git: 9front

Download patch

ref: 85c410ab0f17cc19fb407f9e6c400b081904ea2f
parent: d6069be4911da8512235694905d1518184e73db8
author: cinap_lenrek <cinap_lenrek@felloff.net>
date: Thu Feb 27 20:23:11 EST 2014 

libsec: improve thumbprint code

1) handle errors when loading thumbprint file.
initThumbprints() now returns nil and sets errstr
on error. a syntax error in a thumbprint file
should be reported instead of silently ignored!
(have to check users)

2) fix memory leak in initThumbprints(); we have to use
freeThumbprints() instead of free to release crltab.

3) use the actual head entries for thumbprint
storage in the thumbprints array. most thumbprint
files are rather sparse.

4) remove private emalloc() function. we shouldnt
just exit the calling process on allocation error,
instead handle error properly. this is a library!


--- a/sys/src/libsec/port/thumb.c
+++ b/sys/src/libsec/port/thumb.c
@@ -7,18 +7,10 @@
 
 enum{ ThumbTab = 1<<10 };
 
-static void *
-emalloc(int n)
+static Thumbprint*
+tablehead(uchar *sum, Thumbprint *table)
 {
-	void *p;
-	if(n==0)
-		n=1;
-	p = malloc(n);
-	if(p == nil){
-		exits("out of memory");
-	}
-	memset(p, 0, n);
-	return p;
+	return &table[((sum[0]<<8) + sum[1]) & (ThumbTab-1)];
 }
 
 void
@@ -25,8 +17,11 @@
 freeThumbprints(Thumbprint *table)
 {
 	Thumbprint *hd, *p, *q;
+
+	if(table == nil)
+		return;
 	for(hd = table; hd < table+ThumbTab; hd++){
-		for(p = hd->next; p; p = q){
+		for(p = hd->next; p && p != hd; p = q){
 			q = p->next;
 			free(p);
 		}
@@ -37,61 +32,86 @@
 int
 okThumbprint(uchar *sum, Thumbprint *table)
 {
-	Thumbprint *p;
-	int i = ((sum[0]<<8) + sum[1]) & (ThumbTab-1);
+	Thumbprint *hd, *p;
 
-	for(p = table[i].next; p; p = p->next)
+	hd = tablehead(sum, table);
+	for(p = hd->next; p; p = p->next){
 		if(memcmp(sum, p->sha1, SHA1dlen) == 0)
 			return 1;
+		if(p == hd)
+			break;
+	}
 	return 0;
 }
 
-static void
+static int
 loadThumbprints(char *file, Thumbprint *table, Thumbprint *crltab)
 {
-	Thumbprint *entry;
-	Biobuf *bin;
+	Thumbprint *hd, *entry;
 	char *line, *field[50];
 	uchar sum[SHA1dlen];
-	int i;
+	Biobuf *bin;
 
-	bin = Bopen(file, OREAD);
-	if(bin == nil)
-		return;
-	for(; (line = Brdstr(bin, '\n', 1)) != 0; free(line)){
+	if((bin = Bopen(file, OREAD)) == nil)
+		return -1;
+	for(; (line = Brdstr(bin, '\n', 1)) != nil; free(line)){
 		if(tokenize(line, field, nelem(field)) < 2)
 			continue;
 		if(strcmp(field[0], "#include") == 0){
-			loadThumbprints(field[1], table, crltab);
+			if(loadThumbprints(field[1], table, crltab) < 0)
+				goto err;
 			continue;
 		}
-		if(strcmp(field[0], "x509") != 0 || strncmp(field[1], "sha1=", strlen("sha1=")) != 0)
+		if(strcmp(field[0], "x509") != 0 || strncmp(field[1], "sha1=", 5) != 0)
 			continue;
-		field[1] += strlen("sha1=");
-		dec16(sum, sizeof(sum), field[1], strlen(field[1]));
+		field[1] += 5;
+		if(dec16(sum, SHA1dlen, field[1], strlen(field[1])) != SHA1dlen){
+			werrstr("malformed x509 entry in %s: %s", file, field[1]);
+			goto err;
+		}
 		if(crltab && okThumbprint(sum, crltab))
 			continue;
-		entry = (Thumbprint*)emalloc(sizeof(*entry));
+		hd = tablehead(sum, table);
+		if(hd->next == nil)
+			entry = hd;
+		else {
+			if((entry = malloc(sizeof(*entry))) == nil)
+				goto err;
+			entry->next = hd->next;
+		}
+		hd->next = entry;
 		memcpy(entry->sha1, sum, SHA1dlen);
-		i = ((sum[0]<<8) + sum[1]) & (ThumbTab-1);
-		entry->next = table[i].next;
-		table[i].next = entry;
 	}
 	Bterm(bin);
+	return 0;
+err:
+	free(line);
+	Bterm(bin);
+	return -1;
 }
 
 Thumbprint *
 initThumbprints(char *ok, char *crl)
 {
-	Thumbprint *table, *crltab = nil;
+	Thumbprint *table, *crltab;
 
+	table = crltab = nil;
 	if(crl){
-		crltab = emalloc(ThumbTab * sizeof(*table));
-		loadThumbprints(crl, crltab, nil);
+		if((crltab = malloc(ThumbTab * sizeof(*crltab))) == nil)
+			goto err;
+		memset(crltab, 0, ThumbTab * sizeof(*crltab));
+		if(loadThumbprints(crl, crltab, nil) < 0)
+			goto err;
 	}
-	table = emalloc(ThumbTab * sizeof(*table));
-	loadThumbprints(ok, table, crltab);
-	free(crltab);
+	if((table = malloc(ThumbTab * sizeof(*table))) == nil)
+		goto err;
+	memset(table, 0, ThumbTab * sizeof(*table));
+	if(loadThumbprints(ok, table, crltab) < 0){
+		freeThumbprints(table);
+		table = nil;
+	}
+err:
+	freeThumbprints(crltab);
 	return table;
 }
 
-- 
⑨