From a16703aaeaedec7a8bee5be5522c7c3e75478951 Mon Sep 17 00:00:00 2001 From: Michael Mera Date: Mon, 24 Apr 2017 16:11:57 +0900 Subject: [PATCH] ath10k: fix out of bounds access to local buffer During write to debugfs file simulate_fw_crash, fixed-size local buffer 'buf' is accessed and modified at index 'count-1', where 'count' is the size of the write (so potentially out of bounds). This patch fixes this problem. Signed-off-by: Michael Mera Signed-off-by: Kalle Valo --- drivers/net/wireless/ath/ath10k/debug.c | 16 ++++++++++------ 1 file changed, 10 insertions(+), 6 deletions(-) diff --git a/drivers/net/wireless/ath/ath10k/debug.c b/drivers/net/wireless/ath/ath10k/debug.c index 4cd2a0fd49d6..389fcb7a9fd0 100644 --- a/drivers/net/wireless/ath/ath10k/debug.c +++ b/drivers/net/wireless/ath/ath10k/debug.c @@ -625,17 +625,21 @@ static ssize_t ath10k_write_simulate_fw_crash(struct file *file, size_t count, loff_t *ppos) { struct ath10k *ar = file->private_data; - char buf[32]; + char buf[32] = {0}; + ssize_t rc; int ret; - simple_write_to_buffer(buf, sizeof(buf) - 1, ppos, user_buf, count); + /* filter partial writes and invalid commands */ + if (*ppos != 0 || count >= sizeof(buf) || count == 0) + return -EINVAL; - /* make sure that buf is null terminated */ - buf[sizeof(buf) - 1] = 0; + rc = simple_write_to_buffer(buf, sizeof(buf) - 1, ppos, user_buf, count); + if (rc < 0) + return rc; /* drop the possible '\n' from the end */ - if (buf[count - 1] == '\n') - buf[count - 1] = 0; + if (buf[*ppos - 1] == '\n') + buf[*ppos - 1] = '\0'; mutex_lock(&ar->conf_mutex); -- 2.39.5