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| author | Thiago Macieira <thiago.macieira@intel.com> | 2015-09-27 11:52:35 -0700 |
|---|---|---|
| committer | Thiago Macieira <thiago.macieira@intel.com> | 2015-09-28 16:29:50 +0000 |
| commit | 84a806589f93240ef39696729c6ce4c10bc4ab02 (patch) | |
| tree | 2cce467053f6f9aa000ccb87af0923e302d01412 /src/corelib/tools/qbytearray.cpp | |
| parent | b03d91e3f7d9b3ff96692d4e284b003ca5b90b82 (diff) | |
Fix sign-extension
If data[0] were > 128 (that is, if the full size, encoded in big endian
were > 2 GB), the result of the OR chain would be a negative int (due to
C integer promotion rules). We're shifting into the sign bit, which is
either implementation-defined behavior or, worse, undefined behavior.
This negative number is then sign-extended to ulong (64-bit on 64-bit
platforms), which then becomes a big number. This code was probably
written with only 32-bit in mind, where there would be no size extension
(sign or otherwise).
This isn't too bad because there's a size check for the max size of
QByteArray a few lines below, but we can fix it, so let's do it.
Found by Coverity, CID 22530.
Change-Id: I42e7ef1a481840699a8dffff1407ea6c22e1a0ec
Reviewed-by: Olivier Goffart (Woboq GmbH) <ogoffart@woboq.com>
Diffstat (limited to 'src/corelib/tools/qbytearray.cpp')
| -rw-r--r-- | src/corelib/tools/qbytearray.cpp | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/src/corelib/tools/qbytearray.cpp b/src/corelib/tools/qbytearray.cpp index 5ed72fc341..a9f361c205 100644 --- a/src/corelib/tools/qbytearray.cpp +++ b/src/corelib/tools/qbytearray.cpp @@ -578,8 +578,8 @@ QByteArray qUncompress(const uchar* data, int nbytes) qWarning("qUncompress: Input data is corrupted"); return QByteArray(); } - ulong expectedSize = (data[0] << 24) | (data[1] << 16) | - (data[2] << 8) | (data[3] ); + ulong expectedSize = uint((data[0] << 24) | (data[1] << 16) | + (data[2] << 8) | (data[3] )); ulong len = qMax(expectedSize, 1ul); QScopedPointer<QByteArray::Data, QScopedPointerPodDeleter> d; |