Merge pull request #710 from ARMmbed/mbedtls-2.23.0r0-pr

Prepare Release Candidate for Mbed TLS 2.23.0

ChangeLog

@@ -1,5 +1,128 @@
 mbed TLS ChangeLog (Sorted per branch, date)
 
+= mbed TLS 2.23.0 branch released 2020-07-01
+
+Default behavior changes
+   * In the experimental PSA secure element interface, change the encoding of
+     key lifetimes to encode a persistence level and the location. Although C
+     prototypes do not effectively change, code calling
+     psa_register_se_driver() must be modified to pass the driver's location
+     instead of the keys' lifetime. If the library is upgraded on an existing
+     device, keys created with the old lifetime value will not be readable or
+     removable through Mbed TLS after the upgrade.
+
+Features
+   * New functions in the error module return constant strings for
+     high- and low-level error codes, complementing mbedtls_strerror()
+     which constructs a string for any error code, including compound
+     ones, but requires a writable buffer. Contributed by Gaurav Aggarwal
+     in #3176.
+   * The new utility programs/ssl/ssl_context_info prints a human-readable
+     dump of an SSL context saved with mbedtls_ssl_context_save().
+   * Add support for midipix, a POSIX layer for Microsoft Windows.
+   * Add new mbedtls_x509_crt_parse_der_with_ext_cb() routine which allows
+     parsing unsupported certificate extensions via user provided callback.
+     Contributed by Nicola Di Lieto <nicola.dilieto@gmail.com> in #3243 as
+     a solution to #3241.
+   * Pass the "certificate policies" extension to the callback supplied to
+     mbedtls_x509_crt_parse_der_with_ext_cb() if it contains unsupported
+     policies (#3419).
+   * Added support to entropy_poll for the kern.arandom syscall supported on
+     some BSD systems. Contributed by Nia Alarie in #3423.
+   * Add support for Windows 2000 in net_sockets. Contributed by opatomic. #3239
+
+Security
+   * Fix a side channel vulnerability in modular exponentiation that could
+     reveal an RSA private key used in a secure enclave. Noticed by Sangho Lee,
+     Ming-Wei Shih, Prasun Gera, Taesoo Kim and Hyesoon Kim (Georgia Institute
+     of Technology); and Marcus Peinado (Microsoft Research). Reported by Raoul
+     Strackx (Fortanix) in #3394.
+   * Fix side channel in mbedtls_ecp_check_pub_priv() and
+     mbedtls_pk_parse_key() / mbedtls_pk_parse_keyfile() (when loading a
+     private key that didn't include the uncompressed public key), as well as
+     mbedtls_ecp_mul() / mbedtls_ecp_mul_restartable() when called with a NULL
+     f_rng argument. An attacker with access to precise enough timing and
+     memory access information (typically an untrusted operating system
+     attacking a secure enclave) could fully recover the ECC private key.
+     Found and reported by Alejandro Cabrera Aldaya and Billy Brumley.
+   * Fix issue in Lucky 13 counter-measure that could make it ineffective when
+     hardware accelerators were used (using one of the MBEDTLS_SHAxxx_ALT
+     macros). This would cause the original Lucky 13 attack to be possible in
+     those configurations, allowing an active network attacker to recover
+     plaintext after repeated timing measurements under some conditions.
+     Reported and fix suggested by Luc Perneel in #3246.
+
+Bugfix
+   * Fix the Visual Studio Release x64 build configuration for mbedtls itself.
+     Completes a previous fix in Mbed TLS 2.19 that only fixed the build for
+     the example programs. Reported in #1430 and fix contributed by irwir.
+   * Fix undefined behavior in X.509 certificate parsing if the
+     pathLenConstraint basic constraint value is equal to INT_MAX.
+     The actual effect with almost every compiler is the intended
+     behavior, so this is unlikely to be exploitable anywhere. #3192
+   * Fix issue with a detected HW accelerated record error not being exposed
+     due to shadowed variable. Contributed by Sander Visser in #3310.
+   * Avoid NULL pointer dereferencing if mbedtls_ssl_free() is called with a
+     NULL pointer argument. Contributed by Sander Visser in #3312.
+   * Fix potential linker errors on dual world platforms by inlining
+     mbedtls_gcc_group_to_psa(). This allows the pk.c module to link separately
+     from psa_crypto.c. Fixes #3300.
+   * Remove dead code in X.509 certificate parsing. Contributed by irwir in
+     #2855.
+   * Include asn1.h in error.c. Fixes #3328 reported by David Hu.
+   * Fix potential memory leaks in ecp_randomize_jac() and ecp_randomize_mxz()
+     when PRNG function fails. Contributed by Jonas Lejeune in #3318.
+   * Remove unused macros from MSVC projects. Reported in #3297 and fix
+     submitted in #3333 by irwir.
+   * Add additional bounds checks in ssl_write_client_hello() preventing
+     output buffer overflow if the configuration declared a buffer that was
+     too small.
+   * Set _POSIX_C_SOURCE to at least 200112L in C99 code. Reported in #3420 and
+     fix submitted in #3421 by Nia Alarie.
+   * Fix building library/net_sockets.c and the ssl_mail_client program on
+     NetBSD. Contributed by Nia Alarie in #3422.
+   * Fix false positive uninitialised variable reported by cpp-check.
+     Contributed by Sander Visser in #3311.
+   * Update iv and len context pointers manually when reallocating buffers
+     using the MBEDTLS_SSL_VARIABLE_BUFFER_LENGTH feature. This caused issues
+     when receiving a connection with CID, when these fields were shifted
+     in ssl_parse_record_header().
+
+Changes
+   * Fix warnings about signedness issues in format strings. The build is now
+     clean of -Wformat-signedness warnings. Contributed by Kenneth Soerensen
+     in #3153.
+   * Fix minor performance issue in operations on Curve25519 caused by using a
+     suboptimal modular reduction in one place. Found and fix contributed by
+     Aurelien Jarno in #3209.
+   * Combine identical cases in switch statements in md.c. Contributed
+     by irwir in #3208.
+   * Simplify a bounds check in ssl_write_certificate_request(). Contributed
+     by irwir in #3150.
+   * Unify the example programs termination to call mbedtls_exit() instead of
+     using a return command. This has been done to enable customization of the
+     behavior in bare metal environments.
+   * Fix mbedtls_x509_dn_gets to escape non-ASCII characters as "?".
+     Contributed by Koh M. Nakagawa in #3326.
+   * Use FindPython3 when cmake version >= 3.15.0
+   * Abort the ClientHello writing function as soon as some extension doesn't
+     fit into the record buffer. Previously, such extensions were silently
+     dropped. As a consequence, the TLS handshake now fails when the output
+     buffer is not large enough to hold the ClientHello.
+   * The unit tests now rely on header files in tests/include/test and source
+     files in tests/src. When building with make or cmake, the files in
+     tests/src are compiled and the resulting object linked into each test
+     executable.
+   * The ECP module, enabled by `MBEDTLS_ECP_C`, now depends on
+     `MBEDTLS_CTR_DRBG_C` or `MBEDTLS_HMAC_DRBG_C` for some side-channel
+     coutermeasures. If side channels are not a concern, this dependency can
+     be avoided by enabling the new option `MBEDTLS_ECP_NO_INTERNAL_RNG`.
+   * Align MSVC error flag with GCC and Clang. Contributed by Carlos Gomes
+     Martinho. #3147
+   * Remove superfluous assignment in mbedtls_ssl_parse_certificate(). Reported
+     in #3182 and fix submitted by irwir. #3217
+   * Fix typo in XTS tests. Reported and fix submitted by Kxuan. #3319
+
 = mbed TLS 2.22.0 branch released 2020-04-14
 
