Fix buffer overflow vulnerability in curve, font, particles code.

Solves these security issues from T52924:
CVE-2017-12102
CVE-2017-12103
CVE-2017-12104

While the specific overflow issue may be fixed, loading the repro .blend
files may still crash because they are incomplete and corrupt. The way
they crash may be impossible to exploit, but this is difficult to prove.

Differential Revision: https://developer.blender.org/D3002

1 files changed, 19 insertions, 7 deletions

diff --git a/source/blender/blenkernel/intern/curve.c b/source/blender/blenkernel/intern/curve.c
index 91fe44e4d54..1a744ddaf03 100644
--- a/source/blender/blenkernel/intern/curve.c
+++ b/source/blender/blenkernel/intern/curve.c
@@ -2687,7 +2687,8 @@ void BKE_curve_bevelList_make(Object *ob, ListBase *nurbs, bool for_render)
 		/* check we are a single point? also check we are not a surface and that the orderu is sane,
 		 * enforced in the UI but can go wrong possibly */
 		if (!BKE_nurb_check_valid_u(nu)) {
-			bl = MEM_callocN(sizeof(BevList) + 1 * sizeof(BevPoint), "makeBevelList1");
+			bl = MEM_callocN(sizeof(BevList), "makeBevelList1");
+			bl->bevpoints = MEM_calloc_arrayN(1, sizeof(BevPoint), "makeBevelPoints1");
 			BLI_addtail(bev, bl);
 			bl->nr = 0;
 			bl->charidx = nu->charidx;
@@ -2704,7 +2705,8 @@ void BKE_curve_bevelList_make(Object *ob, ListBase *nurbs, bool for_render)
 
 			if (nu->type == CU_POLY) {
 				len = nu->pntsu;
-				bl = MEM_callocN(sizeof(BevList) + len * sizeof(BevPoint), "makeBevelList2");
+				bl = MEM_callocN(sizeof(BevList), "makeBevelList2");
+				bl->bevpoints = MEM_calloc_arrayN(len, sizeof(BevPoint), "makeBevelPoints2");
 				if (need_seglen && (nu->flagu & CU_NURB_CYCLIC) == 0) {
 					bl->seglen = MEM_malloc_arrayN(segcount, sizeof(float), "makeBevelList2_seglen");
 					bl->segbevcount = MEM_malloc_arrayN(segcount, sizeof(int), "makeBevelList2_segbevcount");
@@ -2750,7 +2752,8 @@ void BKE_curve_bevelList_make(Object *ob, ListBase *nurbs, bool for_render)
 				/* in case last point is not cyclic */
 				len = segcount * resolu + 1;
 
-				bl = MEM_callocN(sizeof(BevList) + len * sizeof(BevPoint), "makeBevelBPoints");
+				bl = MEM_callocN(sizeof(BevList), "makeBevelBPoints");
+				bl->bevpoints = MEM_calloc_arrayN(len, sizeof(BevPoint), "makeBevelBPointsPoints");
 				if (need_seglen && (nu->flagu & CU_NURB_CYCLIC) == 0) {
 					bl->seglen = MEM_malloc_arrayN(segcount, sizeof(float), "makeBevelBPoints_seglen");
 					bl->segbevcount = MEM_malloc_arrayN(segcount, sizeof(int), "makeBevelBPoints_segbevcount");
@@ -2886,7 +2889,8 @@ void BKE_curve_bevelList_make(Object *ob, ListBase *nurbs, bool for_render)
 				if (nu->pntsv == 1) {
 					len = (resolu * segcount);
 
-					bl = MEM_callocN(sizeof(BevList) + len * sizeof(BevPoint), "makeBevelList3");
+					bl = MEM_callocN(sizeof(BevList), "makeBevelList3");
+					bl->bevpoints = MEM_calloc_arrayN(len, sizeof(BevPoint), "makeBevelPoints3");
 					if (need_seglen && (nu->flagu & CU_NURB_CYCLIC) == 0) {
 						bl->seglen = MEM_malloc_arrayN(segcount, sizeof(float), "makeBevelList3_seglen");
 						bl->segbevcount = MEM_malloc_arrayN(segcount, sizeof(int), "makeBevelList3_segbevcount");
@@ -2984,8 +2988,13 @@ void BKE_curve_bevelList_make(Object *ob, ListBase *nurbs, bool for_render)
 		blnext = bl->next;
 		if (bl->nr && bl->dupe_nr) {
 			nr = bl->nr - bl->dupe_nr + 1;  /* +1 because vectorbezier sets flag too */
-			blnew = MEM_mallocN(sizeof(BevList) + nr * sizeof(BevPoint), "makeBevelList4");
+			blnew = MEM_callocN(sizeof(BevList), "makeBevelList4");
 			memcpy(blnew, bl, sizeof(BevList));
+			blnew->bevpoints = MEM_calloc_arrayN(nr, sizeof(BevPoint), "makeBevelPoints4");
+			if (!blnew->bevpoints) {
+				MEM_freeN(blnew);
+				break;
+			}
 			blnew->segbevcount = bl->segbevcount;
 			blnew->seglen = bl->seglen;
 			blnew->nr = 0;
@@ -3002,6 +3011,9 @@ void BKE_curve_bevelList_make(Object *ob, ListBase *nurbs, bool for_render)
 				}
 				bevp0++;
 			}
+			if (bl->bevpoints != NULL) {
+				MEM_freeN(bl->bevpoints);
+			}
 			MEM_freeN(bl);
 			blnew->dupe_nr = 0;
 		}
@@ -3440,7 +3452,7 @@ static void calchandlesNurb_intern(Nurb *nu, bool skip_align)
  */
 static void *allocate_arrays(int count, float ***floats, char ***chars, const char *name)
 {
-	int num_floats = 0, num_chars = 0;
+	size_t num_floats = 0, num_chars = 0;
 
 	while (floats && floats[num_floats]) {
 		num_floats++;
@@ -3450,7 +3462,7 @@ static void *allocate_arrays(int count, float ***floats, char ***chars, const ch
 		num_chars++;
 	}
 
-	void *buffer = (float *)MEM_mallocN(count * (sizeof(float) * num_floats + num_chars), name);
+	void *buffer = (float *)MEM_malloc_arrayN(count, (sizeof(float) * num_floats + num_chars), name);
 
 	if (!buffer)
 		return NULL;