From 281590b4221779dbc4a5e2c33c0c5b0239cfe794 Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Thu, 8 Jun 2017 14:49:42 +0100 Subject: KEYS: DH: don't feed uninitialized "otherinfo" into KDF If userspace called KEYCTL_DH_COMPUTE with kdf_params containing NULL otherinfo but nonzero otherinfolen, the kernel would allocate a buffer for the otherinfo, then feed it into the KDF without initializing it. Fix this by always doing the copy from userspace (which will fail with EFAULT in this scenario). Signed-off-by: Eric Biggers Signed-off-by: David Howells Acked-by: Stephan Mueller Signed-off-by: James Morris --- security/keys/dh.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/security/keys/dh.c b/security/keys/dh.c index 8abc70ebe22d..1c1cac677041 100644 --- a/security/keys/dh.c +++ b/security/keys/dh.c @@ -317,7 +317,7 @@ long __keyctl_dh_compute(struct keyctl_dh_params __user *params, * Concatenate SP800-56A otherinfo past DH shared secret -- the * input to the KDF is (DH shared secret || otherinfo) */ - if (kdfcopy && kdfcopy->otherinfo && + if (kdfcopy && copy_from_user(kbuf + resultlen, kdfcopy->otherinfo, kdfcopy->otherinfolen) != 0) { ret = -EFAULT; -- cgit v1.2.3-58-ga151