Add new tunable "tune.ssl.maxrecord".
Over SSL/TLS, the client can decipher the data only once it has received
a full record. With large records, it means that clients might have to
download up to 16kB of data before starting to process them. Limiting the
record size can improve page load times on browsers located over high
latency or low bandwidth networks. It is suggested to find optimal values
which fit into 1 or 2 TCP segments (generally 1448 bytes over Ethernet
with TCP timestamps enabled, or 1460 when timestamps are disabled), keeping
in mind that SSL/TLS add some overhead. Typical values of 1419 and 2859
gave good results during tests. Use "strace -e trace=write" to find the
best value.
This trick was first suggested by Mike Belshe :
http://www.belshe.com/2010/12/17/performance-and-the-tls-record-size/
Then requested again by Ilya Grigorik who provides some hints here :
http://ofps.oreilly.com/titles/9781449344764/_transport_layer_security_tls.html#ch04_00000101
Openssl needs to access /dev/urandom to initialize its internal random
number generator. It does so when it needs a random for the first time,
which fails if it is a handshake performed after the chroot(), causing
all SSL incoming connections to fail.
This fix consists in calling RAND_bytes() to produce a random before
the chroot, which will in turn open /dev/urandom before it's too late,
and avoid the issue.
If the random generator fails to work while processing the config,
haproxy now fails with an error instead of causing SSL connections to
fail at runtime.
This new option ensures that there is no possible fallback to a default
certificate if the client does not provide an SNI which is explicitly
handled by a certificate.
At the moment, we need trash chunks almost everywhere and the only
correctly implemented one is in the sample code. Let's move this to
the chunks so that all other places can use this allocator.
Additionally, the get_trash_chunk() function now really returns two
different chunks. Previously it used to always overwrite the same
chunk and point it to a different buffer, which was a bit tricky
because it's not obvious that two consecutive results do alias each
other.
J. Maurice reported that ssllabs.com test affects unrelated
legitimate traffic and cause SSL errors and broken connections.
Sometimes openssl store read/write/handshake errors in a global stack. This
stack is not specific to the current session. Openssl API does not clean the
stack at the beginning of a new read/write. And the function used to retrieve
error ID after read/write, returns the generic error SSL_ERROR_SSL if the
global stack is not empty.
The fix consists in cleaning the errors stack after read/write/handshake
errors.
When using ca_ignore_err/crt_ignore_err, a connection to an untrusted
server raises an error which is ignored. But the next SSL_read() that
encounters EAGAIN raises the error again, breaking the connection.
Subsequent connections don't have this problem because the session has
been stored and is correctly reused without performing a verify again.
The solution consists in correctly flushing the SSL error stack when
ignoring the crt/ca error.
It's annoying that handshake handlers remove themselves from the
connection flags when they fail because there is no way to tell
which one fails. So now we only remove them when they succeed.
SSL_do_handshake is not appropriate for reneg, it's only appropriate at the
beginning of a connection. OpenSSL correctly handles renegs using the data
functions, so we use SSL_peek() here to make its state machine progress if
SSL_renegotiate_pending() says a reneg is pending.
SSL may decide to switch to a handshake in the middle of a transfer due to
a reneg. In this case we don't want to re-enable polling because data might
have been left pending in the buffer. We just want to switch immediately to
the handshake mode.
Instead of storing a couple of (int, ptr) in the struct connection
and the struct session, we use a different method : we only store a
pointer to an integer which is stored inside the target object and
which contains a unique type identifier. That way, the pointer allows
us to retrieve the object type (by dereferencing it) and the object's
address (by computing the displacement in the target structure). The
NULL pointer always corresponds to OBJ_TYPE_NONE.
This reduces the size of the connection and session structs. It also
simplifies target assignment and compare.
In order to improve the generated code, we try to put the obj_type
element at the beginning of all the structs (listener, server, proxy,
si_applet), so that the original and target pointers are always equal.
A lot of code was touched by massive replaces, but the changes are not
that important.
The trash is used everywhere to store the results of temporary strings
built out of s(n)printf, or as a storage for a chunk when chunks are
needed.
Using global.tune.bufsize is not the most convenient thing either.
So let's replace trash with a chunk and directly use it as such. We can
then use trash.size as the natural way to get its size, and get rid of
many intermediary chunks that were previously used.
The patch is huge because it touches many areas but it makes the code
a lot more clear and even outlines places where trash was used without
being that obvious.
We will need to be able to switch server connections on a session and
to keep idle connections. In order to achieve this, the preliminary
requirement is that the connections can survive the session and be
detached from them.
Right now they're still allocated at exactly the same place, so when
there is a session, there are always 2 connections. We could soon
improve on this by allocating the outgoing connection only during a
connect().
