drm/nouveau/pm: Prevent overflow in nouveau_perf_init()

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 <emil.l.velikov@gmail.com>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
This commit is contained in:
Emil Velikov 2011-06-11 13:30:32 +01:00 коммит произвёл Ben Skeggs
Родитель 0897554cdd
Коммит 2905544073
1 изменённых файлов: 5 добавлений и 0 удалений

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@ -182,6 +182,11 @@ 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];