CVE-2015-8970

crypto/algif_skcipher.c in the Linux kernel before 4.4.2 does not verify that a setkey operation has been performed on an AF_ALG socket before an accept system call is processed, which allows local users to cause a denial of service (NULL pointer dereference and system crash) via a crafted application that does not supply a key, related to the lrw_crypt function in crypto/lrw.c.

Weakness

A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit.

Affected Software

Potential Mitigations

References

• http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=dd504589577d8e8e70f51f997ad487a4cb6c026f
• http://www.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.4.2
• http://www.openwall.com/lists/oss-security/2016/11/04/3
• http://www.securityfocus.com/bid/94217
• https://access.redhat.com/errata/RHSA-2017:1842
• https://access.redhat.com/errata/RHSA-2017:2077
• https://access.redhat.com/errata/RHSA-2017:2437
• https://access.redhat.com/errata/RHSA-2017:2444
• https://bugzilla.redhat.com/show_bug.cgi?id=1386286
• https://github.com/torvalds/linux/commit/dd504589577d8e8e70f51f997ad487a4cb6c026f
• https://groups.google.com/forum/#%21msg/syzkaller/frb2XrB5aWk/xCXzkIBcDAAJ