Corrects multiplication overflow check code and adds additional check
for emptiness of number of blocks and block number
Cc: Marvin Häuser <mhaeu...@posteo.de>
Cc: Pedro Falcato <pedro.falc...@gmail.com>
Cc: Vitaly Cheptsov <vit9...@protonmail.com>
Fixes: d9ceedca6c8f ("Ext4Pkg: Add Ext4Dxe driver.")
Signed-off-by: Savva Mitrofanov <savva...@gmail.com>
---
Features/Ext4Pkg/Ext4Pkg.dsc | 2 +-
Features/Ext4Pkg/Ext4Dxe/DiskUtil.c | 18 ++++++++++++++----
Features/Ext4Pkg/Ext4Dxe/Extents.c | 15 ++++++++++++---
3 files changed, 27 insertions(+), 8 deletions(-)
diff --git a/Features/Ext4Pkg/Ext4Pkg.dsc b/Features/Ext4Pkg/Ext4Pkg.dsc
index 59bc327ebf6e..621c63eaf92d 100644
--- a/Features/Ext4Pkg/Ext4Pkg.dsc
+++ b/Features/Ext4Pkg/Ext4Pkg.dsc
@@ -46,7 +46,7 @@
DevicePathLib|MdePkg/Library/UefiDevicePathLib/UefiDevicePathLib.inf
OrderedCollectionLib|MdePkg/Library/BaseOrderedCollectionRedBlackTreeLib/BaseOrderedCollectionRedBlackTreeLib.inf
BaseUcs2Utf8Lib|RedfishPkg/Library/BaseUcs2Utf8Lib/BaseUcs2Utf8Lib.inf
-
+
#
# Required for stack protector support
#
diff --git a/Features/Ext4Pkg/Ext4Dxe/DiskUtil.c
b/Features/Ext4Pkg/Ext4Dxe/DiskUtil.c
index 32da35f7d9f5..5df9ce5bafcf 100644
--- a/Features/Ext4Pkg/Ext4Dxe/DiskUtil.c
+++ b/Features/Ext4Pkg/Ext4Dxe/DiskUtil.c
@@ -54,17 +54,20 @@ Ext4ReadBlocks (
UINT64 Offset;
UINTN Length;
+ ASSERT (NumberBlocks != 0);
+ ASSERT (BlockNumber != EXT4_BLOCK_FILE_HOLE);
+
Offset = MultU64x32 (BlockNumber, Partition->BlockSize);
Length = NumberBlocks * Partition->BlockSize;
// Check for overflow on the block -> byte conversions.
// Partition->BlockSize is never 0, so we don't need to check for that.
- if (Offset > DivU64x32 ((UINT64)-1, Partition->BlockSize)) {
+ if (DivU64x64Remainder (Offset, BlockNumber, NULL) != Partition->BlockSize) {
return EFI_INVALID_PARAMETER;
}
- if (Length > (UINTN)-1/Partition->BlockSize) {
+ if (Length / NumberBlocks != Partition->BlockSize) {
return EFI_INVALID_PARAMETER;
}
@@ -92,14 +95,21 @@ Ext4AllocAndReadBlocks (
VOID *Buf;
UINTN Length;
+ // Check that number of blocks isn't empty, because
+ // this is incorrect condition for opened partition,
+ // so we just early-exit
+ if ((NumberBlocks == 0) || (BlockNumber == EXT4_BLOCK_FILE_HOLE)) {
+ return NULL;
+ }
+
Length = NumberBlocks * Partition->BlockSize;
- if (Length > (UINTN)-1/Partition->BlockSize) {
+ // Check for integer overflow
+ if (Length / NumberBlocks != Partition->BlockSize) {
return NULL;
}
Buf = AllocatePool (Length);
-
if (Buf == NULL) {
return NULL;
}
diff --git a/Features/Ext4Pkg/Ext4Dxe/Extents.c
b/Features/Ext4Pkg/Ext4Dxe/Extents.c
index e1001d0a4292..99cb0f204fc2 100644
--- a/Features/Ext4Pkg/Ext4Dxe/Extents.c
+++ b/Features/Ext4Pkg/Ext4Dxe/Extents.c
@@ -237,6 +237,7 @@ Ext4GetExtent (
EXT4_EXTENT_HEADER *ExtHeader;
EXT4_EXTENT_INDEX *Index;
EFI_STATUS Status;
+ EXT4_BLOCK_NR BlockNumber;
Inode = File->Inode;
Ext = NULL;
@@ -288,7 +289,16 @@ Ext4GetExtent (
// Therefore, we can use binary search, and it's actually the standard for
doing so
// (see FreeBSD).
- Index = Ext4BinsearchExtentIndex (ExtHeader, LogicalBlock);
+ Index = Ext4BinsearchExtentIndex (ExtHeader, LogicalBlock);
+ BlockNumber = Ext4ExtentIdxLeafBlock (Index);
+
+ // Check that block isn't file hole
+ if (BlockNumber == EXT4_BLOCK_FILE_HOLE) {
+ if (Buffer != NULL) {
+ FreePool (Buffer);
+ }
+ return EFI_NO_MAPPING;
+ }
if (Buffer == NULL) {
Buffer = AllocatePool (Partition->BlockSize);
@@ -298,8 +308,7 @@ Ext4GetExtent (
}
// Read the leaf block onto the previously-allocated buffer.
-
- Status = Ext4ReadBlocks (Partition, Buffer, 1, Ext4ExtentIdxLeafBlock
(Index));
+ Status = Ext4ReadBlocks (Partition, Buffer, 1, BlockNumber);
if (EFI_ERROR (Status)) {
FreePool (Buffer);
return Status;
--
2.39.1
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