 New deprecations

ChangeLog.d/bugfix.txt

@@ -1,4 +0,0 @@
-Bugfix
-   * Fix the Visual Studio Release x64 build configuration for mbedtls itself.
-     Completes a previous fix in Mbed TLS 2.19 that only fixed the build for
-     the example programs. Reported in #1430 and fix contributed by irwir.

ChangeLog.d/bugfix_PR2855.txt

@@ -1,2 +0,0 @@
-Bugfix
-   * Remove dead code in X.509 certificate parsing. Contributed by irwir in #2855.

ChangeLog.d/bugfix_PR3333.txt

@@ -1,2 +0,0 @@
-Bugfix
-   * Remove unused macros from MSVC projects. Reported in #3297 and fix submitted in #3333 by irwir.

ChangeLog.d/bugfix_PR3405

@@ -1,5 +0,0 @@
-Bugfix
-   * Update iv and len context pointers manually when reallocating buffers
-     using the MBEDTLS_SSL_VARIABLE_BUFFER_LENGTH feature. This caused issues
-     when receiving a connection with CID, when these fields were shifted
-     in ssl_parse_record_header().

ChangeLog.d/bugfix_PR3421.txt

@@ -1,2 +0,0 @@
-Bugfix
-   * Set _POSIX_C_SOURCE to at least 200112L in C99 code. Reported in #3420 and fix submitted in #3421 by Nia Alarie.

ChangeLog.d/bugfix_PR3422.txt

@@ -1,2 +0,0 @@
-Bugfix
-   * Fix building library/net_sockets.c and the ssl_mail_client program on NetBSD. Contributed by Nia Alarie in #3422.

ChangeLog.d/error-asn1.txt

@@ -1,2 +0,0 @@
-Bugfix
-   * Include asn1.h in error.c. Fixes #3328 reported by David Hu.

ChangeLog.d/error_const.txt

@@ -1,6 +0,0 @@
-Features
-   * New functions in the error module return constant strings for
-     high- and low-level error codes, complementing mbedtls_strerror()
-     which constructs a string for any error code, including compound
-     ones, but requires a writable buffer. Contributed by Gaurav Aggarwal
-     in #3176.

ChangeLog.d/fix-ecp-mul-memory-leak.txt

@@ -1,3 +0,0 @@
-Bugfix
-   * Fix potential memory leaks in ecp_randomize_jac() and ecp_randomize_mxz()
-     when PRNG function fails. Contributed by Jonas Lejeune in #3318.

ChangeLog.d/fix-ecp_double_add_mxz.txt

@@ -1,4 +0,0 @@
-Changes
-   * Fix minor performance issue in operations on Curve25519 caused by using a
-     suboptimal modular reduction in one place. Found and fix contributed by
-     Aurelien Jarno in #3209.

ChangeLog.d/fix-gcc-format-signedness-warnings.txt

@@ -1,4 +0,0 @@
-Changes
-   * Fix warnings about signedness issues in format strings. The build is now
-     clean of -Wformat-signedness warnings. Contributed by Kenneth Soerensen
-     in #3153.

ChangeLog.d/fix-masked-hw-record-init-error.txt

@@ -1,3 +0,0 @@
-Bugfix
-   * Fix issue with a detected HW accelerated record error not being exposed
-     due to shadowed variable. Contributed by Sander Visser in #3310.

ChangeLog.d/fix-null-ptr-deref-in-mbedtls_ssl_free.txt

@@ -1,3 +0,0 @@
-Bugfix
-   * Avoid NULL pointer dereferencing if mbedtls_ssl_free() is called with a
-     NULL pointer argument. Contributed by Sander Visser in #3312.

