Linux Kernel 2.6.38 through 3.18 are affected by a flaw in the Crypto API that allows any local user to load any installed kernel module on systems where CONFIG_CRYPTO_USER_API=y by abusing the request_module() call.

In the introduction of Crypto User API in the linux kernel in version 2.6.38 introduced a defect which granted userspace applications to load kernel modules on the system, by abusing the request_module() kernel call.  This patch also fixes the

The kernel accomplished loading algorithms by searching for the matching kernel module name provided when a user attempts to use a socket via the AF_ALG socket type.  Initially there were no checks involved in validating the name of the module, users could provide string and the kernel would attempt to load a module by that name in the default search path for the specific version of the kernel.

This CVE fixes additional attack vector which by abusing the template module loading format.  It solves the attack vector in which target_module(cipher) would evade the existing protection mechanism introduced when fixing in CVE-2013-7421.


External reference:
https://lkml.org/lkml/2013/3/4/70
https://plus.google.com/+MathiasKrause/posts/PqFCo4bfrWu
http://seclists.org/oss-sec/2015/q1/229

Fixed with these 3 commits:
https://git.kernel.org/linus/5d26a105b5a7
https://git.kernel.org/linus/4943ba16bbc2
https://git.kernel.org/linus/3e14dcf7cb80