From: Kees Cook <keescook@chromium.org>
To: linux-hardening@vger.kernel.org
Cc: Kees Cook <keescook@chromium.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Arnd Bergmann <arnd@arndb.de>,
linux-kernel@vger.kernel.org
Subject: [PATCH] lkdtm: Add FAM_BOUNDS test for __counted_by
Date: Thu, 17 Aug 2023 13:09:14 -0700 [thread overview]
Message-ID: <20230817200913.never.960-kees@kernel.org> (raw)
Add new CONFIG_UBSAN_BOUNDS test for __counted_by attribute.
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Kees Cook <keescook@chromium.org>
---
drivers/misc/lkdtm/bugs.c | 47 ++++++++++++++++++++++++++++++++++++---
1 file changed, 44 insertions(+), 3 deletions(-)
diff --git a/drivers/misc/lkdtm/bugs.c b/drivers/misc/lkdtm/bugs.c
index 963b4dee6a7d..c66cc05a68c4 100644
--- a/drivers/misc/lkdtm/bugs.c
+++ b/drivers/misc/lkdtm/bugs.c
@@ -273,8 +273,8 @@ static void lkdtm_HUNG_TASK(void)
schedule();
}
-volatile unsigned int huge = INT_MAX - 2;
-volatile unsigned int ignored;
+static volatile unsigned int huge = INT_MAX - 2;
+static volatile unsigned int ignored;
static void lkdtm_OVERFLOW_SIGNED(void)
{
@@ -305,7 +305,7 @@ static void lkdtm_OVERFLOW_UNSIGNED(void)
ignored = value;
}
-/* Intentionally using old-style flex array definition of 1 byte. */
+/* Intentionally using unannotated flex array definition. */
struct array_bounds_flex_array {
int one;
int two;
@@ -357,6 +357,46 @@ static void lkdtm_ARRAY_BOUNDS(void)
pr_expected_config(CONFIG_UBSAN_BOUNDS);
}
+struct lkdtm_annotated {
+ unsigned long flags;
+ int count;
+ int array[] __counted_by(count);
+};
+
+static volatile int fam_count = 4;
+
+static void lkdtm_FAM_BOUNDS(void)
+{
+ struct lkdtm_annotated *inst;
+
+ inst = kzalloc(struct_size(inst, array, fam_count + 1), GFP_KERNEL);
+ if (!inst) {
+ pr_err("FAIL: could not allocate test struct!\n");
+ return;
+ }
+
+ inst->count = fam_count;
+ pr_info("Array access within bounds ...\n");
+ inst->array[1] = fam_count;
+ ignored = inst->array[1];
+
+ pr_info("Array access beyond bounds ...\n");
+ inst->array[fam_count] = fam_count;
+ ignored = inst->array[fam_count];
+
+ kfree(inst);
+
+ pr_err("FAIL: survived access of invalid flexible array member index!\n");
+
+ if (!__has_attribute(__counted_by__))
+ pr_warn("This is expected since this %s was built a compiler supporting __counted_by\n",
+ lkdtm_kernel_info);
+ else if (IS_ENABLED(CONFIG_UBSAN_BOUNDS))
+ pr_expected_config(CONFIG_UBSAN_TRAP);
+ else
+ pr_expected_config(CONFIG_UBSAN_BOUNDS);
+}
+
static void lkdtm_CORRUPT_LIST_ADD(void)
{
/*
@@ -616,6 +656,7 @@ static struct crashtype crashtypes[] = {
CRASHTYPE(OVERFLOW_SIGNED),
CRASHTYPE(OVERFLOW_UNSIGNED),
CRASHTYPE(ARRAY_BOUNDS),
+ CRASHTYPE(FAM_BOUNDS),
CRASHTYPE(CORRUPT_LIST_ADD),
CRASHTYPE(CORRUPT_LIST_DEL),
CRASHTYPE(STACK_GUARD_PAGE_LEADING),
--
2.34.1
reply other threads:[~2023-08-17 20:09 UTC|newest]
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