[v1] UefiCpuPkg/MpLib: fix potential overflow issue.

[edk2] [Patch] UefiCpuPkg/MpLib: fix potential overflow issue.

Posted by Eric Dong 8 years, 2 months ago

Current calculate timeout logic may have overflow if the input
timeout value too large. This patch fix this potential overflow
issue.

Cc: Michael Kinney <michael.d.kinney@intel.com>
Cc: Ruiyu Ni <ruiyu.ni@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Eric Dong <eric.dong@intel.com>
---
 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

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Re: [edk2] [Patch] UefiCpuPkg/MpLib: fix potential overflow issue.

Posted by Kinney, Michael D 8 years, 2 months ago

Hi Eric,

With this patch GetPerformanceCounterProperties() is called 
twice.  I think you can use TimestampCounterFreq in the else
clause.

Also, the comment blocks are no longer correct.  The original
comment block goes with the else clause, and you need a new
comment block for the if statement that describes the check
for an overflow.

Mike

> -----Original Message-----
> From: Dong, Eric
> Sent: Tuesday, August 22, 2017 10:30 PM
> To: edk2-devel@lists.01.org
> Cc: Kinney, Michael D <michael.d.kinney@intel.com>; Ni, Ruiyu
> <ruiyu.ni@intel.com>
> Subject: [Patch] UefiCpuPkg/MpLib: fix potential overflow
> issue.
> 
> Current calculate timeout logic may have overflow if the input
> timeout value too large. This patch fix this potential overflow
> issue.
> 
> Cc: Michael Kinney <michael.d.kinney@intel.com>
> Cc: Ruiyu Ni <ruiyu.ni@intel.com>
> Contributed-under: TianoCore Contribution Agreement 1.1
> Signed-off-by: Eric Dong <eric.dong@intel.com>
> ---
>  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),

Use TimestampCounterFreq instead.

> +               TimeoutInMicroseconds
> +               ),
> +             1000000
> +             );
> +  }
>  }
> 
>  /**
> --
> 2.7.0.windows.1

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Re: [edk2] [Patch] UefiCpuPkg/MpLib: fix potential overflow issue.

Posted by Dong, Eric 8 years, 2 months ago

Mike, 

Thanks for the comments, I updated the patch, please help to review the new patch.

Thanks,
Eric
-----Original Message-----
From: Kinney, Michael D 
Sent: Thursday, August 24, 2017 5:51 AM
To: Dong, Eric <eric.dong@intel.com>; edk2-devel@lists.01.org; Kinney, Michael D <michael.d.kinney@intel.com>
Cc: Ni, Ruiyu <ruiyu.ni@intel.com>
Subject: RE: [Patch] UefiCpuPkg/MpLib: fix potential overflow issue.

Hi Eric,

With this patch GetPerformanceCounterProperties() is called twice.  I think you can use TimestampCounterFreq in the else clause.

Also, the comment blocks are no longer correct.  The original comment block goes with the else clause, and you need a new comment block for the if statement that describes the check for an overflow.

Mike

> -----Original Message-----
> From: Dong, Eric
> Sent: Tuesday, August 22, 2017 10:30 PM
> To: edk2-devel@lists.01.org
> Cc: Kinney, Michael D <michael.d.kinney@intel.com>; Ni, Ruiyu 
> <ruiyu.ni@intel.com>
> Subject: [Patch] UefiCpuPkg/MpLib: fix potential overflow issue.
> 
> Current calculate timeout logic may have overflow if the input timeout 
> value too large. This patch fix this potential overflow issue.
> 
> Cc: Michael Kinney <michael.d.kinney@intel.com>
> Cc: Ruiyu Ni <ruiyu.ni@intel.com>
> Contributed-under: TianoCore Contribution Agreement 1.1
> Signed-off-by: Eric Dong <eric.dong@intel.com>
> ---
>  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),

Use TimestampCounterFreq instead.

> +               TimeoutInMicroseconds
> +               ),
> +             1000000
> +             );
> +  }
>  }
> 
>  /**
> --
> 2.7.0.windows.1

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