4.9-stable review patch. If anyone has any objections, please let me know.
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From: Michael Mera dev@michaelmera.com
[ Upstream commit a16703aaeaedec7a8bee5be5522c7c3e75478951 ]
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 dev@michaelmera.com Signed-off-by: Kalle Valo kvalo@qca.qualcomm.com Signed-off-by: Sasha Levin alexander.levin@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/net/wireless/ath/ath10k/debug.c | 16 ++++++++++------ 1 file changed, 10 insertions(+), 6 deletions(-)
--- a/drivers/net/wireless/ath/ath10k/debug.c +++ b/drivers/net/wireless/ath/ath10k/debug.c @@ -624,17 +624,21 @@ static ssize_t ath10k_write_simulate_fw_ 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);