Bug 470758 – kernel: file caps: always start with clear bprm->caps_*

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Bug 470758 - kernel: file caps: always start with clear bprm->caps_*

Summary:	kernel: file caps: always start with clear bprm->caps_*

Status:	CLOSED ERRATA

Aliases:	None

Product:	Security Response
Classification:	Other
Component:	vulnerability (Show other bugs)
Sub Component:
Version:	unspecified
Hardware:	All Linux

Priority	high Severity high
Target Milestone:	---
Target Release:	---
Assigned To:	Red Hat Product Security
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Depends On:	470759
Blocks:
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Reported:	2008-11-09 22:38 EST by Eugene Teo (Security Response)
Modified:	2011-09-30 16:59 EDT (History)
CC List:	4 users (show)

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Fixed In Version:
Doc Type:	Bug Fix
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Last Closed:	2011-09-30 16:59:16 EDT
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External Trackers
Tracker	ID	Priority	Status	Summary	Last Updated
Red Hat Product Errata	RHSA-2009:0053	normal	SHIPPED_LIVE	Important: kernel-rt security and bug fix update	2009-02-04 10:05:12 EST

Groups: None (edit)

Description Eugene Teo (Security Response) 2008-11-09 22:38:37 EST

Description of problem:
From: Serge Hallyn <serue@us.ibm.com>

While Linux doesn't honor setuid on scripts.  However, it mistakenly
behaves differently for file capabilities.

This patch fixes that behavior by making sure that get_file_caps()
begins with empty bprm->caps_*.  That way when a script is loaded,
its bprm->caps_* may be filled when binfmt_misc calls prepare_binprm(),
but they will be cleared again when binfmt_elf calls prepare_binprm()
next to read the interpreter's file capabilities.

Comment 1 Eugene Teo (Security Response) 2008-11-09 22:39:21 EST

Proposed upstream patch:
http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=3318a386e4ca68c76e0294363d29bdc46fcad670

Comment 4 Kurt Seifried 2011-09-30 16:59:16 EDT

This issue has been addressed in following products:

  Red Hat Enterprise MRG v1 for Red Hat Enterprise Linux (version 5)
  
Via RHSA-2009:0053 available at https://rhn.redhat.com/errata/RHSA-2009-0053.html

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