From: Mark Wielaard <mark@klomp.org>
To: elfutils-devel@sourceware.org
Cc: Mark Wielaard <mark@klomp.org>
Subject: [PATCH] readelf: Workaround stringop-truncation error
Date: Sat, 4 Dec 2021 22:15:04 +0100 [thread overview]
Message-ID: <20211204211504.276502-1-mark@klomp.org> (raw)
In function ‘strncpy’,
inlined from ‘print_ehdr’ at readelf.c:1175:4:
error: ‘__builtin_strncpy’ specified bound 512 equals destination size
[-Werror=stringop-truncation]
strncpy doesn't terminate the copied string if there is not enough
room. We compensate later by explicitly adding a zero terminator at
buf[sizeof (buf) - 1]. Normally gcc does see this, but with
-fsanitize=address there is too much (checking) code in between. But
it is actually better to not let strncpy do too much work, so
substract one from the size.
Signed-off-by: Mark Wielaard <mark@klomp.org>
---
src/ChangeLog | 4 ++++
src/readelf.c | 2 +-
2 files changed, 5 insertions(+), 1 deletion(-)
diff --git a/src/ChangeLog b/src/ChangeLog
index 05b2522d..263e9faa 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,7 @@
+2021-12-04 Mark Wielaard <mark@klomp.org>
+
+ * readelf.c (print_ehdr): Pass sizeof (buf) - 1 to strncpy.
+
2021-10-20 John M Mellor-Crummey <johnmc@rice.edu>
* readelf.c (print_debug_line_section): Try to read
diff --git a/src/readelf.c b/src/readelf.c
index c10038e3..93fb5989 100644
--- a/src/readelf.c
+++ b/src/readelf.c
@@ -1172,7 +1172,7 @@ print_ehdr (Ebl *ebl, GElf_Ehdr *ehdr)
(uint32_t) shdr->sh_link);
else
{
- strncpy (buf, _(" ([0] not available)"), sizeof (buf));
+ strncpy (buf, _(" ([0] not available)"), sizeof (buf) - 1);
buf[sizeof (buf) - 1] = '\0';
}
--
2.30.2
next reply other threads:[~2021-12-04 21:15 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-04 21:15 Mark Wielaard [this message]
2021-12-08 23:14 ` Mark Wielaard
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=20211204211504.276502-1-mark@klomp.org \
--to=mark@klomp.org \
--cc=elfutils-devel@sourceware.org \
/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).