Merge remote-tracking branch 'public/pr/2270' into development
diff --git a/ChangeLog b/ChangeLog
index b4aef49..e9c783c 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -51,6 +51,8 @@
    * Add validation checks for input parameters to functions in the GCM module.
    * Add validation checks for input parameters to functions in the SHA-1
      module.
+   * Add validation checks for input parameters to functions in the SHA-256
+     module.
 
 New deprecations
    * Deprecate mbedtls_ctr_drbg_update and mbedtls_hmac_drbg_update
diff --git a/include/mbedtls/error.h b/include/mbedtls/error.h
index 57bbfeb..6d97665 100644
--- a/include/mbedtls/error.h
+++ b/include/mbedtls/error.h
@@ -75,7 +75,7 @@
  * MD5       1                  0x002F-0x002F
  * RIPEMD160 1                  0x0031-0x0031
  * SHA1      1                  0x0035-0x0035 0x0073-0x0073
- * SHA256    1                  0x0037-0x0037
+ * SHA256    1                  0x0037-0x0037 0x0074-0x0074
  * SHA512    1                  0x0039-0x0039
  * CHACHA20  3                  0x0051-0x0055
  * POLY1305  3                  0x0057-0x005B
diff --git a/include/mbedtls/sha256.h b/include/mbedtls/sha256.h
index 47a31e8..0e42f0a 100644
--- a/include/mbedtls/sha256.h
+++ b/include/mbedtls/sha256.h
@@ -38,6 +38,7 @@
 
 /* MBEDTLS_ERR_SHA256_HW_ACCEL_FAILED is deprecated and should not be used. */
 #define MBEDTLS_ERR_SHA256_HW_ACCEL_FAILED                -0x0037  /**< SHA-256 hardware accelerator failed */
+#define MBEDTLS_ERR_SHA256_BAD_INPUT_DATA                 -0x0074  /**< SHA-256 input data was malformed. */
 
 #ifdef __cplusplus
 extern "C" {
@@ -71,22 +72,24 @@
 /**
  * \brief          This function initializes a SHA-256 context.
  *
- * \param ctx      The SHA-256 context to initialize.
+ * \param ctx      The SHA-256 context to initialize. This must not be \c NULL.
  */
 void mbedtls_sha256_init( mbedtls_sha256_context *ctx );
 
 /**
  * \brief          This function clears a SHA-256 context.
  *
- * \param ctx      The SHA-256 context to clear.
+ * \param ctx      The SHA-256 context to clear. This may be \c NULL, in which
+ *                 case this function returns immediately. If it is not \c NULL,
+ *                 it must point to an initialized SHA-256 context.
  */
 void mbedtls_sha256_free( mbedtls_sha256_context *ctx );
 
 /**
  * \brief          This function clones the state of a SHA-256 context.
  *
- * \param dst      The destination context.
- * \param src      The context to clone.
+ * \param dst      The destination context. This must be initialized.
+ * \param src      The context to clone. This must be initialized.
  */
 void mbedtls_sha256_clone( mbedtls_sha256_context *dst,
                            const mbedtls_sha256_context *src );
@@ -95,11 +98,12 @@
  * \brief          This function starts a SHA-224 or SHA-256 checksum
  *                 calculation.
  *
- * \param ctx      The context to initialize.
- * \param is224    Determines which function to use:
- *                 0: Use SHA-256, or 1: Use SHA-224.
+ * \param ctx      The context to use. This must be initialized.
+ * \param is224    This determines which function to use. This must be
+ *                 either \c 0 for SHA-256, or \c 1 for SHA-224.
  *
  * \return         \c 0 on success.
+ * \return         A negative error code on failure.
  */
 int mbedtls_sha256_starts_ret( mbedtls_sha256_context *ctx, int is224 );
 
