From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794064524; b=4bXpesiaacW3JTW48vt8fFog743Ld5bXxsI4rnUOZSJPioZNMDIVbDCvtPmyzRFdu6fO yWF5ubDGWiJzzCJUqxbPkifxt3idBhjnZcJTKZHvGqC+1YZ5WDkoKl5eFAN8T+PNyoBq3 mm2vH7Z8Y23x+fk3JngRPY8VWIp+BTH8sUsTSqui0wJk4uNEaNsb/B6oKWuhpTsX6sFNi LcfMegzGRB/DXMC6mToMqhpAGwCbzIGfvbuFAbM0OMK+qbw6iUMcIAEf/oIiI5xO+DJCe j3WDeen7hLUC2l2EUxNhcpMt1qAAAMeEPf7zixm+V0NQaCAzPGY70svwj2revJf0wYA== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794064524; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:User-Agent:X-stable:X-Patchwork-Hint: MIME-Version:Content-Transfer-Encoding; bh=/go96+gT5BG+cnPZxbnSUGfXM/tzstIb2G1CPJl2FmI=; b=js6p+QAixuwrrdTTVdLuhX08eAPa6pwOtxNB98Su9qrzAMsFRVW/RJ6W72rvOArB7kDU cKs9sVSss0nuV47sCDNk3/Mg92qq4aG9x5QyziwcuA1gB+BIvon3uPgIpxzHWs5oLsvV8 iE/FM17ikZLV+p6g3JB1Ui+wvR7iki2/5UET5+H9jawEVOMN6Tyux7AHaxyDa0Am50gxY iwGNWfzl5zFPW9U7nNuDlcw/WzNxzvPNIdCl5f/0I0IV/WrCPFJT5PSCfzK6M40YTl+/Y Zi2sERKZIAHrs/prLI2KcqmbO3oOF7pK0UiggA4poV1sS0xSJE2rQT1U+l4e0OthY5w== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=q7eLhNM6; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7CCC5606B8A2; Sat, 7 Nov 2026 15:15:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=q7eLhNM6 Received: by smtp.kernel.org (Postfix) with ESMTPSA id 28E111F0089F; Sat, 7 Nov 2026 15:15:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1794064524; bh=/go96+gT5BG+cnPZxbnSUGfXM/tzstIb2G1CPJl2FmI=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=q7eLhNM6jAsdVBjrrtXZGxJ0YGVXySxDObm8K8eD96AnpgW/E6BjUKdSH7uU6XIfV zsMMTs17rxw3QLTY23tD3rXytiLuX9dTMaHtFMkLsnGsSSvo2q820fL3f8mrEoZtkF 9bMLuhcOY2Q8I/1qEk3yNT75xPFqv2qYTMimKIkA= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Daehyeon Ko <4ncienth@gmail.com>, Herbert Xu , Sasha Levin Subject: [PATCH 7.3 0555/1257] crypto: algif_skcipher - rewind rounded output bytes Date: Sat, 7 Nov 2026 08:47:31 -0500 Message-ID: <20261107134954.711707504@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261107134939.434104957@linuxfoundation.org> References: <20261107134939.434104957@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: stable@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 7.3-stable review patch. If anyone has any objections, please let me know. ------------------ From: Daehyeon Ko <4ncienth@gmail.com> [ Upstream commit 2f90facc7b94934653eb7ebfadcc25d503b89196 ] af_alg_get_rsgl() advances the receive iterator by the unrounded RX scatterlist length. For a continuing skcipher request, _skcipher_recvmsg() then rounds its local length down to a whole chunksize without restoring the iterator. A later chunk starts after bytes which the provider never wrote, while the syscall returns only the processed length. When copy_splice_read() supplies non-zeroed pages and publishes that return as a dense prefix, the gap exposes stale bytes from a previous page lifetime. With unprivileged xts(aes), a 31-byte MSG_MORE request followed by one final byte advances a 47-byte destination while returning 32 bytes. A hardened v7.2-rc5 image retained all 15 seeded stale bytes in 4,829 of 4,829 records. With init_on_alloc enabled, all 72,345 gap bytes observed were zero. Rewind the iterator by the tail excluded during rounding, before rejecting a zero processed length. The crypto request uses only the rounded length; af_alg_free_resources() releases the entire RX list before another receive iteration. The fixed target-like kernel returned byte-identical dense 48-byte output in 4,771 of 4,771 rounds. The unmodified kernel returned the vulnerable 32-byte short record in 2,409 of 2,409 rounds. Fixes: e870456d8e7c ("crypto: algif_skcipher - overhaul memory management") Cc: stable@vger.kernel.org Assisted-by: LLM Signed-off-by: Daehyeon Ko <4ncienth@gmail.com> Signed-off-by: Herbert Xu Signed-off-by: Sasha Levin --- crypto/algif_skcipher.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/crypto/algif_skcipher.c b/crypto/algif_skcipher.c index 1e61fe6e24b99..291dbd6989325 100644 --- a/crypto/algif_skcipher.c +++ b/crypto/algif_skcipher.c @@ -135,12 +135,16 @@ static int _skcipher_recvmsg(struct socket *sock, struct msghdr *msg, * full block size buffers. */ if (ctx->more || len < ctx->used) { - if (len < bs) { + size_t excess = len % bs; + + len -= excess; + iov_iter_revert(&msg->msg_iter, excess); + + if (!len) { err = -EINVAL; goto free; } - len -= len % bs; cflags |= CRYPTO_SKCIPHER_REQ_NOTFINAL; } -- 2.53.0