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Sigurnosni nedostatak programskog paketa ptrace

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FreeBSD-SA-17:08.ptrace Security Advisory
The FreeBSD Project

Topic: Kernel data leak via ptrace(PT_LWPINFO)

Category: core
Module: ptrace
Announced: 2017-11-15
Credits: John Baldwin
Affects: All supported versions of FreeBSD.
Corrected: 2017-11-10 12:28:43 UTC (stable/11, 11.1-STABLE)
2017-11-15 22:39:41 UTC (releng/11.1, 11.1-RELEASE-p4)
2017-11-15 22:40:15 UTC (releng/11.0, 11.0-RELEASE-p15)
2017-11-10 12:31:58 UTC (stable/10, 10.4-STABLE)
2017-11-15 22:40:32 UTC (releng/10.4, 10.4-RELEASE-p3)
2017-11-15 22:40:46 UTC (releng/10.3, 10.3-RELEASE-p24)
CVE Name: CVE-2017-1086

For general information regarding FreeBSD Security Advisories,
including descriptions of the fields above, security branches, and the
following sections, please visit <URL:https://security.FreeBSD.org/>.

I. Background

The ptrace(2) syscall provides the facility for a debugger to control the
execution of the target process and to obtain necessary status information
about it. The struct ptrace_lwpinfo structure is reported by one of the
ptrace(2) subcommand and contains a lot of the information about the stopped
thread (light-weight process or LWP, thus the name).

II. Problem Description

Not all information in the struct ptrace_lwpinfo is relevant for the state
of any thread, and the kernel does not fill the irrelevant bytes or short
strings. Since the structure filled by the kernel is allocated on the
kernel stack and copied to userspace, a leak of information of the kernel
stack of the thread is possible from the debugger.

III. Impact

Some bytes from the kernel stack of the thread using ptrace(PT_LWPINFO)
call can be observed in userspace.

IV. Workaround

No workaround is available.

V. Solution

Perform one of the following:

1) Upgrade your vulnerable system to a supported FreeBSD stable or
release / security branch (releng) dated after the correction date.

Afterward, reboot the system.

2) To update your vulnerable system via a binary patch:

Systems running a RELEASE version of FreeBSD on the i386 or amd64
platforms can be updated via the freebsd-update(8) utility:

# freebsd-update fetch
# freebsd-update install

Afterward, reboot the system.

3) To update your vulnerable system via a source code patch:

The following patches have been verified to apply to the applicable
FreeBSD release branches.

a) Download the relevant patch from the location below, and verify the
detached PGP signature using your PGP utility.

# fetch https://security.FreeBSD.org/patches/SA-17:08/ptrace.patch
# fetch https://security.FreeBSD.org/patches/SA-17:08/ptrace.patch.asc
# gpg –verify ptrace.patch.asc

b) Apply the patch. Execute the following commands as root:

# cd /usr/src
# patch < /path/to/patch

c) Recompile your kernel as described in
<URL:https://www.FreeBSD.org/handbook/kernelconfig.html> and reboot the
system.

VI. Correction details

The following list contains the correction revision numbers for each
affected branch.

Branch/path Revision
– ————————————————————————-
stable/10/ r325643
releng/10.3/ r325871
releng/10.4/ r325870
stable/11/ r325642
releng/11.0/ r325869
releng/11.1/ r325868
– ————————————————————————-

To see which files were modified by a particular revision, run the
following command, replacing NNNNNN with the revision number, on a
machine with Subversion installed:

# svn diff -cNNNNNN –summarize svn://svn.freebsd.org/base

Or visit the following URL, replacing NNNNNN with the revision number:

<URL:https://svnweb.freebsd.org/base?view=revision&revision=NNNNNN>

VII. References

<URL:https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2017-1086>

The latest revision of this advisory is available at
<URL:https://security.FreeBSD.org/advisories/FreeBSD-SA-17:08.ptrace.asc>
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To unsubscribe, send any mail to “freebsd-security-notifications-unsubscribe@freebsd.org”

 

 

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=============================================================================

FreeBSD-SA-17:08.ptrace                                     Security Advisory

                                                          The FreeBSD Project

 

Topic:          Kernel data leak via ptrace(PT_LWPINFO)

 

Category:       core

Module:         ptrace

Announced:      2017-11-15

Credits:        Ilja van Sprundel

                John Baldwin

Affects:        All supported versions of FreeBSD.

