2018-09-15 10:01:30

by Yue Haibing

Subject: [PATCH net-next] net/smc: cast sizeof to int for comparison

Comparing an int to a size, which is unsigned, causes the int to become
unsigned, giving the wrong result. kernel_sendmsg can return a negative
error code.

Signed-off-by: YueHaibing <[email protected]>
---
net/smc/smc_clc.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/smc/smc_clc.c b/net/smc/smc_clc.c
index 83aba9a..fd0f5ce 100644
--- a/net/smc/smc_clc.c
+++ b/net/smc/smc_clc.c
@@ -446,7 +446,7 @@ int smc_clc_send_proposal(struct smc_sock *smc, int smc_type,
vec[i++].iov_len = sizeof(trl);
/* due to the few bytes needed for clc-handshake this cannot block */
len = kernel_sendmsg(smc->clcsock, &msg, vec, i, plen);
- if (len < sizeof(pclc)) {
+ if (len < (int)sizeof(pclc)) {
if (len >= 0) {
reason_code = -ENETUNREACH;
smc->sk.sk_err = -reason_code;
--
1.8.3.1

2018-09-15 11:36:05

by Andreas Schwab

Subject: Re: [PATCH net-next] net/smc: cast sizeof to int for comparison

On Sep 15 2018, YueHaibing <[email protected]> wrote:

> Comparing an int to a size, which is unsigned, causes the int to become
> unsigned, giving the wrong result. kernel_sendmsg can return a negative
> error code.
>
> Signed-off-by: YueHaibing <[email protected]>
> ---
> net/smc/smc_clc.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/net/smc/smc_clc.c b/net/smc/smc_clc.c
> index 83aba9a..fd0f5ce 100644
> --- a/net/smc/smc_clc.c
> +++ b/net/smc/smc_clc.c
> @@ -446,7 +446,7 @@ int smc_clc_send_proposal(struct smc_sock *smc, int smc_type,
> vec[i++].iov_len = sizeof(trl);
> /* due to the few bytes needed for clc-handshake this cannot block */
> len = kernel_sendmsg(smc->clcsock, &msg, vec, i, plen);
> - if (len < sizeof(pclc)) {
> + if (len < (int)sizeof(pclc)) {
> if (len >= 0) {
> reason_code = -ENETUNREACH;
> smc->sk.sk_err = -reason_code;

It would perhaps be better to handle len < 0 first.

Andreas.

--
Andreas Schwab, [email protected]
GPG Key fingerprint = 7578 EB47 D4E5 4D69 2510 2552 DF73 E780 A9DA AEC1
"And now for something completely different."

2018-09-17 03:58:11

by Yue Haibing

Subject: Re: [PATCH net-next] net/smc: cast sizeof to int for comparison

On 2018/9/15 19:35, Andreas Schwab wrote:
> On Sep 15 2018, YueHaibing <[email protected]> wrote:
>
>> Comparing an int to a size, which is unsigned, causes the int to become
>> unsigned, giving the wrong result. kernel_sendmsg can return a negative
>> error code.
>>
>> Signed-off-by: YueHaibing <[email protected]>
>> ---
>> net/smc/smc_clc.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/net/smc/smc_clc.c b/net/smc/smc_clc.c
>> index 83aba9a..fd0f5ce 100644
>> --- a/net/smc/smc_clc.c
>> +++ b/net/smc/smc_clc.c
>> @@ -446,7 +446,7 @@ int smc_clc_send_proposal(struct smc_sock *smc, int smc_type,
>> vec[i++].iov_len = sizeof(trl);
>> /* due to the few bytes needed for clc-handshake this cannot block */
>> len = kernel_sendmsg(smc->clcsock, &msg, vec, i, plen);
>> - if (len < sizeof(pclc)) {
>> + if (len < (int)sizeof(pclc)) {
>> if (len >= 0) {
>> reason_code = -ENETUNREACH;
>> smc->sk.sk_err = -reason_code;
>
> It would perhaps be better to handle len < 0 first.

That need refactor the err hangding, is worth doing it?

>
> Andreas.
>

2018-09-17 08:43:47

by Andreas Schwab

Subject: Re: [PATCH net-next] net/smc: cast sizeof to int for comparison

On Sep 17 2018, YueHaibing <[email protected]> wrote:

