From 74b327e8fe2cfaa6cdc6b3e4994cdbf5c361938d Mon Sep 17 00:00:00 2001 From: Yunhee Seo Date: Tue, 16 Jul 2024 16:21:32 +0900 Subject: [PATCH] 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 --- src/util.c | 21 ++++++++++----------- 1 file changed, 10 insertions(+), 11 deletions(-) diff --git a/src/util.c b/src/util.c index e2abf4b..87e0fcc 100644 --- a/src/util.c +++ b/src/util.c @@ -30,19 +30,18 @@ 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; } int sysfs_write_buf(char *path, char *buf) @@ -54,7 +53,7 @@ int sysfs_write_buf(char *path, char *buf) fd = open(path, O_WRONLY); if (fd == -1) - return -ENOENT; + return -errno; w = write(fd, buf, strlen(buf)); close(fd); @@ -67,13 +66,13 @@ 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; @@ -97,13 +96,13 @@ 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; -- 2.34.1