@@ -107,11 +111,14 @@
  * \brief          This function feeds an input buffer into an ongoing
  *                 SHA-256 checksum calculation.
  *
- * \param ctx      The SHA-256 context.
- * \param input    The buffer holding the data.
- * \param ilen     The length of the input data.
+ * \param ctx      The SHA-256 context. This must be initialized
+ *                 and have a hash operation started.
+ * \param input    The buffer holding the data. This must be a readable
+ *                 buffer of length \p ilen Bytes.
+ * \param ilen     The length of the input data in Bytes.
  *
  * \return         \c 0 on success.
+ * \return         A negative error code on failure.
  */
 int mbedtls_sha256_update_ret( mbedtls_sha256_context *ctx,
                                const unsigned char *input,
@@ -121,10 +128,13 @@
  * \brief          This function finishes the SHA-256 operation, and writes
  *                 the result to the output buffer.
  *
- * \param ctx      The SHA-256 context.
+ * \param ctx      The SHA-256 context. This must be initialized
+ *                 and have a hash operation started.
  * \param output   The SHA-224 or SHA-256 checksum result.
+ *                 This must be a writable buffer of length \c 32 Bytes.
  *
  * \return         \c 0 on success.
+ * \return         A negative error code on failure.
  */
 int mbedtls_sha256_finish_ret( mbedtls_sha256_context *ctx,
                                unsigned char output[32] );
@@ -134,10 +144,12 @@
  *                 the ongoing SHA-256 computation. This function is for
  *                 internal use only.
  *
- * \param ctx      The SHA-256 context.
- * \param data     The buffer holding one block of data.
+ * \param ctx      The SHA-256 context. This must be initialized.
+ * \param data     The buffer holding one block of data. This must
+ *                 be a readable buffer of length \c 64 Bytes.
  *
  * \return         \c 0 on success.
+ * \return         A negative error code on failure.
  */
 int mbedtls_internal_sha256_process( mbedtls_sha256_context *ctx,
                                      const unsigned char data[64] );
@@ -152,12 +164,11 @@
  * \brief          This function starts a SHA-224 or SHA-256 checksum
  *                 calculation.
  *
- *
  * \deprecated     Superseded by mbedtls_sha256_starts_ret() in 2.7.0.
  *
- * \param ctx      The context to initialize.
- * \param is224    Determines which function to use:
- *                 0: Use SHA-256, or 1: Use SHA-224.
+ * \param ctx      The context to use. This must be initialized.
+ * \param is224    Determines which function to use. This must be
+ *                 either \c 0 for SHA-256, or \c 1 for SHA-224.
  */
 MBEDTLS_DEPRECATED void mbedtls_sha256_starts( mbedtls_sha256_context *ctx,
                                                int is224 );
@@ -168,9 +179,11 @@
  *
  * \deprecated     Superseded by mbedtls_sha256_update_ret() in 2.7.0.
  *
- * \param ctx      The SHA-256 context to initialize.
- * \param input    The buffer holding the data.
- * \param ilen     The length of the input data.
+ * \param ctx      The SHA-256 context to use. This must be
+ *                 initialized and have a hash operation started.
+ * \param input    The buffer holding the data. This must be a readable
+ *                 buffer of length \p ilen Bytes.
+ * \param ilen     The length of the input data in Bytes.
  */
 MBEDTLS_DEPRECATED void mbedtls_sha256_update( mbedtls_sha256_context *ctx,
                                                const unsigned char *input,
@@ -182,8 +195,10 @@
  *
  * \deprecated     Superseded by mbedtls_sha256_finish_ret() in 2.7.0.
  *
- * \param ctx      The SHA-256 context.
- * \param output   The SHA-224 or SHA-256 checksum result.
+ * \param ctx      The SHA-256 context. This must be initialized and
+ *                 have a hash operation started.
+ * \param output   The SHA-224 or SHA-256 checksum result. This must be
+ *                 a writable buffer of length \c 32 Bytes.
  */
 MBEDTLS_DEPRECATED void mbedtls_sha256_finish( mbedtls_sha256_context *ctx,
                                                unsigned char output[32] );
@@ -195,8 +210,9 @@
  *
  * \deprecated     Superseded by mbedtls_internal_sha256_process() in 2.7.0.
  *
- * \param ctx      The SHA-256 context.
- * \param data     The buffer holding one block of data.
+ * \param ctx      The SHA-256 context. This must be initialized.
+ * \param data     The buffer holding one block of data. This must be
+ *                 a readable buffer of size \c 64 Bytes.
  */
 MBEDTLS_DEPRECATED void mbedtls_sha256_process( mbedtls_sha256_context *ctx,
                                                 const unsigned char data[64] );
@@ -214,11 +230,13 @@
  *                 The SHA-256 result is calculated as
  *                 output = SHA-256(input buffer).
  *
- * \param input    The buffer holding the input data.
- * \param ilen     The length of the input data.
- * \param output   The SHA-224 or SHA-256 checksum result.
- * \param is224    Determines which function to use:
- *                 0: Use SHA-256, or 1: Use SHA-224.
+ * \param input    The buffer holding the data. This must be a readable
+ *                 buffer of length \p ilen Bytes.
+ * \param ilen     The length of the input data in Bytes.
+ * \param output   The SHA-224 or SHA-256 checksum result. This must
+ *                 be a writable buffer of length \c 32 Bytes.
+ * \param is224    Determines which function to use. This must be
+ *                 either \c 0 for SHA-256, or \c 1 for SHA-224.
  */
 int mbedtls_sha256_ret( const unsigned char *input,
                         size_t ilen,
@@ -244,11 +262,13 @@
  *
  * \deprecated     Superseded by mbedtls_sha256_ret() in 2.7.0.
  *
- * \param input    The buffer holding the data.
- * \param ilen     The length of the input data.
- * \param output   The SHA-224 or SHA-256 checksum result.
- * \param is224    Determines which function to use:
- *                 0: Use SHA-256, or 1: Use SHA-224.
+ * \param input    The buffer holding the data. This must be a readable
+ *                 buffer of length \p ilen Bytes.
+ * \param ilen     The length of the input data in Bytes.
+ * \param output   The SHA-224 or SHA-256 checksum result. This must be
+ *                 a writable buffer of length \c 32 Bytes.
+ * \param is224    Determines which function to use. This must be either
+ *                 \c 0 for SHA-256, or \c 1 for SHA-224.
  */
 MBEDTLS_DEPRECATED void mbedtls_sha256( const unsigned char *input,
                                         size_t ilen,
diff --git a/library/error.c b/library/error.c
index 94f7cc7..eb00227 100644
--- a/library/error.c
+++ b/library/error.c
@@ -862,6 +862,8 @@
 #if defined(MBEDTLS_SHA256_C)
     if( use_ret == -(MBEDTLS_ERR_SHA256_HW_ACCEL_FAILED) )
         mbedtls_snprintf( buf, buflen, "SHA256 - SHA-256 hardware accelerator failed" );
+    if( use_ret == -(MBEDTLS_ERR_SHA256_BAD_INPUT_DATA) )
+        mbedtls_snprintf( buf, buflen, "SHA256 - SHA-256 input data was malformed" );
 #endif /* MBEDTLS_SHA256_C */
 
