tidy up max size in bytes for decoder input and encoder output (#300)

New #define QCBOR_SIZE_MAX that is the same max size for decoder input and encoder output #define QCBOR_MAX_DECODE_INPUT_SIZE is deprecated This cleans up a TODO: item for the largest size for encoded output Co-authored-by: Laurence Lundblade <[email protected]>
laurencelundblade · Jan 22, 2025 · aa7e30c · aa7e30c
1 parent 4cee345
commit aa7e30c
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Showing 10 changed files with 50 additions and 53 deletions.
diff --git a/inc/qcbor/qcbor_common.h b/inc/qcbor/qcbor_common.h
@@ -270,7 +270,7 @@ typedef enum {
    QCBOR_ERR_ENCODE_UNSUPPORTED = 2,
 
    /** During encoding, the length of the encoded CBOR exceeded
-    *  @ref QCBOR_MAX_ARRAY_OFFSET, which is slightly less than
+    *  @ref QCBOR_MAX_SIZE, which is slightly less than
     *  @c UINT32_MAX. */
    QCBOR_ERR_BUFFER_TOO_LARGE = 3,
 
@@ -361,7 +361,7 @@ typedef enum {
 #define QCBOR_END_OF_NOT_WELL_FORMED_ERRORS 39
 
    /** During decoding, the input is too large. It is greater than
-    *  QCBOR_MAX_DECODE_INPUT_SIZE. This is an implementation limit.
+    *  QCBOR_MAX_SIZE. This is an implementation limit.
     *  This error makes no further decoding possible. */
    QCBOR_ERR_INPUT_TOO_LARGE = 40,
 
@@ -599,7 +599,13 @@ const char *
 qcbor_err_to_str(QCBORError uErr);
 
 
-
+/* The maximum size in bytes for input to decode or encoder output. */
+/* It is slightly less than UINT32_MAX to accommodate
+ * QCBOR_NON_BOUNDED_OFFSET and so the limit can be tested on 32-bit
+ * machines. This will cause trouble where size_t is less than 32
+ * bits.
+ */
+#define QCBOR_MAX_SIZE  (UINT32_MAX - 100)
 
 /**
  * The maximum nesting of arrays and maps when encoding or

diff --git a/inc/qcbor/qcbor_main_decode.h b/inc/qcbor/qcbor_main_decode.h
@@ -2,7 +2,7 @@
  * qcbor_main_decode.h -- The main CBOR decoder.
  *
  * Copyright (c) 2016-2018, The Linux Foundation.
- * Copyright (c) 2018-2024, Laurence Lundblade.
+ * Copyright (c) 2018-2025, Laurence Lundblade.
  * Copyright (c) 2021, Arm Limited.
  * All rights reserved.
  *
@@ -286,11 +286,6 @@ typedef enum {
 
 
 
-/**
- * The maximum size of input to the decoder. Slightly less than
- * @c UINT32_MAX to make room for some special indicator values.
- */
-#define QCBOR_MAX_DECODE_INPUT_SIZE (UINT32_MAX - 2)
 
 /**
  * The maximum number of tags that may occur on an individual nested
@@ -1397,6 +1392,12 @@ QCBORDecode_SetError(QCBORDecodeContext *pCtx, QCBORError uError);
  *    They just have been replaced by something better.                      *
  * ========================================================================= */
 
+/**
+ * @deprecated  Use @ref QCBOR_MAX_SIZE instead.
+ */
+#define QCBOR_MAX_DECODE_INPUT_SIZE QCBOR_MAX_SIZE
+
+
 /**
  * @deprecated The v2 tag number behavior is more correct.
  * @brief [Deprecated] Configure CBOR decoder context for QCBOR v1 compatibility.
@@ -1583,11 +1584,11 @@ QCBORDecode_Private_GetAndTell(QCBORDecodeContext *pMe, QCBORItem *Item, size_t
 
