The glibc packages provide the standard C libraries (libc), POSIX
thread libraries (libpthread), standard math libraries (libm), and the
name service cache daemon (nscd) used by multiple programs on the
system. Without these libraries, the Linux system cannot function
correctly.
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)
The CVE-2015-7547 issue was discovered by the Google Security Team and Red
Hat. Red Hat would like to thank Jeff Layton for reporting the
CVE-2015-5229 issue.
This update also fixes the following bugs:
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. (BZ#1298930)
All glibc users are advised to upgrade to these updated packages, which
contain backported patches to correct these issues.
OS | Version | Architecture | Package | Version | Filename |
---|---|---|---|---|---|
RedHat | 7 | ppc | glibc | < 2.17-106.el7_2.4 | glibc-2.17-106.el7_2.4.ppc.rpm |
RedHat | 7 | ppc64 | glibc-debuginfo-common | < 2.17-106.el7_2.4 | glibc-debuginfo-common-2.17-106.el7_2.4.ppc64.rpm |
RedHat | 7 | s390 | glibc-debuginfo | < 2.17-106.el7_2.4 | glibc-debuginfo-2.17-106.el7_2.4.s390.rpm |
RedHat | 7 | s390 | glibc-static | < 2.17-106.el7_2.4 | glibc-static-2.17-106.el7_2.4.s390.rpm |
RedHat | 7 | s390x | glibc-headers | < 2.17-106.el7_2.4 | glibc-headers-2.17-106.el7_2.4.s390x.rpm |
RedHat | 7 | i686 | glibc-devel | < 2.17-106.el7_2.4 | glibc-devel-2.17-106.el7_2.4.i686.rpm |
RedHat | 7 | s390x | glibc-debuginfo | < 2.17-106.el7_2.4 | glibc-debuginfo-2.17-106.el7_2.4.s390x.rpm |
RedHat | 7 | ppc64le | glibc-headers | < 2.17-106.el7_2.4 | glibc-headers-2.17-106.el7_2.4.ppc64le.rpm |
RedHat | 7 | i686 | glibc-debuginfo-common | < 2.17-106.el7_2.4 | glibc-debuginfo-common-2.17-106.el7_2.4.i686.rpm |
RedHat | 7 | ppc64le | glibc-debuginfo | < 2.17-106.el7_2.4 | glibc-debuginfo-2.17-106.el7_2.4.ppc64le.rpm |