On 07/19/18 01:10, Yao, Jiewen wrote: > Thanks Laszlo. > > Would you please add one line comment on the FilePath, to describe if the > FilePath is internal input or external input? As such the API consumer can > know if caller’s responsibility to verify it or callee’s responsibility.
Good point. The caller is responsible for ensuring the well-formedness of the device path pointed-to by (*FilePath). The function uses DevicePathLib APIs such as NextDevicePathNode(), and if e.g. some device path node headers are invalid (containing bogus lengths, for example), then the function won't work as expected. I'll add such a comment. > For example, if the caller gets path from a read write variable, and input it > directly, the this API need validate before use. > If the caller already does the verification, then this API can use it > directly. Right. (A separate question would be if edk2 offers facilities for verifying the well-formedness of any given device path -- it looks like a complex task, to implement everywhere.) In this series I'd just like to extract the duplicated code to a common location, and fix its bugs. I didn't try to change the interface contract (just to document it more precisely). If we'd like to "armor" this function against maliciously formatted device paths, IMO that should be done separately. So I agree that the comment you suggest should be added. > Sanity check is just for the format, not the content. > The question I have is: Where should the sanity check be? At the moment: in the caller. Thanks! Laszlo > > thank you! > Yao, Jiewen > > >> 在 2018年7月19日，上午4:50，Laszlo Ersek <[email protected]> 写道： >> >> The EfiOpenFileByDevicePath() function centralizes functionality from >> >> - MdeModulePkg/Universal/Disk/RamDiskDxe >> - NetworkPkg/TlsAuthConfigDxe >> - SecurityPkg/VariableAuthenticated/SecureBootConfigDxe >> - ShellPkg/Library/UefiShellLib >> >> unifying the implementation and fixing various bugs. >> >> Cc: Chao Zhang <[email protected]> >> Cc: Eric Dong <[email protected]> >> Cc: Jaben Carsey <[email protected]> >> Cc: Jiaxin Wu <[email protected]> >> Cc: Jiewen Yao <[email protected]> >> Cc: Liming Gao <[email protected]> >> Cc: Michael D Kinney <[email protected]> >> Cc: Roman Bacik <[email protected]> >> Cc: Ruiyu Ni <[email protected]> >> Cc: Siyuan Fu <[email protected]> >> Cc: Star Zeng <[email protected]> >> Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=1008 >> Contributed-under: TianoCore Contribution Agreement 1.1 >> Signed-off-by: Laszlo Ersek <[email protected]> >> --- >> MdePkg/Library/UefiLib/UefiLib.inf | 1 + >> MdePkg/Include/Library/UefiLib.h | 86 ++++++++ >> MdePkg/Library/UefiLib/UefiLib.c | 226 ++++++++++++++++++++ >> 3 files changed, 313 insertions(+) >> >> diff --git a/MdePkg/Library/UefiLib/UefiLib.inf >> b/MdePkg/Library/UefiLib/UefiLib.inf >> index f69f0a43b576..a6c739ef3d6d 100644 >> --- a/MdePkg/Library/UefiLib/UefiLib.inf >> +++ b/MdePkg/Library/UefiLib/UefiLib.inf >> @@ -68,6 +68,7 @@ [Protocols] >> gEfiSimpleTextOutProtocolGuid ## SOMETIMES_CONSUMES >> gEfiGraphicsOutputProtocolGuid ## SOMETIMES_CONSUMES >> gEfiHiiFontProtocolGuid ## SOMETIMES_CONSUMES >> + gEfiSimpleFileSystemProtocolGuid ## SOMETIMES_CONSUMES >> gEfiUgaDrawProtocolGuid | gEfiMdePkgTokenSpaceGuid.PcdUgaConsumeSupport >> ## SOMETIMES_CONSUMES # Consumes if >> gEfiGraphicsOutputProtocolGuid uninstalled >> gEfiComponentNameProtocolGuid | NOT >> gEfiMdePkgTokenSpaceGuid.PcdComponentNameDisable ## SOMETIMES_PRODUCES # >> User chooses to produce it >> gEfiComponentName2ProtocolGuid | NOT >> gEfiMdePkgTokenSpaceGuid.PcdComponentName2Disable ## SOMETIMES_PRODUCES # >> User chooses to produce it >> diff --git a/MdePkg/Include/Library/UefiLib.h >> b/MdePkg/Include/Library/UefiLib.h >> index 7c6fde620c74..2468bf2aee80 100644 >> --- a/MdePkg/Include/Library/UefiLib.h >> +++ b/MdePkg/Include/Library/UefiLib.h >> @@ -33,6 +33,8 @@ WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER >> EXPRESS OR IMPLIED. >> #include <Protocol/DriverDiagnostics.h> >> #include <Protocol/DriverDiagnostics2.h> >> #include <Protocol/GraphicsOutput.h> >> +#include <Protocol/DevicePath.h> >> +#include <Protocol/SimpleFileSystem.h> >> >> #include <Library/BaseLib.h> >> >> @@ -1520,4 +1522,88 @@ EfiLocateProtocolBuffer ( >> OUT UINTN *NoProtocols, >> OUT VOID ***Buffer >> ); >> + >> +/** >> + Open or create a file or directory, possibly creating the chain of >> + directories leading up to the directory. >> + >> + EfiOpenFileByDevicePath() first locates EFI_SIMPLE_FILE_SYSTEM_PROTOCOL on >> + FilePath, and opens the root directory of that filesystem with >> + EFI_SIMPLE_FILE_SYSTEM_PROTOCOL.OpenVolume(). >> + >> + On the remaining device path, the longest initial sequence of >> + FILEPATH_DEVICE_PATH nodes is node-wise traversed with >> + EFI_FILE_PROTOCOL.Open(). For the pathname fragment specified by each >> + traversed FILEPATH_DEVICE_PATH node, EfiOpenFileByDevicePath() first masks >> + EFI_FILE_MODE_CREATE out of OpenMode, and passes 0 for Attributes. If >> + EFI_FILE_PROTOCOL.Open() fails, and OpenMode includes >> EFI_FILE_MODE_CREATE, >> + then the operation is retried with the caller's OpenMode and Attributes >> + unmodified. >> + >> + (As a consequence, if OpenMode includes EFI_FILE_MODE_CREATE, and >> Attributes >> + includes EFI_FILE_DIRECTORY, and each FILEPATH_DEVICE_PATH specifies a >> single >> + pathname component, then EfiOpenFileByDevicePath() ensures that the >> specified >> + series of subdirectories exist on return.) >> + >> + The EFI_FILE_PROTOCOL identified by the last FILEPATH_DEVICE_PATH node is >> + output to the caller; intermediate EFI_FILE_PROTOCOL instances are >> closed. If >> + there are no FILEPATH_DEVICE_PATH nodes past the node that identifies the >> + filesystem, then the EFI_FILE_PROTOCOL of the root directory of the >> + filesystem is output to the caller. If a device path node that is >> different >> + from FILEPATH_DEVICE_PATH is encountered relative to the filesystem, the >> + traversal is stopped with an error, and a NULL EFI_FILE_PROTOCOL is >> output. >> + >> + @param[in,out] FilePath On input, the device path to the file or >> directory >> + to open or create. On output, FilePath points one >> + past the last node in the original device path >> that >> + has been successfully processed. FilePath is set >> on >> + output even if EfiOpenFileByDevicePath() returns >> an >> + error. >> + >> + @param[out] File On error, File is set to NULL. On success, File >> is >> + set