Corrected:      2017-11-10 12:28:43 UTC (stable/11, 11.1-STABLE)

                2017-11-15 22:39:41 UTC (releng/11.1, 11.1-RELEASE-p4)

                2017-11-15 22:40:15 UTC (releng/11.0, 11.0-RELEASE-p15)

                2017-11-10 12:31:58 UTC (stable/10, 10.4-STABLE)

                2017-11-15 22:40:32 UTC (releng/10.4, 10.4-RELEASE-p3)

                2017-11-15 22:40:46 UTC (releng/10.3, 10.3-RELEASE-p24)

CVE Name:       CVE-2017-1086

 

For general information regarding FreeBSD Security Advisories,

including descriptions of the fields above, security branches, and the

following sections, please visit <URL:https://security.FreeBSD.org/>.

 

0.   Revision history

 

v1.0   2017-11-15  Initial release.

v1.1   2017-11-20  Corrected credit. Ilja van Sprundel first reported this

                   issue to the project, but wasn’t cited. The FreeBSD

                   Security Team apologizes to Ilja for this oversight.

 

I.   Background

 

The ptrace(2) syscall provides the facility for a debugger to control the

execution of the target process and to obtain necessary status information

about it.  The struct ptrace_lwpinfo structure is reported by one of the

ptrace(2) subcommand and contains a lot of the information about the stopped

thread (light-weight process or LWP, thus the name).

 

II.  Problem Description

 

Not all information in the struct ptrace_lwpinfo is relevant for the state

of any thread, and the kernel does not fill the irrelevant bytes or short

strings.  Since the structure filled by the kernel is allocated on the

kernel stack and copied to userspace, a leak of information of the kernel

stack of the thread is possible from the debugger.

 

III. Impact

 

Some bytes from the kernel stack of the thread using ptrace(PT_LWPINFO)

call can be observed in userspace.

 

IV.  Workaround

 

No workaround is available.

 

V.   Solution

 

Perform one of the following:

 

1) Upgrade your vulnerable system to a supported FreeBSD stable or

release / security branch (releng) dated after the correction date.

 

Afterward, reboot the system.

 

2) To update your vulnerable system via a binary patch:

 

Systems running a RELEASE version of FreeBSD on the i386 or amd64

platforms can be updated via the freebsd-update(8) utility:

 

# freebsd-update fetch

# freebsd-update install

 

Afterward, reboot the system.

 

3) To update your vulnerable system via a source code patch:

 

The following patches have been verified to apply to the applicable

FreeBSD release branches.

 

a) Download the relevant patch from the location below, and verify the

detached PGP signature using your PGP utility.

 

# fetch https://security.FreeBSD.org/patches/SA-17:08/ptrace.patch

# fetch https://security.FreeBSD.org/patches/SA-17:08/ptrace.patch.asc

# gpg –verify ptrace.patch.asc

 

b) Apply the patch.  Execute the following commands as root:

 

# cd /usr/src

# patch < /path/to/patch

 

c) Recompile your kernel as described in

<URL:https://www.FreeBSD.org/handbook/kernelconfig.html> and reboot the

system.

 

VI.  Correction details

 

The following list contains the correction revision numbers for each

affected branch.

 

Branch/path                                                      Revision

– ————————————————————————-

stable/10/                                                        r325643

releng/10.3/                                                      r325871

releng/10.4/                                                      r325870

stable/11/                                                        r325642

releng/11.0/                                                      r325869

releng/11.1/                                                      r325868

– ————————————————————————-

 

To see which files were modified by a particular revision, run the

following command, replacing NNNNNN with the revision number, on a

machine with Subversion installed:

 

# svn diff -cNNNNNN –summarize svn://svn.freebsd.org/base

 

Or visit the following URL, replacing NNNNNN with the revision number:

 

<URL:https://svnweb.freebsd.org/base?view=revision&revision=NNNNNN>

 

VII. References

 

<URL:https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2017-1086>

 

The latest revision of this advisory is available at

<URL:https://security.FreeBSD.org/advisories/FreeBSD-SA-17:08.ptrace.asc>

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AutorDanijel Kozinovic
Cert idNCERT-REF-2017-11-0085-ADV
CveCERT-CVE-DUMMY
ID izvornikaCERT-ORIGID-DUMMY
ProizvodCERT-DUMMY-PRODUCT
Izvorhttp://www.adobe.com/
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