[edk2-devel] [PATCH] OvmfPkg/VirtioFsDxe: call IsTimeValid() before EfiTimeToEpoch()
Laszlo Ersek
lersek at redhat.com
Thu Jan 7 14:16:20 UTC 2021
On 01/07/21 10:52, Ard Biesheuvel wrote:
> On 1/7/21 10:50 AM, Laszlo Ersek wrote:
>> EmbeddedPkg/TimeBaseLib provides a verification function called
>> IsTimeValid(), for enforcing the UEFI spec requirements on an EFI_TIME
>> object.
>>
>> When EFI_FILE_PROTOCOL.SetInfo() is called in order to update the
>> timestamps on the file, let's invoke IsTimeValid() first, before passing
>> the new EFI_FILE_INFO.{CreateTime,LastAccessTime,ModificationTime} values
>> to EfiTimeToEpoch().
>>
>> This patch is not expected to make a practical difference, but it's better
>> to ascertain the preconditions of EfiTimeToEpoch() on the
>> EFI_FILE_PROTOCOL.SetInfo() caller. The FAT driver (EnhancedFatDxe) has a
>> similar check, namely in FatSetFileInfo() -> FatIsValidTime().
>>
>> Cc: Ard Biesheuvel <ard.biesheuvel at arm.com>
>> Cc: Jordan Justen <jordan.l.justen at intel.com>
>> Cc: Philippe Mathieu-Daudé <philmd at redhat.com>
>> Signed-off-by: Laszlo Ersek <lersek at redhat.com>
>
> Acked-by: Ard Biesheuvel <ard.biesheuvel at arm.com>
Merged via <https://github.com/tianocore/edk2/pull/1314>, as commit
e9c5ff3d2730.
Thanks!
Laszlo
>
>
>> ---
>> OvmfPkg/VirtioFsDxe/Helpers.c | 20 +++++++++++++++-----
>> 1 file changed, 15 insertions(+), 5 deletions(-)
>>
>> diff --git a/OvmfPkg/VirtioFsDxe/Helpers.c b/OvmfPkg/VirtioFsDxe/Helpers.c
>> index 443bbdc616ac..b81c04e0a4e8 100644
>> --- a/OvmfPkg/VirtioFsDxe/Helpers.c
>> +++ b/OvmfPkg/VirtioFsDxe/Helpers.c
>> @@ -2237,26 +2237,33 @@ VirtioFsGetFuseSizeUpdate (
>>
>> @param[out] Atime If UpdateAtime is set to TRUE, then Atime provides
>> the last access timestamp to set (as seconds since
>> the Epoch). Otherwise, Atime is not written to.
>>
>> @param[out] Mtime If UpdateMtime is set to TRUE, then Mtime provides
>> the last modification timestamp to set (as seconds
>> since the Epoch). Otherwise, Mtime is not written
>> to.
>>
>> - @retval EFI_SUCCESS Output parameters have been set successfully.
>> + @retval EFI_SUCCESS Output parameters have been set successfully.
>>
>> - @retval EFI_ACCESS_DENIED NewInfo requests changing both CreateTime and
>> - ModificationTime, but to values that differ from
>> - each other. The Virtio Filesystem device does not
>> - support this.
>> + @retval EFI_INVALID_PARAMETER At least one of the CreateTime, LastAccessTime
>> + and ModificationTime fields in NewInfo
>> + represents an actual update relative to the
>> + current state of the file (expressed in Info),
>> + but does not satisfy the UEFI spec
>> + requirements on EFI_TIME.
>> +
>> + @retval EFI_ACCESS_DENIED NewInfo requests changing both CreateTime and
>> + ModificationTime, but to values that differ
>> + from each other. The Virtio Filesystem device
>> + does not support this.
>> **/
>> EFI_STATUS
>> VirtioFsGetFuseTimeUpdates (
>> IN EFI_FILE_INFO *Info,
>> IN EFI_FILE_INFO *NewInfo,
>> OUT BOOLEAN *UpdateAtime,
>> OUT BOOLEAN *UpdateMtime,
>> OUT UINT64 *Atime,
>> OUT UINT64 *Mtime
>> )
>> @@ -2278,20 +2285,23 @@ VirtioFsGetFuseTimeUpdates (
>> //
>> // Determine which timestamps differ from the current state. (A zero time
>> // means "don't update", per UEFI spec.) For each timestamp that's being
>> // changed, calculate the seconds since the Epoch.
>> //
>> for (Idx = 0; Idx < ARRAY_SIZE (Time); Idx++) {
>> if (CompareMem (NewTime[Idx], &ZeroTime, sizeof (EFI_TIME)) == 0 ||
>> CompareMem (NewTime[Idx], Time[Idx], sizeof (EFI_TIME)) == 0) {
>> Change[Idx] = FALSE;
>> } else {
>> + if (!IsTimeValid (NewTime[Idx])) {
>> + return EFI_INVALID_PARAMETER;
>> + }
>> Change[Idx] = TRUE;
>> Seconds[Idx] = EfiTimeToEpoch (NewTime[Idx]);
>> }
>> }
>>
>> //
>> // If a change is requested for exactly one of CreateTime and
>> // ModificationTime, we'll change the last modification time. If changes are
>> // requested for both, and to the same timestamp, we'll similarly update the
>> // last modification time. If changes are requested for both, but to
>>
>
>
>
>
>
>
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