Commit 0aa171e9 authored by Ard Biesheuvel's avatar Ard Biesheuvel Committed by Herbert Xu
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crypto: ecdh - avoid buffer overflow in ecdh_set_secret() 



Pavel reports that commit 17858b14 ("crypto: ecdh - avoid unaligned
accesses in ecdh_set_secret()") fixes one problem but introduces another:
the unconditional memcpy() introduced by that commit may overflow the
target buffer if the source data is invalid, which could be the result of
intentional tampering.

So check params.key_size explicitly against the size of the target buffer
before validating the key further.

Fixes: 17858b14 ("crypto: ecdh - avoid unaligned accesses in ecdh_set_secret()")
Reported-by: default avatarPavel Machek <pavel@denx.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: default avatarArd Biesheuvel <ardb@kernel.org>
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
parent fd16931a

crypto/ecdh.c

+2 −1
Original line number Diff line number Diff line
@@ -39,7 +39,8 @@ static int ecdh_set_secret(struct crypto_kpp *tfm, const void *buf, 
	struct ecdh params;

	unsigned int ndigits;



	if (crypto_ecdh_decode_key(buf, len, &params) < 0)

	if (crypto_ecdh_decode_key(buf, len, &params) < 0 ||

	    params.key_size > sizeof(ctx->private_key))

		return -EINVAL;



	ndigits = ecdh_supported_curve(params.curve_id);