to the EFI_FILE_PROTOCOL of the root >> directory >> + of the filesystem, if there are no >> + FILEPATH_DEVICE_PATH nodes in FilePath; >> otherwise, >> + File is set to the EFI_FILE_PROTOCOL identified >> by >> + the last node in FilePath. >> + >> + @param[in] OpenMode The OpenMode parameter to pass to >> + EFI_FILE_PROTOCOL.Open(). For each >> + FILEPATH_DEVICE_PATH node in FilePath, >> + EfiOpenFileByDevicePath() first opens the >> specified >> + pathname fragment with EFI_FILE_MODE_CREATE >> masked >> + out of OpenMode and with Attributes set to 0, and >> + only retries the operation with >> EFI_FILE_MODE_CREATE >> + unmasked and Attributes propagated if the first >> open >> + attempt fails. >> + >> + @param[in] Attributes The Attributes parameter to pass to >> + EFI_FILE_PROTOCOL.Open(), when >> EFI_FILE_MODE_CREATE >> + is propagated unmasked in OpenMode. >> + >> + @retval EFI_SUCCESS The file or directory has been opened or >> + created. >> + >> + @retval EFI_INVALID_PARAMETER FilePath is NULL; or File is NULL; or >> FilePath >> + contains a device path node, past the node >> + that identifies >> + EFI_SIMPLE_FILE_SYSTEM_PROTOCOL, that is >> not a >> + FILEPATH_DEVICE_PATH node. >> + >> + @retval EFI_OUT_OF_RESOURCES Memory allocation failed. >> + >> + @return Error codes propagated from the >> + LocateDevicePath() and OpenProtocol() boot >> + services, and from the >> + >> EFI_SIMPLE_FILE_SYSTEM_PROTOCOL.OpenVolume() >> + and EFI_FILE_PROTOCOL.Open() member >> functions. >> +**/ >> +EFI_STATUS >> +EFIAPI >> +EfiOpenFileByDevicePath ( >> + IN OUT EFI_DEVICE_PATH_PROTOCOL **FilePath, >> + OUT EFI_FILE_PROTOCOL **File, >> + IN UINT64 OpenMode, >> + IN UINT64 Attributes >> + ); >> #endif >> diff --git a/MdePkg/Library/UefiLib/UefiLib.c >> b/MdePkg/Library/UefiLib/UefiLib.c >> index 828a54ce7a97..d3e290178cd9 100644 >> --- a/MdePkg/Library/UefiLib/UefiLib.c >> +++ b/MdePkg/Library/UefiLib/UefiLib.c >> @@ -1719,3 +1719,229 @@ EfiLocateProtocolBuffer ( >> >> return EFI_SUCCESS; >> } >> + >> +/** >> + Open or create a file or directory, possibly creating the chain of >> + directories leading up to the directory. >> + >> + EfiOpenFileByDevicePath() first locates EFI_SIMPLE_FILE_SYSTEM_PROTOCOL on >> + FilePath, and opens the root directory of that filesystem with >> + EFI_SIMPLE_FILE_SYSTEM_PROTOCOL.OpenVolume(). >> + >> + On the remaining device path, the longest initial sequence of >> + FILEPATH_DEVICE_PATH nodes is node-wise traversed with >> + EFI_FILE_PROTOCOL.Open(). For the pathname fragment specified by each >> + traversed FILEPATH_DEVICE_PATH node, EfiOpenFileByDevicePath() first masks >> + EFI_FILE_MODE_CREATE out of OpenMode, and passes 0 for Attributes. If >> + EFI_FILE_PROTOCOL.Open() fails, and OpenMode includes >> EFI_FILE_MODE_CREATE, >> + then the operation is retried with the caller's OpenMode and Attributes >> + unmodified. >> + >> + (As a consequence, if OpenMode includes EFI_FILE_MODE_CREATE, and >> Attributes >> + includes EFI_FILE_DIRECTORY, and each FILEPATH_DEVICE_PATH specifies a >> single >> + pathname component, then EfiOpenFileByDevicePath() ensures that the >> specified >> + series of subdirectories exist on return.) >> + >> + The EFI_FILE_PROTOCOL identified by the last