From 0eb6839daece86bb0b13b7b3a64a82fda5363f0c Mon Sep 17 00:00:00 2001
From: Jon Siwek <jsiwek@corelight.com>
Date: Fri, 6 Nov 2020 19:16:39 -0800
Subject: [PATCH] GH-1269: Fix LogAscii::enable_leftover_log_rotation crash in
 bad dirs

Running with that option enabled inside a bad directory (e.g. lack of
permissions) crashed due to not checking for failure of opendir().
---
 src/logging/writers/ascii/Ascii.cc | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/src/logging/writers/ascii/Ascii.cc b/src/logging/writers/ascii/Ascii.cc
index e417998596..5a04807b30 100644
--- a/src/logging/writers/ascii/Ascii.cc
+++ b/src/logging/writers/ascii/Ascii.cc
@@ -710,6 +710,21 @@ static std::vector<LeftoverLog> find_leftover_logs()
 	auto d = opendir(".");
 	struct dirent* dp;
 
+	if ( ! d )
+		{
+		char cwd[PATH_MAX];
+
+		if ( ! getcwd(cwd, sizeof(cwd)) )
+			{
+			cwd[0] = '.';
+			cwd[1] = '\0';
+			}
+
+		reporter->Error("failed to open directory '%s' in search of leftover logs: %s",
+		                cwd, strerror(errno));
+		return rval;
+		}
+
 	while ( (dp = readdir(d)) )
 		{
 		if ( strncmp(dp->d_name, shadow_file_prefix, prefix_len) != 0 )