Messages in this thread | | | Date | Mon, 23 Apr 2018 09:52:49 -0400 (EDT) | Subject | Re: [PATCH net] tcp: don't read out-of-bounds opsize | From | David Miller <> |
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From: Jann Horn <jannh@google.com> Date: Fri, 20 Apr 2018 15:57:30 +0200
> The old code reads the "opsize" variable from out-of-bounds memory (first > byte behind the segment) if a broken TCP segment ends directly after an > opcode that is neither EOL nor NOP. > > The result of the read isn't used for anything, so the worst thing that > could theoretically happen is a pagefault; and since the physmap is usually > mostly contiguous, even that seems pretty unlikely. > > The following C reproducer triggers the uninitialized read - however, you > can't actually see anything happen unless you put something like a > pr_warn() in tcp_parse_md5sig_option() to print the opsize. ... > Fixes: cfb6eeb4c860 ("[TCP]: MD5 Signature Option (RFC2385) support.") > Signed-off-by: Jann Horn <jannh@google.com>
Applied and queued up for -stable, thank you.
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