The following two quantities: SecDataDir->VirtualAddress + SecDataDir->Size SecDataDir->VirtualAddress + SecDataDir->Size - OffSet
are used multiple times in DxeImageVerificationHandler(). Introduce helper variables for them: "SecDataDirEnd" and "SecDataDirLeft", respectively. This saves us multiple calculations and significantly simplifies the code. Note that all three summands above have type UINT32, therefore the new variables are also of type UINT32. This patch does not change behavior. (Note that the code already handles the case when the SecDataDir->VirtualAddress + SecDataDir->Size UINT32 addition overflows -- namely, in that case, the certificate loop is never entered, and the corruption check right after the loop fires.) Cc: Jian J Wang <jian.j.w...@intel.com> Cc: Jiewen Yao <jiewen....@intel.com> Cc: Min Xu <min.m...@intel.com> Cc: Wenyi Xie <xiewen...@huawei.com> Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=2215 Signed-off-by: Laszlo Ersek <ler...@redhat.com> --- SecurityPkg/Library/DxeImageVerificationLib/DxeImageVerificationLib.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) diff --git a/SecurityPkg/Library/DxeImageVerificationLib/DxeImageVerificationLib.c b/SecurityPkg/Library/DxeImageVerificationLib/DxeImageVerificationLib.c index b08fe24e85aa..377feebb205a 100644 --- a/SecurityPkg/Library/DxeImageVerificationLib/DxeImageVerificationLib.c +++ b/SecurityPkg/Library/DxeImageVerificationLib/DxeImageVerificationLib.c @@ -1652,6 +1652,8 @@ DxeImageVerificationHandler ( UINT8 *AuthData; UINTN AuthDataSize; EFI_IMAGE_DATA_DIRECTORY *SecDataDir; + UINT32 SecDataDirEnd; + UINT32 SecDataDirLeft; UINT32 OffSet; CHAR16 *NameStr; RETURN_STATUS PeCoffStatus; @@ -1849,12 +1851,14 @@ DxeImageVerificationHandler ( // "Attribute Certificate Table". // The first certificate starts at offset (SecDataDir->VirtualAddress) from the start of the file. // + SecDataDirEnd = SecDataDir->VirtualAddress + SecDataDir->Size; for (OffSet = SecDataDir->VirtualAddress; - OffSet < (SecDataDir->VirtualAddress + SecDataDir->Size); + OffSet < SecDataDirEnd; OffSet += (WinCertificate->dwLength + ALIGN_SIZE (WinCertificate->dwLength))) { WinCertificate = (WIN_CERTIFICATE *) (mImageBase + OffSet); - if ((SecDataDir->VirtualAddress + SecDataDir->Size - OffSet) <= sizeof (WIN_CERTIFICATE) || - (SecDataDir->VirtualAddress + SecDataDir->Size - OffSet) < WinCertificate->dwLength) { + SecDataDirLeft = SecDataDirEnd - OffSet; + if (SecDataDirLeft <= sizeof (WIN_CERTIFICATE) || + SecDataDirLeft < WinCertificate->dwLength) { break; } @@ -1948,7 +1952,7 @@ DxeImageVerificationHandler ( } } - if (OffSet != (SecDataDir->VirtualAddress + SecDataDir->Size)) { + if (OffSet != SecDataDirEnd) { // // The Size in Certificate Table or the attribute certificate table is corrupted. // -- 2.19.1.3.g30247aa5d201 -=-=-=-=-=-=-=-=-=-=-=- Groups.io Links: You receive all messages sent to this group. View/Reply Online (#64884): https://edk2.groups.io/g/devel/message/64884 Mute This Topic: https://groups.io/mt/76552540/21656 Group Owner: devel+ow...@edk2.groups.io Unsubscribe: https://edk2.groups.io/g/devel/unsub [arch...@mail-archive.com] -=-=-=-=-=-=-=-=-=-=-=-