 
 /* A few cross checks on size constants and special value lengths */
-#if  QCBOR_MAP_OFFSET_CACHE_INVALID < QCBOR_MAX_DECODE_INPUT_SIZE
+#if  QCBOR_MAP_OFFSET_CACHE_INVALID < QCBOR_MAX_SIZE
 #error QCBOR_MAP_OFFSET_CACHE_INVALID is too large
 #endif
 
-#if QCBOR_NON_BOUNDED_OFFSET < QCBOR_MAX_DECODE_INPUT_SIZE
+#if QCBOR_NON_BOUNDED_OFFSET < QCBOR_MAX_SIZE
 #error QCBOR_NON_BOUNDED_OFFSET is too large
 #endif
 

diff --git a/inc/qcbor/qcbor_private.h b/inc/qcbor/qcbor_private.h
@@ -2,7 +2,7 @@
  * qcbor_private -- Non-public data structures for encding and decoding.
  *
  * Copyright (c) 2016-2018, The Linux Foundation.
- * Copyright (c) 2018-2024, Laurence Lundblade.
+ * Copyright (c) 2018-2025, Laurence Lundblade.
  * Copyright (c) 2021, Arm Limited.
  * All rights reserved.
  *
@@ -160,17 +160,6 @@ extern "C" {
 #define CBOR_SIMPLEV_RESERVED_END    CBOR_SIMPLE_BREAK
 
 
-/* The largest offset to the start of an array or map. It is slightly
- * less than UINT32_MAX so the error condition can be tested on 32-bit
- * machines.  UINT32_MAX comes from uStart in QCBORTrackNesting being
- * a uin32_t.
- *
- * This will cause trouble on a machine where size_t is less than 32-bits.
- *
- * TODO: make this public?
- */
-#define QCBOR_MAX_ARRAY_OFFSET  (UINT32_MAX - 100)
-
 
 /* The number of tags that are 16-bit or larger that can be handled
  * in a decode.

diff --git a/src/decode_nesting.h b/src/decode_nesting.h
@@ -2,7 +2,7 @@
  * decode_nesting.c -- All inline implementation of QCBORDecodeNesting
  *
  * Copyright (c) 2016-2018, The Linux Foundation.
- * Copyright (c) 2018-2024, Laurence Lundblade.
+ * Copyright (c) 2018-2025, Laurence Lundblade.
  * Copyright (c) 2021, Arm Limited.
  * All rights reserved.
  *
@@ -336,12 +336,12 @@ DecodeNesting_EnterBoundedMapOrArray(QCBORDecodeNesting *pNesting,
     * Have descended into this before this is called. The job here is
     * just to mark it in bounded mode.
     *
-    * Check against QCBOR_MAX_DECODE_INPUT_SIZE make sure that
+    * Check against QCBOR_MAX_SIZE make sure that
     * uOffset doesn't collide with QCBOR_NON_BOUNDED_OFFSET.
     *
     * Cast of uOffset to uint32_t for cases where SIZE_MAX < UINT32_MAX.
     */
-   if((uint32_t)uOffset >= QCBOR_MAX_DECODE_INPUT_SIZE) {
+   if((uint32_t)uOffset >= QCBOR_MAX_SIZE) {
       return QCBOR_ERR_INPUT_TOO_LARGE;
    }
 

diff --git a/src/qcbor_main_encode.c b/src/qcbor_main_encode.c
@@ -1,6 +1,6 @@
 /* ===========================================================================
  * Copyright (c) 2016-2018, The Linux Foundation.
- * Copyright (c) 2018-2024, Laurence Lundblade.
+ * Copyright (c) 2018-2025, Laurence Lundblade.
  * Copyright (c) 2021, Arm Limited.
  * All rights reserved.
  *
@@ -644,13 +644,13 @@ QCBOREncode_Private_OpenMapOrArray(QCBOREncodeContext *pMe,
     */
    size_t uEndPosition = UsefulOutBuf_GetEndPosition(&(pMe->OutBuf));
 
