Fix mess in nsUUIDGenerator

This commit is contained in:
wuggy 2026-06-29 18:43:00 +01:00
commit fe008c1fc5

View file

@ -96,10 +96,9 @@ nsUUIDGenerator::GenerateUUID(nsID** aRet)
}
NS_IMETHODIMP
nsresult
nsUUIDGenerator::GenerateUUIDInPlace(nsID* aId)
{
// The various code in this method is probably not threadsafe, so lock
// across the whole method.
MutexAutoLock lock(mLock);
#if defined(XP_WIN)
@ -107,6 +106,7 @@ nsUUIDGenerator::GenerateUUIDInPlace(nsID* aId)
if (FAILED(hr)) {
return NS_ERROR_FAILURE;
}
#elif defined(XP_MACOSX)
CFUUIDRef uuid = CFUUIDCreate(kCFAllocatorDefault);
if (!uuid) {
@ -115,90 +115,62 @@ nsUUIDGenerator::GenerateUUIDInPlace(nsID* aId)
CFUUIDBytes bytes = CFUUIDGetUUIDBytes(uuid);
memcpy(aId, &bytes, sizeof(nsID));
CFRelease(uuid);
#else /* not windows or OS X; generate randomness using random(). */
/* XXX we should be saving the return of setstate here and switching
* back to it; instead, we use the value returned when we called
* initstate, since older glibc's have broken setstate() return values
*/
#else /* POSIX randomness */
#ifndef HAVE_ARC4RANDOM
setstate(mState);
#endif
#if defined(__linux__)
// Linux does not provide arc4random_buf or arc4random.
// Use /dev/urandom for secure UUID generation.
// Try /dev/urandom first
int fd = open("/dev/urandom", O_RDONLY);
if (fd >= 0) {
ssize_t n = read(fd, aId, sizeof(nsID));
close(fd);
if (n == sizeof(nsID)) {
return NS_OK;
goto version_bits;
}
}
// Fallback if /dev/urandom fails
size_t bytesLeft = sizeof(nsID);
while (bytesLeft > 0) {
long rval = random();
const size_t mRBytes = 4;
size_t toCopy = std::min(bytesLeft, mRBytes);
memcpy(reinterpret_cast<char*>(aId) + (sizeof(nsID) - bytesLeft),
&rval, toCopy);
bytesLeft -= toCopy;
}
#else
#endif
#ifdef HAVE_ARC4RANDOM_BUF
arc4random_buf(aId, sizeof(nsID));
#else /* HAVE_ARC4RANDOM_BUF */
#else
size_t bytesLeft = sizeof(nsID);
while (bytesLeft > 0) {
#ifdef HAVE_ARC4RANDOM
long rval = arc4random();
const size_t mRBytes = 4;
#else
long rval = random();
const size_t mRBytes = 4;
#endif
const size_t mRBytes = 4;
size_t toCopy = std::min(bytesLeft, mRBytes);
memcpy(reinterpret_cast<char*>(aId) + (sizeof(nsID) - bytesLeft),
&rval, toCopy);
bytesLeft -= toCopy;
}
#endif /* HAVE_ARC4RANDOM_BUF */
uint8_t* src = (uint8_t*)&rval;
// We want to grab the mRBytes least significant bytes of rval, since
// mRBytes less than sizeof(rval) means the high bytes are 0.
#ifdef IS_BIG_ENDIAN
src += sizeof(rval) - mRBytes;
#endif
uint8_t* dst = ((uint8_t*)aId) + (sizeof(nsID) - bytesLeft);
size_t toWrite = (bytesLeft < mRBytes ? bytesLeft : mRBytes);
for (size_t i = 0; i < toWrite; i++) {
dst[i] = src[i];
}
version_bits:
bytesLeft -= toWrite;
}
#endif /* HAVE_ARC4RANDOM_BUF */
/* Put in the version */
/* RFC4122 version */
aId->m2 &= 0x0fff;
aId->m2 |= 0x4000;
/* Put in the variant */
/* RFC4122 variant */
aId->m3[0] &= 0x3f;
aId->m3[0] |= 0x80;
#ifndef HAVE_ARC4RANDOM
/* Restore the previous RNG state */
setstate(mSavedState);
#endif
#endif
#endif /* POSIX randomness */
return NS_OK;
}