Patch "drivers/perf: hisi_pcie: Fix out-of-bound access when valid event group" has been added to the 6.8-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    drivers/perf: hisi_pcie: Fix out-of-bound access when valid event group

to the 6.8-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     drivers-perf-hisi_pcie-fix-out-of-bound-access-when-.patch
and it can be found in the queue-6.8 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 7c76d147d3557c70c2ce0a76681481703e24f6a7
Author: Junhao He <hejunhao3@xxxxxxxxxx>
Date:   Thu Apr 25 20:46:25 2024 +0800

    drivers/perf: hisi_pcie: Fix out-of-bound access when valid event group
    
    [ Upstream commit 77fce82678ea5fd51442e62febec2004f79e041b ]
    
    The perf tool allows users to create event groups through following
    cmd [1], but the driver does not check whether the array index is out of
    bounds when writing data to the event_group array. If the number of events
    in an event_group is greater than HISI_PCIE_MAX_COUNTERS, the memory write
    overflow of event_group array occurs.
    
    Add array index check to fix the possible array out of bounds violation,
    and return directly when write new events are written to array bounds.
    
    There are 9 different events in an event_group.
    [1] perf stat -e '{pmu/event1/, ... ,pmu/event9/}'
    
    Fixes: 8404b0fbc7fb ("drivers/perf: hisi: Add driver for HiSilicon PCIe PMU")
    Signed-off-by: Junhao He <hejunhao3@xxxxxxxxxx>
    Reviewed-by: Jijie Shao <shaojijie@xxxxxxxxxx>
    Acked-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
    Link: https://lore.kernel.org/r/20240425124627.13764-2-hejunhao3@xxxxxxxxxx
    Signed-off-by: Will Deacon <will@xxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/perf/hisilicon/hisi_pcie_pmu.c b/drivers/perf/hisilicon/hisi_pcie_pmu.c
index b90ba8aca3fa5..ec4d5fc30781c 100644
--- a/drivers/perf/hisilicon/hisi_pcie_pmu.c
+++ b/drivers/perf/hisilicon/hisi_pcie_pmu.c
@@ -337,15 +337,27 @@ static bool hisi_pcie_pmu_validate_event_group(struct perf_event *event)
 			return false;
 
 		for (num = 0; num < counters; num++) {
+			/*
+			 * If we find a related event, then it's a valid group
+			 * since we don't need to allocate a new counter for it.
+			 */
 			if (hisi_pcie_pmu_cmp_event(event_group[num], sibling))
 				break;
 		}
 
+		/*
+		 * Otherwise it's a new event but if there's no available counter,
+		 * fail the check since we cannot schedule all the events in
+		 * the group simultaneously.
+		 */
+		if (num == HISI_PCIE_MAX_COUNTERS)
+			return false;
+
 		if (num == counters)
 			event_group[counters++] = sibling;
 	}
 
-	return counters <= HISI_PCIE_MAX_COUNTERS;
+	return true;
 }
 
 static int hisi_pcie_pmu_event_init(struct perf_event *event)