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Fix a buffer overrun on machines with excessively large PCI busses.

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Formerly we sized an array with a compile time constant, then initialized
its size to the same constant, but the Linux PCI init code would increase
that "constant".  So if you happened to have more than 128 PCI devices,
you'd happily scribble into whatever variables happened to be in .bss
after that array.

Only really fixed for Linux atm.  Other OSes will simply (still) fail to
work on video devices above the 128th PCI device.
This commit is contained in:
Adam Jackson 2007-04-25 16:29:48 -04:00
parent 3ba1e8ab6d
commit d322608dc9
1 changed files with 11 additions and 3 deletions
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14
hw/xfree86/os-support/bus/Pci.c
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@ -232,14 +232,14 @@ _X_EXPORT int pciNumBuses = 0; /* Actual number of PCI buses */
int pciMaxBusNum = MAX_PCI_BUSES;
static Bool inProbe = FALSE;
static pciConfigPtr pci_devp[MAX_PCI_DEVICES + 1] = {NULL, };
static pciConfigPtr *pci_devp = NULL;
static int readPciBios( PCITAG Tag, CARD8* tmp, ADDRESS hostbase,
unsigned char * buf, int len, PciBiosType BiosType );
static int (*pciOSHandleBIOS)(PCITAG Tag, int basereg, unsigned char *buf, int len);
int xf86MaxPciDevs = MAX_PCI_DEVICES;
int xf86MaxPciDevs = 0;
/*
* Platform specific PCI function pointers.
@ -272,6 +272,14 @@ pciInit()
if (pciNumBuses <= 0)
ARCH_PCI_OS_INIT();
#endif
if (xf86MaxPciDevs == 0) {
xf86Msg(X_WARNING,
"OS did not count PCI devices, guessing wildly\n");
xf86MaxPciDevs = MAX_PCI_DEVICES;
}
if (pci_devp)
xfree(pci_devp);
pci_devp = xnfcalloc(xf86MaxPciDevs + 1, sizeof(pciConfigPtr));
}
void pciSetOSBIOSPtr(int (*bios_fn)(PCITAG Tag, int basereg, unsigned char * buf, int len))
@ -920,7 +928,7 @@ xf86scanpci(int flags)
* result in an endless recursion if platform/OS specific PCI
* bus probing code calls this function from with in it.
*/
if (done || pci_devp[0])
if (done || pci_devp)
return pci_devp;
done = TRUE;