ChangeLog.d/fix-print-non-ascii-string-in-mbedtls_x509_dn_gets.txt

@@ -1,3 +0,0 @@
-Changes
-   * Fix mbedtls_x509_dn_gets to escape non-ASCII characters as "?".
-     Contributed by Koh M. Nakagawa in #3326.

ChangeLog.d/inline-mbedtls_gcc_group_to_psa.txt

@@ -1,4 +0,0 @@
-Bugfix
-   * Fix potential linker errors on dual world platforms by inlining
-     mbedtls_gcc_group_to_psa(). This allows the pk.c module to link separately
-     from psa_crypto.c. Fixes #3300.

ChangeLog.d/max_pathlen.txt

@@ -1,5 +0,0 @@
-Bugfix
-   * Fix undefined behavior in X.509 certificate parsing if the
-     pathLenConstraint basic constraint value is equal to INT_MAX.
-     The actual effect with almost every compiler is the intended
-     behavior, so this is unlikely to be exploitable anywhere. #3192

ChangeLog.d/md_switch.txt

@@ -1,3 +0,0 @@
-Changes
-   * Combine identical cases in switch statements in md.c. Contributed
-     by irwir in #3208.

ChangeLog.d/midipix-support.txt

@@ -1,2 +0,0 @@
-Features
-   * Add support for midipix, a POSIX layer for Microsoft Windows.

ChangeLog.d/montmul-cmp-branch.txt

@@ -1,6 +0,0 @@
-Security
-   * Fix a side channel vulnerability in modular exponentiation that could
-     reveal an RSA private key used in a secure enclave. Noticed by Sangho Lee,
-     Ming-Wei Shih, Prasun Gera, Taesoo Kim and Hyesoon Kim (Georgia Institute
-     of Technology); and Marcus Peinado (Microsoft Research). Reported by Raoul
-     Strackx (Fortanix) in #3394.

ChangeLog.d/new-mbedtls_x509_crt_parse_der_with_ext_cb_routine.txt

@@ -1,5 +0,0 @@
-Features
-   * Add new mbedtls_x509_crt_parse_der_with_ext_cb() routine which allows
-     parsing unsupported certificate extensions via user provided callback.
-     Contributed by Nicola Di Lieto <nicola.dilieto@gmail.com> in #3243 as
-     a solution to #3241.

ChangeLog.d/pass-unsupported-policies-to-callback.txt

@@ -1,4 +0,0 @@
-Features
-   * Pass the "certificate policies" extension to the callback supplied to
-     mbedtls_x509_crt_parse_der_with_ext_cb() if it contains unsupported
-     policies (#3419).

ChangeLog.d/psa-lifetime-locations.txt

@@ -1,8 +0,0 @@
-Default behavior changes
-   * In the experimental PSA secure element interface, change the encoding of
-     key lifetimes to encode a persistence level and the location. Although C
-     prototypes do not effectively change, code calling
-     psa_register_se_driver() must be modified to pass the driver's location
-     instead of the keys' lifetime. If the library is upgraded on an existing
-     device, keys created with the old lifetime value will not be readable or
-     removable through Mbed TLS after the upgrade.

ChangeLog.d/ssl_context_info.txt

@@ -1,3 +0,0 @@
-Features
-   * The new utility programs/ssl/ssl_context_info prints a human-readable
-     dump of an SSL context saved with mbedtls_ssl_context_save().

ChangeLog.d/ssl_write_certificate_request.txt

@@ -1,3 +0,0 @@
-Changes
-   * Simplify a bounds check in ssl_write_certificate_request(). Contributed
-     by irwir in #3150.

ChangeLog.d/sysctl-arnd-support.txt

@@ -1,2 +0,0 @@
-Features
-   * Added support to entropy_poll for the kern.arandom syscall supported on some BSD systems. Contributed by Nia Alarie in #3423.

ChangeLog.d/tests-common-code.txt

@@ -1,5 +0,0 @@
-Changes
-   * The unit tests now rely on header files in tests/include/test and source
-     files in tests/src. When building with make or cmake, the files in
-     tests/src are compiled and the resulting object linked into each test
-     executable.

ChangeLog.d/unified-exit-in-examples.txt

@@ -1,4 +0,0 @@
-Changes
-   * Unify the example programs termination to call mbedtls_exit() instead of
-     using a return command. This has been done to enable customization of the
-     behavior in bare metal environments.

ChangeLog.d/uniformize_bounds_checks.txt

@@ -1,9 +0,0 @@
-Bugfix
-   * Add additional bounds checks in ssl_write_client_hello() preventing
-     output buffer overflow if the configuration declared a buffer that was
-     too small.
-Changes
-   * Abort the ClientHello writing function as soon as some extension doesn't
-     fit into the record buffer. Previously, such extensions were silently
-     dropped. As a consequence, the TLS handshake now fails when the output
-     buffer is not large enough to hold the ClientHello.

ChangeLog.d/use-find-python3-cmake.txt

@@ -1,2 +0,0 @@
-Changes
-  * Use FindPython3 when cmake version >= 3.15.0

doxygen/input/doc_mainpage.h

@@ -24,7 +24,7 @@
  */
 
 /**
- * @mainpage mbed TLS v2.22.0 source code documentation
+ * @mainpage mbed TLS v2.23.0 source code documentation
  *
  * This documentation describes the internal structure of mbed TLS.  It was
  * automatically generated from specially formatted comment blocks in

doxygen/mbedtls.doxyfile

@@ -28,7 +28,7 @@ DOXYFILE_ENCODING      = UTF-8
 # identify the project. Note that if you do not use Doxywizard you need
 # to put quotes around the project name if it contains spaces.
 
