https://git.reactos.org/?p=reactos.git;a=commitdiff;h=ba9a1c3abba3b795a55186f289704ec8eeaf1cb9
commit ba9a1c3abba3b795a55186f289704ec8eeaf1cb9 Author: Serge Gautherie <[email protected]> AuthorDate: Tue Oct 10 03:39:44 2017 +0200 [FREELDR] Additional safety checks for PcMemGetBiosMemoryMap. CORE-13332 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. --- boot/freeldr/freeldr/arch/i386/pcmem.c | 20 +++++++++++++++++++- 1 file changed, 19 insertions(+), 1 deletion(-) diff --git a/boot/freeldr/freeldr/arch/i386/pcmem.c b/boot/freeldr/freeldr/arch/i386/pcmem.c index 2c615914f1..aa5b18d226 100644 --- a/boot/freeldr/freeldr/arch/i386/pcmem.c +++ b/boot/freeldr/freeldr/arch/i386/pcmem.c @@ -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;