 #if defined(MBEDTLS_SHA512_C)
diff --git a/library/sha256.c b/library/sha256.c
index dbb4a89..8a540ad 100644
--- a/library/sha256.c
+++ b/library/sha256.c
@@ -49,6 +49,10 @@
 #endif /* MBEDTLS_PLATFORM_C */
 #endif /* MBEDTLS_SELF_TEST */
 
+#define SHA256_VALIDATE_RET(cond)                           \
+    MBEDTLS_INTERNAL_VALIDATE_RET( cond, MBEDTLS_ERR_SHA256_BAD_INPUT_DATA )
+#define SHA256_VALIDATE(cond)  MBEDTLS_INTERNAL_VALIDATE( cond )
+
 #if !defined(MBEDTLS_SHA256_ALT)
 
 /*
@@ -76,6 +80,8 @@
 
 void mbedtls_sha256_init( mbedtls_sha256_context *ctx )
 {
+    SHA256_VALIDATE( ctx != NULL );
+
     memset( ctx, 0, sizeof( mbedtls_sha256_context ) );
 }
 
@@ -90,6 +96,9 @@
 void mbedtls_sha256_clone( mbedtls_sha256_context *dst,
                            const mbedtls_sha256_context *src )
 {
+    SHA256_VALIDATE( dst != NULL );
+    SHA256_VALIDATE( src != NULL );
+
     *dst = *src;
 }
 
@@ -98,6 +107,9 @@
  */
 int mbedtls_sha256_starts_ret( mbedtls_sha256_context *ctx, int is224 )
 {
+    SHA256_VALIDATE_RET( ctx != NULL );
+    SHA256_VALIDATE_RET( is224 == 0 || is224 == 1 );
+
     ctx->total[0] = 0;
     ctx->total[1] = 0;
 
@@ -192,6 +204,9 @@
     uint32_t A[8];
     unsigned int i;
 
+    SHA256_VALIDATE_RET( ctx != NULL );
+    SHA256_VALIDATE_RET( (const unsigned char *)data != NULL );
+
     for( i = 0; i < 8; i++ )
         A[i] = ctx->state[i];
 
@@ -263,6 +278,9 @@
     size_t fill;
     uint32_t left;
 
+    SHA256_VALIDATE_RET( ctx != NULL );
+    SHA256_VALIDATE_RET( ilen == 0 || input != NULL );
+
     if( ilen == 0 )
         return( 0 );
 
@@ -321,6 +339,9 @@
     uint32_t used;
     uint32_t high, low;
 
+    SHA256_VALIDATE_RET( ctx != NULL );
+    SHA256_VALIDATE_RET( (unsigned char *)output != NULL );
+
     /*
      * Add padding: 0x80 then 0x00 until 8 bytes remain for the length
      */
@@ -395,6 +416,10 @@
     int ret;
     mbedtls_sha256_context ctx;
 