-PROJECT_NAME           = "mbed TLS v2.22.0"
+PROJECT_NAME           = "mbed TLS v2.23.0"
 
 # The PROJECT_NUMBER tag can be used to enter a project or revision number.
 # This could be handy for archiving the generated documentation or

include/mbedtls/check_config.h

@@ -156,6 +156,14 @@
 #error "MBEDTLS_ECP_C defined, but not all prerequisites"
 #endif
 
+#if defined(MBEDTLS_ECP_C) && !(            \
+    defined(MBEDTLS_ECP_ALT) ||             \
+    defined(MBEDTLS_CTR_DRBG_C) ||          \
+    defined(MBEDTLS_HMAC_DRBG_C) ||         \
+    defined(MBEDTLS_ECP_NO_INTERNAL_RNG))
+#error "MBEDTLS_ECP_C requires a DRBG module unless MBEDTLS_ECP_NO_INTERNAL_RNG is defined or an alternative implementation is used"
+#endif
+
 #if defined(MBEDTLS_PK_PARSE_C) && !defined(MBEDTLS_ASN1_PARSE_C)
 #error "MBEDTLS_PK_PARSE_C defined, but not all prerequesites"
 #endif

include/mbedtls/config.h

@@ -781,6 +781,28 @@
  */
 #define MBEDTLS_ECP_NIST_OPTIM
 
+/**
+ * \def MBEDTLS_ECP_NO_INTERNAL_RNG
+ *
+ * When this option is disabled, mbedtls_ecp_mul() will make use of an
+ * internal RNG when called with a NULL \c f_rng argument, in order to protect
+ * against some side-channel attacks.
+ *
+ * This protection introduces a dependency of the ECP module on one of the
+ * DRBG modules. For very constrained implementations that don't require this
+ * protection (for example, because you're only doing signature verification,
+ * so not manipulating any secret, or because local/physical side-channel
+ * attacks are outside your threat model), it might be desirable to get rid of
+ * that dependency.
+ *
+ * \warning Enabling this option makes some uses of ECP vulnerable to some
+ * side-channel attacks. Only enable it if you know that's not a problem for
+ * your use case.
+ *
+ * Uncomment this macro to disable some counter-measures in ECP.
+ */
+//#define MBEDTLS_ECP_NO_INTERNAL_RNG
+
 /**
  * \def MBEDTLS_ECP_RESTARTABLE
  *

include/mbedtls/ecp.h

@@ -846,6 +846,9 @@ int mbedtls_ecp_tls_write_group( const mbedtls_ecp_group *grp,
  *                  intermediate results to prevent potential timing attacks
  *                  targeting these results. We recommend always providing
  *                  a non-NULL \p f_rng. The overhead is negligible.
+ *                  Note: unless #MBEDTLS_ECP_NO_INTERNAL_RNG is defined, when
+ *                  \p f_rng is NULL, an internal RNG (seeded from the value
+ *                  of \p m) will be used instead.
  *
  * \param grp       The ECP group to use.
  *                  This must be initialized and have group parameters

include/mbedtls/md.h

@@ -104,6 +104,8 @@ typedef struct mbedtls_md_context_t
  * \brief           This function returns the list of digests supported by the
  *                  generic digest module.
  *
+ * \note            The list starts with the strongest available hashes.
+ *
  * \return          A statically allocated array of digests. Each element
  *                  in the returned list is an integer belonging to the
  *                  message-digest enumeration #mbedtls_md_type_t.

include/mbedtls/version.h

@@ -39,7 +39,7 @@
  * Major, Minor, Patchlevel
  */
 #define MBEDTLS_VERSION_MAJOR  2
-#define MBEDTLS_VERSION_MINOR  22
+#define MBEDTLS_VERSION_MINOR  23
 #define MBEDTLS_VERSION_PATCH  0
 
 /**
@@ -47,9 +47,9 @@
  *    MMNNPP00
  *    Major version | Minor version | Patch version
  */
-#define MBEDTLS_VERSION_NUMBER         0x02160000
+#define MBEDTLS_VERSION_NUMBER         0x02170000
-#define MBEDTLS_VERSION_STRING         "2.22.0"
+#define MBEDTLS_VERSION_STRING         "2.23.0"
-#define MBEDTLS_VERSION_STRING_FULL    "mbed TLS 2.22.0"
+#define MBEDTLS_VERSION_STRING_FULL    "mbed TLS 2.23.0"
 
 #if defined(MBEDTLS_VERSION_C)
 

library/CMakeLists.txt

@@ -181,19 +181,19 @@ endif(USE_STATIC_MBEDTLS_LIBRARY)
 if(USE_SHARED_MBEDTLS_LIBRARY)
 
     add_library(mbedcrypto SHARED ${src_crypto})
-    set_target_properties(mbedcrypto PROPERTIES VERSION 2.22.0 SOVERSION 4)
+    set_target_properties(mbedcrypto PROPERTIES VERSION 2.23.0 SOVERSION 5)
     target_link_libraries(mbedcrypto ${libs})
     target_include_directories(mbedcrypto
         PUBLIC ${MBEDTLS_DIR}/include/)
 
     add_library(mbedx509 SHARED ${src_x509})
-    set_target_properties(mbedx509 PROPERTIES VERSION 2.22.0 SOVERSION 1)
+    set_target_properties(mbedx509 PROPERTIES VERSION 2.23.0 SOVERSION 1)
     target_link_libraries(mbedx509 ${libs} mbedcrypto)
     target_include_directories(mbedx509
         PUBLIC ${MBEDTLS_DIR}/include/)
 
