platform/mellanox: mlxbf-pmc: Fix potential buffer overflows

[ Upstream commit 80ccd40 ]

Replace sprintf with sysfs_emit where possible.
Size check in mlxbf_pmc_event_list_show should account for "\0".

Fixes: 1a218d3 ("platform/mellanox: mlxbf-pmc: Add Mellanox BlueField PMC driver")
Signed-off-by: Shravan Kumar Ramani <shravankr@nvidia.com>
Reviewed-by: Vadim Pasternak <vadimp@nvidia.com>
Reviewed-by: David Thompson <davthompson@nvidia.com>
Link: https://lore.kernel.org/r/bef39ef32319a31b32f999065911f61b0d3b17c3.1693917738.git.shravankr@nvidia.com
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

drivers/platform/mellanox/mlxbf-pmc.c

@@ -1008,7 +1008,7 @@ static ssize_t mlxbf_pmc_counter_show(struct device *dev,
 	} else
 		return -EINVAL;
 
-	return sprintf(buf, "0x%llx\n", value);
+	return sysfs_emit(buf, "0x%llx\n", value);
 }
 
 /* Store function for "counter" sysfs files */
@@ -1078,13 +1078,13 @@ static ssize_t mlxbf_pmc_event_show(struct device *dev,
 
 	err = mlxbf_pmc_read_event(blk_num, cnt_num, is_l3, &evt_num);
 	if (err)
-		return sprintf(buf, "No event being monitored\n");
+		return sysfs_emit(buf, "No event being monitored\n");
 
 	evt_name = mlxbf_pmc_get_event_name(pmc->block_name[blk_num], evt_num);
 	if (!evt_name)
 		return -EINVAL;
 
-	return sprintf(buf, "0x%llx: %s\n", evt_num, evt_name);
+	return sysfs_emit(buf, "0x%llx: %s\n", evt_num, evt_name);
 }
 
 /* Store function for "event" sysfs files */
@@ -1139,9 +1139,9 @@ static ssize_t mlxbf_pmc_event_list_show(struct device *dev,
 		return -EINVAL;
 
 	for (i = 0, buf[0] = '\0'; i < size; ++i) {
-		len += sprintf(e_info, "0x%x: %s\n", events[i].evt_num,
-			       events[i].evt_name);
-		if (len > PAGE_SIZE)
+		len += snprintf(e_info, sizeof(e_info), "0x%x: %s\n",
+				events[i].evt_num, events[i].evt_name);
+		if (len >= PAGE_SIZE)
 			break;
 		strcat(buf, e_info);
 		ret = len;
@@ -1168,7 +1168,7 @@ static ssize_t mlxbf_pmc_enable_show(struct device *dev,
 
 	value = FIELD_GET(MLXBF_PMC_L3C_PERF_CNT_CFG_EN, perfcnt_cfg);
 
-	return sprintf(buf, "%d\n", value);
+	return sysfs_emit(buf, "%d\n", value);
 }
 
 /* Store function for "enable" sysfs files - only for l3cache */