| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-Id: <20250625095224.118679-2-snovitoll@gmail.com>
Date: Wed, 25 Jun 2025 14:52:16 +0500
From: Sabyrzhan Tasbolatov <snovitoll@...il.com>
To: ryabinin.a.a@...il.com,
glider@...gle.com,
andreyknvl@...il.com,
dvyukov@...gle.com,
vincenzo.frascino@....com,
catalin.marinas@....com,
will@...nel.org,
chenhuacai@...nel.org,
kernel@...0n.name,
maddy@...ux.ibm.com,
mpe@...erman.id.au,
npiggin@...il.com,
christophe.leroy@...roup.eu,
hca@...ux.ibm.com,
gor@...ux.ibm.com,
agordeev@...ux.ibm.com,
borntraeger@...ux.ibm.com,
svens@...ux.ibm.com,
richard@....at,
anton.ivanov@...bridgegreys.com,
johannes@...solutions.net,
dave.hansen@...ux.intel.com,
luto@...nel.org,
peterz@...radead.org,
tglx@...utronix.de,
mingo@...hat.com,
bp@...en8.de,
x86@...nel.org,
hpa@...or.com,
chris@...kel.net,
jcmvbkbc@...il.com,
akpm@...ux-foundation.org
Cc: guoweikang.kernel@...il.com,
geert@...ux-m68k.org,
rppt@...nel.org,
tiwei.btw@...group.com,
richard.weiyang@...il.com,
benjamin.berg@...el.com,
kevin.brodsky@....com,
kasan-dev@...glegroups.com,
linux-arm-kernel@...ts.infradead.org,
linux-kernel@...r.kernel.org,
loongarch@...ts.linux.dev,
linuxppc-dev@...ts.ozlabs.org,
linux-s390@...r.kernel.org,
linux-um@...ts.infradead.org,
linux-mm@...ck.org,
snovitoll@...il.com
Subject: [PATCH 1/9] kasan: unify static kasan_flag_enabled across modes
Historically the fast-path static key `kasan_flag_enabled` existed
only for `CONFIG_KASAN_HW_TAGS`. Generic and SW_TAGS either relied on
`kasan_arch_is_ready()` or evaluated KASAN checks unconditionally.
As a result every architecture had to toggle a private flag
in its `kasan_init()`.
This patch turns the flag into a single global runtime predicate that
is built for every `CONFIG_KASAN` mode and adds a helper that flips
the key once KASAN is ready.
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=218315
Signed-off-by: Sabyrzhan Tasbolatov <snovitoll@...il.com>
---
include/linux/kasan-enabled.h | 22 ++++++++++++++++------
include/linux/kasan.h | 6 ++++++
mm/kasan/common.c | 7 +++++++
mm/kasan/generic.c | 11 +++++++++++
mm/kasan/hw_tags.c | 7 -------
mm/kasan/sw_tags.c | 2 ++
6 files changed, 42 insertions(+), 13 deletions(-)
diff --git a/include/linux/kasan-enabled.h b/include/linux/kasan-enabled.h
index 6f612d69ea0c..2436eb45cfee 100644
--- a/include/linux/kasan-enabled.h
+++ b/include/linux/kasan-enabled.h
@@ -4,8 +4,12 @@
#include <linux/static_key.h>
-#ifdef CONFIG_KASAN_HW_TAGS
+#ifdef CONFIG_KASAN
+/*
+ * Global runtime flag. Starts ‘false’; switched to ‘true’ by
+ * the appropriate kasan_init_*() once KASAN is fully initialized.
