From: Eric Biggers <ebiggers@xxxxxxxxxx> Requesting "digest_null" in the keyctl_kdf_params caused an infinite loop in kdf_ctr() because the "null" hash has a digest size of 0. Fix it by rejecting hash algorithms with a digest size of 0. Signed-off-by: Eric Biggers <ebiggers@xxxxxxxxxx> --- security/keys/dh.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) diff --git a/security/keys/dh.c b/security/keys/dh.c index e603bd912e4c..8abc70ebe22d 100644 --- a/security/keys/dh.c +++ b/security/keys/dh.c @@ -89,6 +89,7 @@ static int kdf_alloc(struct kdf_sdesc **sdesc_ret, char *hashname) struct crypto_shash *tfm; struct kdf_sdesc *sdesc; int size; + int err; /* allocate synchronous hash */ tfm = crypto_alloc_shash(hashname, 0, 0); @@ -97,16 +98,25 @@ static int kdf_alloc(struct kdf_sdesc **sdesc_ret, char *hashname) return PTR_ERR(tfm); } + err = -EINVAL; + if (crypto_shash_digestsize(tfm) == 0) + goto out_free_tfm; + + err = -ENOMEM; size = sizeof(struct shash_desc) + crypto_shash_descsize(tfm); sdesc = kmalloc(size, GFP_KERNEL); if (!sdesc) - return -ENOMEM; + goto out_free_tfm; sdesc->shash.tfm = tfm; sdesc->shash.flags = 0x0; *sdesc_ret = sdesc; return 0; + +out_free_tfm: + crypto_free_shash(tfm); + return err; } static void kdf_dealloc(struct kdf_sdesc *sdesc) -- 2.12.2
