[PATCH] sctp: Fix COMM_LOST/CANT_STR_ASSOC err reporting on big-endian platforms

[PATCH] sctp: Fix COMM_LOST/CANT_STR_ASSOC err reporting on big-endian platforms

[Petr Malat]

Commit 978aa0474115 ("sctp: fix some type cast warnings introduced since
very beginning")' broke err reading from sctp_arg, because it reads the
value as 32-bit integer, although the value is stored as 16-bit integer.
Later this value is passed to the userspace in 16-bit variable, thus the
user always gets 0 on big-endian platforms. Fix it by reading the __u16
field of sctp_arg union, as reading err field would produce a sparse
warning.

Signed-off-by: Petr Malat <oss@malat.biz>
---
 net/sctp/sm_sideeffect.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/sctp/sm_sideeffect.c b/net/sctp/sm_sideeffect.c
index aa821e71f05e..813d30767204 100644
--- a/net/sctp/sm_sideeffect.c
+++ b/net/sctp/sm_sideeffect.c
@@ -1601,12 +1601,12 @@ static int sctp_cmd_interpreter(enum sctp_event_type event_type,
 			break;
 
 		case SCTP_CMD_INIT_FAILED:
-			sctp_cmd_init_failed(commands, asoc, cmd->obj.u32);
+			sctp_cmd_init_failed(commands, asoc, cmd->obj.u16);
 			break;
 
 		case SCTP_CMD_ASSOC_FAILED:
 			sctp_cmd_assoc_failed(commands, asoc, event_type,
-					      subtype, chunk, cmd->obj.u32);
+					      subtype, chunk, cmd->obj.u16);
 			break;
 
 		case SCTP_CMD_INIT_COUNTER_INC:
-- 
2.20.1

Re: [PATCH] sctp: Fix COMM_LOST/CANT_STR_ASSOC err reporting on big-endian platforms

[Marcelo Ricardo Leitner]

On Fri, Oct 30, 2020 at 02:26:33PM +0100, Petr Malat wrote:
> Commit 978aa0474115 ("sctp: fix some type cast warnings introduced since
> very beginning")' broke err reading from sctp_arg, because it reads the
> value as 32-bit integer, although the value is stored as 16-bit integer.
> Later this value is passed to the userspace in 16-bit variable, thus the
> user always gets 0 on big-endian platforms. Fix it by reading the __u16
> field of sctp_arg union, as reading err field would produce a sparse
> warning.

Makes sense.

> 
> Signed-off-by: Petr Malat <oss@malat.biz>

Then, it also needs:
Fixes: 978aa0474115 ("sctp: fix some type cast warnings introduced since very beginning")'

Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
(If the maintainers can't add the Fixes tag above, please keep the ack
on the v2)

Thanks.

Re: [PATCH] sctp: Fix COMM_LOST/CANT_STR_ASSOC err reporting on big-endian platforms

[Jakub Kicinski]

On Mon, 2 Nov 2020 10:27:17 -0300 Marcelo Ricardo Leitner wrote:
> On Fri, Oct 30, 2020 at 02:26:33PM +0100, Petr Malat wrote:
> > Commit 978aa0474115 ("sctp: fix some type cast warnings introduced since
> > very beginning")' broke err reading from sctp_arg, because it reads the
> > value as 32-bit integer, although the value is stored as 16-bit integer.
> > Later this value is passed to the userspace in 16-bit variable, thus the
> > user always gets 0 on big-endian platforms. Fix it by reading the __u16
> > field of sctp_arg union, as reading err field would produce a sparse
> > warning.  
> 
> Makes sense.
> 
> > 
> > Signed-off-by: Petr Malat <oss@malat.biz>  
> 
> Then, it also needs:
> Fixes: 978aa0474115 ("sctp: fix some type cast warnings introduced since very beginning")'
> 
> Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
> (If the maintainers can't add the Fixes tag above, please keep the ack
> on the v2)

Applied, thanks!