From: Ard Biesheuvel <ardb@kernel.org>
To: linux-kernel@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org,
Ard Biesheuvel <ardb@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Josh Poimboeuf <jpoimboe@redhat.com>,
Jason Baron <jbaron@akamai.com>,
Steven Rostedt <rostedt@goodmis.org>,
Mark Rutland <mark.rutland@arm.com>,
Kees Cook <keescook@chromium.org>
Subject: [RFC PATCH 5/7] static_call: use non-function types to refer to the trampolines
Date: Tue, 9 Nov 2021 17:45:47 +0100 [thread overview]
Message-ID: <20211109164549.1724710-6-ardb@kernel.org> (raw)
In-Reply-To: <20211109164549.1724710-1-ardb@kernel.org>
In order to prevent CFI enabled code from grabbing a jump table entry
that jumps to the trampoline, rather than the trampoline itself, use an
incomplete non-function type for the trampoline, and cast it to the
right type only when invoking it.
Acked-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
include/linux/static_call.h | 2 +-
include/linux/static_call_types.h | 6 +++---
tools/include/linux/static_call_types.h | 6 +++---
3 files changed, 7 insertions(+), 7 deletions(-)
diff --git a/include/linux/static_call.h b/include/linux/static_call.h
index 391f737496eb..6b261fe96ba3 100644
--- a/include/linux/static_call.h
+++ b/include/linux/static_call.h
@@ -144,7 +144,7 @@ extern void arch_static_call_transform(void *site, void *tramp, void *func, bool
#define static_call_update(name, func) \
({ \
- typeof(&STATIC_CALL_TRAMP(name)) __F = (func); \
+ typeof(STATIC_CALL_QUERY(name)()) __F = (func); \
__static_call_update(&STATIC_CALL_KEY(name), \
STATIC_CALL_TRAMP_ADDR(name), __F); \
})
diff --git a/include/linux/static_call_types.h b/include/linux/static_call_types.h
index 2fce9aa8a995..eae11c5b015d 100644
--- a/include/linux/static_call_types.h
+++ b/include/linux/static_call_types.h
@@ -47,7 +47,7 @@ struct static_call_site {
extern __weak struct static_call_key STATIC_CALL_KEY(name); \
extern __weak struct static_call_key *STATIC_CALL_GETKEY(name)(void);\
extern __weak typeof(func) *STATIC_CALL_QUERY(name)(void); \
- extern typeof(func) STATIC_CALL_TRAMP(name)
+ extern struct static_call_tramp STATIC_CALL_TRAMP(name)
#define __static_call_query(name) \
((typeof(STATIC_CALL_QUERY(name)()))READ_ONCE(STATIC_CALL_KEY(name).func))
@@ -66,7 +66,7 @@ struct static_call_site {
#define static_call(name) \
({ \
__STATIC_CALL_ADDRESSABLE(name); \
- (&STATIC_CALL_TRAMP(name)); \
+ ((typeof(STATIC_CALL_QUERY(name)()))&STATIC_CALL_TRAMP(name)); \
})
#ifdef CONFIG_HAVE_STATIC_CALL_INLINE
@@ -107,7 +107,7 @@ struct static_call_key {
};
#define static_call(name) \
- ((typeof(STATIC_CALL_TRAMP(name))*)(STATIC_CALL_KEY(name).func))
+ ((typeof(STATIC_CALL_QUERY(name)()))(STATIC_CALL_KEY(name).func))
#endif /* CONFIG_HAVE_STATIC_CALL */
diff --git a/tools/include/linux/static_call_types.h b/tools/include/linux/static_call_types.h
index 2fce9aa8a995..eae11c5b015d 100644
--- a/tools/include/linux/static_call_types.h
+++ b/tools/include/linux/static_call_types.h
@@ -47,7 +47,7 @@ struct static_call_site {
extern __weak struct static_call_key STATIC_CALL_KEY(name); \
extern __weak struct static_call_key *STATIC_CALL_GETKEY(name)(void);\
extern __weak typeof(func) *STATIC_CALL_QUERY(name)(void); \
- extern typeof(func) STATIC_CALL_TRAMP(name)
+ extern struct static_call_tramp STATIC_CALL_TRAMP(name)
#define __static_call_query(name) \
((typeof(STATIC_CALL_QUERY(name)()))READ_ONCE(STATIC_CALL_KEY(name).func))
@@ -66,7 +66,7 @@ struct static_call_site {
#define static_call(name) \
({ \
__STATIC_CALL_ADDRESSABLE(name); \
- (&STATIC_CALL_TRAMP(name)); \
+ ((typeof(STATIC_CALL_QUERY(name)()))&STATIC_CALL_TRAMP(name)); \
})
#ifdef CONFIG_HAVE_STATIC_CALL_INLINE
@@ -107,7 +107,7 @@ struct static_call_key {
};
#define static_call(name) \
- ((typeof(STATIC_CALL_TRAMP(name))*)(STATIC_CALL_KEY(name).func))
+ ((typeof(STATIC_CALL_QUERY(name)()))(STATIC_CALL_KEY(name).func))
#endif /* CONFIG_HAVE_STATIC_CALL */
--
2.30.2
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next prev parent reply other threads:[~2021-11-09 16:49 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-09 16:45 [RFC PATCH 0/7] static call updates Ard Biesheuvel
2021-11-09 16:45 ` [RFC PATCH 1/7] static_call: get rid of static_call_cond() Ard Biesheuvel
2021-11-09 18:38 ` Peter Zijlstra
2021-11-09 18:41 ` Ard Biesheuvel
2021-11-09 19:22 ` Peter Zijlstra
2021-11-09 19:32 ` Peter Zijlstra
2021-11-09 16:45 ` [RFC PATCH 2/7] static_call: deal with unexported keys without cluttering up the API Ard Biesheuvel
2021-11-09 18:49 ` Peter Zijlstra
2021-11-09 18:53 ` Ard Biesheuvel
2021-11-09 19:41 ` Peter Zijlstra
2021-11-09 16:45 ` [RFC PATCH 3/7] static_call: use helper to access non-exported key Ard Biesheuvel
2021-11-09 18:53 ` Peter Zijlstra
2021-11-09 18:54 ` Ard Biesheuvel
2021-11-09 19:42 ` Peter Zijlstra
2021-11-09 19:45 ` Ard Biesheuvel
2021-11-09 16:45 ` [RFC PATCH 4/7] static_call: fix broken static_call_query() for non-exported keys Ard Biesheuvel
2021-11-09 18:56 ` Peter Zijlstra
2021-11-09 16:45 ` Ard Biesheuvel [this message]
2021-11-09 16:45 ` [RFC PATCH 6/7] static_call: rename EXPORT_ macros to be more self-explanatory Ard Biesheuvel
2021-11-09 19:00 ` Peter Zijlstra
2021-11-09 19:03 ` Ard Biesheuvel
2021-11-09 16:45 ` [RFC PATCH 7/7] static_call: add generic support for non-exported keys Ard Biesheuvel
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