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fix heap overflow in cupsJSONExportString for non-root nodes #187

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Merged
michaelrsweet merged 1 commit into from
Oct 22, 2026
Merged

fix heap overflow in cupsJSONExportString for non-root nodes #187

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2 changes: 2 additions & 0 deletions CHANGES.md
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Original file line number Diff line number Diff line change
Expand Up @@ -43,6 +43,8 @@ v3.0.4 - YYYY-MM-DD
- Fixed `ippValidateAttribute` not returning `false` for too-long URIs.
- Fixed a memory leak in `httpGetSecurity` when using GNU TLS.
- Fixed a memory leak in `cupsJWTImportString`.
- Fixed a buffer overflow in `cupsJSONExportString` when exporting a child
node.
- Fixed a bug in `cupsJWTExportString` with JSON output.


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30 changes: 25 additions & 5 deletions cups/json.c
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Original file line number Diff line number Diff line change
Expand Up @@ -250,7 +250,7 @@ cupsJSONExportString(cups_json_t *json) // I - JSON root node

while (current)
{
if (current->parent && current->parent->value.child != current)
if (current != json && current->parent && current->parent->value.child != current)
length ++; // Comma or colon separator

switch (current->type)
Expand Down Expand Up @@ -295,6 +295,11 @@ cupsJSONExportString(cups_json_t *json) // I - JSON root node
// Descend
current = current->value.child;
}
else if (current == json)
{
// Done with the node being exported...
current = NULL;
}
else if (current->sibling)
{
// Visit sibling
Expand All @@ -306,7 +311,12 @@ cupsJSONExportString(cups_json_t *json) // I - JSON root node
current = current->parent;
while (current)
{
if (current->sibling)
if (current == json)
{
current = NULL;
break;
}
else if (current->sibling)
{
current = current->sibling;
break;
Expand Down Expand Up @@ -335,7 +345,7 @@ cupsJSONExportString(cups_json_t *json) // I - JSON root node

while (current)
{
if (current->parent && current->parent->value.child != current)
if (current != json && current->parent && current->parent->value.child != current)
{
// Add separator
if (current->type == CUPS_JTYPE_KEY || current->parent->type == CUPS_JTYPE_ARRAY)
Expand Down Expand Up @@ -443,7 +453,12 @@ cupsJSONExportString(cups_json_t *json) // I - JSON root node
else if (current->type == CUPS_JTYPE_OBJECT)
*ptr++ = '}';

if (current->sibling)
if (current == json)
{
// Done with the node being exported...
current = NULL;
}
else if (current->sibling)
{
// Visit sibling
current = current->sibling;
Expand All @@ -459,7 +474,12 @@ cupsJSONExportString(cups_json_t *json) // I - JSON root node
else if (current->type == CUPS_JTYPE_OBJECT)
*ptr++ = '}';

if (current->sibling)
if (current == json)
{
current = NULL;
break;
}
else if (current->sibling)
{
current = current->sibling;
break;
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18 changes: 18 additions & 0 deletions cups/testjson.c
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Expand Up @@ -267,6 +267,24 @@ main(int argc, // I - Number of command-line arguments
testEndMessage(false, "unable to load Unicode surrogate escapes");
}

testBegin("cupsJSONExportString(child object)");
if ((json = cupsJSONImportString("{\"a\":{\"b\":[1,2],\"c\":{\"d\":true}},\"e\":null}")) != NULL)
{
if ((s = cupsJSONExportString(cupsJSONFind(json, "a"))) == NULL)
testEndMessage(false, "%s", cupsGetErrorString());
else if (strcmp(s, "{\"b\":[1,2],\"c\":{\"d\":true}}"))
testEndMessage(false, "got '%s'", s);
else
testEndMessage(true, "%s", s);

free(s);
cupsJSONDelete(json);
}
else
{
testEndMessage(false, "%s", cupsGetErrorString());
}

testBegin("cupsJSONImportURL('https://accounts.google.com/.well-known/openid-configuration', no last modified)");
json = cupsJSONImportURL("https://accounts.google.com/.well-known/openid-configuration", &last_modified);

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