Commit 281590b4 authored Jun 08, 2017 by Eric Biggers Committed by James Morris Jun 09, 2017

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 <ebiggers@google.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Stephan Mueller <smueller@chronox.de>
Signed-off-by: James Morris <james.l.morris@oracle.com>

parent bbe24045

security/keys/dh.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -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;

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