[Backport 7.x] (PUP-11122) Ensure reg values are null terminated #9219
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(cherry picked from commit 493a8b7)
RegQueryValueExW doesn't guarantee the returned buffer for the `lpData`
parameter is null terminated, so ensure that it is.
When retrieving a registry value of type REG_SZ or REG_EXPAND_SZ extend the
buffer by 1 wchar (2 bytes) so we can always write a wchar null terminator that
is guaranteed not to overwrite user data.
The resulting wchar array is then guaranteed to be properly wchar null
terminated:
\u0041
\u0042
\u0000
which when UTF-16LE encoded will result in the byte array:
\x41 \x00
\x42 \x00
\x00 \x00
If Windows does null terminate, then we will add an additional wchar null
terminator, which won't hurt anything.
The same applies to REG_MULTI_SZ, except it is supposed to have two wchar null
terminators, for a total of 4 bytes. One terminator is for the last string in
the array, and one terminator is for the entire array. For example, if the array
contains the strings ['A', 'B'] and Windows does not null terminate the
`lpData` buffer, then the resulting UTF-16LE encoded byte array will contain:
\x41 \x00
\x00 \x00
\x42 \x00
\x00 \x00
\x00 \x00
(cherry picked from commit 25a33df)
|
Can one of the admins verify this patch? |
joshcooper
approved these changes
Jan 24, 2024
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Description
Backport of #9205 to
7.x.