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

From: Petr Malat <oss@malat.biz>
To: linux-sctp@vger.kernel.org
Cc: Petr Malat <oss@malat.biz>, Vlad Yasevich <vyasevich@gmail.com>,
	Neil Horman <nhorman@tuxdriver.com>,
	Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>,
	"David S. Miller" <davem@davemloft.net>,
	Jakub Kicinski <kuba@kernel.org>,
	netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH] sctp: Fix COMM_LOST/CANT_STR_ASSOC err reporting on big-endian platforms
Date: Fri, 30 Oct 2020 14:26:33 +0100	[thread overview]
Message-ID: <20201030132633.7045-1-oss@malat.biz> (raw)

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

