Debian Security Advisory

DSA-3480-1 eglibc -- security update

Date Reported:
16 Feb 2016
Affected Packages:
Security database references:
In the Debian bugtracking system: Bug 779587, Bug 796105, Bug 798316, Bug 801691, Bug 803927, Bug 812441, Bug 812445, Bug 812455.
In Mitre's CVE dictionary: CVE-2014-8121, CVE-2015-1781, CVE-2015-7547, CVE-2015-8776, CVE-2015-8777, CVE-2015-8778, CVE-2015-8779.
More information:

Several vulnerabilities have been fixed in the GNU C Library, eglibc.

The CVE-2015-7547 vulnerability listed below is considered to have critical impact.

  • CVE-2014-8121

    Robin Hack discovered that the nss_files database did not correctly implement enumeration interleaved with name-based or ID-based lookups. This could cause the enumeration enter an endless loop, leading to a denial of service.

  • CVE-2015-1781

    Arjun Shankar discovered that the _r variants of host name resolution functions (like gethostbyname_r), when performing DNS name resolution, suffered from a buffer overflow if a misaligned buffer was supplied by the applications, leading to a crash or, potentially, arbitrary code execution. Most applications are not affected by this vulnerability because they use aligned buffers.

  • CVE-2015-7547

    The Google Security Team and Red Hat discovered that the eglibc host name resolver function, getaddrinfo, when processing AF_UNSPEC queries (for dual A/AAAA lookups), could mismanage its internal buffers, leading to a stack-based buffer overflow and arbitrary code execution. This vulnerability affects most applications which perform host name resolution using getaddrinfo, including system services.

  • CVE-2015-8776

    Adam Nielsen discovered that if an invalid separated time value is passed to strftime, the strftime function could crash or leak information. Applications normally pass only valid time information to strftime; no affected applications are known.

  • CVE-2015-8777

    Hector Marco-Gisbert reported that LD_POINTER_GUARD was not ignored for SUID programs, enabling an unintended bypass of a security feature. This update causes eglibc to always ignore the LD_POINTER_GUARD environment variable.

  • CVE-2015-8778

    Szabolcs Nagy reported that the rarely-used hcreate and hcreate_r functions did not check the size argument properly, leading to a crash (denial of service) for certain arguments. No impacted applications are known at this time.

  • CVE-2015-8779

    The catopen function contains several unbound stack allocations (stack overflows), causing it the crash the process (denial of service). No applications where this issue has a security impact are currently known.

The following fixed vulnerabilities currently lack CVE assignment:

  • Joseph Myers reported that an integer overflow in the strxfrm can lead to heap-based buffer overflow, possibly allowing arbitrary code execution. In addition, a fallback path in strxfrm uses an unbounded stack allocation (stack overflow), leading to a crash or erroneous application behavior.

  • Kostya Serebryany reported that the fnmatch function could skip over the terminating NUL character of a malformed pattern, causing an application calling fnmatch to crash (denial of service).

  • Joseph Myers reported that the IO_wstr_overflow function, internally used by wide-oriented character streams, suffered from an integer overflow, leading to a heap-based buffer overflow. On GNU/Linux systems, wide-oriented character streams are rarely used, and no affected applications are known.

  • Andreas Schwab reported a memory leak (memory allocation without a matching deallocation) while processing certain DNS answers in getaddrinfo, related to the _nss_dns_gethostbyname4_r function. This vulnerability could lead to a denial of service.

While it is only necessary to ensure that all processes are not using the old eglibc anymore, it is recommended to reboot the machines after applying the security upgrade.

For the oldstable distribution (wheezy), these problems have been fixed in version 2.13-38+deb7u10.

We recommend that you upgrade your eglibc packages.