[PATCH] scsi: qedf: replace memset/memcpy with safer strscpy

[PATCH] scsi: qedf: replace memset/memcpy with safer strscpy

[Colin King]

From: Colin Ian King <colin.king@canonical.com>

Currently the qedf_dbg_* family of functions can overrun the end
of the source string if it is less than the destination buffer
length because of the use of a fixed sized memcpy. Replace the
memset/memcpy calls with the safer strscpy as this won't overrun
the end of the source string and it ensures the destination
string is always terminated with NUL.

Addresses-Coverity: ("Out-of-bounds access")
Fixes: 61d8658b4a43 ("scsi: qedf: Add QLogic FastLinQ offload FCoE driver framework.")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
---
 drivers/scsi/qedf/qedf_dbg.c | 12 ++++--------
 1 file changed, 4 insertions(+), 8 deletions(-)

diff --git a/drivers/scsi/qedf/qedf_dbg.c b/drivers/scsi/qedf/qedf_dbg.c
index f2397ee9ba69..b491bebeaca9 100644
--- a/drivers/scsi/qedf/qedf_dbg.c
+++ b/drivers/scsi/qedf/qedf_dbg.c
@@ -17,8 +17,7 @@ qedf_dbg_err(struct qedf_dbg_ctx *qedf, const char *func, u32 line,
 	struct va_format vaf;
 	char nfunc[32];
 
-	memset(nfunc, 0, sizeof(nfunc));
-	memcpy(nfunc, func, sizeof(nfunc) - 1);
+	strscpy(nfunc, func, sizeof(nfunc));
 
 	va_start(va, fmt);
 
@@ -42,8 +41,7 @@ qedf_dbg_warn(struct qedf_dbg_ctx *qedf, const char *func, u32 line,
 	struct va_format vaf;
 	char nfunc[32];
 
-	memset(nfunc, 0, sizeof(nfunc));
-	memcpy(nfunc, func, sizeof(nfunc) - 1);
+	strscpy(nfunc, func, sizeof(nfunc));
 
 	va_start(va, fmt);
 
@@ -71,8 +69,7 @@ qedf_dbg_notice(struct qedf_dbg_ctx *qedf, const char *func, u32 line,
 	struct va_format vaf;
 	char nfunc[32];
 
-	memset(nfunc, 0, sizeof(nfunc));
-	memcpy(nfunc, func, sizeof(nfunc) - 1);
+	strscpy(nfunc, func, sizeof(nfunc));
 
 	va_start(va, fmt);
 
@@ -101,8 +98,7 @@ qedf_dbg_info(struct qedf_dbg_ctx *qedf, const char *func, u32 line,
 	struct va_format vaf;
 	char nfunc[32];
 
-	memset(nfunc, 0, sizeof(nfunc));
-	memcpy(nfunc, func, sizeof(nfunc) - 1);
+	strscpy(nfunc, func, sizeof(nfunc));
 
 	va_start(va, fmt);
 
-- 
2.20.1

Re: [PATCH] scsi: qedf: replace memset/memcpy with safer strscpy

[YueHaibing]

I send a similar fix earlier, but it seems not be picked.

