warn on use of deprecated EVP functions

This adds a linker warning for EVP_EncryptFinal(), EVP_DecryptFinal(),
EVP_CipherFinal(), and documents the recent behavior updates.

ok beck@

4 files changed, 46 insertions, 14 deletions

diff --git a/lib/libcrypto/doc/EVP_EncryptInit.pod b/lib/libcrypto/doc/EVP_EncryptInit.pod
index 02d02ba5f57..e72c101c948 100644
--- a/lib/libcrypto/doc/EVP_EncryptInit.pod
+++ b/lib/libcrypto/doc/EVP_EncryptInit.pod
@@ -23,7 +23,7 @@ EVP_des_ede3_cfb, EVP_desx_cbc, EVP_rc4, EVP_rc4_40, EVP_idea_cbc,
 EVP_idea_ecb, EVP_idea_cfb, EVP_idea_ofb, EVP_idea_cbc, EVP_rc2_cbc,
 EVP_rc2_ecb, EVP_rc2_cfb, EVP_rc2_ofb, EVP_rc2_40_cbc, EVP_rc2_64_cbc,
 EVP_bf_cbc, EVP_bf_ecb, EVP_bf_cfb, EVP_bf_ofb, EVP_cast5_cbc,
-EVP_cast5_ecb, EVP_cast5_cfb, EVP_cast5_ofb, 
+EVP_cast5_ecb, EVP_cast5_cfb, EVP_cast5_ofb,
 EVP_aes_128_gcm, EVP_aes_192_gcm, EVP_aes_256_gcm, EVP_aes_128_ccm,
 EVP_aes_192_ccm, EVP_aes_256_ccm, EVP_rc5_32_12_16_cbc,
 EVP_rc5_32_12_16_cfb, EVP_rc5_32_12_16_ecb, EVP_rc5_32_12_16_ofb
@@ -168,9 +168,13 @@ initialized and they always use the default cipher implementation.
 
 EVP_EncryptFinal(), EVP_DecryptFinal() and EVP_CipherFinal() are
 identical to EVP_EncryptFinal_ex(), EVP_DecryptFinal_ex() and
-EVP_CipherFinal_ex(). In previous releases they also used to clean up
-the B<ctx>, but this is no longer done and EVP_CIPHER_CTX_clean()
-must be called to free any context resources.
+EVP_CipherFinal_ex(). In previous releases of OpenSSL they also used to clean
+up the B<ctx>, but this is no longer done and EVP_CIPHER_CTX_clean()
+must be called to free any context resources. As of LibreSSL 2.4,
+EVP_EncryptFinal() and EVP_DecryptFinal() will always clean up, and
+EVP_CipherFinal() also cleans up as of LibreSSL 2.5. The use of
+EVP_EncryptFinal(), EVP_DecryptFinal() and EVP_CipherFinal() is not
+recommended.
 
 EVP_get_cipherbyname(), EVP_get_cipherbynid() and EVP_get_cipherbyobj()
 return an EVP_CIPHER structure when passed a cipher name, a NID or an
diff --git a/lib/libcrypto/evp/evp_enc.c b/lib/libcrypto/evp/evp_enc.c
index f8d2cb78d4c..5f710347ae1 100644
--- a/lib/libcrypto/evp/evp_enc.c
+++ b/lib/libcrypto/evp/evp_enc.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: evp_enc.c,v 1.31 2016/05/30 13:42:54 beck Exp $ */
+/* $OpenBSD: evp_enc.c,v 1.32 2016/09/02 15:36:38 bcook Exp $ */
 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
@@ -260,13 +260,19 @@ EVP_CipherFinal_ex(EVP_CIPHER_CTX *ctx, unsigned char *out, int *outl)
 		return EVP_DecryptFinal_ex(ctx, out, outl);
 }
 
+__warn_references(EVP_CipherFinal,
+    "warning: EVP_CipherFinal is often misused, please use EVP_CipherFinal_ex and EVP_CIPHER_CTX_cleanup");
+
 int
 EVP_CipherFinal(EVP_CIPHER_CTX *ctx, unsigned char *out, int *outl)
 {
+	int ret;
 	if (ctx->encrypt)
-		return EVP_EncryptFinal_ex(ctx, out, outl);
+		ret = EVP_EncryptFinal_ex(ctx, out, outl);
 	else
-		return EVP_DecryptFinal_ex(ctx, out, outl);
+		ret = EVP_DecryptFinal_ex(ctx, out, outl);
+	(void) EVP_CIPHER_CTX_cleanup(ctx);
+	return ret;
 }
 
 int
@@ -365,6 +371,9 @@ EVP_EncryptUpdate(EVP_CIPHER_CTX *ctx, unsigned char *out, int *outl,
 	return 1;
 }
 
+__warn_references(EVP_EncryptFinal,
+    "warning: EVP_EncryptFinal is often misused, please use EVP_EncryptFinal_ex and EVP_CIPHER_CTX_cleanup");
+
 int
 EVP_EncryptFinal(EVP_CIPHER_CTX *ctx, unsigned char *out, int *outl)
 {
@@ -479,6 +488,9 @@ EVP_DecryptUpdate(EVP_CIPHER_CTX *ctx, unsigned char *out, int *outl,
 	return 1;
 }
 
