Arch Linux: Denial of service (CVE-2017-17805)

The Salsa20 encryption algorithm in the Linux kernel before 4.14.8, 4.9.71, 4.4.107, 3.18.89, 3.16.52 and 3.2.97 does not correctly handle zero-length inputs, allowing a local attacker able to use the AF_ALG-based skcipher interface (CONFIG_CRYPTO_USER_API_SKCIPHER) to cause a denial of service (uninitialized-memory free and kernel crash) or have unspecified other impact by executing a crafted sequence of system calls that use the blkcipher_walk API. Both the generic implementation (crypto/salsa20_generic.c) and x86 implementation (arch/x86/crypto/salsa20_glue.c) of Salsa20 were vulnerable.