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                   Red Hat, Inc. Security Advisory



Synopsis:          glibc vulnerabilities in ld.so, locale and gettext

Advisory ID:       RHSA-2000:057-01

Issue date:        2000-09-01

Updated on:        2000-09-01

Product:           Red Hat Linux

Keywords:          glibc ld.so locale LANG gettext LD_PRELOAD threads

Cross references:  N/A

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1. Topic:



Several bugs were discovered in glibc which could allow local users to

gain root privileges.



2. Relevant releases/architectures:



Red Hat Linux 5.0 - i386, alpha

Red Hat Linux 5.1 - i386, alpha, sparc

Red Hat Linux 5.2 - i386, alpha, sparc

Red Hat Linux 6.0 - i386, alpha, sparc

Red Hat Linux 6.1 - i386, alpha, sparc, sparcv9

Red Hat Linux 6.2 - i386, alpha, sparc, sparcv9



3. Problem description:



The dynamic linker ld.so uses several environment variables like LD_PRELOAD

and LD_LIBRARY_PATH to load additional libraries or modify the library

search path. It is unsafe to accept arbitrary user specified values

of these variables when executing setuid applications, so ld.so handles

them specially in setuid programs and also removes them from the

environment.



One of the discovered bugs causes these variables not to be

removed from the environment under certain circumstances. This does not

cause any threat to setuid application themselves, but it could be

exploited if a setuid application does not either drop privileges or clean

up its environment prior to executing other programs.



A number of additional bugs have been found in glibc locale and

internationalization security checks. In internationalized programs, users

are permitted to select a locale or choose message catalogues using

environment variables such as LANG or LC_*. The content of these variables

is then used as part of pathnames for searching message catalogues or

locale files.



Normally, if these variables contain "/" characters, a program can load the

internationalization files from arbitrary directories. This is

unnacceptable for setuid programs, which is why glibc does not allow

certain settings of these variables if the program is setuid or setgid.

However, some of these checks were done in inappropriate places, contained

bugs or were completely missing. It is highly probable that some of these

bugs can be used for local root exploits.



The Red Hat Linux 6.x updates also fix a linuxthreads deadlock bug and

handling of certain values of the TZ environment variable.



4. Solution:



For each RPM for your particular architecture, run:



rpm -Fvh [filename]



where filename is the name of the RPM.



5. Bug IDs fixed (http://bugzilla.redhat.com/bugzilla for more info):



13785 - Bug in pthreads blocks ability to preempt suspend and resume threads on SMP machines





6. RPMs required:



Red Hat Linux 5.x:



sparc:

http://updates.redhat.com/5.2/sparc/glibc-2.0.7-29.2.sparc.rpm

http://updates.redhat.com/5.2/sparc/glibc-debug-2.0.7-29.2.sparc.rpm

http://updates.redhat.com/5.2/sparc/glibc-devel-2.0.7-29.2.sparc.rpm

http://updates.redhat.com/5.2/sparc/glibc-profile-2.0.7-29.2.sparc.rpm



alpha:

http://updates.redhat.com/5.2/alpha/glibc-2.0.7-29.2.alpha.rpm

http://updates.redhat.com/5.2/alpha/glibc-debug-2.0.7-29.2.alpha.rpm

http://updates.redhat.com/5.2/alpha/glibc-devel-2.0.7-29.2.alpha.rpm

http://updates.redhat.com/5.2/alpha/glibc-profile-2.0.7-29.2.alpha.rpm



i386:

http://updates.redhat.com/5.2/i386/glibc-2.0.7-29.2.i386.rpm

http://updates.redhat.com/5.2/i386/glibc-debug-2.0.7-29.2.i386.rpm

http://updates.redhat.com/5.2/i386/glibc-devel-2.0.7-29.2.i386.rpm

http://updates.redhat.com/5.2/i386/glibc-profile-2.0.7-29.2.i386.rpm



sources:

http://updates.redhat.com/5.2/SRPMS/glibc-2.0.7-29.2.src.rpm



Red Hat Linux 6.x:



sparc:

http://updates.redhat.com/6.2/sparc/glibc-2.1.3-19.sparc.rpm

http://updates.redhat.com/6.2/sparc/glibc-devel-2.1.3-19.sparc.rpm

http://updates.redhat.com/6.2/sparc/glibc-profile-2.1.3-19.sparc.rpm

http://updates.redhat.com/6.2/sparc/nscd-2.1.3-19.sparc.rpm



i386:

http://updates.redhat.com/6.2/i386/glibc-2.1.3-19.i386.rpm

http://updates.redhat.com/6.2/i386/glibc-devel-2.1.3-19.i386.rpm

http://updates.redhat.com/6.2/i386/glibc-profile-2.1.3-19.i386.rpm

http://updates.redhat.com/6.2/i386/nscd-2.1.3-19.i386.rpm



alpha:

