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Gentoo Linux Security Advisory GLSA 201603-04 |
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https://security.gentoo.org/ |
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Severity: Normal |
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Title: FUSE: incorrect filtering of environment variables leading to |
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privilege escalation |
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Date: March 09, 2016 |
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Bugs: #550152 |
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ID: 201603-04 |
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Synopsis |
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======== |
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|
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The fusermount binary in FUSE does not properly clear the environment |
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before invoking mount or umount as root that allows a local user to |
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overwrite arbitrary files. |
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|
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Background |
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========== |
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|
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FUSE provides an interface for filesystems implemented in userspace. |
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|
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Affected packages |
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================= |
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|
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------------------------------------------------------------------- |
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Package / Vulnerable / Unaffected |
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------------------------------------------------------------------- |
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1 sys-fs/fuse < 2.9.4 >= 2.9.4 |
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Description |
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=========== |
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|
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The fusermount binary calls setuid(geteuid()) to reset the RUID when it |
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invokes /bin/mount so that it can use privileged mount options that are |
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normally restricted if RUID != EUID. FUSE does not properly clear |
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environment variables before invoking mount or umount as root allowing |
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this to be passed to operations using elevated privileges such as |
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LIBMOUNT_MTAB that is used by the mount commands debugging feature. |
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|
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Impact |
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====== |
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|
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The FUSE vulnerability allows a local, unprivileged user to overwrite |
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arbitrary files on the system. |
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Workaround |
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========== |
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There is no known work around at this time. |
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Resolution |
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========== |
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All FUSE users should upgrade to the latest version: |
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# emerge --sync |
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# emerge --ask --oneshot --verbose ">=sys-fs/fuse-2.9.4" |
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|
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References |
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========== |
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[ 1 ] CVE-2015-3202 |
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http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-3202 |
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|
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Availability |
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============ |
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This GLSA and any updates to it are available for viewing at |
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the Gentoo Security Website: |
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https://security.gentoo.org/glsa/201603-04 |
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Concerns? |
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========= |
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Security is a primary focus of Gentoo Linux and ensuring the |
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confidentiality and security of our users' machines is of utmost |
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importance to us. Any security concerns should be addressed to |
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security@g.o or alternatively, you may file a bug at |
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https://bugs.gentoo.org. |
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License |
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======= |
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Copyright 2016 Gentoo Foundation, Inc; referenced text |
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belongs to its owner(s). |
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The contents of this document are licensed under the |
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Creative Commons - Attribution / Share Alike license. |
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http://creativecommons.org/licenses/by-sa/2.5 |
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