> On 2018/9/15 19:35, Andreas Schwab wrote:
>> On Sep 15 2018, YueHaibing <[email protected]> wrote:
>>
>>> Comparing an int to a size, which is unsigned, causes the int to become
>>> unsigned, giving the wrong result. kernel_sendmsg can return a negative
>>> error code.
>>>
>>> Signed-off-by: YueHaibing <[email protected]>
>>> ---
>>> net/smc/smc_clc.c | 2 +-
>>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/net/smc/smc_clc.c b/net/smc/smc_clc.c
>>> index 83aba9a..fd0f5ce 100644
>>> --- a/net/smc/smc_clc.c
>>> +++ b/net/smc/smc_clc.c
>>> @@ -446,7 +446,7 @@ int smc_clc_send_proposal(struct smc_sock *smc, int smc_type,
>>> vec[i++].iov_len = sizeof(trl);
>>> /* due to the few bytes needed for clc-handshake this cannot block */
>>> len = kernel_sendmsg(smc->clcsock, &msg, vec, i, plen);
>>> - if (len < sizeof(pclc)) {
>>> + if (len < (int)sizeof(pclc)) {
>>> if (len >= 0) {
>>> reason_code = -ENETUNREACH;
>>> smc->sk.sk_err = -reason_code;
>>
>> It would perhaps be better to handle len < 0 first.
>
> That need refactor the err hangding, is worth doing it?

Just a few lines moving around, IFAICS.

Andreas.

--
Andreas Schwab, [email protected]
GPG Key fingerprint = 7578 EB47 D4E5 4D69 2510 2552 DF73 E780 A9DA AEC1
"And now for something completely different."

2018-09-17 08:50:36

by Ursula Braun

Subject: Re: [PATCH net-next] net/smc: cast sizeof to int for comparison

On 09/15/2018 12:00 PM, YueHaibing wrote:
> Comparing an int to a size, which is unsigned, causes the int to become
> unsigned, giving the wrong result. kernel_sendmsg can return a negative
> error code.
>

Thanks for reporting this issue!

> Signed-off-by: YueHaibing <[email protected]>
> ---
> net/smc/smc_clc.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/net/smc/smc_clc.c b/net/smc/smc_clc.c
> index 83aba9a..fd0f5ce 100644
> --- a/net/smc/smc_clc.c
> +++ b/net/smc/smc_clc.c
> @@ -446,7 +446,7 @@ int smc_clc_send_proposal(struct smc_sock *smc, int smc_type,
> vec[i++].iov_len = sizeof(trl);
> /* due to the few bytes needed for clc-handshake this cannot block */
> len = kernel_sendmsg(smc->clcsock, &msg, vec, i, plen);
> - if (len < sizeof(pclc)) {
> + if (len < (int)sizeof(pclc)) {
> if (len >= 0) {
> reason_code = -ENETUNREACH;
> smc->sk.sk_err = -reason_code;
>

Your fix helps, but I would like to follow the hint of Andreas Schwab, and split
the return value check like this:

---
net/smc/smc_clc.c | 14 ++++++--------
1 file changed, 6 insertions(+), 8 deletions(-)

--- a/net/smc/smc_clc.c
+++ b/net/smc/smc_clc.c
@@ -446,14 +446,12 @@ int smc_clc_send_proposal(struct smc_soc
vec[i++].iov_len = sizeof(trl);
/* due to the few bytes needed for clc-handshake this cannot block */
len = kernel_sendmsg(smc->clcsock, &msg, vec, i, plen);
- if (len < sizeof(pclc)) {
- if (len >= 0) {
- reason_code = -ENETUNREACH;
- smc->sk.sk_err = -reason_code;
- } else {
- smc->sk.sk_err = smc->clcsock->sk->sk_err;
- reason_code = -smc->sk.sk_err;
- }
+ if (len < 0) {
+ smc->sk.sk_err = smc->clcsock->sk->sk_err;
+ reason_code = -smc->sk.sk_err;
+ } else if (len < (int)sizeof(pclc)) {
+ reason_code = -ENETUNREACH;
+ smc->sk.sk_err = -reason_code;
}

return reason_code;

Agreed?

