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In MemoryBuffer::getOpenFile() make sure that the buffer is null-terminated if

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the caller requested a null-terminated one.

When mapping the file there could be a racing issue that resulted in the file being larger
than the FileSize passed by the caller. We already have an assertion
for this in MemoryBuffer::init() but have a runtime guarantee that
the buffer will be null-terminated, so do a copy that adds a null-terminator.

Protects against crash of rdar://11161822.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@154082 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Argyrios Kyrtzidis 2012-04-05 04:23:56 +00:00
parent b657a90929
commit 541b2a4aa3
1 changed files with 11 additions and 0 deletions
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11
lib/Support/MemoryBuffer.cpp
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@ -304,6 +304,16 @@ error_code MemoryBuffer::getOpenFile(int FD, const char *Filename,
RealMapOffset)) {
result.reset(GetNamedBuffer<MemoryBufferMMapFile>(
StringRef(Pages + Delta, MapSize), Filename, RequiresNullTerminator));
if (RequiresNullTerminator && result->getBufferEnd()[0] != '\0') {
// There could be a racing issue that resulted in the file being larger
// than the FileSize passed by the caller. We already have an assertion
// for this in MemoryBuffer::init() but have a runtime guarantee that
// the buffer will be null-terminated here, so do a copy that adds a
// null-terminator.
result.reset(MemoryBuffer::getMemBufferCopy(result->getBuffer(),
Filename));
}
return error_code::success();
}
}
@ -339,6 +349,7 @@ error_code MemoryBuffer::getOpenFile(int FD, const char *Filename,
if (NumRead == 0) {
assert(0 && "We got inaccurate FileSize value or fstat reported an "
"invalid file size.");
*BufPtr = '\0'; // null-terminate at the actual size.
break;
}
BytesLeft -= NumRead;