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From: Siddhesh Poyarekar <siddhesh@sourceware.org>
To: libc-alpha@sourceware.org
Subject: [PATCH] manual: Document __wur usage under _FORTIFY_SOURCE
Date: Fri, 24 Mar 2023 10:40:05 -0400	[thread overview]
Message-ID: <20230324144005.26782-1-siddhesh@sourceware.org> (raw)

The __warn_unused_result__ attribute is only enabled when fortification
is enabled.  Mention that in the document.  The rationale for this is
essentially to mitigate against CWE-252:

[1] https://cwe.mitre.org/data/definitions/252.html

Signed-off-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
---
 manual/maint.texi | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/manual/maint.texi b/manual/maint.texi
index 76d4a1a147..ae651c2a4a 100644
--- a/manual/maint.texi
+++ b/manual/maint.texi
@@ -206,7 +206,10 @@ to the function call are safe, the call may be replaced by a call to its
 hardened variant that does additional safety checks at runtime.  Some
 hardened variants need the size of the buffer to perform access
 validation and this is provided by the @code{__builtin_object_size} or
-the @code{__builtin_dynamic_object_size} builtin functions.
+the @code{__builtin_dynamic_object_size} builtin functions.  The macro
+also enables additional compile time diagnostics, such as unchecked
+return values from some functions, to encourage developers to add error
+checking for those functions.
 
 At runtime, if any of those safety checks fail, the program will
 terminate with a @code{SIGABRT} signal.  @code{_FORTIFY_SOURCE} may be
-- 
2.39.2


             reply	other threads:[~2023-03-24 14:40 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-03-24 14:40 Siddhesh Poyarekar [this message]
2023-03-24 15:15 ` Florian Weimer
2023-03-24 15:23   ` Siddhesh Poyarekar
2023-03-24 15:25 ` [PATCH v2] " Siddhesh Poyarekar
2023-04-03 13:54   ` Florian Weimer

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