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| author | tim <tim.c.chen@linux.intel.com> | 2016-12-05 11:46:31 -0800 |
|---|---|---|
| committer | Herbert Xu <herbert@gondor.apana.org.au> | 2016-12-07 19:55:37 +0800 |
| commit | 48a992727d82cb7db076fa15d372178743b1f4cd (patch) | |
| tree | 2cc24a02c43a2d4d6382916f4614b118b82d27b4 /crypto/mcryptd.c | |
| parent | 0c1e16cd1ec41987cc6671a2bff46ac958c41eb5 (diff) | |
| download | lwn-48a992727d82cb7db076fa15d372178743b1f4cd.tar.gz lwn-48a992727d82cb7db076fa15d372178743b1f4cd.zip | |
crypto: mcryptd - Check mcryptd algorithm compatibility
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
Cc: stable@vger.kernel.org
Reported-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Tim Chen <tim.c.chen@linux.intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Diffstat (limited to 'crypto/mcryptd.c')
| -rw-r--r-- | crypto/mcryptd.c | 19 |
1 files changed, 12 insertions, 7 deletions
diff --git a/crypto/mcryptd.c b/crypto/mcryptd.c index 94ee44acd465..c207458d6299 100644 --- a/crypto/mcryptd.c +++ b/crypto/mcryptd.c @@ -254,18 +254,22 @@ 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) @@ -492,7 +496,8 @@ 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; halg = ahash_attr_alg(tb[1], type, mask); if (IS_ERR(halg)) |