From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-180.mta1.migadu.com (out-180.mta1.migadu.com [95.215.58.180]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2383F283CB1 for ; Thu, 13 Nov 2025 21:56:23 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.180 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763070985; cv=none; b=aDNBxtEchTVU6O1VCmxhHHMHx23dh4B9VIuFZo8d+08VzuVZZnMZzRaM37ik7jKxiyYLP3tJCJYxh+loQ0kw/DqP9KeSS5CJxAKI8PfhgbavZalvmBIRNniGFseIPoVokgNG0XuzfrsdoQB6B85n7v+luDKxiDiv5hoFJk9poAo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763070985; c=relaxed/simple; bh=Hj/vGHJkGTDEUCDpd6JRPpsho1dl2+jAEyv7pA6d87E=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=XEG2o8FAyxbbn41MbHU21TmMjO3dSdFxFQLDNmKF5Y7Xqeq+OzCGYV4x+cSpOeAjV4Ksmg5x8j9p3DDclgwLUGhwPo1Ke+zcf3zMQ0wWNoqI553ABLuB4aE5mz72fMk/5MtR4lVUtiN7OFAEJErGXI4jT1hojMOv5Zo6jN8p3wE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=hxtL6MJm; arc=none smtp.client-ip=95.215.58.180 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="hxtL6MJm" X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1763070972; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=HqcCOeVHkjMug9T3azqzq6UC1S5Mba8UPr7MVprreyE=; b=hxtL6MJmKMt9lIBsmDsAkAdKqG70sSThtNAGYQqC+f+fQHG0MtYgI5r1se925VckiEK+BS wZhX2F5Yy97M1YPcTizFSw7THeNhUoyfDXOBN6cGJ0a+mMapVP9KHiQRGLcpfkB95vEUjU CkIUYspqSEvGKNe6zY1T+r5qSRjOQ4A= From: Thorsten Blum To: Eric Biggers , Mimi Zohar , David Howells , Jarkko Sakkinen , Paul Moore , James Morris , "Serge E. Hallyn" Cc: linux-hardening@vger.kernel.org, Thorsten Blum , linux-integrity@vger.kernel.org, keyrings@vger.kernel.org, linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v2] KEYS: encrypted: Replace deprecated strcpy and improve get_derived_key Date: Thu, 13 Nov 2025 22:55:45 +0100 Message-ID: <20251113215546.136145-1-thorsten.blum@linux.dev> Precedence: bulk X-Mailing-List: linux-security-module@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT strcpy() is deprecated; use the safer strscpy() and use its return value, the number of bytes copied, instead of calling strlen() on the destination buffer again. String truncation can be ignored since 'derived_buf' is guaranteed to be large enough. Link: https://github.com/KSPP/linux/issues/88 Signed-off-by: Thorsten Blum --- Changes in v2: - Revert some changes to include the trailing '\0' even if key_type == 0 since this would change the bytes passed to sha256() (Eric Biggers) - Use strscpy() and its return value instead - Link to v1: https://lore.kernel.org/lkml/20251113135831.98587-1-thorsten.blum@linux.dev/ --- security/keys/encrypted-keys/encrypted.c | 21 ++++++++------------- 1 file changed, 8 insertions(+), 13 deletions(-) diff --git a/security/keys/encrypted-keys/encrypted.c b/security/keys/encrypted-keys/encrypted.c index 15841466b5d4..94408909f1dd 100644 --- a/security/keys/encrypted-keys/encrypted.c +++ b/security/keys/encrypted-keys/encrypted.c @@ -12,6 +12,7 @@ */ #include +#include #include #include #include @@ -330,23 +331,17 @@ static int get_derived_key(u8 *derived_key, enum derived_key_type key_type, const u8 *master_key, size_t master_keylen) { u8 *derived_buf; - unsigned int derived_buf_len; - - derived_buf_len = strlen("AUTH_KEY") + 1 + master_keylen; - if (derived_buf_len < HASH_SIZE) - derived_buf_len = HASH_SIZE; + size_t derived_buf_len; + const char *key_name; + ssize_t len; + derived_buf_len = max(strlen("AUTH_KEY") + 1 + master_keylen, HASH_SIZE); derived_buf = kzalloc(derived_buf_len, GFP_KERNEL); if (!derived_buf) return -ENOMEM; - - if (key_type) - strcpy(derived_buf, "AUTH_KEY"); - else - strcpy(derived_buf, "ENC_KEY"); - - memcpy(derived_buf + strlen(derived_buf) + 1, master_key, - master_keylen); + key_name = key_type ? "AUTH_KEY" : "ENC_KEY"; + len = strscpy(derived_buf, key_name, derived_buf_len); + memcpy(derived_buf + len + 1, master_key, master_keylen); sha256(derived_buf, derived_buf_len, derived_key); kfree_sensitive(derived_buf); return 0; -- 2.51.1