From 1e5f505c977a59b2c220776e50a7699dcd47fcf2 Mon Sep 17 00:00:00 2001
From: Yunhee Seo <yuni.seo@samsung.com>
Date: Tue, 16 Jul 2024 16:21:32 +0900
Subject: util: Add handling code to safely read and write arrays

There was a missing code for handling the null character
so that it doesn't exceed the array size when reading and storing strings.
The code has been modified to handle the array safely.
To avoid overflow issue, this is necessary.

Change-Id: Ib75301a07906391c57fb739ef3399ff211cd1503
Signed-off-by: Yunhee Seo <yuni.seo@samsung.com>
---
 src/util.c | 24 ++++++++++++------------
 1 file changed, 12 insertions(+), 12 deletions(-)

diff --git a/src/util.c b/src/util.c
index 80660b5..60311a0 100644
--- a/src/util.c
+++ b/src/util.c
@@ -30,31 +30,30 @@ static int sysfs_read_buf(char *path, char *buf, int len)
 
 	fd = open(path, O_RDONLY);
 	if (fd == -1)
-		return -ENOENT;
+		return -errno;
 
 	r = read(fd, buf, len);
 	close(fd);
 
-	if ((r < 0) || (r > len))
+	if ((r < 0) || (r >= len)) {
+		buf[0] = '\0';
 		return -EIO;
+	}
 
-	/* Replace '\n' with space (ascii code is 32) */
-	buf[strcspn(buf, "\n")] = (char)32;
 	buf[r] = '\0';
-
-	return 0;
+	return r;
 }
 
 static int sysfs_write_buf(char *path, char *buf)
 {
 	int w, fd;
 
-	if ((!path) || (!buf))
+	if (!path || !buf)
 		return -EINVAL;
 
 	fd = open(path, O_WRONLY);
 	if (fd == -1)
-		return -ENOENT;
+		return -errno;
 
 	w = write(fd, buf, strlen(buf));
 	close(fd);
@@ -67,17 +66,18 @@ static int sysfs_write_buf(char *path, char *buf)
 
 int sysfs_read_int(char *path, int *val)
 {
-	char buf[MAX_BUF_SIZE + 1];
+	char buf[MAX_BUF_SIZE];
 	int r;
 
 	if ((!path) || (!val))
 		return -EINVAL;
 
-	r = sysfs_read_buf(path, buf, MAX_BUF_SIZE);
+	r = sysfs_read_buf(path, buf, sizeof(buf));
 	if (r < 0)
 		return r;
 
 	*val = atoi(buf);
+
 	return 0;
 }
 
@@ -97,13 +97,13 @@ int sysfs_read_str(char *path, char *str, int len)
 
 int sysfs_write_int(char *path, int val)
 {
-	char buf[MAX_BUF_SIZE + 1];
+	char buf[MAX_BUF_SIZE];
 	int w;
 
 	if (!path)
 		return -EINVAL;
 
-	snprintf(buf, MAX_BUF_SIZE, "%d", val);
+	snprintf(buf, sizeof(buf), "%d", val);
 	w = sysfs_write_buf(path, buf);
 	if (w < 0)
 		return w;
-- 
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