http://updates.redhat.com/6.2/alpha/glibc-2.1.3-19.alpha.rpm

http://updates.redhat.com/6.2/alpha/glibc-devel-2.1.3-19.alpha.rpm

http://updates.redhat.com/6.2/alpha/glibc-profile-2.1.3-19.alpha.rpm

http://updates.redhat.com/6.2/alpha/nscd-2.1.3-19.alpha.rpm



sparcv9:

http://updates.redhat.com/6.2/sparcv9/glibc-2.1.3-19.sparcv9.rpm



sources:

http://updates.redhat.com/6.2/SRPMS/glibc-2.1.3-19.src.rpm



7. Verification:



MD5 sum                           Package Name

--------------------------------------------------------------------------

6ca1331b30257a5a34417d9e3374540a  5.2/SRPMS/glibc-2.0.7-29.2.src.rpm

ef8f379f37e9fde8f67c087db45570c2  5.2/alpha/glibc-2.0.7-29.2.alpha.rpm

0d39f139ea5b23d08b5f3241a23d0731  5.2/alpha/glibc-debug-2.0.7-29.2.alpha.rpm

81e6df8260f301f5934910451fa14786  5.2/alpha/glibc-devel-2.0.7-29.2.alpha.rpm

658f0a9982cad961ab590e6cca5f1b6a  5.2/alpha/glibc-profile-2.0.7-29.2.alpha.rpm

b9963bc927e540815df84d64ba3b94c0  5.2/i386/glibc-2.0.7-29.2.i386.rpm

fc0c7b551073a9bffb65c49dba4800f3  5.2/i386/glibc-debug-2.0.7-29.2.i386.rpm

e0795db373902c9e2ffadc0c32dbbfff  5.2/i386/glibc-devel-2.0.7-29.2.i386.rpm

1b4d3d34588b19374fe6b29c6147bbcc  5.2/i386/glibc-profile-2.0.7-29.2.i386.rpm

dc215c32131cb25628a6be096dd3e539  5.2/sparc/glibc-2.0.7-29.2.sparc.rpm

19b3c1dd1f4f63885343202ae4ddb73c  5.2/sparc/glibc-debug-2.0.7-29.2.sparc.rpm

fb1c1437e8652cf799666198785c6890  5.2/sparc/glibc-devel-2.0.7-29.2.sparc.rpm

bcd19af1741f2704f38e74e89506bb86  5.2/sparc/glibc-profile-2.0.7-29.2.sparc.rpm

ab3e9097d3b105d0011befa30b75592e  6.2/SRPMS/glibc-2.1.3-19.src.rpm

96348fca0030190f920eb3e4769494bc  6.2/alpha/glibc-2.1.3-19.alpha.rpm

aff1e8a826da615c8737d2723618939e  6.2/alpha/glibc-devel-2.1.3-19.alpha.rpm

5a10a0874d44e9cb2a22c65c11d35062  6.2/alpha/glibc-profile-2.1.3-19.alpha.rpm

9136b639e89a8b873055cf259d711576  6.2/alpha/nscd-2.1.3-19.alpha.rpm

cb42ed08fea80af2f292ae2a6e3cc0a1  6.2/i386/glibc-2.1.3-19.i386.rpm

86a4b0d01f6a2b254b109c7a8078c3df  6.2/i386/glibc-devel-2.1.3-19.i386.rpm

2e93114d8487ba44d9a8c2be74e1d160  6.2/i386/glibc-profile-2.1.3-19.i386.rpm

0b9120417f2647a22992c98987218874  6.2/i386/nscd-2.1.3-19.i386.rpm

aa96cbcabf21eefb06df8d1f7da79ed8  6.2/sparc/glibc-2.1.3-19.sparc.rpm

a7cd77d25a30d2bfe884bd2dfd66cf04  6.2/sparc/glibc-devel-2.1.3-19.sparc.rpm

6ba0b5a628b226e0cc9cc2ba8d419f84  6.2/sparc/glibc-profile-2.1.3-19.sparc.rpm

3b93647462f192058c646e841c7a804f  6.2/sparc/nscd-2.1.3-19.sparc.rpm

94e92becb2c06e0e67b2cd39c8b19b14  6.2/sparcv9/glibc-2.1.3-19.sparcv9.rpm



These packages are GPG signed by Red Hat, Inc. for security.  Our key

is available at:

    http://www.redhat.com/corp/contact.html



You can verify each package with the following command:

    rpm --checksig  



If you only wish to verify that each package has not been corrupted or

tampered with, examine only the md5sum with the following command:

    rpm --checksig --nogpg 



8. References:



http://www.securityfocus.com/templates/archive.pike?threads=0&start=2000-08-27&mid=79537&fromthread=1&list=1&end=2000-09-02&





Copyright(c) 2000 Red Hat, Inc.