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[FREELDR] Additional safety checks for PcMemGetBiosMemoryMap. CORE-13332

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Cast MAX_BIOS_DESCRIPTORS to explicit ULONG from implicit int.
Comment/Add checks for PcMemoryMap/PcBiosMemoryMap arrays being full and bare handling of error cases.
This commit is contained in:
Serge Gautherie 2017-10-10 03:39:44 +02:00 committed by Thomas Faber
parent fe3eb29287
commit ba9a1c3abb
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1 changed files with 19 additions and 1 deletions
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20
boot/freeldr/freeldr/arch/i386/pcmem.c
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@ -33,7 +33,7 @@ DBG_DEFAULT_CHANNEL(MEMORY);
#define ULONGLONG_ALIGN_UP_BY(size, align) \
(ULONGLONG_ALIGN_DOWN_BY(((ULONGLONG)(size) + align - 1), align))
#define MAX_BIOS_DESCRIPTORS 80
#define MAX_BIOS_DESCRIPTORS 80ul
BIOS_MEMORY_MAP PcBiosMemoryMap[MAX_BIOS_DESCRIPTORS];
ULONG PcBiosMapCount;
@ -368,6 +368,12 @@ PcMemGetBiosMemoryMap(PFREELDR_MEMORY_DESCRIPTOR MemoryMap, ULONG MaxMemoryMapSi
{
ERR("PcMemoryMap is already full! (PcBiosMapCount = %lu, PcMapCount = %lu (>= %lu))\n",
PcBiosMapCount, PcMapCount, MaxMemoryMapSize);
// NotWantedForPublicBuilds: ASSERTMSG("PcMemoryMap is already full!", FALSE);
/* We keep previous entries, and half-retrieve current/next entries.
* We assume all these entries are good to use as is. If they are not, we are in trouble...
*
* FIXME: Safer = revert (half-)retrieved entries, Safest = increase MaxMemoryMapSize.
*/
}
else
{
@ -390,6 +396,18 @@ nextRange:
break;
}
}
/* Check whether there would be more entries to process. */
if (PcBiosMapCount >= MAX_BIOS_DESCRIPTORS && Regs.x.ebx != 0x00000000)
{
ERR("PcBiosMapCount is already full! (PcBiosMapCount = %lu (>= %lu), PcMapCount = %lu)\n",
PcBiosMapCount, MAX_BIOS_DESCRIPTORS, PcMapCount);
// NotWantedForPublicBuilds: ASSERTMSG("PcBiosMapCount is already full!", FALSE);
/* We keep retrieved entries, but ignore next entries.
* We assume these entries are good to use as is. If they are not, we are in trouble...
*
* FIXME: Safer = revert retrieved entries, Safest = increase MAX_BIOS_DESCRIPTORS.
*/
}
TRACE("PcMemGetBiosMemoryMap end: PcBiosMapCount = %lu\n", PcBiosMapCount);
return PcBiosMapCount;