From e6d54da788004c43a76bcc007ef28b1bc7b2b7ca Mon Sep 17 00:00:00 2001 From: Ard Biesheuvel Date: Tue, 19 Jan 2021 11:25:56 +0000 Subject: [PATCH] crypto: ecdh - avoid buffer overflow in ecdh_set_secret() stable inclusion from stable-5.10.7 commit 3f20005ab271c93b5c26736aa3fcf43aacddab39 bugzilla: 47429 -------------------------------- commit 0aa171e9b267ce7c52d3a3df7bc9c1fc0203dec5 upstream. Pavel reports that commit 17858b140bf4 ("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: 17858b140bf4 ("crypto: ecdh - avoid unaligned accesses in ecdh_set_secret()") Reported-by: Pavel Machek Cc: Signed-off-by: Ard Biesheuvel Signed-off-by: Herbert Xu Signed-off-by: Greg Kroah-Hartman Signed-off-by: Chen Jun Acked-by: Xie XiuQi --- crypto/ecdh.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/crypto/ecdh.c b/crypto/ecdh.c index d56b8603dec9..96f80c8f8e30 100644 --- a/crypto/ecdh.c +++ b/crypto/ecdh.c @@ -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, ¶ms) < 0) + if (crypto_ecdh_decode_key(buf, len, ¶ms) < 0 || + params.key_size > sizeof(ctx->private_key)) return -EINVAL; ndigits = ecdh_supported_curve(params.curve_id); -- GitLab