Bug 608583 - (CVE-2010-2248) CVE-2010-2248 kernel: cifs: Fix a kernel BUG with remote OS/2 server
CVE-2010-2248 kernel: cifs: Fix a kernel BUG with remote OS/2 server
Status: NEW
Product: Security Response
Classification: Other
Component: vulnerability (Show other bugs)
unspecified
All Linux
high Severity high
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Assigned To: Red Hat Product Security
reported=20100628,public=20100331,imp...
: Security
Depends On: 608584 608585 608586 608587 608588
Blocks:
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Reported: 2010-06-28 04:19 EDT by Eugene Teo (Security Response)
Modified: 2015-05-04 21:26 EDT (History)
11 users (show)

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Doc Type: Bug Fix
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RHEL 7.3 requirements from Atomic Host:


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Description Eugene Teo (Security Response) 2010-06-28 04:19:38 EDT
Description of problem:
While chasing a bug report involving a OS/2 server, I noticed the server sets pSMBr->CountHigh to a incorrect value even in case of normal writes. This results in 'nbytes' being computed wrongly and triggers a kernel BUG at mm/filemap.c.
    
    void iov_iter_advance(struct iov_iter *i, size_t bytes)
    {
            BUG_ON(i->count < bytes);    <--- BUG here
    
Why the server is setting 'CountHigh' is not clear but only does so after writing 64k bytes. Though this looks like the server bug, the client side crash may not be acceptable.
    
The workaround is to mask off high 16 bits if the number of bytes written as returned by the server is greater than the bytes requested by the client.

Upstream commit:
http://git.kernel.org/linus/6513a81e9325d712f1bfb9a1d7b750134e49ff18 (v2.6.34-rc4)
Comment 4 Eugene Teo (Security Response) 2010-06-28 22:22:43 EDT
Statement:

This issue did not affect the version of Linux kernel as shipped with Red Hat Enterprise Linux 3 as it did not have support for CIFS. Future updates in Red Hat Enterprise Linux 4, 5, and Red Hat Enterprise MRG may address this flaw.
Comment 5 errata-xmlrpc 2010-08-05 12:47:51 EDT
This issue has been addressed in following products:

  Red Hat Enterprise Linux 4

Via RHSA-2010:0606 https://rhn.redhat.com/errata/RHSA-2010-0606.html
Comment 6 errata-xmlrpc 2010-08-10 14:01:36 EDT
This issue has been addressed in following products:

  Red Hat Enterprise Linux 5

Via RHSA-2010:0610 https://rhn.redhat.com/errata/RHSA-2010-0610.html
Comment 7 errata-xmlrpc 2010-08-17 11:53:02 EDT
This issue has been addressed in following products:

  MRG for RHEL-5

Via RHSA-2010:0631 https://rhn.redhat.com/errata/RHSA-2010-0631.html

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