-   /* QCBOR_MAX_ARRAY_OFFSET is slightly less than UINT32_MAX so this
+   /* QCBOR_MAX_SIZE is slightly less than UINT32_MAX so this
     * code can run on a 32-bit machine and tests can pass on a 32-bit
     * machine. If it was exactly UINT32_MAX, then this code would not
     * compile or run on a 32-bit machine and an #ifdef or some machine
-    * size detection would be needed reducing portability.
+    * size detection would be needed, reducing portability.
     */
-   if(uEndPosition >= QCBOR_MAX_ARRAY_OFFSET) {
+   if(uEndPosition >= QCBOR_MAX_SIZE) {
       pMe->uError = QCBOR_ERR_BUFFER_TOO_LARGE;
 
    } else {

diff --git a/src/qcbor_spiffy_decode.c b/src/qcbor_spiffy_decode.c
@@ -2,7 +2,7 @@
  * qcbor_spiffy_decode.c -- "Spiffy" QCBOR decoding
  *
  * Copyright (c) 2016-2018, The Linux Foundation.
- * Copyright (c) 2018-2024, Laurence Lundblade.
+ * Copyright (c) 2018-2025, Laurence Lundblade.
  * Copyright (c) 2021, Arm Limited.
  * All rights reserved.
  *
@@ -359,9 +359,9 @@ QCBORDecode_Private_MapSearch(QCBORDecodeContext *pMe,
 
    // Check here makes sure that this won't accidentally be
    // QCBOR_MAP_OFFSET_CACHE_INVALID which is larger than
-   // QCBOR_MAX_DECODE_INPUT_SIZE.
+   // QCBOR_MAX_SIZE.
    // Cast to uint32_t to possibly address cases where SIZE_MAX < UINT32_MAX
-   if((uint32_t)uEndOffset >= QCBOR_MAX_DECODE_INPUT_SIZE) {
+   if((uint32_t)uEndOffset >= QCBOR_MAX_SIZE) {
       uReturn = QCBOR_ERR_INPUT_TOO_LARGE;
       goto Done;
    }

diff --git a/src/qcbor_tag_decode.c b/src/qcbor_tag_decode.c
@@ -1,7 +1,7 @@
 /* ==========================================================================
  * qcbor_tag_decode.c -- Tag content decoders
  *
- * Copyright (c) 2024, Laurence Lundblade. All rights reserved.
+ * Copyright (c) 2025, Laurence Lundblade. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  *
@@ -658,14 +658,14 @@ QCBORDecode_Private_EnterBstrWrapped(QCBORDecodeContext          *pMe,
 
    const size_t uPreviousLength = UsefulInputBuf_GetBufferLength(&(pMe->InBuf));
    /* This check makes the cast of uPreviousLength to uint32_t below safe. */
-   if(uPreviousLength >= QCBOR_MAX_DECODE_INPUT_SIZE) {
+   if(uPreviousLength >= QCBOR_MAX_SIZE) {
       uError = QCBOR_ERR_INPUT_TOO_LARGE;
       goto Done;
    }
 
    const size_t uStartOfBstr = UsefulInputBuf_PointerToOffset(&(pMe->InBuf), pItem->val.string.ptr);
    /* This check makes the cast of uStartOfBstr to uint32_t below safe. */
-   if(uStartOfBstr == SIZE_MAX || uStartOfBstr > QCBOR_MAX_DECODE_INPUT_SIZE) {
+   if(uStartOfBstr == SIZE_MAX || uStartOfBstr > QCBOR_MAX_SIZE) {
       /* This should never happen because pItem->val.string.ptr should
        * always be valid since it was just returned.
        */

diff --git a/test/qcbor_decode_tests.c b/test/qcbor_decode_tests.c
@@ -1,6 +1,6 @@
 /*==============================================================================
  * Copyright (c) 2016-2018, The Linux Foundation.
- * Copyright (c) 2018-2024, Laurence Lundblade.
+ * Copyright (c) 2018-2025, Laurence Lundblade.
  * Copyright (c) 2021, Arm Limited.
  * All rights reserved.
  *
@@ -9210,19 +9210,20 @@ int32_t TooLargeInputTest(void)
    QCBORError         uErr;
    UsefulBufC         String;
 
