From: Mateusz Kusiak <mateusz.kusiak@intel.com>
Date: Tue, 20 Feb 2024 10:56:09 +0000 (+0100)
Subject: Monitor: open file before check in check_one_sharer()
X-Git-Tag: mdadm-4.4~239
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=b7d7837128e90c8b496ebc3d88eda1a8ff477392;p=thirdparty%2Fmdadm.git

Monitor: open file before check in check_one_sharer()

Open file before performing checks in check_one_sharer() to avoid
file tampering.
Remove redundant access check.

Signed-off-by: Mateusz Kusiak <mateusz.kusiak@intel.com>
Signed-off-by: Mariusz Tkaczyk <mariusz.tkaczyk@linux.intel.com>
---

diff --git a/Monitor.c b/Monitor.c
index 824a69fc..7cee95d4 100644
--- a/Monitor.c
+++ b/Monitor.c
@@ -451,20 +451,17 @@ static int check_one_sharer(int scan)
 		return 2;
 	}
 
-	if (access(AUTOREBUILD_PID_PATH, F_OK) != 0)
-		return 0;
-
-	if (!is_file(AUTOREBUILD_PID_PATH)) {
-		pr_err("%s is not a regular file.\n", AUTOREBUILD_PID_PATH);
-		return 2;
-	}
-
 	fp = fopen(AUTOREBUILD_PID_PATH, "r");
 	if (!fp) {
 		pr_err("Cannot open %s file.\n", AUTOREBUILD_PID_PATH);
 		return 2;
 	}
 
+	if (!is_file(AUTOREBUILD_PID_PATH)) {
+		pr_err("%s is not a regular file.\n", AUTOREBUILD_PID_PATH);
+		return 2;
+	}
+
 	if (fscanf(fp, "%d", &pid) != 1) {
 		pr_err("Cannot read pid from %s file.\n", AUTOREBUILD_PID_PATH);
 		fclose(fp);