From b5a3d0864ee7e43a6ef8a2820f901d60bf4e0703 Mon Sep 17 00:00:00 2001 From: Marc Kleine-Budde Date: Tue, 6 Sep 2022 19:15:28 +0200 Subject: [PATCH] can: bittiming: can_sjw_check(): check that SJW is not longer than either Phase Buffer Segment According to "The Configuration of the CAN Bit Timing" [1] the SJW "may not be longer than either Phase Buffer Segment". Check SJW against length of both Phase buffers. In case the SJW is greater, report an error via netlink to user space and bail out. [1] http://web.archive.org/http://www.oertel-halle.de/files/cia99paper.pdf Link: https://lore.kernel.org/all/20230202110854.2318594-14-mkl@pengutronix.de Suggested-by: Vincent Mailhol Signed-off-by: Marc Kleine-Budde --- drivers/net/can/dev/bittiming.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/drivers/net/can/dev/bittiming.c b/drivers/net/can/dev/bittiming.c index 0a2a9b12565fd..68287b79afe89 100644 --- a/drivers/net/can/dev/bittiming.c +++ b/drivers/net/can/dev/bittiming.c @@ -24,6 +24,20 @@ int can_sjw_check(const struct net_device *dev, const struct can_bittiming *bt, return -EINVAL; } + if (bt->sjw > bt->phase_seg1) { + NL_SET_ERR_MSG_FMT(extack, + "sjw: %u greater than phase-seg1: %u", + bt->sjw, bt->phase_seg1); + return -EINVAL; + } + + if (bt->sjw > bt->phase_seg2) { + NL_SET_ERR_MSG_FMT(extack, + "sjw: %u greater than phase-seg2: %u", + bt->sjw, bt->phase_seg2); + return -EINVAL; + } + return 0; } -- 2.30.2