From: Dan Carpenter Date: Thu, 23 Mar 2017 10:40:00 +0000 (+0300) Subject: iwlwifi: mvm: writing zero bytes to debugfs causes a crash X-Git-Tag: v4.10.16~71 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=bcb28cb399309a4c1172b748704a1682cad7f4de;p=thirdparty%2Fkernel%2Fstable.git iwlwifi: mvm: writing zero bytes to debugfs causes a crash commit 251fe09f13bfb54c1ede66ee8bf8ddd0061c4f7c upstream. This is a static analysis fix. The warning is: drivers/net/wireless/intel/iwlwifi/mvm/fw-dbg.c:912 iwl_mvm_fw_dbg_collect() warn: integer overflows 'sizeof(*desc) + len' I guess this code is supposed to take a NUL character, but if we write zero bytes then it tries to write -1 characters and crashes. Fixes: c91b865cb14d ("iwlwifi: mvm: support description for user triggered fw dbg collection") Signed-off-by: Dan Carpenter Signed-off-by: Luca Coelho Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/net/wireless/intel/iwlwifi/mvm/debugfs.c b/drivers/net/wireless/intel/iwlwifi/mvm/debugfs.c index 7b7d2a146e302..0bda91ffc6088 100644 --- a/drivers/net/wireless/intel/iwlwifi/mvm/debugfs.c +++ b/drivers/net/wireless/intel/iwlwifi/mvm/debugfs.c @@ -1056,6 +1056,8 @@ static ssize_t iwl_dbgfs_fw_dbg_collect_write(struct iwl_mvm *mvm, if (ret) return ret; + if (count == 0) + return 0; iwl_mvm_fw_dbg_collect(mvm, FW_DBG_TRIGGER_USER, buf, (count - 1), NULL);