https://patchwork.kernel.org/patch/10874565/

On 2019/4/12 17:05, Colin King wrote:
> From: Colin Ian King <colin.king@canonical.com>
> 
> Currently the qedf_dbg_* family of functions can overrun the end
> of the source string if it is less than the destination buffer
> length because of the use of a fixed sized memcpy. Replace the
> memset/memcpy calls with the safer strscpy as this won't overrun
> the end of the source string and it ensures the destination
> string is always terminated with NUL.
> 
> Addresses-Coverity: ("Out-of-bounds access")
> Fixes: 61d8658b4a43 ("scsi: qedf: Add QLogic FastLinQ offload FCoE driver framework.")
> Signed-off-by: Colin Ian King <colin.king@canonical.com>
> ---
>  drivers/scsi/qedf/qedf_dbg.c | 12 ++++--------
>  1 file changed, 4 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/scsi/qedf/qedf_dbg.c b/drivers/scsi/qedf/qedf_dbg.c
> index f2397ee9ba69..b491bebeaca9 100644
> --- a/drivers/scsi/qedf/qedf_dbg.c
> +++ b/drivers/scsi/qedf/qedf_dbg.c
> @@ -17,8 +17,7 @@ qedf_dbg_err(struct qedf_dbg_ctx *qedf, const char *func, u32 line,
>  	struct va_format vaf;
>  	char nfunc[32];
>  
> -	memset(nfunc, 0, sizeof(nfunc));
> -	memcpy(nfunc, func, sizeof(nfunc) - 1);
> +	strscpy(nfunc, func, sizeof(nfunc));
>  
>  	va_start(va, fmt);
>  
> @@ -42,8 +41,7 @@ qedf_dbg_warn(struct qedf_dbg_ctx *qedf, const char *func, u32 line,
>  	struct va_format vaf;
>  	char nfunc[32];
>  
> -	memset(nfunc, 0, sizeof(nfunc));
> -	memcpy(nfunc, func, sizeof(nfunc) - 1);
> +	strscpy(nfunc, func, sizeof(nfunc));
>  
>  	va_start(va, fmt);
>  
> @@ -71,8 +69,7 @@ qedf_dbg_notice(struct qedf_dbg_ctx *qedf, const char *func, u32 line,
>  	struct va_format vaf;
>  	char nfunc[32];
>  
> -	memset(nfunc, 0, sizeof(nfunc));
> -	memcpy(nfunc, func, sizeof(nfunc) - 1);
> +	strscpy(nfunc, func, sizeof(nfunc));
>  
>  	va_start(va, fmt);
>  
> @@ -101,8 +98,7 @@ qedf_dbg_info(struct qedf_dbg_ctx *qedf, const char *func, u32 line,
>  	struct va_format vaf;
>  	char nfunc[32];
>  
> -	memset(nfunc, 0, sizeof(nfunc));
> -	memcpy(nfunc, func, sizeof(nfunc) - 1);
> +	strscpy(nfunc, func, sizeof(nfunc));
>  
>  	va_start(va, fmt);
>  
> 

Re: [PATCH] scsi: qedf: replace memset/memcpy with safer strscpy

[Colin Ian King]

On 12/04/2019 10:20, YueHaibing wrote:
> 
> I send a similar fix earlier, but it seems not be picked.

It would be useful to get a fix for this applied as I'm seeing many
multiple of reports of this issue with Coverity and it is a relatively
simple fix.

