[v2] tipc: set sk_err correctly when connection fails

From: Erik Hugne <erik.hugne@ericsson.com>

Should a connect fail, if the publication/server is unavailable or
due to some other error, a positive value will be returned and errno
is never set. If the application code checks for an explicit zero
return from connect (success) or a negative return (failure), it
will not catch the error and subsequent send() calls will fail as
shown from the strace snippet below.

socket(0x1e /* PF_??? */, SOCK_SEQPACKET, 0) = 3
connect(3, {sa_family=0x1e /* AF_??? */, sa_data="\2\1\322\4\0\0\322\4\0\0\0\0\0\0"}, 16) = 111
sendto(3, "test", 4, 0, NULL, 0)        = -1 EPIPE (Broken pipe)

The reason for this behaviour is that TIPC wrongly inverts error
codes set in sk_err.

Signed-off-by: Erik Hugne <erik.hugne@ericsson.com>
---

[v2: add more details to commit message]

 net/tipc/socket.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

On 13-08-28 03:29 AM, erik.hugne@ericsson.com wrote:
> From: Erik Hugne <erik.hugne@ericsson.com>
> 
> Should a connect fail, if the publication/server is unavailable or
> due to some other error, a positive value will be returned and errno
> is never set. If the application code checks for an explicit zero
> return from connect (success) or a negative return (failure), it
> will not catch the error and subsequent send() calls will fail as
> shown from the strace snippet below.
> 
> socket(0x1e /* PF_??? */, SOCK_SEQPACKET, 0) = 3
> connect(3, {sa_family=0x1e /* AF_??? */, sa_data="\2\1\322\4\0\0\322\4\0\0\0\0\0\0"}, 16) = 111
> sendto(3, "test", 4, 0, NULL, 0)        = -1 EPIPE (Broken pipe)
> 
> The reason for this behaviour is that TIPC wrongly inverts error
> codes set in sk_err.
> 
> Signed-off-by: Erik Hugne <erik.hugne@ericsson.com>
> ---
> 
> [v2: add more details to commit message]

Thanks -- this now conveys the required triplet: 1) user visible symptom,
2) underlying technical cause, and 3) the why and how of the fix.

Paul.
--

--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

From: Paul Gortmaker <paul.gortmaker@windriver.com>
Date: Thu, 29 Aug 2013 11:03:10 -0400

> On 13-08-28 03:29 AM, erik.hugne@ericsson.com wrote:
>> From: Erik Hugne <erik.hugne@ericsson.com>
>> 
>> Should a connect fail, if the publication/server is unavailable or
>> due to some other error, a positive value will be returned and errno
>> is never set. If the application code checks for an explicit zero
>> return from connect (success) or a negative return (failure), it
>> will not catch the error and subsequent send() calls will fail as
>> shown from the strace snippet below.
>> 
>> socket(0x1e /* PF_??? */, SOCK_SEQPACKET, 0) = 3
>> connect(3, {sa_family=0x1e /* AF_??? */, sa_data="\2\1\322\4\0\0\322\4\0\0\0\0\0\0"}, 16) = 111
>> sendto(3, "test", 4, 0, NULL, 0)        = -1 EPIPE (Broken pipe)
>> 
>> The reason for this behaviour is that TIPC wrongly inverts error
>> codes set in sk_err.
>> 
>> Signed-off-by: Erik Hugne <erik.hugne@ericsson.com>
>> ---
>> 
>> [v2: add more details to commit message]
> 
> Thanks -- this now conveys the required triplet: 1) user visible symptom,
> 2) underlying technical cause, and 3) the why and how of the fix.

Applied and queued up for -stable, thanks everyone.
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html