[PATCH 2/2] mcstrans: bound Include nesting depth

process_trans() handles Include directives by calling
read_translations() on each matched path, which in turn calls
process_trans() line by line. A configuration file that Includes
itself (directly or via a cycle) recurses until the daemon runs out of
file descriptors or stack. Cap the nesting depth at 32.

Signed-off-by: Stephen Smalley <[email protected]>
---
 mcstrans/src/mcstrans.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/mcstrans/src/mcstrans.c b/mcstrans/src/mcstrans.c
index b5c8d54a..e79aa3d5 100644
--- a/mcstrans/src/mcstrans.c
+++ b/mcstrans/src/mcstrans.c
@@ -911,16 +911,23 @@ static int process_trans(char *buffer)
 
 int read_translations(const char *filename)
 {
+	static unsigned int depth;
 	size_t size = 0;
 	char *buffer = NULL;
 	int rval = 0;
 
+	if (depth >= 32) {
+		syslog(LOG_ERR, "%s: Include nesting too deep", filename);
+		return -1;
+	}
+
 	FILE *cfg = fopen(filename, "r");
 	if (!cfg) {
 		syslog(LOG_ERR, "%s file open failed", filename);
 		return -1;
 	}
 
+	depth++;
 	__fsetlocking(cfg, FSETLOCKING_BYCALLER);
 	while (getline(&buffer, &size, cfg) > 0) {
 		if (process_trans(buffer) < 0) {
@@ -931,6 +938,7 @@ int read_translations(const char *filename)
 	}
 	free(buffer);
 	fclose(cfg);
+	depth--;
 	return rval;
 }
 
-- 
2.55.0