Current calculate timeout logic may have overflow if the input timeout value too large. This patch fix this potential overflow issue.
Cc: Michael Kinney <[email protected]> Cc: Ruiyu Ni <[email protected]> Contributed-under: TianoCore Contribution Agreement 1.1 Signed-off-by: Eric Dong <[email protected]> --- UefiCpuPkg/Library/MpInitLib/MpLib.c | 30 +++++++++++++++++++++++------- 1 file changed, 23 insertions(+), 7 deletions(-) diff --git a/UefiCpuPkg/Library/MpInitLib/MpLib.c b/UefiCpuPkg/Library/MpInitLib/MpLib.c index ed1f55e..005dec4 100644 --- a/UefiCpuPkg/Library/MpInitLib/MpLib.c +++ b/UefiCpuPkg/Library/MpInitLib/MpLib.c @@ -1001,6 +1001,9 @@ CalculateTimeout ( OUT UINT64 *CurrentTime ) { + UINT64 TimeoutInSeconds; + UINT64 TimestampCounterFreq; + // // Read the current value of the performance counter // @@ -1019,13 +1022,26 @@ CalculateTimeout ( // in Hz. So multiply the return value with TimeoutInMicroseconds and then divide // it by 1,000,000, to get the number of ticks for the timeout value. // - return DivU64x32 ( - MultU64x64 ( - GetPerformanceCounterProperties (NULL, NULL), - TimeoutInMicroseconds - ), - 1000000 - ); + TimestampCounterFreq = GetPerformanceCounterProperties (NULL, NULL); + if (DivU64x64Remainder (MAX_UINT64, TimeoutInMicroseconds, NULL) < TimestampCounterFreq) { + // + // Convert microseconds into seconds if direct multiplication overflows + // + TimeoutInSeconds = DivU64x32 (TimeoutInMicroseconds, 1000000); + // + // Assertion if the final tick count exceeds MAX_UINT64 + // + ASSERT (DivU64x64Remainder (MAX_UINT64, TimeoutInSeconds, NULL) >= TimestampCounterFreq); + return MultU64x64 (TimestampCounterFreq, TimeoutInSeconds); + } else { + return DivU64x32 ( + MultU64x64 ( + GetPerformanceCounterProperties (NULL, NULL), + TimeoutInMicroseconds + ), + 1000000 + ); + } } /** -- 2.7.0.windows.1 _______________________________________________ edk2-devel mailing list [email protected] https://lists.01.org/mailman/listinfo/edk2-devel
