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Guard use of volatile cast in TEA and XTEA

pull/853/head
Jeffrey Walton 2019-06-02 05:29:08 -04:00
parent 9538f2d715
commit 959494871f
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GPG Key ID: B36AB348921B1838
1 changed files with 11 additions and 4 deletions
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15
tea.cpp
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@ -4,6 +4,13 @@
#include "tea.h" #include "tea.h"
#include "misc.h" #include "misc.h"
// http://github.com/weidai11/cryptopp/issues/503
#if defined(__xlC__) || defined(__SUNPRO_CC)
# define MAYBE_VOLATILE(x) (*const_cast<volatile word32*>(&x))
#else
# define MAYBE_VOLATILE(x) (x)
#endif
NAMESPACE_BEGIN(CryptoPP) NAMESPACE_BEGIN(CryptoPP)
static const word32 DELTA = 0x9e3779b9; static const word32 DELTA = 0x9e3779b9;
@ -26,7 +33,7 @@ void TEA::Enc::ProcessAndXorBlock(const byte *inBlock, const byte *xorBlock, byt
Block::Get(inBlock)(y)(z); Block::Get(inBlock)(y)(z);
// http://github.com/weidai11/cryptopp/issues/503 // http://github.com/weidai11/cryptopp/issues/503
while (*const_cast<volatile word32*>(&sum) != m_limit) while (MAYBE_VOLATILE(sum) != m_limit)
{ {
sum += DELTA; sum += DELTA;
y += ((z << 4) + m_k[0]) ^ (z + sum) ^ ((z >> 5) + m_k[1]); y += ((z << 4) + m_k[0]) ^ (z + sum) ^ ((z >> 5) + m_k[1]);
@ -42,7 +49,7 @@ void TEA::Dec::ProcessAndXorBlock(const byte *inBlock, const byte *xorBlock, byt
Block::Get(inBlock)(y)(z); Block::Get(inBlock)(y)(z);
// http://github.com/weidai11/cryptopp/issues/503 // http://github.com/weidai11/cryptopp/issues/503
while (*const_cast<volatile word32*>(&sum) != 0) while (MAYBE_VOLATILE(sum) != 0)
{ {
z -= ((y << 4) + m_k[2]) ^ (y + sum) ^ ((y >> 5) + m_k[3]); z -= ((y << 4) + m_k[2]) ^ (y + sum) ^ ((y >> 5) + m_k[3]);
y -= ((z << 4) + m_k[0]) ^ (z + sum) ^ ((z >> 5) + m_k[1]); y -= ((z << 4) + m_k[0]) ^ (z + sum) ^ ((z >> 5) + m_k[1]);
@ -66,7 +73,7 @@ void XTEA::Enc::ProcessAndXorBlock(const byte *inBlock, const byte *xorBlock, by
Block::Get(inBlock)(y)(z); Block::Get(inBlock)(y)(z);
// http://github.com/weidai11/cryptopp/issues/503 // http://github.com/weidai11/cryptopp/issues/503
while (*const_cast<volatile word32*>(&sum) != m_limit) while (MAYBE_VOLATILE(sum) != m_limit)
{ {
y += ((z<<4 ^ z>>5) + z) ^ (sum + m_k[sum&3]); y += ((z<<4 ^ z>>5) + z) ^ (sum + m_k[sum&3]);
sum += DELTA; sum += DELTA;
@ -82,7 +89,7 @@ void XTEA::Dec::ProcessAndXorBlock(const byte *inBlock, const byte *xorBlock, by
Block::Get(inBlock)(y)(z); Block::Get(inBlock)(y)(z);
// http://github.com/weidai11/cryptopp/issues/503 // http://github.com/weidai11/cryptopp/issues/503
while (*const_cast<volatile word32*>(&sum) != 0) while (MAYBE_VOLATILE(sum) != 0)
{ {
z -= ((y<<4 ^ y>>5) + y) ^ (sum + m_k[sum>>11 & 3]); z -= ((y<<4 ^ y>>5) + y) ^ (sum + m_k[sum>>11 & 3]);
sum -= DELTA; sum -= DELTA;