EPICS_driver_modules/StreamDevice
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fix crash due to length underflow

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This commit is contained in:
zimoch
2021-11-11 11:49:23 +01:00
parent bf0e755913
commit 94721c2b0e
1 changed files with 14 additions and 5 deletions
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19
src/ChecksumConverter.cc
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@ -734,8 +734,13 @@ printPseudo(const StreamFormat& format, StreamBuffer& output)
uint_fast8_t fnum = extract<uint8_t>(info);
size_t start = format.width;
size_t length = output.length()-format.width;
if (format.prec > 0) length -= format.prec;
size_t length = output.length();
if (length >= start) length -= start;
else length = 0;
if (format.prec > 0) {
if (length >= (size_t)format.prec) length -= format.prec;
else length = 0;
}
debug("ChecksumConverter %s: output to check: \"%s\"\n",
checksumMap[fnum].name, output.expand(start,length)());
@ -808,9 +813,13 @@ scanPseudo(const StreamFormat& format, StreamBuffer& input, size_t& cursor)
uint32_t xorout = extract<uint32_t>(info);
size_t start = format.width;
uint_fast8_t fnum = extract<uint8_t>(info);
size_t length = cursor-format.width;
if (format.prec > 0) length -= format.prec;
size_t length = cursor;
if (length >= start) length -= start;
else length = 0;
if (format.prec > 0) {
if (length >= (size_t)format.prec) length -= format.prec;
else length = 0;
}
debug("ChecksumConverter %s: input to check: \"%s\n",
checksumMap[fnum].name, input.expand(start,length)());