+    SHA256_VALIDATE_RET( is224 == 0 || is224 == 1 );
+    SHA256_VALIDATE_RET( ilen == 0 || input != NULL );
+    SHA256_VALIDATE_RET( (unsigned char *)output != NULL );
+
     mbedtls_sha256_init( &ctx );
 
     if( ( ret = mbedtls_sha256_starts_ret( &ctx, is224 ) ) != 0 )
diff --git a/tests/suites/test_suite_shax.data b/tests/suites/test_suite_shax.data
index 5bd70af..6042a8a 100644
--- a/tests/suites/test_suite_shax.data
+++ b/tests/suites/test_suite_shax.data
@@ -45,6 +45,12 @@
 depends_on:MBEDTLS_SHA1_C
 mbedtls_sha1:"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":"11863b483809ef88413ca9b0084ac4a5390640af"
 
+SHA-256 Valid parameters
+sha256_valid_param:
+
+SHA-256 Invalid parameters
+sha256_invalid_param:
+
 SHA-224 Test Vector NIST CAVS #1
 depends_on:MBEDTLS_SHA256_C
 sha224:"":"d14a028c2a3a2bc9476102bb288234c415a2b01f828ea62ac5b3e42f"
diff --git a/tests/suites/test_suite_shax.function b/tests/suites/test_suite_shax.function
index c035ae9..c57c99e 100644
--- a/tests/suites/test_suite_shax.function
+++ b/tests/suites/test_suite_shax.function
@@ -66,6 +66,62 @@
 /* END_CASE */
 
 /* BEGIN_CASE depends_on:MBEDTLS_SHA256_C */
+void sha256_valid_param( )
+{
+    TEST_VALID_PARAM( mbedtls_sha256_free( NULL ) );
+}
+/* END_CASE */
+
+/* BEGIN_CASE depends_on:MBEDTLS_SHA256_C:MBEDTLS_CHECK_PARAMS:!MBEDTLS_PARAM_FAILED_ALT */
+void sha256_invalid_param( )
+{
+    mbedtls_sha256_context ctx;
+    unsigned char buf[64] = { 0 };
+    size_t const buflen = sizeof( buf );
+    int valid_type = 0;
+    int invalid_type = 42;
+
+    TEST_INVALID_PARAM( mbedtls_sha256_init( NULL ) );
+
+    TEST_INVALID_PARAM( mbedtls_sha256_clone( NULL, &ctx ) );
+    TEST_INVALID_PARAM( mbedtls_sha256_clone( &ctx, NULL ) );
+
+    TEST_INVALID_PARAM_RET( MBEDTLS_ERR_SHA256_BAD_INPUT_DATA,
+                            mbedtls_sha256_starts_ret( NULL, valid_type ) );
+    TEST_INVALID_PARAM_RET( MBEDTLS_ERR_SHA256_BAD_INPUT_DATA,
+                            mbedtls_sha256_starts_ret( &ctx, invalid_type ) );
+
+    TEST_INVALID_PARAM_RET( MBEDTLS_ERR_SHA256_BAD_INPUT_DATA,
+                            mbedtls_sha256_update_ret( NULL, buf, buflen ) );
+    TEST_INVALID_PARAM_RET( MBEDTLS_ERR_SHA256_BAD_INPUT_DATA,
+                            mbedtls_sha256_update_ret( &ctx, NULL, buflen ) );
+
+    TEST_INVALID_PARAM_RET( MBEDTLS_ERR_SHA256_BAD_INPUT_DATA,
+                            mbedtls_sha256_finish_ret( NULL, buf ) );
+    TEST_INVALID_PARAM_RET( MBEDTLS_ERR_SHA256_BAD_INPUT_DATA,
+                            mbedtls_sha256_finish_ret( &ctx, NULL ) );
+
+    TEST_INVALID_PARAM_RET( MBEDTLS_ERR_SHA256_BAD_INPUT_DATA,
+                            mbedtls_internal_sha256_process( NULL, buf ) );
+    TEST_INVALID_PARAM_RET( MBEDTLS_ERR_SHA256_BAD_INPUT_DATA,
+                            mbedtls_internal_sha256_process( &ctx, NULL ) );
+
+    TEST_INVALID_PARAM_RET( MBEDTLS_ERR_SHA256_BAD_INPUT_DATA,
+                            mbedtls_sha256_ret( NULL, buflen,
+                                                buf, valid_type ) );
+    TEST_INVALID_PARAM_RET( MBEDTLS_ERR_SHA256_BAD_INPUT_DATA,
+                            mbedtls_sha256_ret( buf, buflen,
+                                                NULL, valid_type ) );
+    TEST_INVALID_PARAM_RET( MBEDTLS_ERR_SHA256_BAD_INPUT_DATA,
+                            mbedtls_sha256_ret( buf, buflen,
+                                                buf, invalid_type ) );
+
+exit:
+    return;
+}
+/* END_CASE */
+
+/* BEGIN_CASE depends_on:MBEDTLS_SHA256_C */
 void sha224( data_t * src_str, data_t * hex_hash_string )
 {
     unsigned char output[57];