+ */
DECLARE_STATIC_KEY_FALSE(kasan_flag_enabled);
static __always_inline bool kasan_enabled(void)
@@ -13,18 +17,24 @@ static __always_inline bool kasan_enabled(void)
return static_branch_likely(&kasan_flag_enabled);
}
-static inline bool kasan_hw_tags_enabled(void)
+#else /* !CONFIG_KASAN */
+
+static __always_inline bool kasan_enabled(void)
{
- return kasan_enabled();
+ return false;
}
-#else /* CONFIG_KASAN_HW_TAGS */
+#endif /* CONFIG_KASAN */
-static inline bool kasan_enabled(void)
+#ifdef CONFIG_KASAN_HW_TAGS
+
+static inline bool kasan_hw_tags_enabled(void)
{
- return IS_ENABLED(CONFIG_KASAN);
+ return kasan_enabled();
}
+#else /* !CONFIG_KASAN_HW_TAGS */
+
static inline bool kasan_hw_tags_enabled(void)
{
return false;
diff --git a/include/linux/kasan.h b/include/linux/kasan.h
index 890011071f2b..51a8293d1af6 100644
--- a/include/linux/kasan.h
+++ b/include/linux/kasan.h
@@ -543,6 +543,12 @@ void kasan_report_async(void);
#endif /* CONFIG_KASAN_HW_TAGS */
+#ifdef CONFIG_KASAN_GENERIC
+void __init kasan_init_generic(void);
+#else
+static inline void kasan_init_generic(void) { }
+#endif
+
#ifdef CONFIG_KASAN_SW_TAGS
void __init kasan_init_sw_tags(void);
#else
diff --git a/mm/kasan/common.c b/mm/kasan/common.c
index ed4873e18c75..525194da25fa 100644
--- a/mm/kasan/common.c
+++ b/mm/kasan/common.c
@@ -32,6 +32,13 @@
#include "kasan.h"
#include "../slab.h"
+/*
+ * Definition of the unified static key declared in kasan-enabled.h.
+ * This provides consistent runtime enable/disable across all KASAN modes.
+ */
+DEFINE_STATIC_KEY_FALSE(kasan_flag_enabled);
+EXPORT_SYMBOL(kasan_flag_enabled);
+
struct slab *kasan_addr_to_slab(const void *addr)
{
if (virt_addr_valid(addr))
diff --git a/mm/kasan/generic.c b/mm/kasan/generic.c
index d54e89f8c3e7..32c432df24aa 100644
--- a/mm/kasan/generic.c
+++ b/mm/kasan/generic.c
@@ -36,6 +36,17 @@
#include "kasan.h"
#include "../slab.h"
+/*
+ * Initialize Generic KASAN and enable runtime checks.
+ * This should be called from arch kasan_init() once shadow memory is ready.
+ */
+void __init kasan_init_generic(void)
+{
+ static_branch_enable(&kasan_flag_enabled);
+
+ pr_info("KernelAddressSanitizer initialized (generic)\n");
+}
+
/*
* All functions below always inlined so compiler could
* perform better optimizations in each of __asan_loadX/__assn_storeX
diff --git a/mm/kasan/hw_tags.c b/mm/kasan/hw_tags.c
index 9a6927394b54..8e819fc4a260 100644
--- a/mm/kasan/hw_tags.c
+++ b/mm/kasan/hw_tags.c
@@ -45,13 +45,6 @@ static enum kasan_arg kasan_arg __ro_after_init;
static enum kasan_arg_mode kasan_arg_mode __ro_after_init;
static enum kasan_arg_vmalloc kasan_arg_vmalloc __initdata;
-/*
- * Whether KASAN is enabled at all.
- * The value remains false until KASAN is initialized by kasan_init_hw_tags().
- */
-DEFINE_STATIC_KEY_FALSE(kasan_flag_enabled);
-EXPORT_SYMBOL(kasan_flag_enabled);
-
/*
* Whether the selected mode is synchronous, asynchronous, or asymmetric.
* Defaults to KASAN_MODE_SYNC.
diff --git a/mm/kasan/sw_tags.c b/mm/kasan/sw_tags.c
index b9382b5b6a37..525bc91e2fcd 100644
--- a/mm/kasan/sw_tags.c
+++ b/mm/kasan/sw_tags.c
@@ -45,6 +45,8 @@ void __init kasan_init_sw_tags(void)
kasan_init_tags();
+ static_branch_enable(&kasan_flag_enabled);
+
pr_info("KernelAddressSanitizer initialized (sw-tags, stacktrace=%s)\n",
str_on_off(kasan_stack_collection_enabled()));
}
--
2.34.1
Powered by blists - more mailing lists