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Simon McVittie authored
Running the "embedded tests" through valgrind revealed that before this commit, we would have been willing to read up to 3 bytes off the end of a message if the message is truncated part way through a boolean. Any practical allocator will round up allocations to the next 32-bit (or larger) boundary, so in practice this will not leave the memory buffer (and in particular did not crash during unit testing), but it could read uninitialized contents. On little-endian CPUs, an attacker might be able to use this to learn whether up to 3 bytes of uninitialized memory in the dbus-daemon were all-zero (their crafted message would be relayed) or not (their connection would be disconnected for sending an invalid message). On big-endian CPUs, an attacker might be able to use this to learn whether up to 3 bytes were all-zeroes (relayed to a cooperating peer), 0-2 bytes of all-zeroes followed by 0x01 (relayed to a cooperating peer), or something else (disconnected). This is not believed to be exploitable to leak interesting information. Fixes: 62e46533 "hardcode dbus_bool_t to 32 bits" Bug: https://bugs.freedesktop.org/show_bug.cgi?id=107332 Signed-off-by: Simon McVittie <smcv@collabora.com> Reviewed-by: Thiago Macieira <thiago@kde.org> Reviewed-by: Philip Withnall <withnall@endlessm.com>
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