From 18d52ec86efcc4e42f2bad0fc47ac1a3d5b69435 Mon Sep 17 00:00:00 2001 From: Dirk Hohndel Date: Sun, 21 Jun 2015 21:38:12 -0700 Subject: Prevent possible null pointer dereference Neither of these functions should ever be called with dc == NULL. But it's easy to prevent the potential crash. Signed-off-by: Dirk Hohndel --- dive.c | 17 ++++++++++------- 1 file changed, 10 insertions(+), 7 deletions(-) diff --git a/dive.c b/dive.c index f187e13c8..37f99048f 100644 --- a/dive.c +++ b/dive.c @@ -728,6 +728,8 @@ void per_cylinder_mean_depth(struct dive *dive, struct divecomputer *dc, int *me for (i = 0; i < MAX_CYLINDERS; i++) mean[i] = duration[i] = 0; + if (!dc) + return; struct event *ev = get_next_event(dc->events, "gaschange"); if (!ev || (dc && dc->sample && ev->time.seconds == dc->sample[0].time.seconds && get_next_event(ev->next, "gaschange") == NULL)) { // we have either no gas change or only one gas change and that's setting an explicit first cylinder @@ -861,13 +863,14 @@ static int same_rounded_pressure(pressure_t a, pressure_t b) * first cylinder - in which case cylinder 0 is indeed the first cylinder */ int explicit_first_cylinder(struct dive *dive, struct divecomputer *dc) { - struct event *ev = get_next_event(dc->events, "gaschange"); - if (ev && dc && dc->sample && ev->time.seconds == dc->sample[0].time.seconds) - return get_cylinder_index(dive, ev); - else if (dc->divemode == CCR) - return MAX(get_cylinder_idx_by_use(dive, DILUENT), 0); - else - return 0; + if (dc) { + struct event *ev = get_next_event(dc->events, "gaschange"); + if (ev && dc->sample && ev->time.seconds == dc->sample[0].time.seconds) + return get_cylinder_index(dive, ev); + else if (dc->divemode == CCR) + return MAX(get_cylinder_idx_by_use(dive, DILUENT), 0); + } + return 0; } /* this gets called when the dive mode has changed (so OC vs. CC) -- cgit v1.2.3-70-g09d2