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NetworkPkg: Refine casting expression result to bigger size

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There are cases that the operands of an expression are all with rank less
than UINT64/INT64 and the result of the expression is explicitly cast to
UINT64/INT64 to fit the target size.

An example will be:
UINT32 a,b;
// a and b can be any unsigned int type with rank less than UINT64, like
// UINT8, UINT16, etc.
UINT64 c;
c = (UINT64) (a + b);

Some static code checkers may warn that the expression result might
overflow within the rank of "int" (integer promotions) and the result is
then cast to a bigger size.

The commit refines codes by the following rules:
1). When the expression is possible to overflow the range of unsigned int/
int:
c = (UINT64)a + b;

2). When the expression will not overflow within the rank of "int", remove
the explicit type casts:
c = a + b;

3). When the expression will be cast to pointer of possible greater size:
UINT32 a,b;
VOID *c;
c = (VOID *)(UINTN)(a + b); --> c = (VOID *)((UINTN)a + b);

4). When one side of a comparison expression contains only operands with
rank less than UINT32:
UINT8 a;
UINT16 b;
UINTN c;
if ((UINTN)(a + b) > c) {...} --> if (((UINT32)a + b) > c) {...}

For rule 4), if we remove the 'UINTN' type cast like:
if (a + b > c) {...}
The VS compiler will complain with warning C4018 (signed/unsigned
mismatch, level 3 warning) due to promoting 'a + b' to type 'int'.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Hao Wu <hao.a.wu@intel.com>
Reviewed-by: Wu Jiaxin <jiaxin.wu@intel.com>
This commit is contained in:
Hao Wu
2017-02-16 14:58:03 +08:00
parent bcee1b9f17
commit ce5c3273c3
5 changed files with 15 additions and 15 deletions
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8
NetworkPkg/IpSecDxe/IpSecConfigImpl.c
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@@ -1,7 +1,7 @@
/** @file
The implementation of IPSEC_CONFIG_PROTOCOL.
Copyright (c) 2009 - 2016, Intel Corporation. All rights reserved.<BR>
Copyright (c) 2009 - 2017, Intel Corporation. All rights reserved.<BR>
This program and the accompanying materials
are licensed and made available under the terms and conditions of the BSD License
@@ -1152,7 +1152,7 @@ SetSpdEntry (
// Do Padding for the different Arch.
//
SpdEntrySize = ALIGN_VARIABLE (sizeof (IPSEC_SPD_ENTRY));
SpdEntrySize = ALIGN_VARIABLE (SpdEntrySize + (UINTN)SIZE_OF_SPD_SELECTOR (SpdSel));
SpdEntrySize = ALIGN_VARIABLE (SpdEntrySize + SIZE_OF_SPD_SELECTOR (SpdSel));
SpdEntrySize += IpSecGetSizeOfEfiSpdData (SpdData);
SpdEntry = AllocateZeroPool (SpdEntrySize);
@@ -1357,7 +1357,7 @@ SetSadEntry (
}
if (SaData->SpdSelector != NULL) {
SadEntrySize += SadEntrySize + (UINTN)SIZE_OF_SPD_SELECTOR (SaData->SpdSelector);
SadEntrySize += SadEntrySize + SIZE_OF_SPD_SELECTOR (SaData->SpdSelector);
}
SadEntry = AllocateZeroPool (SadEntrySize);
@@ -1458,7 +1458,7 @@ SetSadEntry (
SadEntry->Data->SpdEntry = SpdEntry;
SadEntry->Data->SpdSelector = (EFI_IPSEC_SPD_SELECTOR *)((UINT8 *)SadEntry +
SadEntrySize -
(UINTN)SIZE_OF_SPD_SELECTOR (SaData->SpdSelector)
SIZE_OF_SPD_SELECTOR (SaData->SpdSelector)
);
DuplicateSpdSelector (
(EFI_IPSEC_CONFIG_SELECTOR *) SadEntry->Data->SpdSelector,