From: James Prestwood <prestwoj at gmail.com>
To: ell at lists.01.org
Subject: [PATCH 2/2] missing: use PTRDIFF_MAX instead of -1
Date: Fri, 10 Jun 2022 10:11:32 -0700 [thread overview]
Message-ID: <20220610171132.334641-2-prestwoj@gmail.com> (raw)
In-Reply-To: 20220610171132.334641-1-prestwoj@gmail.com
[-- Attachment #1: Type: text/plain, Size: 1339 bytes --]
On musl-gcc the compiler complains that the size passed to
memchr (-1) is larger than the object size (size_t). Looking
at the values its limiting size_t to a max size of a signed
integer (0x7FFF....) and we are passing 0xFFFFF....
Since this size is quite large its not expected that anyone
will ever need to use memchr with a buffer this big.
Limiting the size to a signed integer max value should be just
fine.
Instead, use PTRDIFF_MAX rather than -1. Below is the warning
produced in upstream:
In file included from ell/pem.c:45:
In function 'rawmemchr',
inlined from 'pem_load_buffer' at ell/pem.c:227:21:
ell/missing.h:76:16: error: 'memchr' specified bound
18446744073709551615 may exceed maximum object size
9223372036854775807 [-Werror=stringop-overread]
76 | return memchr(s, c, (size_t) -1);
---
ell/missing.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/ell/missing.h b/ell/missing.h
index 2a3e647..11d6a8e 100644
--- a/ell/missing.h
+++ b/ell/missing.h
@@ -73,7 +73,7 @@ static inline void *rawmemchr(const void *s, int c)
{
_Pragma("GCC diagnostic push")
_Pragma("GCC diagnostic ignored \"-Wstringop-overflow=\"")
- return memchr(s, c, (size_t) -1);
+ return memchr(s, c, PTRDIFF_MAX);
_Pragma("GCC diagnostic pop")
}
#endif
--
2.34.1
reply other threads:[~2022-06-10 17:11 UTC|newest]
Thread overview: [no followups] expand[flat|nested] mbox.gz Atom feed
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20220610171132.334641-2-prestwoj@gmail.com \
--to=ell@lists.linux.dev \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).