     add_library(mbedtls SHARED ${src_tls})
-    set_target_properties(mbedtls PROPERTIES VERSION 2.22.0 SOVERSION 13)
+    set_target_properties(mbedtls PROPERTIES VERSION 2.23.0 SOVERSION 13)
     target_link_libraries(mbedtls ${libs} mbedx509)
     target_include_directories(mbedtls
         PUBLIC ${MBEDTLS_DIR}/include/)

library/Makefile

@@ -37,7 +37,7 @@ endif
 
 SOEXT_TLS=so.13
 SOEXT_X509=so.1
-SOEXT_CRYPTO=so.4
+SOEXT_CRYPTO=so.5
 
 # Set AR_DASH= (empty string) to use an ar implementation that does not accept
 # the - prefix for command line options (e.g. llvm-ar)

library/ecp.c

@@ -105,6 +105,16 @@
 
 #include "mbedtls/ecp_internal.h"
 
+#if !defined(MBEDTLS_ECP_NO_INTERNAL_RNG)
+#if defined(MBEDTLS_HMAC_DRBG_C)
+#include "mbedtls/hmac_drbg.h"
+#elif defined(MBEDTLS_CTR_DRBG_C)
+#include "mbedtls/ctr_drbg.h"
+#else
+#error "Invalid configuration detected. Include check_config.h to ensure that the configuration is valid."
+#endif
+#endif /* MBEDTLS_ECP_NO_INTERNAL_RNG */
+
 #if ( defined(__ARMCC_VERSION) || defined(_MSC_VER) ) && \
     !defined(inline) && !defined(__cplusplus)
 #define inline __inline
@@ -118,6 +128,144 @@
 static unsigned long add_count, dbl_count, mul_count;
 #endif
 
+#if !defined(MBEDTLS_ECP_NO_INTERNAL_RNG)
+/*
+ * Currently ecp_mul() takes a RNG function as an argument, used for
+ * side-channel protection, but it can be NULL. The initial reasoning was
+ * that people will pass non-NULL RNG when they care about side-channels, but
+ * unfortunately we have some APIs that call ecp_mul() with a NULL RNG, with
+ * no opportunity for the user to do anything about it.
+ *
+ * The obvious strategies for addressing that include:
+ * - change those APIs so that they take RNG arguments;
+ * - require a global RNG to be available to all crypto modules.
+ *
+ * Unfortunately those would break compatibility. So what we do instead is
+ * have our own internal DRBG instance, seeded from the secret scalar.
+ *
+ * The following is a light-weight abstraction layer for doing that with
+ * HMAC_DRBG (first choice) or CTR_DRBG.
+ */
+
+#if defined(MBEDTLS_HMAC_DRBG_C)
+
+/* DRBG context type */
+typedef mbedtls_hmac_drbg_context ecp_drbg_context;
+
+/* DRBG context init */
+static inline void ecp_drbg_init( ecp_drbg_context *ctx )
+{
+    mbedtls_hmac_drbg_init( ctx );
+}
+
+/* DRBG context free */
+static inline void ecp_drbg_free( ecp_drbg_context *ctx )
+{
+    mbedtls_hmac_drbg_free( ctx );
+}
+
+/* DRBG function */
+static inline int ecp_drbg_random( void *p_rng,
+                                   unsigned char *output, size_t output_len )
+{
+    return( mbedtls_hmac_drbg_random( p_rng, output, output_len ) );
+}
+
+/* DRBG context seeding */
+static int ecp_drbg_seed( ecp_drbg_context *ctx,
+                   const mbedtls_mpi *secret, size_t secret_len )
+{
+    int ret;
+    unsigned char secret_bytes[MBEDTLS_ECP_MAX_BYTES];
+    /* The list starts with strong hashes */
+    const mbedtls_md_type_t md_type = mbedtls_md_list()[0];
+    const mbedtls_md_info_t *md_info = mbedtls_md_info_from_type( md_type );
+
+    if( secret_len > MBEDTLS_ECP_MAX_BYTES )
+    {
+        ret = MBEDTLS_ERR_ECP_RANDOM_FAILED;
+        goto cleanup;
+    }
+
+    MBEDTLS_MPI_CHK( mbedtls_mpi_write_binary( secret,
+                                               secret_bytes, secret_len ) );
+
+    ret = mbedtls_hmac_drbg_seed_buf( ctx, md_info, secret_bytes, secret_len );
+
+cleanup:
+    mbedtls_platform_zeroize( secret_bytes, secret_len );
+
+    return( ret );
+}
+
+#elif defined(MBEDTLS_CTR_DRBG_C)
+
+/* DRBG context type */
+typedef mbedtls_ctr_drbg_context ecp_drbg_context;
+
+/* DRBG context init */
+static inline void ecp_drbg_init( ecp_drbg_context *ctx )
+{
+    mbedtls_ctr_drbg_init( ctx );
+}
+
+/* DRBG context free */
+static inline void ecp_drbg_free( ecp_drbg_context *ctx )
+{
+    mbedtls_ctr_drbg_free( ctx );
+}
+
+/* DRBG function */
+static inline int ecp_drbg_random( void *p_rng,
+                                   unsigned char *output, size_t output_len )
+{
+    return( mbedtls_ctr_drbg_random( p_rng, output, output_len ) );
+}
+
+/*
+ * Since CTR_DRBG doesn't have a seed_buf() function the way HMAC_DRBG does,
+ * we need to pass an entropy function when seeding. So we use a dummy
+ * function for that, and pass the actual entropy as customisation string.
+ * (During seeding of CTR_DRBG the entropy input and customisation string are
+ * concatenated before being used to update the secret state.)
+ */
+static int ecp_ctr_drbg_null_entropy(void *ctx, unsigned char *out, size_t len)
+{
+    (void) ctx;
+    memset( out, 0, len );
+    return( 0 );
+}
+
+/* DRBG context seeding */
+static int ecp_drbg_seed( ecp_drbg_context *ctx,
+                   const mbedtls_mpi *secret, size_t secret_len )
+{
+    int ret;
+    unsigned char secret_bytes[MBEDTLS_ECP_MAX_BYTES];
+
+    if( secret_len > MBEDTLS_ECP_MAX_BYTES )
+    {
+        ret = MBEDTLS_ERR_ECP_RANDOM_FAILED;
+        goto cleanup;
+    }
+
+    MBEDTLS_MPI_CHK( mbedtls_mpi_write_binary( secret,
+                                               secret_bytes, secret_len ) );
+
+    ret = mbedtls_ctr_drbg_seed( ctx, ecp_ctr_drbg_null_entropy, NULL,
+                                 secret_bytes, secret_len );
+
+cleanup:
+    mbedtls_platform_zeroize( secret_bytes, secret_len );
+
+    return( ret );
+}
+
+#else
+#error "Invalid configuration detected. Include check_config.h to ensure that the configuration is valid."
+#endif /* DRBG modules */
+#endif /* MBEDTLS_ECP_NO_INTERNAL_RNG */
+
 #if defined(MBEDTLS_ECP_RESTARTABLE)
 /*
  * Maximum number of "basic operations" to be done in a row.
@@ -165,6 +313,10 @@ struct mbedtls_ecp_restart_mul
         ecp_rsm_comb_core,      /* ecp_mul_comb_core()                      */
         ecp_rsm_final_norm,     /* do the final normalization               */
     } state;
+#if !defined(MBEDTLS_ECP_NO_INTERNAL_RNG)
+    ecp_drbg_context drbg_ctx;
+    unsigned char drbg_seeded;
+#endif
 };
 
