Synopsis: Critical: glibc security and bug fix update
Advisory ID: SLSA-2016:0176-1
Issue Date: 2016-02-16
CVE Numbers: CVE-2015-7547
CVE-2015-5229
--
A stack-based buffer overflow was found in the way the libresolv library
performed dual A/AAAA DNS queries. A remote attacker could create a
specially crafted DNS response which could cause libresolv to crash or,
potentially, execute code with the permissions of the user running the
library. Note: this issue is only exposed when libresolv is called from
the nss_dns NSS service module. (CVE-2015-7547)
It was discovered that the calloc implementation in glibc could return
memory areas which contain non-zero bytes. This could result in unexpected
application behavior such as hangs or crashes. (CVE-2015-5229)
This update also fixes the following bugs:
* The existing implementation of the "free" function causes all memory
pools beyond the first to return freed memory directly to the operating
system as quickly as possible. This can result in performance degradation
when the rate of free calls is very high. The first memory pool (the main
pool) does provide a method to rate limit the returns via
M_TRIM_THRESHOLD, but this method is not available to subsequent memory
pools.
With this update, the M_TRIM_THRESHOLD method is extended to apply to all
memory pools, which improves performance for threads with very high
amounts of free calls and limits the number of "madvise" system calls. The
change also increases the total transient memory usage by processes
because the trim threshold must be reached before memory can be freed.
To return to the previous behavior, you can either set M_TRIM_THRESHOLD
using the "mallopt" function, or set the MALLOC_TRIM_THRESHOLD environment
variable to 0.
* On the little-endian variant of 64-bit IBM Power Systems (ppc64le), a
bug in the dynamic loader could cause applications compiled with profiling
enabled to fail to start with the error "monstartup: out of memory". The
bug has been corrected and applications compiled for profiling now start
correctly.
--
SL7
x86_64
glibc-2.17-106.el7_2.4.i686.rpm
glibc-2.17-106.el7_2.4.x86_64.rpm
glibc-common-2.17-106.el7_2.4.x86_64.rpm
glibc-debuginfo-2.17-106.el7_2.4.i686.rpm
glibc-debuginfo-2.17-106.el7_2.4.x86_64.rpm
glibc-debuginfo-common-2.17-106.el7_2.4.i686.rpm
glibc-debuginfo-common-2.17-106.el7_2.4.x86_64.rpm
glibc-devel-2.17-106.el7_2.4.i686.rpm
glibc-devel-2.17-106.el7_2.4.x86_64.rpm
glibc-headers-2.17-106.el7_2.4.x86_64.rpm
glibc-utils-2.17-106.el7_2.4.x86_64.rpm
nscd-2.17-106.el7_2.4.x86_64.rpm
glibc-static-2.17-106.el7_2.4.i686.rpm
glibc-static-2.17-106.el7_2.4.x86_64.rpm
- Scientific Linux Development Team
