public inbox for glibc-bugs@sourceware.org
help / color / mirror / Atom feed
From: "siddhesh at sourceware dot org" <sourceware-bugzilla@sourceware.org>
To: glibc-bugs@sourceware.org
Subject: [Bug libc/28769] New: Off-by-one buffer overflow/underflow in getcwd() (CVE-2021-3999)
Date: Wed, 12 Jan 2022 13:44:34 +0000	[thread overview]
Message-ID: <bug-28769-131@http.sourceware.org/bugzilla/> (raw)

https://sourceware.org/bugzilla/show_bug.cgi?id=28769

            Bug ID: 28769
           Summary: Off-by-one buffer overflow/underflow in getcwd()
                    (CVE-2021-3999)
           Product: glibc
           Version: 2.35
            Status: NEW
          Severity: normal
          Priority: P2
         Component: libc
          Assignee: siddhesh at sourceware dot org
          Reporter: siddhesh at sourceware dot org
                CC: drepper.fsp at gmail dot com
  Target Milestone: ---
             Flags: security+

For very long file names, the getcwd syscall returns ENAMETOOLONG, resulting in
a call to __getcwd_generic.  That function in turn assumes a size that's
suficient for at least a '/', so a size of 1 results in access that's one byte
beyond bounds of buf.

We always need a minimum size of 2 bytes, so the glibc function should set
ERANGE and return NULL for size of 1 byte.

-- 
You are receiving this mail because:
You are on the CC list for the bug.

             reply	other threads:[~2022-01-12 13:44 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-01-12 13:44 siddhesh at sourceware dot org [this message]
2022-01-12 13:45 ` [Bug libc/28769] " siddhesh at sourceware dot org
2022-01-12 13:48 ` fweimer at redhat dot com
2022-01-12 13:48 ` fweimer at redhat dot com
2022-01-15 15:41 ` aurelien at aurel32 dot net
2022-01-17  9:07 ` pgowda.cve at gmail dot com
2022-01-24  6:01 ` cvs-commit at gcc dot gnu.org
2022-01-24  6:46 ` cvs-commit at gcc dot gnu.org
2022-01-24  6:47 ` siddhesh at sourceware dot org
2022-01-24 22:46 ` cvs-commit at gcc dot gnu.org
2022-01-24 22:49 ` cvs-commit at gcc dot gnu.org

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=bug-28769-131@http.sourceware.org/bugzilla/ \
    --to=sourceware-bugzilla@sourceware.org \
    --cc=glibc-bugs@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).