The functions FatGetDirEntInfo and FatOpenDirEnt in the file FatPkg/EnhancedFatDxe/DirectoryManage.c contains the code statements
Cluster = (Entry->FileClusterHigh << 16) | Entry->FileCluster; and OFile->FileCluster = ((DirEnt->Entry.FileClusterHigh) << 16) | (DirEnt->Entry.FileCluster); respectively. In both these statements, there is an "Operand1" with type "UINT16" (16 bits, unsigned) which is promoted in the operation "(Operand1 << 16) | Operand2" to type "int" (32 bits, signed), then sign-extended to type "unsigned long long" (64 bits, unsigned). If the result of "(Operand1 << 16) | Operand2" is greater than 0x7FFFFFFF, the upper bits of the result will all be 1. So to avoid sign-extension, typecast "Operand1" with UINTN which is the data type of the variable on the LHS of the assignment. The function FatInitializeDiskCache in the file FatPkg/EnhancedFatDxe/DiskCache.c evaluates an expression FAT_DATACACHE_GROUP_COUNT << DiskCache[CacheData].PageAlignment and assigns it to DataCacheSize which is of type UINTN; As per Coverity report, FAT_DATACACHE_GROUP_COUNT << DiskCache[CacheData].PageAlignment is a potentially overflowing expression with type "int" (32 bits, signed) evaluated using 32-bit arithmetic, and then used in a context that expects an expression of type "UINTN" (64 bits, unsigned). To avoid overflow, cast "FAT_DATACACHE_GROUP_COUNT" to type "UINTN". REF: https://bugzilla.tianocore.org/show_bug.cgi?id=4249 Signed-off-by: Ranbir Singh <ranbir.sin...@dell.com> --- FatPkg/EnhancedFatDxe/DirectoryManage.c | 4 ++-- FatPkg/EnhancedFatDxe/DiskCache.c | 2 +- 2 files changed, 3 insertions(+), 3 deletions(-) diff --git a/FatPkg/EnhancedFatDxe/DirectoryManage.c b/FatPkg/EnhancedFatDxe/DirectoryManage.c index 723fc35f38..cdae864be0 100644 --- a/FatPkg/EnhancedFatDxe/DirectoryManage.c +++ b/FatPkg/EnhancedFatDxe/DirectoryManage.c @@ -474,7 +474,7 @@ FatGetDirEntInfo ( Info = Buffer; Info->Size = ResultSize; if ((Entry->Attributes & FAT_ATTRIBUTE_DIRECTORY) != 0) { - Cluster = (Entry->FileClusterHigh << 16) | Entry->FileCluster; + Cluster = ((UINTN)(Entry->FileClusterHigh) << 16) | (UINTN)Entry->FileCluster; Info->PhysicalSize = FatPhysicalDirSize (Volume, Cluster); Info->FileSize = Info->PhysicalSize; } else { @@ -1167,7 +1167,7 @@ FatOpenDirEnt ( // Volume = Parent->Volume; OFile->FullPathLen = Parent->FullPathLen + 1 + StrLen (DirEnt->FileString); - OFile->FileCluster = ((DirEnt->Entry.FileClusterHigh) << 16) | (DirEnt->Entry.FileCluster); + OFile->FileCluster = ((UINTN)(DirEnt->Entry.FileClusterHigh) << 16) | (DirEnt->Entry.FileCluster); InsertTailList (&Parent->ChildHead, &OFile->ChildLink); } else { // diff --git a/FatPkg/EnhancedFatDxe/DiskCache.c b/FatPkg/EnhancedFatDxe/DiskCache.c index d1a34a6a64..d56e338586 100644 --- a/FatPkg/EnhancedFatDxe/DiskCache.c +++ b/FatPkg/EnhancedFatDxe/DiskCache.c @@ -477,7 +477,7 @@ FatInitializeDiskCache ( DiskCache[CacheFat].BaseAddress = Volume->FatPos; DiskCache[CacheFat].LimitAddress = Volume->FatPos + Volume->FatSize; FatCacheSize = FatCacheGroupCount << DiskCache[CacheFat].PageAlignment; - DataCacheSize = FAT_DATACACHE_GROUP_COUNT << DiskCache[CacheData].PageAlignment; + DataCacheSize = (UINTN)FAT_DATACACHE_GROUP_COUNT << DiskCache[CacheData].PageAlignment; // // Allocate the Fat Cache buffer // -- 2.36.1.windows.1 -=-=-=-=-=-=-=-=-=-=-=- Groups.io Links: You receive all messages sent to this group. View/Reply Online (#97942): https://edk2.groups.io/g/devel/message/97942 Mute This Topic: https://groups.io/mt/96050605/21656 Group Owner: devel+ow...@edk2.groups.io Unsubscribe: https://edk2.groups.io/g/devel/unsub [arch...@mail-archive.com] -=-=-=-=-=-=-=-=-=-=-=-