wifi: iwlwifi: fix out of bound copy_from_user

[ Upstream commit cb2dfacb197bed0241fbb4f84bd0995a47f4465e ]

The driver copies the userspace buffer into an internal NUL
byte terminated buffer. While doing so, it was reading beyond
the end of the userspace buffer, overwriting its own NUL
termination in the process.

Fix this by only copying the correct number of bytes.

Fixes: 3f244876ef73 ("wifi: iwlwifi: make debugfs entries link specific")
Signed-off-by: Anjaneyulu <pagadala.yesu.anjaneyulu@intel.com>
Reviewed-by: Gregory Greenman <gregory.greenman@intel.com>
Reviewed-by: Benjamin Berg <benjamin.berg@intel.com>
Signed-off-by: Miri Korenblit <miriam.rachel.korenblit@intel.com>
Link: https://msgid.link/20231219215605.e4913deb2ad4.Idcf6a7e909ff4b7801cd49c2f691f84a2f68eff9@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/net/wireless/intel/iwlwifi/mvm/debugfs.c b/drivers/net/wireless/intel/iwlwifi/mvm/debugfs.c
index cf27f10..7057421 100644 (file)
--- a/drivers/net/wireless/intel/iwlwifi/mvm/debugfs.c
+++ b/drivers/net/wireless/intel/iwlwifi/mvm/debugfs.c
@@ -1673,7 +1673,7 @@ static ssize_t _iwl_dbgfs_link_sta_##name##_write(struct file *file,      \
        char buf[buflen] = {};                                          \
        size_t buf_size = min(count, sizeof(buf) -  1);                 \
                                                                        \
-       if (copy_from_user(buf, user_buf, sizeof(buf)))                 \
+       if (copy_from_user(buf, user_buf, buf_size))                    \
                return -EFAULT;                                         \
                                                                        \
        return _iwl_dbgfs_link_sta_wrap_write(iwl_dbgfs_##name##_write, \