lbutils: don't use stack memory for path strings

Signed-off-by: Leah Rowe <leah@libreboot.org>

util/libreboot-utils/include/common.h

@@ -366,6 +366,8 @@ int scmp(const char *a, const char *b,
     size_t maxlen, int *rval);
 int ccmp(const char *a, const char *b, size_t i,
     int *rval);
+int dup_pair(char **dir, const char *d,
+    char **base, const char *b);
 char *sdup(const char *s,
     size_t n, char **dest);
 char *scatn(ssize_t sc, const char **sv,

util/libreboot-utils/lib/file.c

@@ -521,6 +521,8 @@ fs_dirname_basename(const char *path,
 	char *buf = NULL;
 	char *slash;
 	size_t len;
+	const char *d = NULL;
+	const char *b = NULL;
 	errno = 0;
 
 	if (if_err(path == NULL || dir == NULL || base == NULL, EFAULT))
@@ -539,22 +541,27 @@ fs_dirname_basename(const char *path,
 	if (slash) {
 
 		*slash = '\0';
-		*dir = buf;
+		d = buf;
-		*base = slash + 1;
+		b = slash + 1;
 
-		if (**dir == '\0') {
+		if (*d == '\0')
-			(*dir)[0] = '/';
+			d = "/";
-			(*dir)[1] = '\0';
-		}
 	} else if (allow_relative) {
 
-		sdup(".", PATH_MAX, dir);
+		d = ".";
-		*base = buf;
+		b = buf;
 	} else {
 		free_and_set_null(&buf);
 		goto err;
 	}
 
+	if (dup_pair(dir, d, base, b) < 0) {
+		free_and_set_null(&buf);
+		goto err;
+	}
+
+	free_and_set_null(&buf);
+
 	reset_caller_errno(0);
 	return 0;
 err:

util/libreboot-utils/lib/mkhtemp.c

@@ -195,7 +195,11 @@ env_tmpdir(int bypass_all_sticky_checks, char **tmpdir,
 		    bypass_all_sticky_checks))
 			goto err;
 
-		rval = t;
+		rval = NULL;
+		if (t != NULL) {
+			if (sdup(t, PATH_MAX, &rval) == NULL)
+				goto err;
+		}
 		goto out;
 	}
 

util/libreboot-utils/lib/string.c

@@ -270,6 +270,27 @@ out:
 	return *rval;
 }
 
+int
+dup_pair(char **dir, const char *d,
+    char **base, const char *b)
+{
+	char *dtmp = NULL;
+	char *btmp = NULL;
+
+	if (d && sdup(d, PATH_MAX, &dtmp) == NULL)
+		return -1;
+
+	if (b && sdup(b, PATH_MAX, &btmp) == NULL) {
+		free(dtmp);
+		return -1;
+	}
+
+	*dir = dtmp;
+	*base = btmp;
+
+	return 0;
+}
+
 /* strict word-based strdup */
 char *
 sdup(const char *s,