public inbox for glibc-cvs@sourceware.org
help / color / mirror / Atom feed
From: Adhemerval Zanella <azanella@sourceware.org>
To: glibc-cvs@sourceware.org
Subject: [glibc] hppa: Fix undefined behaviour in feclearexcept (BZ 30983)
Date: Tue, 19 Dec 2023 18:35:55 +0000 (GMT)	[thread overview]
Message-ID: <20231219183555.5438D3857BAE@sourceware.org> (raw)

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=d0829302728954e0abacfc01551c17daf4d61c87

commit d0829302728954e0abacfc01551c17daf4d61c87
Author: Bruno Haible <bruno@clisp.org>
Date:   Thu Nov 2 16:19:44 2023 -0300

    hppa: Fix undefined behaviour in feclearexcept (BZ 30983)
    
    The expression
    
      (excepts & FE_ALL_EXCEPT) << 27
    
    produces a signed integer overflow when 'excepts' is specified as
    FE_INVALID (= 0x10), because
      - excepts is of type 'int',
      - FE_ALL_EXCEPT is of type 'int',
      - thus (excepts & FE_ALL_EXCEPT) is (int) 0x10,
      - 'int' is 32 bits wide.
    
    The patched code produces the same instruction sequence as
    previosuly.
    
    Reviewed-by: Carlos O'Donell <carlos@redhat.com>

Diff:
---
 sysdeps/hppa/fpu/fclrexcpt.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sysdeps/hppa/fpu/fclrexcpt.c b/sysdeps/hppa/fpu/fclrexcpt.c
index 055fb04ccc..46caf39ec1 100644
--- a/sysdeps/hppa/fpu/fclrexcpt.c
+++ b/sysdeps/hppa/fpu/fclrexcpt.c
@@ -26,7 +26,7 @@ feclearexcept (int excepts)
   /* Get the current status word. */
   __asm__ ("fstd %%fr0,0(%1)" : "=m" (s.l) : "r" (&s.l) : "%r0");
   /* Clear all the relevant bits. */
-  s.sw[0] &= ~((excepts & FE_ALL_EXCEPT) << 27);
+  s.sw[0] &= ~(((unsigned int) excepts & FE_ALL_EXCEPT) << 27);
   __asm__ ("fldd 0(%0),%%fr0" : : "r" (&s.l), "m" (s.l) : "%r0");
 
   /* Success.  */

                 reply	other threads:[~2023-12-19 18:35 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=20231219183555.5438D3857BAE@sourceware.org \
    --to=azanella@sourceware.org \
    --cc=glibc-cvs@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).