FILEPATH_DEVICE_PATH node is >> + output to the caller; intermediate EFI_FILE_PROTOCOL instances are >> closed. If >> + there are no FILEPATH_DEVICE_PATH nodes past the node that identifies the >> + filesystem, then the EFI_FILE_PROTOCOL of the root directory of the >> + filesystem is output to the caller. If a device path node that is >> different >> + from FILEPATH_DEVICE_PATH is encountered relative to the filesystem, the >> + traversal is stopped with an error, and a NULL EFI_FILE_PROTOCOL is >> output. >> + >> + @param[in,out] FilePath On input, the device path to the file or >> directory >> + to open or create. On output, FilePath points one >> + past the last node in the original device path >> that >> + has been successfully processed. FilePath is set >> on >> + output even if EfiOpenFileByDevicePath() returns >> an >> + error. >> + >> + @param[out] File On error, File is set to NULL. On success, File >> is >> + set to the EFI_FILE_PROTOCOL of the root >> directory >> + of the filesystem, if there are no >> + FILEPATH_DEVICE_PATH nodes in FilePath; >> otherwise, >> + File is set to the EFI_FILE_PROTOCOL identified >> by >> + the last node in FilePath. >> + >> + @param[in] OpenMode The OpenMode parameter to pass to >> + EFI_FILE_PROTOCOL.Open(). For each >> + FILEPATH_DEVICE_PATH node in FilePath, >> + EfiOpenFileByDevicePath() first opens the >> specified >> + pathname fragment with EFI_FILE_MODE_CREATE >> masked >> + out of OpenMode and with Attributes set to 0, and >> + only retries the operation with >> EFI_FILE_MODE_CREATE >> + unmasked and Attributes propagated if the first >> open >> + attempt fails. >> + >> + @param[in] Attributes The Attributes parameter to pass to >> + EFI_FILE_PROTOCOL.Open(), when >> EFI_FILE_MODE_CREATE >> + is propagated unmasked in OpenMode. >> + >> + @retval EFI_SUCCESS The file or directory has been opened or >> + created. >> + >> + @retval EFI_INVALID_PARAMETER FilePath is NULL; or File is NULL; or >> FilePath >> + contains a device path node, past the node >> + that identifies >> + EFI_SIMPLE_FILE_SYSTEM_PROTOCOL, that is >> not a >> + FILEPATH_DEVICE_PATH node. >> + >> + @retval EFI_OUT_OF_RESOURCES Memory allocation failed. >> + >> + @return Error codes propagated from the >> + LocateDevicePath() and OpenProtocol() boot >> + services, and from the >> + >> EFI_SIMPLE_FILE_SYSTEM_PROTOCOL.OpenVolume() >> + and EFI_FILE_PROTOCOL.Open() member >> functions. >> +**/ >> +EFI_STATUS >> +EFIAPI >> +EfiOpenFileByDevicePath ( >> + IN OUT EFI_DEVICE_PATH_PROTOCOL **FilePath, >> + OUT EFI_FILE_PROTOCOL **File, >> + IN UINT64 OpenMode, >> + IN UINT64 Attributes >> + ) >> +{ >> + EFI_STATUS Status; >> + EFI_HANDLE FileSystemHandle; >> + EFI_SIMPLE_FILE_SYSTEM_PROTOCOL *FileSystem; >> + EFI_FILE_PROTOCOL *LastFile; >> + >> + if (File == NULL) { >> + return EFI_INVALID_PARAMETER; >> + } >> + *File = NULL; >> + >> + if (FilePath == NULL) { >> + return EFI_INVALID_PARAMETER; >> + } >> + >> + // >> + // Look up the filesystem. >> + // >> + Status = gBS->LocateDevicePath ( >> + &gEfiSimpleFileSystemProtocolGuid, >> + FilePath, >> + &FileSystemHandle >> + ); >> + if (EFI_ERROR (Status)) { >> + return Status; >> + } >> + Status = gBS->OpenProtocol ( >> + FileSystemHandle, >> + &gEfiSimpleFileSystemProtocolGuid, >> + (VOID **)&FileSystem, >> + gImageHandle, >> + NULL, >> + EFI_OPEN_PROTOCOL_GET_PROTOCOL >> + ); >> + if (EFI_ERROR (Status)) { >> + return Status; >> + } >> + >> + // >> + // Open the root directory of the filesystem. After this operation >> succeeds, >> + // we have to release LastFile on error. >> + // >> + Status = FileSystem->OpenVolume (FileSystem, &LastFile); >> + if (EFI_ERROR (Status)) { >> + return Status; >> + } >> + >> + // >> + // Traverse the device path nodes relative to the filesystem. >> + // >> + while (!IsDevicePathEnd (*FilePath)) { >> + // >> + // Keep local variables that relate to the current device path node >> tightly >> + // scoped. >> + // >> + FILEPATH_DEVICE_PATH *FilePathNode; >> + CHAR16 *AlignedPathName; >> + CHAR16 *PathName; >> + EFI_FILE_PROTOCOL *NextFile; >> + >> + if (DevicePathType (*FilePath) != MEDIA_DEVICE_PATH || >> + DevicePathSubType (*FilePath) != MEDIA_FILEPATH_DP) { >> + Status = EFI_INVALID_PARAMETER; >> + goto CloseLastFile; >> + } >> + FilePathNode = (FILEPATH_DEVICE_PATH *)*FilePath; >> + >> + // >> + // FilePathNode->PathName may be unaligned, and the UEFI specification >> + // requires pointers that are passed to protocol member functions to be >> + // aligned. Create an aligned copy of the pathname if necessary. >> + // >> + if ((UINTN)FilePathNode->PathName % sizeof *FilePathNode->PathName == >> 0) { >> + AlignedPathName = NULL; >> + PathName = FilePathNode->PathName; >> + } else { >> + AlignedPathName = AllocateCopyPool ( >> + (DevicePathNodeLength (FilePathNode) - >> + SIZE_OF_FILEPATH_DEVICE_PATH), >> + FilePathNode->PathName >> + ); >> + if (AlignedPathName == NULL) { >> + Status = EFI_OUT_OF_RESOURCES; >> + goto CloseLastFile; >> + } >> + PathName = AlignedPathName; >> + } >> + >> + // >> + // Open the next pathname fragment with EFI_FILE_MODE_CREATE masked out >> and >> + // with Attributes set to 0. >> + // >> + Status = LastFile->Open ( >> + LastFile, >> + &NextFile, >> + PathName, >> + OpenMode & ~(UINT64)EFI_FILE_MODE_CREATE, >> + 0 >> + ); >> + >> + // >> + // Retry with EFI_FILE_MODE_CREATE and the original Attributes if the >> first >> + // attempt failed, and the caller specified EFI_FILE_MODE_CREATE. >> + // >> + if (EFI_ERROR (Status) && (OpenMode & EFI_FILE_MODE_CREATE) != 0) { >> + Status = LastFile->Open ( >> + LastFile, >> + &NextFile, >> + PathName, >> + OpenMode, >> + Attributes >> + ); >> + } >> + >> + // >> + // Release any AlignedPathName on both error and success paths; >> PathName is >> + // no longer needed. >> + // >> + if (AlignedPathName != NULL) { >> + FreePool (AlignedPathName); >> + } >> + if (EFI_ERROR (Status)) { >> + goto CloseLastFile; >> + } >> + >> + // >> + // Advance to the next device path node. >> + // >> + LastFile->Close (LastFile); >> + LastFile = NextFile; >> + *FilePath = NextDevicePathNode (FilePathNode); >> + } >> + >> + *File = LastFile; >> + return EFI_SUCCESS; >> + >> +CloseLastFile: >> + LastFile->Close (LastFile); >> + >> + ASSERT (EFI_ERROR (Status)); >> + return Status; >> +} >> -- >> 2.14.1.3.gb7cf6e02401b >> >> _______________________________________________ edk2-devel mailing list [email protected] https://lists.01.org/mailman/listinfo/edk2-devel
