scc

commit 591e4244db86933b8a9993ded234564c35451842
parent 9cb39b5284c0779a969928f0e1cb00d976686bf6
Author: Roberto E. Vargas Caballero <k0ga@shike2.com>
Date:   Wed, 27 Oct 2021 08:52:26 +0200

libmach/coff32: Improve error checks

Cases with number of items 0 were not correctly handled,
and in some cases dangling pointers were generated.

Diffstat:
M
src/libmach/coff32/coff32read.c
 | 
25
+++++++++++++++++--------

1 file changed, 17 insertions(+), 8 deletions(-)
diff --git a/src/libmach/coff32/coff32read.c b/src/libmach/coff32/coff32read.c
@@ -148,13 +148,15 @@ readstr(Obj *obj, FILE *fp)
 	coff  = obj->data;
 	hdr = &coff->hdr;
 
+	coff->strsiz = 0;
+	coff->strtbl = NULL;
+
 	if (hdr->f_nsyms == 0)
 		return 1;
 
 	if (fread(buf, 4, 1, fp) != 1)
 		return 0;
 	unpack(ORDER(obj->type), buf, "l", &siz);
-	coff->strsiz = 0;
 	if (siz < 4 || siz > SIZE_MAX) {
 		errno = ERANGE;
 		return 0;
@@ -184,6 +186,9 @@ readreloc(Obj *obj, FILE *fp)
 	coff  = obj->data;
 	hdr = &coff->hdr;
 
+	if (hdr->f_nscns == 0)
+		return 1;
+
 	rels = calloc(hdr->f_nscns, sizeof(*rels));
 	if (!rels)
 		return 0;
@@ -261,12 +266,13 @@ readscns(Obj *obj, FILE *fp)
 	coff  = obj->data;
 	hdr = &coff->hdr;
 
-	if (hdr->f_nscns > 0) {
-		scn = calloc(hdr->f_nscns, sizeof(*scn));
-		if (!scn)
-			return 0;
-		coff->scns = scn;
-	}
+	if (hdr->f_nscns == 0)
+		return 1;
+
+	scn = calloc(hdr->f_nscns, sizeof(*scn));
+	if (!scn)
+		return 0;
+	coff->scns = scn;
 
 	for (i = 0; i < hdr->f_nscns; i++) {
 		if (fread(buf, SCNHSZ, 1, fp) < 0)
@@ -290,7 +296,10 @@ readlines(Obj *obj, FILE *fp)
 	coff  = obj->data;
 	hdr = &coff->hdr;
 
-	lines = calloc(sizeof(lp), hdr->f_nscns);
+	if (hdr->f_nscns == 0)
+		return 1;
+
+	lines = calloc(hdr->f_nscns, sizeof(lp));
 	if (!lines)
 		return 0;
 	coff->lines = lines;