From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Kees Cook <keescook@chromium.org>,
Sasha Levin <sashal@kernel.org>,
linux-hardening@vger.kernel.org
Subject: [PATCH AUTOSEL 6.6 40/52] overflow: Allow non-type arg to type_max() and type_min()
Date: Fri, 29 Mar 2024 08:29:10 -0400 [thread overview]
Message-ID: <20240329122956.3083859-40-sashal@kernel.org> (raw)
In-Reply-To: <20240329122956.3083859-1-sashal@kernel.org>
From: Kees Cook <keescook@chromium.org>
[ Upstream commit bd1ebf2467f9c5d157bec7b025e83f8ffdae1318 ]
A common use of type_max() is to find the max for the type of a
variable. Using the pattern type_max(typeof(var)) is needlessly
verbose. Instead, since typeof(type) == type we can just explicitly
call typeof() on the argument to type_max() and type_min(). Add
wrappers for readability.
We can do some replacements right away:
$ git grep '\btype_\(min\|max\)(typeof' | wc -l
11
Link: https://lore.kernel.org/r/20240301062221.work.840-kees@kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
include/linux/overflow.h | 12 +++++++-----
1 file changed, 7 insertions(+), 5 deletions(-)
diff --git a/include/linux/overflow.h b/include/linux/overflow.h
index f9b60313eaea2..e04f679476473 100644
--- a/include/linux/overflow.h
+++ b/include/linux/overflow.h
@@ -31,8 +31,10 @@
* credit to Christian Biere.
*/
#define __type_half_max(type) ((type)1 << (8*sizeof(type) - 1 - is_signed_type(type)))
-#define type_max(T) ((T)((__type_half_max(T) - 1) + __type_half_max(T)))
-#define type_min(T) ((T)((T)-type_max(T)-(T)1))
+#define __type_max(T) ((T)((__type_half_max(T) - 1) + __type_half_max(T)))
+#define type_max(t) __type_max(typeof(t))
+#define __type_min(T) ((T)((T)-type_max(T)-(T)1))
+#define type_min(t) __type_min(typeof(t))
/*
* Avoids triggering -Wtype-limits compilation warning,
@@ -130,10 +132,10 @@ static inline bool __must_check __must_check_overflow(bool overflow)
#define __overflows_type_constexpr(x, T) ( \
is_unsigned_type(typeof(x)) ? \
- (x) > type_max(typeof(T)) : \
+ (x) > type_max(T) : \
is_unsigned_type(typeof(T)) ? \
- (x) < 0 || (x) > type_max(typeof(T)) : \
- (x) < type_min(typeof(T)) || (x) > type_max(typeof(T)))
+ (x) < 0 || (x) > type_max(T) : \
+ (x) < type_min(T) || (x) > type_max(T))
#define __overflows_type(x, T) ({ \
typeof(T) v = 0; \
--
2.43.0
prev parent reply other threads:[~2024-03-29 12:31 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20240329122956.3083859-1-sashal@kernel.org>
2024-03-29 12:29 ` [PATCH AUTOSEL 6.6 33/52] pstore/zone: Add a null pointer check to the psz_kmsg_read Sasha Levin
2024-03-29 12:29 ` Sasha Levin [this message]
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