 /*
@@ -177,6 +329,10 @@ static void ecp_restart_rsm_init( mbedtls_ecp_restart_mul_ctx *ctx )
     ctx->T = NULL;
     ctx->T_size = 0;
     ctx->state = ecp_rsm_init;
+#if !defined(MBEDTLS_ECP_NO_INTERNAL_RNG)
+    ecp_drbg_init( &ctx->drbg_ctx );
+    ctx->drbg_seeded = 0;
+#endif
 }
 
 /*
@@ -198,6 +354,10 @@ static void ecp_restart_rsm_free( mbedtls_ecp_restart_mul_ctx *ctx )
         mbedtls_free( ctx->T );
     }
 
+#if !defined(MBEDTLS_ECP_NO_INTERNAL_RNG)
+    ecp_drbg_free( &ctx->drbg_ctx );
+#endif
+
     ecp_restart_rsm_init( ctx );
 }
 
@@ -1897,7 +2057,9 @@ static int ecp_mul_comb_core( const mbedtls_ecp_group *grp, mbedtls_ecp_point *R
         i = d;
         MBEDTLS_MPI_CHK( ecp_select_comb( grp, R, T, T_size, x[i] ) );
         MBEDTLS_MPI_CHK( mbedtls_mpi_lset( &R->Z, 1 ) );
+#if defined(MBEDTLS_ECP_NO_INTERNAL_RNG)
         if( f_rng != 0 )
+#endif
             MBEDTLS_MPI_CHK( ecp_randomize_jac( grp, R, f_rng, p_rng ) );
     }
 
@@ -2018,6 +2180,7 @@ static int ecp_mul_comb_after_precomp( const mbedtls_ecp_group *grp,
         rs_ctx->rsm->state = ecp_rsm_final_norm;
 
 final_norm:
+    MBEDTLS_ECP_BUDGET( MBEDTLS_ECP_OPS_INV );
 #endif
     /*
      * Knowledge of the jacobian coordinates may leak the last few bits of the
@@ -2030,10 +2193,11 @@ final_norm:
      *
      * Avoid the leak by randomizing coordinates before we normalize them.
      */
+#if defined(MBEDTLS_ECP_NO_INTERNAL_RNG)
     if( f_rng != 0 )
+#endif
         MBEDTLS_MPI_CHK( ecp_randomize_jac( grp, RR, f_rng, p_rng ) );
 
-    MBEDTLS_ECP_BUDGET( MBEDTLS_ECP_OPS_INV );
     MBEDTLS_MPI_CHK( ecp_normalize_jac( grp, RR ) );
 
 #if defined(MBEDTLS_ECP_RESTARTABLE)
@@ -2104,11 +2268,44 @@ static int ecp_mul_comb( mbedtls_ecp_group *grp, mbedtls_ecp_point *R,
     int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     unsigned char w, p_eq_g, i;
     size_t d;
-    unsigned char T_size, T_ok;
+    unsigned char T_size = 0, T_ok = 0;
-    mbedtls_ecp_point *T;
+    mbedtls_ecp_point *T = NULL;
+#if !defined(MBEDTLS_ECP_NO_INTERNAL_RNG)
+    ecp_drbg_context drbg_ctx;
+
+    ecp_drbg_init( &drbg_ctx );
+#endif
 
     ECP_RS_ENTER( rsm );
 
