From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received-SPF: Pass (sender SPF authorized) identity=mailfrom; client-ip=66.187.233.73; helo=mx1.redhat.com; envelope-from=lersek@redhat.com; receiver=edk2-devel@lists.01.org Received: from mx1.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id 66F602265A359 for ; Wed, 11 Apr 2018 03:43:02 -0700 (PDT) Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.rdu2.redhat.com [10.11.54.4]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id AB92E8DC24; Wed, 11 Apr 2018 10:43:01 +0000 (UTC) Received: from lacos-laptop-7.usersys.redhat.com (ovpn-120-97.rdu2.redhat.com [10.10.120.97]) by smtp.corp.redhat.com (Postfix) with ESMTP id AE50A2026E03; Wed, 11 Apr 2018 10:43:00 +0000 (UTC) From: Laszlo Ersek To: edk2-devel@lists.01.org Cc: Jiaxin Wu , Qin Long , Siyuan Fu , Ting Ye Date: Wed, 11 Apr 2018 12:42:47 +0200 Message-Id: <20180411104247.3758-10-lersek@redhat.com> In-Reply-To: <20180411104247.3758-1-lersek@redhat.com> References: <20180411104247.3758-1-lersek@redhat.com> X-Scanned-By: MIMEDefang 2.78 on 10.11.54.4 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.2]); Wed, 11 Apr 2018 10:43:01 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.2]); Wed, 11 Apr 2018 10:43:01 +0000 (UTC) for IP:'10.11.54.4' DOMAIN:'int-mx04.intmail.prod.int.rdu2.redhat.com' HELO:'smtp.corp.redhat.com' FROM:'lersek@redhat.com' RCPT:'' Subject: [PATCH v2 9/9] CryptoPkg/TlsLib: rewrite TlsSetCipherList() X-BeenThere: edk2-devel@lists.01.org X-Mailman-Version: 2.1.26 Precedence: list List-Id: EDK II Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 11 Apr 2018 10:43:02 -0000 Rewrite the TlsSetCipherList() function in order to fix the following issues: - Any cipher identifier in CipherId that is not recognized by TlsGetCipherMapping() will cause the function to return EFI_UNSUPPORTED. This is a problem because CipherId is an ordered preference list, and a caller should not get EFI_UNSUPPORTED just because it has an elaborate CipherId preference list. Instead, we can filter out cipher identifiers that we don't recognize, as long as we keep the relative order intact. - CipherString is allocated on the stack, with 500 bytes. While processing a large CipherId preference list, this room may not be enough. Although no buffer overflow is possible, CipherString exhaustion can lead to a failed TLS connection, because any cipher names that don't fit on CipherString cannot be negotiated. Compute CipherStringSize first, and allocate CipherString dynamically. - Finally, the "@STRENGTH" pseudo cipher name is appended to CipherString. (Assuming there is enough room left in CipherString.) This causes OpenSSL to sort the cipher list "in order of encryption algorithm key length". This is a bad idea. The caller specifically passes an ordered preference list in CipherId. Therefore TlsSetCipherList() must not ask OpenSSL to reorder the list, for any reason. Drop "@STRENGTH". While at it, fix and unify the documentation of the CipherId parameter. Cc: Jiaxin Wu Cc: Qin Long Cc: Siyuan Fu Cc: Ting Ye Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=915 Contributed-under: TianoCore Contribution Agreement 1.1 Signed-off-by: Laszlo Ersek --- Notes: v2: - incorporate patch "CryptoPkg/TlsLib: clean up leading comment for TlsSetCipherList()" from v1 CryptoPkg/Library/TlsLib/TlsLib.inf | 3 +- CryptoPkg/Include/Library/TlsLib.h | 9 +- CryptoPkg/Library/TlsLib/InternalTlsLib.h | 3 +- CryptoPkg/Library/TlsLib/TlsConfig.c | 168 +++++++++++++++++--- 4 files changed, 157 insertions(+), 26 deletions(-) diff --git a/CryptoPkg/Library/TlsLib/TlsLib.inf b/CryptoPkg/Library/TlsLib/TlsLib.inf index ae17a7d87444..4dacb2fab014 100644 --- a/CryptoPkg/Library/TlsLib/TlsLib.inf +++ b/CryptoPkg/Library/TlsLib/TlsLib.inf @@ -37,17 +37,18 @@ [Sources] [Packages] MdePkg/MdePkg.dec CryptoPkg/CryptoPkg.dec [LibraryClasses] BaseCryptLib - BaseLib BaseMemoryLib DebugLib IntrinsicLib + MemoryAllocationLib OpensslLib + SafeIntLib [BuildOptions] # # suppress the following warnings so we do not break the build with warnings-as-errors: # C4090: 'function' : different 'const' qualifiers # diff --git a/CryptoPkg/Include/Library/TlsLib.h b/CryptoPkg/Include/Library/TlsLib.h index e19a38a214ce..e71291eaea45 100644 --- a/CryptoPkg/Include/Library/TlsLib.h +++ b/CryptoPkg/Include/Library/TlsLib.h @@ -345,19 +345,22 @@ TlsSetConnectionEnd ( /** Set the ciphers list to be used by the TLS object. This function sets the ciphers for use by a specified TLS object. @param[in] Tls Pointer to a TLS object. - @param[in] CipherId Pointer to a string that contains one or more - ciphers separated by a colon. + @param[in] CipherId Array of UINT16 cipher identifiers. Each UINT16 + cipher identifier comes from the TLS Cipher Suite + Registry of the IANA, interpreting Byte1 and Byte2 + in network (big endian) byte order. @param[in] CipherNum The number of cipher in the list. @retval EFI_SUCCESS The ciphers list was set successfully. @retval EFI_INVALID_PARAMETER The parameter is invalid. - @retval EFI_UNSUPPORTED Unsupported TLS cipher in the list. + @retval EFI_UNSUPPORTED No supported TLS cipher was found in CipherId. + @retval EFI_OUT_OF_RESOURCES Memory allocation failed. **/ EFI_STATUS EFIAPI TlsSetCipherList ( IN VOID *Tls, diff --git a/CryptoPkg/Library/TlsLib/InternalTlsLib.h b/CryptoPkg/Library/TlsLib/InternalTlsLib.h index 3f18a461a8d1..b6cf9816aa38 100644 --- a/CryptoPkg/Library/TlsLib/InternalTlsLib.h +++ b/CryptoPkg/Library/TlsLib/InternalTlsLib.h @@ -16,15 +16,16 @@ WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED. #define __INTERNAL_TLS_LIB_H__ #undef _WIN32 #undef _WIN64 #include -#include #include #include +#include +#include #include #include #include typedef struct { // diff --git a/CryptoPkg/Library/TlsLib/TlsConfig.c b/CryptoPkg/Library/TlsLib/TlsConfig.c index e2f819b9035f..9154686610e0 100644 --- a/CryptoPkg/Library/TlsLib/TlsConfig.c +++ b/CryptoPkg/Library/TlsLib/TlsConfig.c @@ -232,74 +232,200 @@ TlsSetConnectionEnd ( /** Set the ciphers list to be used by the TLS object. This function sets the ciphers for use by a specified TLS object. @param[in] Tls Pointer to a TLS object. - @param[in] CipherId Pointer to a UINT16 cipher Id. + @param[in] CipherId Array of UINT16 cipher identifiers. Each UINT16 + cipher identifier comes from the TLS Cipher Suite + Registry of the IANA, interpreting Byte1 and Byte2 + in network (big endian) byte order. @param[in] CipherNum The number of cipher in the list. @retval EFI_SUCCESS The ciphers list was set successfully. @retval EFI_INVALID_PARAMETER The parameter is invalid. - @retval EFI_UNSUPPORTED Unsupported TLS cipher in the list. + @retval EFI_UNSUPPORTED No supported TLS cipher was found in CipherId. + @retval EFI_OUT_OF_RESOURCES Memory allocation failed. **/ EFI_STATUS EFIAPI TlsSetCipherList ( IN VOID *Tls, IN UINT16 *CipherId, IN UINTN CipherNum ) { TLS_CONNECTION *TlsConn; + EFI_STATUS Status; + CONST TLS_CIPHER_MAPPING **MappedCipher; + UINTN MappedCipherBytes; + UINTN MappedCipherCount; + UINTN CipherStringSize; UINTN Index; CONST TLS_CIPHER_MAPPING *Mapping; - CONST CHAR8 *MappingName; - CHAR8 CipherString[500]; + CHAR8 *CipherString; + CHAR8 *CipherStringPosition; TlsConn = (TLS_CONNECTION *) Tls; if (TlsConn == NULL || TlsConn->Ssl == NULL || CipherId == NULL) { return EFI_INVALID_PARAMETER; } - Mapping = NULL; - MappingName = NULL; - - memset (CipherString, 0, sizeof (CipherString)); + // + // Allocate the MappedCipher array for recording the mappings that we find + // for the input IANA identifiers in CipherId. + // + Status = SafeUintnMult (CipherNum, sizeof (*MappedCipher), + &MappedCipherBytes); + if (EFI_ERROR (Status)) { + return EFI_OUT_OF_RESOURCES; + } + MappedCipher = AllocatePool (MappedCipherBytes); + if (MappedCipher == NULL) { + return EFI_OUT_OF_RESOURCES; + } + // + // Map the cipher IDs, and count the number of bytes for the full + // CipherString. + // + MappedCipherCount = 0; + CipherStringSize = 0; for (Index = 0; Index < CipherNum; Index++) { // - // Handling OpenSSL / RFC Cipher name mapping. + // Look up the IANA-to-OpenSSL mapping. // - Mapping = TlsGetCipherMapping (*(CipherId + Index)); + Mapping = TlsGetCipherMapping (CipherId[Index]); if (Mapping == NULL) { - return