While parsing the perf table, there is no check if
the num of entries read from the vbios is less than
the currently allocated number.

In case of a buggy vbios this will cause overwriting
of kernel memory, causing aditional problems.

Add a simple check in order to prevent the case

Signed-off-by: Emil Velikov <[email protected]>
---
 drivers/gpu/drm/nouveau/nouveau_perf.c |    5 +++++
 1 files changed, 5 insertions(+), 0 deletions(-)

diff --git a/drivers/gpu/drm/nouveau/nouveau_perf.c 
b/drivers/gpu/drm/nouveau/nouveau_perf.c
index f2d98c9..b0e995f 100644
--- a/drivers/gpu/drm/nouveau/nouveau_perf.c
+++ b/drivers/gpu/drm/nouveau/nouveau_perf.c
@@ -225,6 +225,11 @@ nouveau_perf_init(struct drm_device *dev)
                entries   = perf[2];
        }
 
+       if (entries > NOUVEAU_PM_MAX_LEVEL) {
+               NV_DEBUG(dev, "perf table has too many entries - buggy 
vbios?\n");
+               entries = NOUVEAU_PM_MAX_LEVEL;
+       }
+
        entry = perf + headerlen;
        for (i = 0; i < entries; i++) {
                struct nouveau_pm_level *perflvl = &pm->perflvl[pm->nr_perflvl];
-- 
1.7.1

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