From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-174.mta1.migadu.com (out-174.mta1.migadu.com [95.215.58.174]) (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 0A2B51F3D56 for ; Thu, 13 Nov 2025 13:59:03 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.174 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763042346; cv=none; b=EchkS2OHMbetXBzUczAOObHslzMvPtuE2+PW1a1DfunxZiKbe3fZ0APue9ILrvFiar2YRKXDYqG/RlHVGYNTY7CeIN+mEqUV/Inqf1EqifH824BgYLdCUPsjI240BdXaptDu2IFnNDjvUe/NYB9AqjpctyvvvbHq5jSGnZof0lQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763042346; c=relaxed/simple; bh=kfd3RyhY4DVWYu8nmIBTbsxRwtREU+3sF2ZT8G9U/3M=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=PIAPS/qAhROLQ0NE54M9wyH0+mV8jHYKXMJ7cuji4rOq2mCMdmvnyacSPuqBtFo8lEgVQx5JBrFZ2r+q90RUCy7I8mgi5baM6q92J4s8DgLIMmaSiGbXgif9jHYxaXVwdCMYinMPlgXy0MuENfGZ3I8nX1wyW33hzkKLT7KA7Vo= 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=Hfx+M/ag; arc=none smtp.client-ip=95.215.58.174 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="Hfx+M/ag" 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=1763042332; 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=0MNWm6Lip8Ocum3HyzjrIKBsn/zjzGl1/AKODQ4rsM4=; b=Hfx+M/agSYpYvlAwaquDtryNqbnRDrenQ3vOdWcwPWn9kCPPlQfx3+KfAJnj3C5yWw+5SY GJmqz/17VpljQPZISfU5oU9AD9GYsL4TBscVVvTVquqwxUWNwdexEmXDdnnZ2Wp17eTWzW FJsXvJeCmWNLWvhtMXMU5Bc9QzFgaec= From: Thorsten Blum To: 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] KEYS: encrypted: Replace deprecated strcpy and improve get_derived_key Date: Thu, 13 Nov 2025 14:58:31 +0100 Message-ID: <20251113135831.98587-1-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 Determine 'key_name' before allocating memory for 'derived_buf' to only allocate as many bytes as needed. Currently, we potentially allocate one more byte than necessary when 'key_name' is "ENC_KEY". strcpy() is deprecated and uses an additional strlen() internally; use memcpy() directly to copy 'key_name' since we already know its length and that it is guaranteed to be NUL-terminated. Also reuse 'key_name_len' when copying 'master_key' instead of calling strlen() again. Link: https://github.com/KSPP/linux/issues/88 Signed-off-by: Thorsten Blum --- security/keys/encrypted-keys/encrypted.c | 22 +++++++++------------- 1 file changed, 9 insertions(+), 13 deletions(-) diff --git a/security/keys/encrypted-keys/encrypted.c b/security/keys/encrypted-keys/encrypted.c index 15841466b5d4..b16a5b8b935b 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 +331,18 @@ 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; + size_t key_name_len; + key_name = key_type ? "AUTH_KEY" : "ENC_KEY"; + key_name_len = strlen(key_name) + 1; + derived_buf_len = max(key_name_len + 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); + memcpy(derived_buf, key_name, key_name_len); + memcpy(derived_buf + key_name_len, master_key, master_keylen); sha256(derived_buf, derived_buf_len, derived_key); kfree_sensitive(derived_buf); return 0; -- 2.51.1