Colin

> 
> https://patchwork.kernel.org/patch/10874565/
> 
> On 2019/4/12 17:05, Colin King wrote:
>> From: Colin Ian King <colin.king@canonical.com>
>>
>> Currently the qedf_dbg_* family of functions can overrun the end
>> of the source string if it is less than the destination buffer
>> length because of the use of a fixed sized memcpy. Replace the
>> memset/memcpy calls with the safer strscpy as this won't overrun
>> the end of the source string and it ensures the destination
>> string is always terminated with NUL.
>>
>> Addresses-Coverity: ("Out-of-bounds access")
>> Fixes: 61d8658b4a43 ("scsi: qedf: Add QLogic FastLinQ offload FCoE driver framework.")
>> Signed-off-by: Colin Ian King <colin.king@canonical.com>
>> ---
>>  drivers/scsi/qedf/qedf_dbg.c | 12 ++++--------
>>  1 file changed, 4 insertions(+), 8 deletions(-)
>>
>> diff --git a/drivers/scsi/qedf/qedf_dbg.c b/drivers/scsi/qedf/qedf_dbg.c
>> index f2397ee9ba69..b491bebeaca9 100644
>> --- a/drivers/scsi/qedf/qedf_dbg.c
>> +++ b/drivers/scsi/qedf/qedf_dbg.c
>> @@ -17,8 +17,7 @@ qedf_dbg_err(struct qedf_dbg_ctx *qedf, const char *func, u32 line,
>>  	struct va_format vaf;
>>  	char nfunc[32];
>>  
>> -	memset(nfunc, 0, sizeof(nfunc));
>> -	memcpy(nfunc, func, sizeof(nfunc) - 1);
>> +	strscpy(nfunc, func, sizeof(nfunc));
>>  
>>  	va_start(va, fmt);
>>  
>> @@ -42,8 +41,7 @@ qedf_dbg_warn(struct qedf_dbg_ctx *qedf, const char *func, u32 line,
>>  	struct va_format vaf;
>>  	char nfunc[32];
>>  
>> -	memset(nfunc, 0, sizeof(nfunc));
>> -	memcpy(nfunc, func, sizeof(nfunc) - 1);
>> +	strscpy(nfunc, func, sizeof(nfunc));
>>  
>>  	va_start(va, fmt);
>>  
>> @@ -71,8 +69,7 @@ qedf_dbg_notice(struct qedf_dbg_ctx *qedf, const char *func, u32 line,
>>  	struct va_format vaf;
>>  	char nfunc[32];
>>  
>> -	memset(nfunc, 0, sizeof(nfunc));
>> -	memcpy(nfunc, func, sizeof(nfunc) - 1);
>> +	strscpy(nfunc, func, sizeof(nfunc));
>>  
>>  	va_start(va, fmt);
>>  
>> @@ -101,8 +98,7 @@ qedf_dbg_info(struct qedf_dbg_ctx *qedf, const char *func, u32 line,
>>  	struct va_format vaf;
>>  	char nfunc[32];
>>  
>> -	memset(nfunc, 0, sizeof(nfunc));
>> -	memcpy(nfunc, func, sizeof(nfunc) - 1);
>> +	strscpy(nfunc, func, sizeof(nfunc));
>>  
>>  	va_start(va, fmt);
>>  
>>
> 

Re: [PATCH] scsi: qedf: replace memset/memcpy with safer strscpy

[Rasmus Villemoes]

On 12/04/2019 11.05, Colin King wrote:
> From: Colin Ian King <colin.king@canonical.com>
> 
> Currently the qedf_dbg_* family of functions can overrun the end
> of the source string if it is less than the destination buffer
> length because of the use of a fixed sized memcpy. Replace the
> memset/memcpy calls with the safer strscpy as this won't overrun
> the end of the source string and it ensures the destination
> string is always terminated with NUL.
> 
> Addresses-Coverity: ("Out-of-bounds access")
> Fixes: 61d8658b4a43 ("scsi: qedf: Add QLogic FastLinQ offload FCoE driver framework.")
> Signed-off-by: Colin Ian King <colin.king@canonical.com>
> ---
>  drivers/scsi/qedf/qedf_dbg.c | 12 ++++--------
>  1 file changed, 4 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/scsi/qedf/qedf_dbg.c b/drivers/scsi/qedf/qedf_dbg.c
> index f2397ee9ba69..b491bebeaca9 100644
> --- a/drivers/scsi/qedf/qedf_dbg.c
> +++ b/drivers/scsi/qedf/qedf_dbg.c
> @@ -17,8 +17,7 @@ qedf_dbg_err(struct qedf_dbg_ctx *qedf, const char *func, u32 line,
>  	struct va_format vaf;
>  	char nfunc[32];
>  
> -	memset(nfunc, 0, sizeof(nfunc));
> -	memcpy(nfunc, func, sizeof(nfunc) - 1);
> +	strscpy(nfunc, func, sizeof(nfunc));

Why not drop the pointless nfunc and stack copying and just pass func as
the %s parameter; these are only called via macros that pass __func__ as
the func argument, and that is always a proper nul-terminated string.

Rasmus