[reactos] 01/01: [FREELDR] hwdisk: Add sanity checks to avoid infinite loop (#1731)

[Stanislav Motylkov]

https://git.reactos.org/?p=reactos.git;a=commitdiff;h=31aca248a1a94cb3ae1d8…

commit 31aca248a1a94cb3ae1d8b6dad5c97ad43e61ab3
Author:     Stanislav Motylkov <x86corez(a)gmail.com>
AuthorDate: Thu Jul 18 23:49:11 2019 +0300
Commit:     Hermès BÉLUSCA - MAÏTO <hermes.belusca-maito(a)reactos.org>
CommitDate: Thu Jul 18 22:49:11 2019 +0200

    [FREELDR] hwdisk: Add sanity checks to avoid infinite loop (#1731)
    
    CORE-16204 CORE-16205
---
 boot/freeldr/freeldr/arch/i386/hwdisk.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/boot/freeldr/freeldr/arch/i386/hwdisk.c
b/boot/freeldr/freeldr/arch/i386/hwdisk.c
index a254aeeaa70..826780a07fb 100644
--- a/boot/freeldr/freeldr/arch/i386/hwdisk.c
+++ b/boot/freeldr/freeldr/arch/i386/hwdisk.c
@@ -82,6 +82,13 @@ DiskOpen(CHAR* Path, OPENMODE OpenMode, ULONG* FileId)
     PARTITION_TABLE_ENTRY PartitionTableEntry;
     CHAR FileName[1];
 
+    if (DiskReadBufferSize == 0)
+    {
+        ERR("DiskOpen(): DiskReadBufferSize is 0, something is wrong.\n");
+        ASSERT(FALSE);
+        return ENOMEM;
+    }
+
     if (!DissectArcPath(Path, FileName, &DriveNumber, &DrivePartition))
         return EINVAL;
 
@@ -139,10 +146,16 @@ DiskRead(ULONG FileId, VOID* Buffer, ULONG N, ULONG* Count)
     BOOLEAN ret;
     ULONGLONG SectorOffset;
 
+    ASSERT(DiskReadBufferSize > 0);
+
     TotalSectors = (N + Context->SectorSize - 1) / Context->SectorSize;
     MaxSectors   = DiskReadBufferSize / Context->SectorSize;
     SectorOffset = Context->SectorNumber + Context->SectorOffset;
 
+    // If MaxSectors is 0, this will lead to infinite loop
+    // In release builds assertions are disabled, however we also have sanity checks in
DiskOpen()
+    ASSERT(MaxSectors > 0);
+
     ret = TRUE;
 
     while (TotalSectors)