Merge pull request #612 from besser82/topic/besser82/json-c-0.11/CVE-2020-12762

json-c-0.11: Fix CVE-2020-12762 - json-c through 0.14 has an integer overflow and out-of-bounds write ...

linkhash.c

@@ -10,6 +10,7 @@
  *
  */
 
+#include <assert.h>
 #include <stdio.h>
 #include <string.h>
 #include <stdlib.h>
@@ -62,6 +63,8 @@ struct lh_table* lh_table_new(int size, const char *name,
 	int i;
 	struct lh_table *t;
 
+	/* Allocate space for elements to avoid divisions by zero. */
+	assert(size > 0);
 	t = (struct lh_table*)calloc(1, sizeof(struct lh_table));
 	if(!t) lh_abort("lh_table_new: calloc failed\n");
 	t->count = 0;
@@ -126,7 +129,14 @@ int lh_table_insert(struct lh_table *t, void *k, const void *v)
 	unsigned long h, n;
 
 	t->inserts++;
-	if(t->count >= t->size * LH_LOAD_FACTOR) lh_table_resize(t, t->size * 2);
+	if (t->count >= t->size * LH_LOAD_FACTOR) {
+		/* Avoid signed integer overflow with large tables. */
+		int new_size = (t->size > INT_MAX / 2) ? INT_MAX : (t->size * 2);
+		if (t->size == INT_MAX)
+			return -1;
+
+		lh_table_resize(t, new_size);
+	}
 
 	h = t->hash_fn(k);
 	n = h % t->size;

printbuf.c

@@ -15,6 +15,7 @@
 
 #include "config.h"
 
+#include <limits.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -63,7 +64,16 @@ static int printbuf_extend(struct printbuf *p, int min_size)
 	if (p->size >= min_size)
 		return 0;
 
-	new_size = json_max(p->size * 2, min_size + 8);
+	/* Prevent signed integer overflows with large buffers. */
+	if (min_size > INT_MAX - 8)
+		return -1;
+	if (p->size > INT_MAX / 2)
+		new_size =  min_size + 8;
+	else {
+		new_size = p->size * 2;
+		if (new_size < min_size + 8)
+			new_size = min_size + 8;
+	}
 #ifdef PRINTBUF_DEBUG
 	MC_DEBUG("printbuf_memappend: realloc "
 	  "bpos=%d min_size=%d old_size=%d new_size=%d\n",
@@ -78,6 +88,9 @@ static int printbuf_extend(struct printbuf *p, int min_size)
 
 int printbuf_memappend(struct printbuf *p, const char *buf, int size)
 {
+  /* Prevent signed integer overflows with large buffers. */
+  if (size > INT_MAX - p->bpos - 1)
+    return -1;
   if (p->size <= p->bpos + size + 1) {
     if (printbuf_extend(p, p->bpos + size + 1) < 0)
       return -1;
@@ -94,6 +107,9 @@ int printbuf_memset(struct printbuf *pb, int offset, int charvalue, int len)
 
 	if (offset == -1)
 		offset = pb->bpos;
+	/* Prevent signed integer overflows with large buffers. */
+	if (len > INT_MAX - offset)
+		return -1;
 	size_needed = offset + len;
 	if (pb->size < size_needed)
 	{

tests/test4.c

@@ -2,9 +2,11 @@
  * gcc -o utf8 utf8.c -I/home/y/include -L./.libs -ljson
  */
 
-#include <stdio.h>
-#include <string.h>
 #include "config.h"
+#include <assert.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
 
 #include "json_inttypes.h"
 #include "json_object.h"
@@ -24,6 +26,30 @@ void print_hex( const char* s)
 	printf("\n");
 }
 
