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Merged
dlang-bot merged 3 commits into from
Jan 3, 2018
Merged

file.d: add overflow checks #5990

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85eb47b
file.d: add overflow checks
WalterBright Aug 4, 2016
3eadd00
Merge branch 'file-overflow' of https://github.com/WalterBright/phobo…
JackStouffer Jan 3, 2018
9d8a331
address Andrei's review
JackStouffer Jan 3, 2018
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28 changes: 18 additions & 10 deletions std/file.d
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Original file line number Diff line number Diff line change
Expand Up @@ -336,6 +336,7 @@ version (Posix) private void[] readImpl(const(char)[] name, const(FSChar)* namez
import std.algorithm.comparison : min;
import std.array : uninitializedArray;
import std.conv : to;
import std.experimental.checkedint : checked;

// A few internal configuration parameters {
enum size_t
Expand All @@ -358,24 +359,25 @@ version (Posix) private void[] readImpl(const(char)[] name, const(FSChar)* namez
: minInitialAlloc));
void[] result = uninitializedArray!(ubyte[])(initialAlloc);
scope(failure) GC.free(result.ptr);
size_t size = 0;

auto size = checked(size_t(0));

for (;;)
{
immutable actual = core.sys.posix.unistd.read(fd, result.ptr + size,
min(result.length, upTo) - size);
immutable actual = core.sys.posix.unistd.read(fd, result.ptr + size.get,
(min(result.length, upTo) - size).get);
cenforce(actual != -1, name, namez);
if (actual == 0) break;
size += actual;
if (size >= upTo) break;
if (size < result.length) continue;
immutable newAlloc = size + sizeIncrement;
result = GC.realloc(result.ptr, newAlloc, GC.BlkAttr.NO_SCAN)[0 .. newAlloc];
result = GC.realloc(result.ptr, newAlloc.get, GC.BlkAttr.NO_SCAN)[0 .. newAlloc.get];
}

return result.length - size >= maxSlackMemoryAllowed
? GC.realloc(result.ptr, size, GC.BlkAttr.NO_SCAN)[0 .. size]
: result[0 .. size];
? GC.realloc(result.ptr, size.get, GC.BlkAttr.NO_SCAN)[0 .. size.get]
: result[0 .. size.get];
}


Expand Down Expand Up @@ -2645,14 +2647,19 @@ version(Posix) @system unittest // input range of dchars
version(Windows) string getcwd()
{
import std.conv : to;
import std.experimental.checkedint : checked;
/* GetCurrentDirectory's return value:
1. function succeeds: the number of characters that are written to
the buffer, not including the terminating null character.
2. function fails: zero
3. the buffer (lpBuffer) is not large enough: the required size of
the buffer, in characters, including the null-terminating character.
*/
wchar[4096] buffW = void; //enough for most common case
version (StdUnittest)
enum BUF_SIZE = 10; // trigger reallocation code
else
enum BUF_SIZE = 4096; // enough for most common case
wchar[BUF_SIZE] buffW = void;
immutable n = cenforce(GetCurrentDirectoryW(to!DWORD(buffW.length), buffW.ptr),
"getcwd");
// we can do it because toUTFX always produces a fresh string
Expand All @@ -2662,10 +2669,11 @@ version(Windows) string getcwd()
}
else //staticBuff isn't enough
{
auto ptr = cast(wchar*) malloc(wchar.sizeof * n);
auto cn = checked(n);
auto ptr = cast(wchar*) malloc((cn * wchar.sizeof).get);
scope(exit) free(ptr);
immutable n2 = GetCurrentDirectoryW(n, ptr);
cenforce(n2 && n2 < n, "getcwd");
immutable n2 = GetCurrentDirectoryW(cn.get, ptr);
cenforce(n2 && n2 < cn, "getcwd");
return ptr[0 .. n2].to!string;
}
}
Expand Down