7.8 - MDVSA-2015:168

Updated glibc packages fix security vulnerabilities:

Stephane Chazelas discovered that directory traversal issue in locale handling in glibc. glibc accepts relative paths with .. components in the LC_* and LANG variables. Together with typical OpenSSH configurations (with suitable AcceptEnv settings in sshd_config), this could conceivably be used to bypass ForceCommand restrictions (or restricted shells), assuming the attacker has sufficient level of access to a file system location on the host to create crafted locale definitions there (CVE-2014-0475).

David Reid, Glyph Lefkowitz, and Alex Gaynor discovered a bug where posix_spawn_file_actions_addopen fails to copy the path argument (glibc bz #17048) which can, in conjunction with many common memory management techniques from an application, lead to a use after free, or other vulnerabilities (CVE-2014-4043).

This update also fixes the following issues: x86: Disable x87 inline functions for SSE2 math (glibc bz #16510) malloc: Fix race in free() of fastbin chunk (glibc bz #15073)

Tavis Ormandy discovered a heap-based buffer overflow in the transliteration module loading code. As a result, an attacker who can supply a crafted destination character set argument to iconv-related character conversation functions could achieve arbitrary code execution.

This update removes support of loadable gconv transliteration modules. Besides the security vulnerability, the module loading code had functionality defects which prevented it from working for the intended purpose (CVE-2014-5119).

Adhemerval Zanella Netto discovered out-of-bounds reads in additional code page decoding functions (IBM933, IBM935, IBM937, IBM939, IBM1364) that can be used to crash the systems, causing a denial of service conditions (CVE-2014-6040).

The function wordexp() fails to properly handle the WRDE_NOCMD flag when processing arithmetic inputs in the form of "$((... ))" where "..." can be anything valid. The backticks in the arithmetic epxression are evaluated by in a shell even if WRDE_NOCMD forbade command substitution. This allows an attacker to attempt to pass dangerous commands via constructs of the above form, and bypass the WRDE_NOCMD flag. This update fixes the issue (CVE-2014-7817).

The vfprintf function in stdio-common/vfprintf.c in GNU C Library (aka glibc) 2.5, 2.12, and probably other versions does not properly restrict the use of the alloca function when allocating the SPECS array, which allows context-dependent attackers to bypass the FORTIFY_SOURCE format-string protection mechanism and cause a denial of service (crash) or possibly execute arbitrary code via a crafted format string using positional parameters and a large number of format specifiers (CVE-2012-3406).

The nss_dns implementation of getnetbyname could run into an infinite loop if the DNS response contained a PTR record of an unexpected format (CVE-2014-9402).

Also glibc lock elision (new feature in glibc 2.18) has been disabled as it can break glibc at runtime on newer Intel hardware (due to hardware bug)

Under certain conditions wscanf can allocate too little memory for the to-be-scanned arguments and overflow the allocated buffer (CVE-2015-1472).

The incorrect use of "__libc_use_alloca (newsize)" caused a different (and weaker) policy to be enforced which could allow a denial of service attack (CVE-2015-1473).