+static void test_lot_of_adds(void);
+static void test_lot_of_adds()
+{
+	int ii;
+	char key[50];
+	json_object *jobj = json_object_new_object();
+	assert(jobj != NULL);
+	for (ii = 0; ii < 500; ii++)
+	{
+		snprintf(key, sizeof(key), "k%d", ii);
+		json_object *iobj = json_object_new_int(ii);
+		assert(iobj != NULL);
+		json_object_object_add(jobj, key, iobj);
+		if (json_object_object_get_ex(jobj, key, &iobj) == FALSE)
+		{
+			fprintf(stderr, "FAILED to add object #%d\n", ii);
+			abort();
+		}
+	}
+	printf("%s\n", json_object_to_json_string(jobj));
+	assert(json_object_object_length(jobj) == 500);
+	json_object_put(jobj);
+}
+
 int main()
 {
 	const char *input = "\"\\ud840\\udd26,\\ud840\\udd27,\\ud800\\udd26,\\ud800\\udd27\"";
@@ -49,5 +75,8 @@ int main()
 		retval = 1;
 	}
 	json_object_put(parse_result);
+
+	test_lot_of_adds();
+
 	return retval;
 }

tests/test4.expected

@@ -1,3 +1,4 @@
 input: "\ud840\udd26,\ud840\udd27,\ud800\udd26,\ud800\udd27"
 JSON parse result is correct: 𠄦,𠄧,𐄦,𐄧
 PASS
+{ "k0": 0, "k1": 1, "k2": 2, "k3": 3, "k4": 4, "k5": 5, "k6": 6, "k7": 7, "k8": 8, "k9": 9, "k10": 10, "k11": 11, "k12": 12, "k13": 13, "k14": 14, "k15": 15, "k16": 16, "k17": 17, "k18": 18, "k19": 19, "k20": 20, "k21": 21, "k22": 22, "k23": 23, "k24": 24, "k25": 25, "k26": 26, "k27": 27, "k28": 28, "k29": 29, "k30": 30, "k31": 31, "k32": 32, "k33": 33, "k34": 34, "k35": 35, "k36": 36, "k37": 37, "k38": 38, "k39": 39, "k40": 40, "k41": 41, "k42": 42, "k43": 43, "k44": 44, "k45": 45, "k46": 46, "k47": 47, "k48": 48, "k49": 49, "k50": 50, "k51": 51, "k52": 52, "k53": 53, "k54": 54, "k55": 55, "k56": 56, "k57": 57, "k58": 58, "k59": 59, "k60": 60, "k61": 61, "k62": 62, "k63": 63, "k64": 64, "k65": 65, "k66": 66, "k67": 67, "k68": 68, "k69": 69, "k70": 70, "k71": 71, "k72": 72, "k73": 73, "k74": 74, "k75": 75, "k76": 76, "k77": 77, "k78": 78, "k79": 79, "k80": 80, "k81": 81, "k82": 82, "k83": 83, "k84": 84, "k85": 85, "k86": 86, "k87": 87, "k88": 88, "k89": 89, "k90": 90, "k91": 91, "k92": 92, "k93": 93, "k94": 94, "k95": 95, "k96": 96, "k97": 97, "k98": 98, "k99": 99, "k100": 100, "k101": 101, "k102": 102, "k103": 103, "k104": 104, "k105": 105, "k106": 106, "k107": 107, "k108": 108, "k109": 109, "k110": 110, "k111": 111, "k112": 112, "k113": 113, "k114": 114, "k115": 115, "k116": 116, "k117": 117, "k118": 118, "k119": 119, "k120": 120, "k121": 121, "k122": 122, "k123": 123, "k124": 124, "k125": 125, "k126": 126, "k127": 127, "k128": 128, "k129": 129, "k130": 130, "k131": 131, "k132": 132, "k133": 133, "k134": 134, "k135": 135, "k136": 136, "k137": 137, "k138": 138, "k139": 139, "k140": 140, "k141": 141, "k142": 142, "k143": 143, "k144": 144, "k145": 145, "k146": 146, "k147": 147, "k148": 148, "k149": 149, "k150": 150, "k151": 151, "k152": 152, "k153": 153, "k154": 154, "k155": 155, "k156": 156, "k157": 157, "k158": 158, "k159": 159, "k160": 160, "k161": 161, "k162": 162, "k163": 163, "k164": 164, "k165": 165, "k166": 166, "k167": 167, "k168": 168, "k169": 169, "k170": 