+__warn_references(EVP_DecryptFinal,
+    "warning: EVP_DecryptFinal is often misused, please use EVP_DecryptFinal_ex and EVP_CIPHER_CTX_cleanup");
+
 int
 EVP_DecryptFinal(EVP_CIPHER_CTX *ctx, unsigned char *out, int *outl)
 {
diff --git a/lib/libssl/src/crypto/evp/evp_enc.c b/lib/libssl/src/crypto/evp/evp_enc.c
index f8d2cb78d4c..5f710347ae1 100644
--- a/lib/libssl/src/crypto/evp/evp_enc.c
+++ b/lib/libssl/src/crypto/evp/evp_enc.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: evp_enc.c,v 1.31 2016/05/30 13:42:54 beck Exp $ */
+/* $OpenBSD: evp_enc.c,v 1.32 2016/09/02 15:36:38 bcook Exp $ */
 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
@@ -260,13 +260,19 @@ EVP_CipherFinal_ex(EVP_CIPHER_CTX *ctx, unsigned char *out, int *outl)
 		return EVP_DecryptFinal_ex(ctx, out, outl);
 }
 
+__warn_references(EVP_CipherFinal,
+    "warning: EVP_CipherFinal is often misused, please use EVP_CipherFinal_ex and EVP_CIPHER_CTX_cleanup");
+
 int
 EVP_CipherFinal(EVP_CIPHER_CTX *ctx, unsigned char *out, int *outl)
 {
+	int ret;
 	if (ctx->encrypt)
-		return EVP_EncryptFinal_ex(ctx, out, outl);
+		ret = EVP_EncryptFinal_ex(ctx, out, outl);
 	else
-		return EVP_DecryptFinal_ex(ctx, out, outl);
+		ret = EVP_DecryptFinal_ex(ctx, out, outl);
+	(void) EVP_CIPHER_CTX_cleanup(ctx);
+	return ret;
 }
 
 int
@@ -365,6 +371,9 @@ EVP_EncryptUpdate(EVP_CIPHER_CTX *ctx, unsigned char *out, int *outl,
 	return 1;
 }
 
+__warn_references(EVP_EncryptFinal,
+    "warning: EVP_EncryptFinal is often misused, please use EVP_EncryptFinal_ex and EVP_CIPHER_CTX_cleanup");
+
 int
 EVP_EncryptFinal(EVP_CIPHER_CTX *ctx, unsigned char *out, int *outl)
 {
@@ -479,6 +488,9 @@ EVP_DecryptUpdate(EVP_CIPHER_CTX *ctx, unsigned char *out, int *outl,
 	return 1;
 }
 
+__warn_references(EVP_DecryptFinal,
+    "warning: EVP_DecryptFinal is often misused, please use EVP_DecryptFinal_ex and EVP_CIPHER_CTX_cleanup");
+
 int
 EVP_DecryptFinal(EVP_CIPHER_CTX *ctx, unsigned char *out, int *outl)
 {
diff --git a/lib/libssl/src/doc/crypto/EVP_EncryptInit.pod b/lib/libssl/src/doc/crypto/EVP_EncryptInit.pod
index 02d02ba5f57..e72c101c948 100644
--- a/lib/libssl/src/doc/crypto/EVP_EncryptInit.pod
+++ b/lib/libssl/src/doc/crypto/EVP_EncryptInit.pod
@@ -23,7 +23,7 @@ EVP_des_ede3_cfb, EVP_desx_cbc, EVP_rc4, EVP_rc4_40, EVP_idea_cbc,
 EVP_idea_ecb, EVP_idea_cfb, EVP_idea_ofb, EVP_idea_cbc, EVP_rc2_cbc,
 EVP_rc2_ecb, EVP_rc2_cfb, EVP_rc2_ofb, EVP_rc2_40_cbc, EVP_rc2_64_cbc,
 EVP_bf_cbc, EVP_bf_ecb, EVP_bf_cfb, EVP_bf_ofb, EVP_cast5_cbc,
-EVP_cast5_ecb, EVP_cast5_cfb, EVP_cast5_ofb, 
+EVP_cast5_ecb, EVP_cast5_cfb, EVP_cast5_ofb,
 EVP_aes_128_gcm, EVP_aes_192_gcm, EVP_aes_256_gcm, EVP_aes_128_ccm,
 EVP_aes_192_ccm, EVP_aes_256_ccm, EVP_rc5_32_12_16_cbc,
 EVP_rc5_32_12_16_cfb, EVP_rc5_32_12_16_ecb, EVP_rc5_32_12_16_ofb
@@ -168,9 +168,13 @@ initialized and they always use the default cipher implementation.
 
 EVP_EncryptFinal(), EVP_DecryptFinal() and EVP_CipherFinal() are
 identical to EVP_EncryptFinal_ex(), EVP_DecryptFinal_ex() and
-EVP_CipherFinal_ex(). In previous releases they also used to clean up
-the B<ctx>, but this is no longer done and EVP_CIPHER_CTX_clean()
-must be called to free any context resources.
+EVP_CipherFinal_ex(). In previous releases of OpenSSL they also used to clean
+up the B<ctx>, but this is no longer done and EVP_CIPHER_CTX_clean()
+must be called to free any context resources. As of LibreSSL 2.4,
+EVP_EncryptFinal() and EVP_DecryptFinal() will always clean up, and
+EVP_CipherFinal() also cleans up as of LibreSSL 2.5. The use of
+EVP_EncryptFinal(), EVP_DecryptFinal() and EVP_CipherFinal() is not
+recommended.
 
 EVP_get_cipherbyname(), EVP_get_cipherbynid() and EVP_get_cipherbyobj()
 return an EVP_CIPHER structure when passed a cipher name, a NID or an