Move the boot parameter 'kasan.fault' from hw_tags.c to report.c, so it
can support all KASAN modes - generic, and both tag-based.
Signed-off-by: Woody Lin <woodylin@xxxxxxxxxx>
---
Documentation/dev-tools/kasan.rst | 13 ++++++----
mm/kasan/hw_tags.c | 43 -------------------------------
mm/kasan/kasan.h | 1 -
mm/kasan/report.c | 29 ++++++++++++++++++---
4 files changed, 34 insertions(+), 52 deletions(-)
diff --git a/Documentation/dev-tools/kasan.rst b/Documentation/dev-tools/kasan.rst
index 83ec4a556c19..21dc03bc10a4 100644
--- a/Documentation/dev-tools/kasan.rst
+++ b/Documentation/dev-tools/kasan.rst
@@ -181,9 +181,16 @@ By default, KASAN prints a bug report only for the first invalid memory access.
With ``kasan_multi_shot``, KASAN prints a report on every invalid access. This
effectively disables ``panic_on_warn`` for KASAN reports.
+Alternatively, independent of ``panic_on_warn`` the ``kasan.fault=`` boot
+parameter can be used to control panic and reporting behaviour:
+
+- ``kasan.fault=report`` or ``=panic`` controls whether to only print a KASAN
+ report or also panic the kernel (default: ``report``). The panic happens even
+ if ``kasan_multi_shot`` is enabled.
+
Hardware tag-based KASAN mode (see the section about various modes below) is
intended for use in production as a security mitigation. Therefore, it supports
-boot parameters that allow disabling KASAN or controlling its features.
+additional boot parameters that allow disabling KASAN or controlling features:
- ``kasan=off`` or ``=on`` controls whether KASAN is enabled (default: ``on``).
@@ -199,10 +206,6 @@ boot parameters that allow disabling KASAN or controlling its features.
- ``kasan.stacktrace=off`` or ``=on`` disables or enables alloc and free stack
traces collection (default: ``on``).
-- ``kasan.fault=report`` or ``=panic`` controls whether to only print a KASAN
- report or also panic the kernel (default: ``report``). The panic happens even
- if ``kasan_multi_shot`` is enabled.
-
Implementation details
----------------------
diff --git a/mm/kasan/hw_tags.c b/mm/kasan/hw_tags.c
index 4ea8c368b5b8..51903639e55f 100644
--- a/mm/kasan/hw_tags.c
+++ b/mm/kasan/hw_tags.c
@@ -37,16 +37,9 @@ enum kasan_arg_stacktrace {
KASAN_ARG_STACKTRACE_ON,
};
-enum kasan_arg_fault {
- KASAN_ARG_FAULT_DEFAULT,
- KASAN_ARG_FAULT_REPORT,
- KASAN_ARG_FAULT_PANIC,
-};
-
static enum kasan_arg kasan_arg __ro_after_init;
static enum kasan_arg_mode kasan_arg_mode __ro_after_init;
static enum kasan_arg_stacktrace kasan_arg_stacktrace __ro_after_init;
-static enum kasan_arg_fault kasan_arg_fault __ro_after_init;
/* Whether KASAN is enabled at all. */
DEFINE_STATIC_KEY_FALSE(kasan_flag_enabled);
@@ -59,9 +52,6 @@ EXPORT_SYMBOL_GPL(kasan_flag_async);
/* Whether to collect alloc/free stack traces. */
DEFINE_STATIC_KEY_FALSE(kasan_flag_stacktrace);
-/* Whether to panic or print a report and disable tag checking on fault. */
-bool kasan_flag_panic __ro_after_init;
-
/* kasan=off/on */
static int __init early_kasan_flag(char *arg)
{
@@ -113,23 +103,6 @@ static int __init early_kasan_flag_stacktrace(char *arg)
}
early_param("kasan.stacktrace", early_kasan_flag_stacktrace);
-/* kasan.fault=report/panic */
-static int __init early_kasan_fault(char *arg)
-{
- if (!arg)
- return -EINVAL;
-
- if (!strcmp(arg, "report"))
- kasan_arg_fault = KASAN_ARG_FAULT_REPORT;
- else if (!strcmp(arg, "panic"))
- kasan_arg_fault = KASAN_ARG_FAULT_PANIC;
- else
- return -EINVAL;
-
- return 0;
-}
-early_param("kasan.fault", early_kasan_fault);
-
/* kasan_init_hw_tags_cpu() is called for each CPU. */
void kasan_init_hw_tags_cpu(void)
{
@@ -197,22 +170,6 @@ void __init kasan_init_hw_tags(void)
break;
}
- switch (kasan_arg_fault) {
- case KASAN_ARG_FAULT_DEFAULT:
- /*
- * Default to no panic on report.
- * Do nothing, kasan_flag_panic keeps its default value.
- */
- break;
- case KASAN_ARG_FAULT_REPORT:
- /* Do nothing, kasan_flag_panic keeps its default value. */
- break;
- case KASAN_ARG_FAULT_PANIC:
- /* Enable panic on report. */
- kasan_flag_panic = true;
- break;
- }
-
pr_info("KernelAddressSanitizer initialized\n");
}
diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h
index 98e3059bfea4..9d57383ce1fa 100644
--- a/mm/kasan/kasan.h
+++ b/mm/kasan/kasan.h
@@ -36,7 +36,6 @@ static inline bool kasan_async_mode_enabled(void)
#endif
-extern bool kasan_flag_panic __ro_after_init;
extern bool kasan_flag_async __ro_after_init;
#if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)
diff --git a/mm/kasan/report.c b/mm/kasan/report.c
index 8fff1825b22c..884a950c7026 100644
--- a/mm/kasan/report.c
+++ b/mm/kasan/report.c
@@ -39,6 +39,31 @@ static unsigned long kasan_flags;
#define KASAN_BIT_REPORTED 0
#define KASAN_BIT_MULTI_SHOT 1
+enum kasan_arg_fault {
+ KASAN_ARG_FAULT_DEFAULT,
+ KASAN_ARG_FAULT_REPORT,
+ KASAN_ARG_FAULT_PANIC,
+};
+
+static enum kasan_arg_fault kasan_arg_fault __ro_after_init = KASAN_ARG_FAULT_DEFAULT;
+
+/* kasan.fault=report/panic */
+static int __init early_kasan_fault(char *arg)
+{
+ if (!arg)
+ return -EINVAL;
+
+ if (!strcmp(arg, "report"))
+ kasan_arg_fault = KASAN_ARG_FAULT_REPORT;
+ else if (!strcmp(arg, "panic"))
+ kasan_arg_fault = KASAN_ARG_FAULT_PANIC;
+ else
+ return -EINVAL;
+
+ return 0;
+}
+early_param("kasan.fault", early_kasan_fault);
+
bool kasan_save_enable_multi_shot(void)
{
return test_and_set_bit(KASAN_BIT_MULTI_SHOT, &kasan_flags);
@@ -102,10 +127,8 @@ static void end_report(unsigned long *flags, unsigned long addr)
panic_on_warn = 0;
panic("panic_on_warn set ...\n");
}
-#ifdef CONFIG_KASAN_HW_TAGS
- if (kasan_flag_panic)
+ if (kasan_arg_fault == KASAN_ARG_FAULT_PANIC)
panic("kasan.fault=panic set ...\n");
-#endif
kasan_enable_current();
}
--
2.32.0.93.g670b81a890-goog