Regards, Ursula

2018-09-17 09:39:30

by Yue Haibing

Subject: Re: [PATCH net-next] net/smc: cast sizeof to int for comparison

On 2018/9/17 16:49, Ursula Braun wrote:
>
>
> On 09/15/2018 12:00 PM, YueHaibing wrote:
>> Comparing an int to a size, which is unsigned, causes the int to become
>> unsigned, giving the wrong result. kernel_sendmsg can return a negative
>> error code.
>>
>
> Thanks for reporting this issue!
>
>> Signed-off-by: YueHaibing <[email protected]>
>> ---
>> net/smc/smc_clc.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/net/smc/smc_clc.c b/net/smc/smc_clc.c
>> index 83aba9a..fd0f5ce 100644
>> --- a/net/smc/smc_clc.c
>> +++ b/net/smc/smc_clc.c
>> @@ -446,7 +446,7 @@ int smc_clc_send_proposal(struct smc_sock *smc, int smc_type,
>> vec[i++].iov_len = sizeof(trl);
>> /* due to the few bytes needed for clc-handshake this cannot block */
>> len = kernel_sendmsg(smc->clcsock, &msg, vec, i, plen);
>> - if (len < sizeof(pclc)) {
>> + if (len < (int)sizeof(pclc)) {
>> if (len >= 0) {
>> reason_code = -ENETUNREACH;
>> smc->sk.sk_err = -reason_code;
>>
>
> Your fix helps, but I would like to follow the hint of Andreas Schwab, and split
> the return value check like this:
>
> ---
> net/smc/smc_clc.c | 14 ++++++--------
> 1 file changed, 6 insertions(+), 8 deletions(-)
>
> --- a/net/smc/smc_clc.c
> +++ b/net/smc/smc_clc.c
> @@ -446,14 +446,12 @@ int smc_clc_send_proposal(struct smc_soc
> vec[i++].iov_len = sizeof(trl);
> /* due to the few bytes needed for clc-handshake this cannot block */
> len = kernel_sendmsg(smc->clcsock, &msg, vec, i, plen);
> - if (len < sizeof(pclc)) {
> - if (len >= 0) {
> - reason_code = -ENETUNREACH;
> - smc->sk.sk_err = -reason_code;
> - } else {
> - smc->sk.sk_err = smc->clcsock->sk->sk_err;
> - reason_code = -smc->sk.sk_err;
> - }
> + if (len < 0) {
> + smc->sk.sk_err = smc->clcsock->sk->sk_err;
> + reason_code = -smc->sk.sk_err;
> + } else if (len < (int)sizeof(pclc)) {
> + reason_code = -ENETUNREACH;
> + smc->sk.sk_err = -reason_code;
> }
>
> return reason_code;
>
> Agreed?

Yes, Need a new patch from me?

>
> Regards, Ursula
>
>
>

2018-09-17 11:50:14

by Ursula Braun

Subject: Re: [PATCH net-next] net/smc: cast sizeof to int for comparison

On 09/17/2018 11:38 AM, YueHaibing wrote:
>
> On 2018/9/17 16:49, Ursula Braun wrote:
>>
>>
>> On 09/15/2018 12:00 PM, YueHaibing wrote:
>>> Comparing an int to a size, which is unsigned, causes the int to become
>>> unsigned, giving the wrong result. kernel_sendmsg can return a negative
>>> error code.
>>>
>>
>> Thanks for reporting this issue!
>>
>>> Signed-off-by: YueHaibing <[email protected]>
>>> ---
>>> net/smc/smc_clc.c | 2 +-
>>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/net/smc/smc_clc.c b/net/smc/smc_clc.c
>>> index 83aba9a..fd0f5ce 100644
>>> --- a/net/smc/smc_clc.c
>>> +++ b/net/smc/smc_clc.c
>>> @@ -446,7 +446,7 @@ int smc_clc_send_proposal(struct smc_sock *smc, int smc_type,
>>> vec[i++].iov_len = sizeof(trl);
>>> /* due to the few bytes needed for clc-handshake this cannot block */
>>> len = kernel_sendmsg(smc->clcsock, &msg, vec, i, plen);
>>> - if (len < sizeof(pclc)) {
>>> + if (len < (int)sizeof(pclc)) {
>>> if (len >= 0) {
>>> reason_code = -ENETUNREACH;
>>> smc->sk.sk_err = -reason_code;
>>>
>>
>> Your fix helps, but I would like to follow the hint of Andreas Schwab, and split
>> the return value check like this:
>>
>> ---
>> net/smc/smc_clc.c | 14 ++++++--------
>> 1 file changed, 6 insertions(+), 8 deletions(-)
>>
>> --- a/net/smc/smc_clc.c
>> +++ b/net/smc/smc_clc.c
>> @@ -446,14 +446,12 @@ int smc_clc_send_proposal(struct smc_soc
>> vec[i++].iov_len = sizeof(trl);
>> /* due to the few bytes needed for clc-handshake this cannot block */
>> len = kernel_sendmsg(smc->clcsock, &msg, vec, i, plen);
>> - if (len < sizeof(pclc)) {
>> - if (len >= 0) {
>> - reason_code = -ENETUNREACH;
>> - smc->sk.sk_err = -reason_code;
>> - } else {
>> - smc->sk.sk_err = smc->clcsock->sk->sk_err;
>> - reason_code = -smc->sk.sk_err;
>> - }
>> + if (len < 0) {
>> + smc->sk.sk_err = smc->clcsock->sk->sk_err;
>> + reason_code = -smc->sk.sk_err;
>> + } else if (len < (int)sizeof(pclc)) {
>> + reason_code = -ENETUNREACH;
>> + smc->sk.sk_err = -reason_code;
>> }
>>
>> return reason_code;
>>
>> Agreed?
>
> Yes, Need a new patch from me?
>

Not necessary, I will make sure this patch version is added to the smc code.

>>
>> Regards, Ursula
>>
>>
>>
>