+#if !defined(MBEDTLS_ECP_NO_INTERNAL_RNG)
+    if( f_rng == NULL )
+    {
+        /* Adjust pointers */
+        f_rng = &ecp_drbg_random;
+#if defined(MBEDTLS_ECP_RESTARTABLE)
+        if( rs_ctx != NULL && rs_ctx->rsm != NULL )
+            p_rng = &rs_ctx->rsm->drbg_ctx;
+        else
+#endif
+            p_rng = &drbg_ctx;
+
+        /* Initialize internal DRBG if necessary */
+#if defined(MBEDTLS_ECP_RESTARTABLE)
+        if( rs_ctx == NULL || rs_ctx->rsm == NULL ||
+            rs_ctx->rsm->drbg_seeded == 0 )
+#endif
+        {
+            const size_t m_len = ( grp->nbits + 7 ) / 8;
+            MBEDTLS_MPI_CHK( ecp_drbg_seed( p_rng, m, m_len ) );
+        }
+#if defined(MBEDTLS_ECP_RESTARTABLE)
+        if( rs_ctx != NULL && rs_ctx->rsm != NULL )
+            rs_ctx->rsm->drbg_seeded = 1;
+#endif
+    }
+#endif /* !MBEDTLS_ECP_NO_INTERNAL_RNG */
+
     /* Is P the base point ? */
 #if MBEDTLS_ECP_FIXED_POINT_OPTIM == 1
     p_eq_g = ( mbedtls_mpi_cmp_mpi( &P->Y, &grp->G.Y ) == 0 &&
@@ -2180,6 +2377,10 @@ static int ecp_mul_comb( mbedtls_ecp_group *grp, mbedtls_ecp_point *R,
 
 cleanup:
 
+#if !defined(MBEDTLS_ECP_NO_INTERNAL_RNG)
+    ecp_drbg_free( &drbg_ctx );
+#endif
+
     /* does T belong to the group? */
     if( T == grp->T )
         T = NULL;
@@ -2370,9 +2571,23 @@ static int ecp_mul_mxz( mbedtls_ecp_group *grp, mbedtls_ecp_point *R,
     unsigned char b;
     mbedtls_ecp_point RP;
     mbedtls_mpi PX;
+#if !defined(MBEDTLS_ECP_NO_INTERNAL_RNG)
+    ecp_drbg_context drbg_ctx;
 
+    ecp_drbg_init( &drbg_ctx );
+#endif
     mbedtls_ecp_point_init( &RP ); mbedtls_mpi_init( &PX );
 
+#if !defined(MBEDTLS_ECP_NO_INTERNAL_RNG)
+    if( f_rng == NULL )
+    {
+        const size_t m_len = ( grp->nbits + 7 ) / 8;
+        MBEDTLS_MPI_CHK( ecp_drbg_seed( &drbg_ctx, m, m_len ) );
+        f_rng = &ecp_drbg_random;
+        p_rng = &drbg_ctx;
+    }
+#endif /* !MBEDTLS_ECP_NO_INTERNAL_RNG */
+
     /* Save PX and read from P before writing to R, in case P == R */
     MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &PX, &P->X ) );
     MBEDTLS_MPI_CHK( mbedtls_ecp_copy( &RP, P ) );
@@ -2386,7 +2601,9 @@ static int ecp_mul_mxz( mbedtls_ecp_group *grp, mbedtls_ecp_point *R,
     MOD_ADD( RP.X );
 
     /* Randomize coordinates of the starting point */
+#if defined(MBEDTLS_ECP_NO_INTERNAL_RNG)
     if( f_rng != NULL )
+#endif
         MBEDTLS_MPI_CHK( ecp_randomize_mxz( grp, &RP, f_rng, p_rng ) );
 
     /* Loop invariant: R = result so far, RP = R + P */
@@ -2419,12 +2636,18 @@ static int ecp_mul_mxz( mbedtls_ecp_group *grp, mbedtls_ecp_point *R,
      *
      * Avoid the leak by randomizing coordinates before we normalize them.
      */
+#if defined(MBEDTLS_ECP_NO_INTERNAL_RNG)
     if( f_rng != NULL )
+#endif
         MBEDTLS_MPI_CHK( ecp_randomize_mxz( grp, R, f_rng, p_rng ) );
 
     MBEDTLS_MPI_CHK( ecp_normalize_mxz( grp, R ) );
 
 cleanup:
+#if !defined(MBEDTLS_ECP_NO_INTERNAL_RNG)
+    ecp_drbg_free( &drbg_ctx );
+#endif
+
     mbedtls_ecp_point_free( &RP ); mbedtls_mpi_free( &PX );
 
     return( ret );

library/ssl_msg.c

@@ -1578,6 +1578,8 @@ int mbedtls_ssl_decrypt_buf( mbedtls_ssl_context const *ssl,
              * linking an extra division function in some builds).
              */
             size_t j, extra_run = 0;
+            /* This size is enough to server either as input to
+             * md_process() or as output to md_finish() */
             unsigned char tmp[MBEDTLS_MD_MAX_BLOCK_SIZE];
 
             /*
@@ -1633,10 +1635,15 @@ int mbedtls_ssl_decrypt_buf( mbedtls_ssl_context const *ssl,
             ssl_read_memory( data + rec->data_len, padlen );
             mbedtls_md_hmac_finish( &transform->md_ctx_dec, mac_expect );
 
