When the write size was exactly SSL3_RT_MAX_PLAIN_LENGTH+1 and record
splitting is needed, an extra byte would be added to the max size of the
message to be written. This would cause the requested size to not exceed
the max. If the SSL_WANT_WRITE error were returned, the next packet
would not get the extra byte added to the max packet size since
record_split_done is set. Since a different set of arguments
(SSL3_RT_MAX_PLAIN_LENGTH+1 vs SSL3_RT_MAX_PLAIN_LENGTH) would be passed
to do_ssl3_write, it would return an "SSL3_WRITE_PENDING:bad write
retry" error.
To avoid a failure in the opposite direction, the max variable increment
is removed as well. This can happen when SSL_MODE_ENABLE_PARTIAL_WRITE
is not enabled and the call to ssl3_write_bytes contains, e.g., a buffer
of 2*SSL3_RT_MAX_PLAIN_LENGTH, where the first call into do_ssl3_write
succeeds writing the first SSL3_RT_MAX_PLAIN_LENGTH bytes, but writing
the second SSL3_RT_MAX_PLAIN_LENGTH bytes fails. This means the first
time the the second section of SSL3_RT_MAX_PLAIN_LENGTH bytes has called
do_ssl3_write with "max" bytes, but next call to ssl3_write_bytes in
turn calls into do_ssl3_write with "max+1" bytes.
Change-Id: Icf8453195c1145a54d31b8e8146801118207df03
Reviewed-on: https://boringssl-review.googlesource.com/1420
Reviewed-by: Kenny Root <kroot@google.com>
Reviewed-by: David Benjamin <davidben@chromium.org>
Reviewed-by: Adam Langley <agl@google.com>
A modern TLS library without full support for TLS does not make sense.
Change-Id: I032537d1412f6e4effc9a2dd47123baf0084b4c6
Reviewed-on: https://boringssl-review.googlesource.com/1382
Reviewed-by: Adam Langley <agl@google.com>
Now that the flag is set accurately, use it to enforce that the handshake and
CCS synchronization. If EXPECT_CCS is set, enforce that:
(a) No handshake records may be received before ChangeCipherSpec.
(b) There is no pending handshake data at the point EXPECT_CCS is set.
Change-Id: I04b228fe6a7a771cf6600b7d38aa762b2d553f08
Reviewed-on: https://boringssl-review.googlesource.com/1299
Reviewed-by: Adam Langley <agl@google.com>
Only accept change cipher spec when it is expected instead of at any
time. This prevents premature setting of session keys before the master
secret is determined which an attacker could use as a MITM attack.
Thanks to KIKUCHI Masashi (Lepidum Co. Ltd.) for reporting this issue
and providing the initial fix this patch is based on.
(Imported from upstream's 77719aefb8f549ccc7f04222174889615d62057b)
This patch removes support for empty records (which is almost
universally disabled via SSL_OP_ALL) and adds optional support for 1/n-1
record splitting.
The latter is not enabled by default, since it's not typically used on
servers, but it should be enabled in web browsers since there are known
attacks in that case (see BEAST).
Limit the number of empty records that will be processed consecutively
in order to prevent ssl3_get_record from never returning.
Reported by "oftc_must_be_destroyed" and George Kadianakis.
Initial fork from f2d678e6e89b6508147086610e985d4e8416e867 (1.0.2 beta).
(This change contains substantial changes from the original and
effectively starts a new history.)
