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Fix issue with DoHandShakeMsgType/ShrinkInputBuffer when encryption is on (e.g.

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during renegotiation).

This issue was brought to light by ZD 10911. When encryption is on (indicated
by the return value of IsEncryptionOn), DoHandShakeMsgType will finish up by
incrementing the input buffer index past the padding and MAC (if encrypt-then-
mac is enabled). In ProcessReply, if there are more messages to be read, the
index is decremented back before the padding and MAC. The issue arises when
ShrinkInputBuffer is called in between and copies data from the dynamic input
buffer to the static one. That function will get called with the index post-
increment, and thus the padding and MAC won't get copied into the static buffer,
which isn't what we want, since ProcessReply is going to decrement the index
since it thinks the padding and MAC are still there. This commit makes it so
the padding and MAC get included in the call to ShrinkInputBuffer when
encryption is on.
This commit is contained in:
Hayden Roche 2020-12-23 13:50:35 -06:00
parent 311a0d25dd
commit fc845da9f0
1 changed files with 19 additions and 1 deletions
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20
src/internal.c
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@ -12950,7 +12950,25 @@ static int DoHandShakeMsgType(WOLFSSL* ssl, byte* input, word32* inOutIdx,
&& ssl->error != WC_PENDING_E && ssl->error != OCSP_WANT_READ
#endif
) {
ShrinkInputBuffer(ssl, NO_FORCED_FREE);
if (IsEncryptionOn(ssl, 0)) {
word32 extra = ssl->keys.padSz;
#if defined(HAVE_ENCRYPT_THEN_MAC) && !defined(WOLFSSL_AEAD_ONLY)
if (ssl->options.startedETMRead)
extra += MacSize(ssl);
#endif
if (extra > ssl->buffers.inputBuffer.idx)
return BUFFER_E;
ssl->buffers.inputBuffer.idx -= extra;
ShrinkInputBuffer(ssl, NO_FORCED_FREE);
ssl->buffers.inputBuffer.idx += extra;
}
else {
ShrinkInputBuffer(ssl, NO_FORCED_FREE);
}
}
#if defined(WOLFSSL_ASYNC_CRYPT) || defined(WOLFSSL_NONBLOCK_OCSP)