From 9a3baed9103bc413a5e98e13e31cd8ae7c0b5563 Mon Sep 17 00:00:00 2001 From: tim Date: Mon, 5 Dec 2016 11:46:31 -0800 Subject: crypto: mcryptd - Check mcryptd algorithm compatibility commit 48a992727d82cb7db076fa15d372178743b1f4cd upstream. Algorithms not compatible with mcryptd could be spawned by mcryptd with a direct crypto_alloc_tfm invocation using a "mcryptd(alg)" name construct. This causes mcryptd to crash the kernel if an arbitrary "alg" is incompatible and not intended to be used with mcryptd. It is an issue if AF_ALG tries to spawn mcryptd(alg) to expose it externally. But such algorithms must be used internally and not be exposed. We added a check to enforce that only internal algorithms are allowed with mcryptd at the time mcryptd is spawning an algorithm. Link: http://marc.info/?l=linux-crypto-vger&m=148063683310477&w=2 Reported-by: Mikulas Patocka Signed-off-by: Tim Chen Signed-off-by: Herbert Xu Signed-off-by: Greg Kroah-Hartman --- crypto/mcryptd.c | 19 ++++++++++++------- 1 file changed, 12 insertions(+), 7 deletions(-) (limited to 'crypto') diff --git a/crypto/mcryptd.c b/crypto/mcryptd.c index fe5b495a434d..a0ceb41d5ccc 100644 --- a/crypto/mcryptd.c +++ b/crypto/mcryptd.c @@ -258,18 +258,22 @@ out_free_inst: goto out; } -static inline void mcryptd_check_internal(struct rtattr **tb, u32 *type, +static inline bool mcryptd_check_internal(struct rtattr **tb, u32 *type, u32 *mask) { struct crypto_attr_type *algt; algt = crypto_get_attr_type(tb); if (IS_ERR(algt)) - return; - if ((algt->type & CRYPTO_ALG_INTERNAL)) - *type |= CRYPTO_ALG_INTERNAL; - if ((algt->mask & CRYPTO_ALG_INTERNAL)) - *mask |= CRYPTO_ALG_INTERNAL; + return false; + + *type |= algt->type & CRYPTO_ALG_INTERNAL; + *mask |= algt->mask & CRYPTO_ALG_INTERNAL; + + if (*type & *mask & CRYPTO_ALG_INTERNAL) + return true; + else + return false; } static int mcryptd_hash_init_tfm(struct crypto_tfm *tfm) @@ -498,7 +502,8 @@ static int mcryptd_create_hash(struct crypto_template *tmpl, struct rtattr **tb, u32 mask = 0; int err; - mcryptd_check_internal(tb, &type, &mask); + if (!mcryptd_check_internal(tb, &type, &mask)) + return -EINVAL; salg = shash_attr_alg(tb[1], type, mask); if (IS_ERR(salg)) -- cgit v1.2.3