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dummynet: Avoid an out-of-bounds read in do_config()
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Authored by markj on Nov 26 2021, 4:01 PM.

Details

Summary

do_config() processes a buffer of variable-length dummynet commands.
The loop which processes this buffer loads the fixed-length header
before checking whether there are any bytes left to read, so it performs
a 4-byte read past the end of the buffer before terminating.

Restructure the loop to avoid this.

Reported by: Jenkins (KASAN job)
MFC after: 1 week
Sponsored by: The FreeBSD Foundation

Diff Detail

Repository
R10 FreeBSD src repository
Lint
Automatic diff as part of commit; lint not applicable.
Unit
Automatic diff as part of commit; unit tests not applicable.