EFI_UNSUPPORTED; - } - MappingName = Mapping->OpensslCipher; - - if (Index != 0) { + DEBUG ((DEBUG_VERBOSE, "%a:%a: skipping CipherId=0x%04x\n", + gEfiCallerBaseName, __FUNCTION__, CipherId[Index])); // - // The ciphers were separated by a colon. + // Skipping the cipher is valid because CipherId is an ordered + // preference list of ciphers, thus we can filter it as long as we + // don't change the relative order of elements on it. // - AsciiStrCatS (CipherString, sizeof (CipherString), ":"); + continue; + } + // + // Accumulate Mapping->OpensslCipherLength into CipherStringSize. If this + // is not the first successful mapping, account for a colon (":") prefix + // too. + // + if (MappedCipherCount > 0) { + Status = SafeUintnAdd (CipherStringSize, 1, &CipherStringSize); + if (EFI_ERROR (Status)) { + Status = EFI_OUT_OF_RESOURCES; + goto FreeMappedCipher; + } + } + Status = SafeUintnAdd (CipherStringSize, Mapping->OpensslCipherLength, + &CipherStringSize); + if (EFI_ERROR (Status)) { + Status = EFI_OUT_OF_RESOURCES; + goto FreeMappedCipher; } + // + // Record the mapping. + // + MappedCipher[MappedCipherCount++] = Mapping; + } - AsciiStrCatS (CipherString, sizeof (CipherString), MappingName); + // + // Verify that at least one IANA cipher ID could be mapped; account for the + // terminating NUL character in CipherStringSize; allocate CipherString. + // + if (MappedCipherCount == 0) { + DEBUG ((DEBUG_ERROR, "%a:%a: no CipherId could be mapped\n", + gEfiCallerBaseName, __FUNCTION__)); + Status = EFI_UNSUPPORTED; + goto FreeMappedCipher; + } + Status = SafeUintnAdd (CipherStringSize, 1, &CipherStringSize); + if (EFI_ERROR (Status)) { + Status = EFI_OUT_OF_RESOURCES; + goto FreeMappedCipher; + } + CipherString = AllocatePool (CipherStringSize); + if (CipherString == NULL) { + Status = EFI_OUT_OF_RESOURCES; + goto FreeMappedCipher; } - AsciiStrCatS (CipherString, sizeof (CipherString), ":@STRENGTH"); + // + // Go over the collected mappings and populate CipherString. + // + CipherStringPosition = CipherString; + for (Index = 0; Index < MappedCipherCount; Index++) { + Mapping = MappedCipher[Index]; + // + // Append the colon (":") prefix except for the first mapping, then append + // Mapping->OpensslCipher. + // + if (Index > 0) { + *(CipherStringPosition++) = ':'; + } + CopyMem (CipherStringPosition, Mapping->OpensslCipher, + Mapping->OpensslCipherLength); + CipherStringPosition += Mapping->OpensslCipherLength; + } + + // + // NUL-terminate CipherString. + // + *(CipherStringPosition++) = '\0'; + ASSERT (CipherStringPosition == CipherString + CipherStringSize); + + // + // Log CipherString for debugging. CipherString can be very long if the + // caller provided a large CipherId array, so log CipherString in segments of + // 79 non-newline characters. (MAX_DEBUG_MESSAGE_LENGTH is usually 0x100 in + // DebugLib instances.) + // + DEBUG_CODE ( + UINTN FullLength; + UINTN SegmentLength; + + FullLength = CipherStringSize - 1; + DEBUG ((DEBUG_VERBOSE, "%a:%a: CipherString={\n", gEfiCallerBaseName, + __FUNCTION__)); + for (CipherStringPosition = CipherString; + CipherStringPosition < CipherString + FullLength; + CipherStringPosition += SegmentLength) { + SegmentLength = FullLength - (CipherStringPosition - CipherString); + if (SegmentLength > 79) { + SegmentLength = 79; + } + DEBUG ((DEBUG_VERBOSE, "%.*a\n", SegmentLength, CipherStringPosition)); + } + DEBUG ((DEBUG_VERBOSE, "}\n")); + // + // Restore the pre-debug value of CipherStringPosition by skipping over the + // trailing NUL. + // + CipherStringPosition++; + ASSERT (CipherStringPosition == CipherString + CipherStringSize); + ); // // Sets the ciphers for use by the Tls object. // if (SSL_set_cipher_list (TlsConn->Ssl, CipherString) <= 0) { - return EFI_UNSUPPORTED; + Status = EFI_UNSUPPORTED; + goto FreeCipherString; } - return EFI_SUCCESS; + Status = EFI_SUCCESS; + +FreeCipherString: + FreePool (CipherString); + +FreeMappedCipher: + FreePool (MappedCipher); + + return Status; } /** Set the compression method for TLS/SSL operations. This function handles TLS/SSL integrated compression methods. -- 2.14.1.3.gb7cf6e02401b