From 06236821aeac480a0835dd8dd9fb20e3b5a5d80d Mon Sep 17 00:00:00 2001 From: Takashi Iwai Date: Sun, 15 Mar 2020 10:37:15 +0100 Subject: perf: arm-ccn: Use scnprintf() for robustness snprintf() is a hard-to-use function, it's especially difficult to use it for concatenating substrings in a buffer with a limited size. Since snprintf() returns the would-be-output size, not the actual size, the subsequent use of snprintf() may point to the incorrect position easily. Although the current code doesn't actually overflow the buffer, it's an incorrect usage. This patch replaces such snprintf() calls with a safer version, scnprintf(). Acked-by: Mark Rutland Signed-off-by: Takashi Iwai Signed-off-by: Will Deacon --- drivers/perf/arm-ccn.c | 20 ++++++++++---------- 1 file changed, 10 insertions(+), 10 deletions(-) (limited to 'drivers/perf') diff --git a/drivers/perf/arm-ccn.c b/drivers/perf/arm-ccn.c index fea354d6fb29..d50edef91f59 100644 --- a/drivers/perf/arm-ccn.c +++ b/drivers/perf/arm-ccn.c @@ -328,15 +328,15 @@ static ssize_t arm_ccn_pmu_event_show(struct device *dev, struct arm_ccn_pmu_event, attr); ssize_t res; - res = snprintf(buf, PAGE_SIZE, "type=0x%x", event->type); + res = scnprintf(buf, PAGE_SIZE, "type=0x%x", event->type); if (event->event) - res += snprintf(buf + res, PAGE_SIZE - res, ",event=0x%x", + res += scnprintf(buf + res, PAGE_SIZE - res, ",event=0x%x", event->event); if (event->def) - res += snprintf(buf + res, PAGE_SIZE - res, ",%s", + res += scnprintf(buf + res, PAGE_SIZE - res, ",%s", event->def); if (event->mask) - res += snprintf(buf + res, PAGE_SIZE - res, ",mask=0x%x", + res += scnprintf(buf + res, PAGE_SIZE - res, ",mask=0x%x", event->mask); /* Arguments required by an event */ @@ -344,25 +344,25 @@ static ssize_t arm_ccn_pmu_event_show(struct device *dev, case CCN_TYPE_CYCLES: break; case CCN_TYPE_XP: - res += snprintf(buf + res, PAGE_SIZE - res, + res += scnprintf(buf + res, PAGE_SIZE - res, ",xp=?,vc=?"); if (event->event == CCN_EVENT_WATCHPOINT) - res += snprintf(buf + res, PAGE_SIZE - res, + res += scnprintf(buf + res, PAGE_SIZE - res, ",port=?,dir=?,cmp_l=?,cmp_h=?,mask=?"); else - res += snprintf(buf + res, PAGE_SIZE - res, + res += scnprintf(buf + res, PAGE_SIZE - res, ",bus=?"); break; case CCN_TYPE_MN: - res += snprintf(buf + res, PAGE_SIZE - res, ",node=%d", ccn->mn_id); + res += scnprintf(buf + res, PAGE_SIZE - res, ",node=%d", ccn->mn_id); break; default: - res += snprintf(buf + res, PAGE_SIZE - res, ",node=?"); + res += scnprintf(buf + res, PAGE_SIZE - res, ",node=?"); break; } - res += snprintf(buf + res, PAGE_SIZE - res, "\n"); + res += scnprintf(buf + res, PAGE_SIZE - res, "\n"); return res; } -- cgit