-   // These tests require a build with QCBOR_MAX_DECODE_INPUT_SIZE set
-   // to 10 There's not really any way to test this error
-   // condition. The error condition is not complex, so setting
-   // QCBOR_MAX_DECODE_INPUT_SIZE gives an OK test.
-
-   // The input CBOR is only too large because the
-   // QCBOR_MAX_DECODE_INPUT_SIZE is 10.
-   //
-   // This test is disabled for the normal test runs because of the
-   // special build requirement.
+   /* These tests require a build with QCBOR_MAX_SIZE set
+    * to 10. There's not really any way to test this error
+    * condition. The error condition is not complex, so setting
+    * QCBOR_MAX_SIZE gives an OK test.
+    *
+    * The input CBOR is only too large because the
+    * QCBOR_MAX_SIZE is 10.
+    *
+    * This test is disabled for the normal test runs because of the
+    * special build requirement.
+    */
 
 
-   // Tests the start of a map being too large
+   /* Tests the start of a map being too large */
    QCBORDecode_Init(&DC, UsefulBuf_FROM_BYTE_ARRAY_LITERAL(spTooLarge1), QCBOR_DECODE_MODE_NORMAL);
    QCBORDecode_EnterArray(&DC, NULL);
    QCBORDecode_GetTextString(&DC, &String);
@@ -9236,7 +9237,7 @@ int32_t TooLargeInputTest(void)
       return 2;
    }
 
-   // Tests the end of a map being too large
+   /* Tests the end of a map being too large */
    QCBORDecode_Init(&DC, UsefulBuf_FROM_BYTE_ARRAY_LITERAL(spTooLarge2), QCBOR_DECODE_MODE_NORMAL);
    QCBORDecode_EnterArray(&DC, NULL);
    QCBORDecode_EnterMap(&DC, NULL);
@@ -9250,7 +9251,7 @@ int32_t TooLargeInputTest(void)
       return 4;
    }
 
-   // Tests the entire input CBOR being too large when processing bstr wrapping
+   /* Tests the entire input CBOR being too large when processing bstr wrapping */
    QCBORDecode_Init(&DC, UsefulBuf_FROM_BYTE_ARRAY_LITERAL(spTooLarge3), QCBOR_DECODE_MODE_NORMAL);
    QCBORDecode_EnterBstrWrapped(&DC, QCBOR_TAG_REQUIREMENT_NOT_A_TAG, NULL);
    uErr = QCBORDecode_GetError(&DC);

diff --git a/test/qcbor_decode_tests.h b/test/qcbor_decode_tests.h
@@ -291,7 +291,7 @@ int32_t DecodeTaggedTypeTests(void);
 
 /*
  Test the detection of input that is too large. Requires
- a special build that makes QCBOR_MAX_DECODE_INPUT_SIZE small.
+ a special build that makes QCBOR_MAX_SIZE small.
  */
 int32_t TooLargeInputTest(void);
 

diff --git a/test/qcbor_encode_tests.c b/test/qcbor_encode_tests.c
@@ -1,6 +1,6 @@
 /*==============================================================================
  Copyright (c) 2016-2018, The Linux Foundation.
- Copyright (c) 2018-2024, Laurence Lundblade.
+ Copyright (c) 2018-2025, Laurence Lundblade.
  Copyright (c) 2022, Arm Limited. All rights reserved.
 
 Redistribution and use in source and binary forms, with or without
@@ -2742,7 +2742,7 @@ int32_t EncodeErrorTests(void)
    // Third, fit an array in exactly at max position allowed
    QCBOREncode_Init(&EC, Buffer);
    QCBOREncode_OpenArray(&EC);
-   QCBOREncode_AddBytes(&EC, (UsefulBufC){NULL, QCBOR_MAX_ARRAY_OFFSET-6});
+   QCBOREncode_AddBytes(&EC, (UsefulBufC){NULL, QCBOR_MAX_SIZE-6});
    QCBOREncode_OpenArray(&EC);
    QCBOREncode_CloseArray(&EC);
    QCBOREncode_CloseArray(&EC);