_alloc() failed!?\n");
+ return;
+ }
+ addr = folio_address(folio);
+ if (addr)
+ do_usercopy_page_span("folio", addr + PAGE_SIZE);
+ else
+ pr_err("folio_address() failed?!\n");
+ folio_put(folio);
+}
+
void __init lkdtm_usercopy_init(void)
{
/* Prepare cache that lacks SLAB_USERCOPY flag. */
@@ -345,3 +437,21 @@ void __exit lkdtm_usercopy_exit(void)
{
kmem_cache_destroy(whitelist_cache);
}
+
+static struct crashtype crashtypes[] = {
+ CRASHTYPE(USERCOPY_SLAB_SIZE_TO),
+ CRASHTYPE(USERCOPY_SLAB_SIZE_FROM),
+ CRASHTYPE(USERCOPY_SLAB_WHITELIST_TO),
+ CRASHTYPE(USERCOPY_SLAB_WHITELIST_FROM),
+ CRASHTYPE(USERCOPY_STACK_FRAME_TO),
+ CRASHTYPE(USERCOPY_STACK_FRAME_FROM),
+ CRASHTYPE(USERCOPY_STACK_BEYOND),
+ CRASHTYPE(USERCOPY_VMALLOC),
+ CRASHTYPE(USERCOPY_FOLIO),
+ CRASHTYPE(USERCOPY_KERNEL),
+};
+
+struct crashtype_category usercopy_crashtypes = {
+ .crashtypes = crashtypes,
+ .len = ARRAY_SIZE(crashtypes),
+};