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* [PATCH] iwlwifi: mvm: writing zero bytes to debugfs causes a crash
@ 2017-03-23 10:40 Dan Carpenter
  2017-03-23 12:25 ` Luca Coelho
  0 siblings, 1 reply; 2+ messages in thread
From: Dan Carpenter @ 2017-03-23 10:40 UTC (permalink / raw)
  To: Johannes Berg, Golan Ben-Ami
  Cc: Emmanuel Grumbach, Luca Coelho, Intel Linux Wireless, Kalle Valo,
	Sara Sharon, Ido Yariv, linux-wireless, kernel-janitors

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 <dan.carpenter@oracle.com>

diff --git a/drivers/net/wireless/intel/iwlwifi/mvm/debugfs.c b/drivers/net/wireless/intel/iwlwifi/mvm/debugfs.c
index a260cd503200..077bfd8f4c0c 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);

^ permalink raw reply related	[flat|nested] 2+ messages in thread

* Re: [PATCH] iwlwifi: mvm: writing zero bytes to debugfs causes a crash
  2017-03-23 10:40 [PATCH] iwlwifi: mvm: writing zero bytes to debugfs causes a crash Dan Carpenter
@ 2017-03-23 12:25 ` Luca Coelho
  0 siblings, 0 replies; 2+ messages in thread
From: Luca Coelho @ 2017-03-23 12:25 UTC (permalink / raw)
  To: Dan Carpenter, Johannes Berg, Golan Ben-Ami
  Cc: Emmanuel Grumbach, Intel Linux Wireless, Kalle Valo, Sara Sharon,
	Ido Yariv, linux-wireless, kernel-janitors

On Thu, 2017-03-23 at 13:40 +0300, Dan Carpenter wrote:
> 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 <dan.carpenter@oracle.com>
> 
> diff --git a/drivers/net/wireless/intel/iwlwifi/mvm/debugfs.c b/drivers/net/wireless/intel/iwlwifi/mvm/debugfs.c
> index a260cd503200..077bfd8f4c0c 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);

Thanks! I'm going to push this via our internal tree.

--
Cheers,
Luca.

^ permalink raw reply	[flat|nested] 2+ messages in thread

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