170, "k171": 171, "k172": 172, "k173": 173, "k174": 174, "k175": 175, "k176": 176, "k177": 177, "k178": 178, "k179": 179, "k180": 180, "k181": 181, "k182": 182, "k183": 183, "k184": 184, "k185": 185, "k186": 186, "k187": 187, "k188": 188, "k189": 189, "k190": 190, "k191": 191, "k192": 192, "k193": 193, "k194": 194, "k195": 195, "k196": 196, "k197": 197, "k198": 198, "k199": 199, "k200": 200, "k201": 201, "k202": 202, "k203": 203, "k204": 204, "k205": 205, "k206": 206, "k207": 207, "k208": 208, "k209": 209, "k210": 210, "k211": 211, "k212": 212, "k213": 213, "k214": 214, "k215": 215, "k216": 216, "k217": 217, "k218": 218, "k219": 219, "k220": 220, "k221": 221, "k222": 222, "k223": 223, "k224": 224, "k225": 225, "k226": 226, "k227": 227, "k228": 228, "k229": 229, "k230": 230, "k231": 231, "k232": 232, "k233": 233, "k234": 234, "k235": 235, "k236": 236, "k237": 237, "k238": 238, "k239": 239, "k240": 240, "k241": 241, "k242": 242, "k243": 243, "k244": 244, "k245": 245, "k246": 246, "k247": 247, "k248": 248, "k249": 249, "k250": 250, "k251": 251, "k252": 252, "k253": 253, "k254": 254, "k255": 255, "k256": 256, "k257": 257, "k258": 258, "k259": 259, "k260": 260, "k261": 261, "k262": 262, "k263": 263, "k264": 264, "k265": 265, "k266": 266, "k267": 267, "k268": 268, "k269": 269, "k270": 270, "k271": 271, "k272": 272, "k273": 273, "k274": 274, "k275": 275, "k276": 276, "k277": 277, "k278": 278, "k279": 279, "k280": 280, "k281": 281, "k282": 282, "k283": 283, "k284": 284, "k285": 285, "k286": 286, "k287": 287, "k288": 288, "k289": 289, "k290": 290, "k291": 291, "k292": 292, "k293": 293, "k294": 294, "k295": 295, "k296": 296, "k297": 297, "k298": 298, "k299": 299, "k300": 300, "k301": 301, "k302": 302, "k303": 303, "k304": 304, "k305": 305, "k306": 306, "k307": 307, "k308": 308, "k309": 309, "k310": 310, "k311": 311, "k312": 312, "k313": 313, "k314": 314, "k315": 315, "k316": 316, "k317": 317, "k318": 318, "k319": 319, "k320": 320, "k321": 321, "k322": 322, "k323": 323, "k324": 324, "k325": 325, "k326": 326, "k327": 327, "k328": 328, "k329": 329, "k330": 330, "k331": 331, "k332": 332, "k333": 333, "k334": 334, "k335": 335, "k336": 336, "k337": 337, "k338": 338, "k339": 339, "k340": 340, "k341": 341, "k342": 342, "k343": 343, "k344": 344, "k345": 345, "k346": 346, "k347": 347, "k348": 348, "k349": 349, "k350": 350, "k351": 351, "k352": 352, "k353": 353, "k354": 354, "k355": 355, "k356": 356, "k357": 357, "k358": 358, "k359": 359, "k360": 360, "k361": 361, "k362": 362, "k363": 363, "k364": 364, "k365": 365, "k366": 366, "k367": 367, "k368": 368, "k369": 369, "k370": 370, "k371": 371, "k372": 372, "k373": 373, "k374": 374, "k375": 375, "k376": 376, "k377": 377, "k378": 378, "k379": 379, "k380": 380, "k381": 381, "k382": 382, "k383": 383, "k384": 384, "k385": 385, "k386": 386, "k387": 387, "k388": 388, "k389": 389, "k390": 390, "k391": 391, "k392": 392, "k393": 393, "k394": 394, "k395": 395, "k396": 396, "k397": 397, "k398": 398, "k399": 399, "k400": 400, "k40Line truncated