-            /* Call mbedtls_md_process at least once due to cache attacks
+            /* Dummy calls to compression function.
-             * that observe whether md_process() was called of not */
+             * Call mbedtls_md_process at least once due to cache attacks
+             * that observe whether md_process() was called of not.
+             * Respect the usual start-(process|update)-finish sequence for
+             * the sake of hardware accelerators that might require it. */
+            mbedtls_md_starts( &transform->md_ctx_dec );
             for( j = 0; j < extra_run + 1; j++ )
                 mbedtls_md_process( &transform->md_ctx_dec, tmp );
+            mbedtls_md_finish( &transform->md_ctx_dec, tmp );
 
             mbedtls_md_hmac_reset( &transform->md_ctx_dec );
 

library/version_features.c

@@ -354,6 +354,9 @@ static const char * const features[] = {
 #if defined(MBEDTLS_ECP_NIST_OPTIM)
     "MBEDTLS_ECP_NIST_OPTIM",
 #endif /* MBEDTLS_ECP_NIST_OPTIM */
+#if defined(MBEDTLS_ECP_NO_INTERNAL_RNG)
+    "MBEDTLS_ECP_NO_INTERNAL_RNG",
+#endif /* MBEDTLS_ECP_NO_INTERNAL_RNG */
 #if defined(MBEDTLS_ECP_RESTARTABLE)
     "MBEDTLS_ECP_RESTARTABLE",
 #endif /* MBEDTLS_ECP_RESTARTABLE */

programs/test/query_config.c

@@ -986,6 +986,14 @@ int query_config( const char *config )
     }
 #endif /* MBEDTLS_ECP_NIST_OPTIM */
 
+#if defined(MBEDTLS_ECP_NO_INTERNAL_RNG)
+    if( strcmp( "MBEDTLS_ECP_NO_INTERNAL_RNG", config ) == 0 )
+    {
+        MACRO_EXPANSION_TO_STR( MBEDTLS_ECP_NO_INTERNAL_RNG );
+        return( 0 );
+    }
+#endif /* MBEDTLS_ECP_NO_INTERNAL_RNG */
+
 #if defined(MBEDTLS_ECP_RESTARTABLE)
     if( strcmp( "MBEDTLS_ECP_RESTARTABLE", config ) == 0 )
     {

scripts/config.py

@@ -173,6 +173,7 @@ EXCLUDE_FROM_FULL = frozenset([
     'MBEDTLS_DEPRECATED_REMOVED', # conflicts with deprecated options
     'MBEDTLS_DEPRECATED_WARNING', # conflicts with deprecated options
     'MBEDTLS_ECDH_VARIANT_EVEREST_ENABLED', # influences the use of ECDH in TLS
+    'MBEDTLS_ECP_NO_INTERNAL_RNG', # removes a feature
     'MBEDTLS_ECP_RESTARTABLE', # incompatible with USE_PSA_CRYPTO
     'MBEDTLS_ENTROPY_FORCE_SHA256', # interacts with CTR_DRBG_128_BIT_KEY
     'MBEDTLS_HAVE_SSE2', # hardware dependency

tests/scripts/all.sh

@@ -929,6 +929,43 @@ component_test_no_hmac_drbg () {
     # so there's little value in running those lengthy tests here.
 }
 
+component_test_ecp_no_internal_rng () {
+    msg "build: Default plus ECP_NO_INTERNAL_RNG minus DRBG modules"
+    scripts/config.py set MBEDTLS_ECP_NO_INTERNAL_RNG
+    scripts/config.py unset MBEDTLS_CTR_DRBG_C
+    scripts/config.py unset MBEDTLS_HMAC_DRBG_C
+    scripts/config.py unset MBEDTLS_ECDSA_DETERMINISTIC # requires HMAC_DRBG
+    scripts/config.py unset MBEDTLS_PSA_CRYPTO_C # requires a DRBG
+    scripts/config.py unset MBEDTLS_PSA_CRYPTO_STORAGE_C # requires PSA Crypto
+
+    CC=gcc cmake -D CMAKE_BUILD_TYPE:String=Asan .
+    make
+
+    msg "test: ECP_NO_INTERNAL_RNG, no DRBG module"
+    make test
+
+    # no SSL tests as they all depend on having a DRBG
+}
+
+component_test_ecp_restartable_no_internal_rng () {
+    msg "build: Default plus ECP_RESTARTABLE and ECP_NO_INTERNAL_RNG, no DRBG"
+    scripts/config.py set MBEDTLS_ECP_NO_INTERNAL_RNG
+    scripts/config.py set MBEDTLS_ECP_RESTARTABLE
+    scripts/config.py unset MBEDTLS_CTR_DRBG_C
+    scripts/config.py unset MBEDTLS_HMAC_DRBG_C
+    scripts/config.py unset MBEDTLS_ECDSA_DETERMINISTIC # requires HMAC_DRBG
+    scripts/config.py unset MBEDTLS_PSA_CRYPTO_C # requires CTR_DRBG
+    scripts/config.py unset MBEDTLS_PSA_CRYPTO_STORAGE_C # requires PSA Crypto
+
+    CC=gcc cmake -D CMAKE_BUILD_TYPE:String=Asan .
+    make
+
+    msg "test: ECP_RESTARTABLE and ECP_NO_INTERNAL_RNG, no DRBG module"
+    make test
+
+    # no SSL tests as they all depend on having a DRBG
+}
+
 component_test_new_ecdh_context () {
     msg "build: new ECDH context (ASan build)" # ~ 6 min
     scripts/config.py unset MBEDTLS_ECDH_LEGACY_CONTEXT

tests/suites/test_suite_version.data

@@ -1,8 +1,8 @@
 Check compiletime library version
-check_compiletime_version:"2.22.0"
+check_compiletime_version:"2.23.0"
 
 Check runtime library version
-check_runtime_version:"2.22.0"
+check_runtime_version:"2.23.0"
 
 Check for MBEDTLS_VERSION_C
 check_feature:"MBEDTLS_VERSION_C":0