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Bug 680798 - (CVE-2011-1098) CVE-2011-1098 logrotate: TOCTOU race condition by creation of new files (between opening the file and moment, final permissions have been applied) [information disclosure]
CVE-2011-1098 logrotate: TOCTOU race condition by creation of new files (betw...
Product: Security Response
Classification: Other
Component: vulnerability (Show other bugs)
All Linux
low Severity low
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Assigned To: Red Hat Product Security
: Security
Depends On: 688518 688519 688520
  Show dependency treegraph
Reported: 2011-02-27 14:41 EST by Jan Lieskovsky
Modified: 2016-03-04 06:35 EST (History)
5 users (show)

See Also:
Fixed In Version:
Doc Type: Bug Fix
Doc Text:
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Clone Of:
Last Closed: 2015-07-30 09:14:03 EDT
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oVirt Team: ---
RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: ---

Attachments (Terms of Use)
proposed patch (1.75 KB, patch)
2011-03-16 07:02 EDT, Jan Kaluža
no flags Details | Diff

  None (edit)
Description Jan Lieskovsky 2011-02-27 14:41:45 EST
It was found that logrotate utility used insecure default
permissions, when creating of new files (time-of-check,
time-of-use, TOCTOU race condition). In some specific
configurations, a local attacker could use this flaw to
open the new file before the final permissions have been
applied, leading to disclosure of sensitive information.
Comment 3 Jan Lieskovsky 2011-03-03 05:44:32 EST
Further flaw details from Stefan Fritsch of Debian Security Team:

The race is between

192 fd = open(fileName, flags, sb->st_mode);


198 if (fchmod(fd, (S_IRUSR | S_IWUSR) & sb->st_mode)) {

and later

204 if (fchown(fd, sb->st_uid, sb->st_gid)) {

An attacker may be able to open the newly created file after line 192,
even if he has no permissions to open the file after lines 198 and 204
have been executed. Once he has the open file descriptor, he can read
what will be written into the file. No symlink attack is needed.
Comment 4 Huzaifa S. Sidhpurwala 2011-03-11 01:28:08 EST
This has been assigned CVE-2011-1098
Comment 8 Jan Kaluža 2011-03-16 07:02:53 EDT
Created attachment 485707 [details]
proposed patch

This patch fixes the issue by creating temp file with umask 0000, then change owner/mode and renames it to log file.

Upstream fixed it by use of "su" directive patch described in Bug
680799 Comment 2, but this patch breaks backward compatibility for some configurations. Attached patch is possible workaround which keeps backward compatibility.
Comment 10 Huzaifa S. Sidhpurwala 2011-03-17 05:53:11 EDT
Created logrotate tracking bugs for this issue

Affects: fedora-all [bug 688520]
Comment 11 errata-xmlrpc 2011-03-31 11:16:37 EDT
This issue has been addressed in following products:

  Red Hat Enterprise Linux 6

Via RHSA-2011:0407
Comment 13 Josh Bressers 2011-06-29 13:42:12 EDT

The Red Hat Security Response Team has rated this issue as having low security impact, a future update may address this flaw.

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