This current patch touches a lot of code and intentionally does not
change any functionnality. Performance tests show no regression (even
a very minor improvement). The doc has not yet been updated.
ssl_c_notbefore: start date of client cert (string, eg: "121022182230Z" for YYMMDDhhmmss[Z])
ssl_c_notafter: end date of client cert (string, eg: "121022182230Z" for YYMMDDhhmmss[Z])
ssl_f_notbefore: start date of frontend cert (string, eg: "121022182230Z" for YYMMDDhhmmss[Z])
ssl_f_notafter: end date of frontend cert (string, eg: "121022182230Z" for YYMMDDhhmmss[Z])
ssl_c_key_alg: algo used to encrypt the client's cert key (ex: rsaEncryption)
ssl_f_key_alg: algo used to encrypt the frontend's cert key (ex: rsaEncryption)
ssl_c_s_dn : client cert subject DN (string)
ssl_c_i_dn : client cert issuer DN (string)
ssl_f_s_dn : frontend cert subject DN (string)
ssl_f_i_dn : frontend cert issuer DN (string)
Return either the full DN without params, or just the DN entry (first param) or
its specific occurrence (second param).
While checking haproxy's SSL stack with www.ssllabs.com, it appeared that
immediately closing upon a failed handshake caused a TCP reset to be emitted.
This is because OpenSSL does not consume pending data in the socket buffers.
One side effect is that if the reset packet is lost, the client might not get
it. So now when a handshake fails, we try to clean the socket buffers before
closing, resulting in a clean FIN instead of an RST.
The ssl_npn match could not work by itself because clients do not use
the NPN extension unless the server advertises the protocols it supports.
Thanks to Simone Bordet for the explanations on how to get it right.
These two new log-format tags report the SSL protocol version (%sslv) and the
SSL ciphers (%sslc) used for the connection with the client. For instance, to
append these information just after the client's IP/port address information
on an HTTP log line, use the following configuration :
log-format %Ci:%Cp\ %sslv:%sslc\ [%t]\ %ft\ %b/%s\ %Tq/%Tw/%Tc/%Tr/%Tt\ %st\ %B\ %cc\ \ %cs\ %tsc\ %ac/%fc/%bc/%sc/%rc\ %sq/%bq\ %hr\ %hs\ %{+Q}r
It will report a line such as the following one :
Oct 12 20:47:30 haproxy[9643]: 127.0.0.1:43602 TLSv1:AES-SHA [12/Oct/2012:20:47:30.303] stick2~ stick2/s1 7/0/12/0/19 200 145 - - ---- 0/0/0/0/0 0/0 "GET /?t=0 HTTP/1.0"
It now becomes possible to verify the server's certificate using the "verify"
directive. This one only supports "none" and "required", as it does not make
much sense to also support "optional" here.
All SSL-specific "server" keywords are now processed in ssl_sock.c. At
the moment, there is no more "not implemented" hint when SSL is disabled,
but keywords could be added in server.c if needed.
These ones are used to set the default ciphers suite on "bind" lines and
"server" lines respectively, instead of using OpenSSL's defaults. These
are probably mainly useful for distro packagers.
On server's configuration change, if the previously used
cipher is disabled, all subsequent connect attempts fail.
Fix consists in freeing cached session on handshake failure.
While working on the changes required to make the health checks use the
new connections, it started to become obvious that some naming was not
logical at all in the connections. Specifically, it is not logical to
call the "data layer" the layer which is in charge for all the handshake
and which does not yet provide a data layer once established until a
session has allocated all the required buffers.
In fact, it's more a transport layer, which makes much more sense. The
transport layer offers a medium on which data can transit, and it offers
the functions to move these data when the upper layer requests this. And
it is the upper layer which iterates over the transport layer's functions
to move data which should be called the data layer.
The use case where it's obvious is with embryonic sessions : an incoming
SSL connection is accepted. Only the connection is allocated, not the
buffers nor stream interface, etc... The connection handles the SSL
handshake by itself. Once this handshake is complete, we can't use the
data functions because the buffers and stream interface are not there
yet. Hence we have to first call a specific function to complete the
session initialization, after which we'll be able to use the data
functions. This clearly proves that SSL here is only a transport layer
and that the stream interface constitutes the data layer.
A similar change will be performed to rename app_cb => data, but the
two could not be in the same commit for obvious reasons.
If we get an SSL error during the handshake, we at least try to see
if a syscall reported an error or not. In case of an error, it generally
means that the connection failed. If there is no error, then the connection
established successfully.
The difference is important for health checks which report the precise cause
to the logs and to the stats.
Disables the stateless session resumption (RFC 5077 TLS Ticket extension)
and force to use stateful session resumption.
Stateless session resumption is more expensive in CPU usage.
This is because "notlsv1" used to disable TLSv1.0 only and had no effect
on v1.1/v1.2. so better have an option for each version. This applies both
to "bind" and "server" statements.
Add fetch 'ssl_verify_caerr':
returns the first ssl verify error at depth > 0 (CA chain).
Add fetch 'ssl_verify_caerr_depth':
returns the first ssl verify error depth (max returns is 15 if depth > 15).
Add fetch 'ssl_verify_crterr':
returns the fist ssl verify error at depth == 0.
Allow to ignore some verify errors and to let them pass the handshake.
Add option 'crt-ignore-err <list>'
Ignore verify errors at depth == 0 (client certificate)
<list> is string 'all' or a comma separated list of verify error IDs
(see http://www.openssl.org/docs/apps/verify.html)
Add option 'ca-ignore-err <list>'
Same as 'crt-ignore-err' for all depths > 0 (CA chain certs)
Ex ignore all errors on CA and expired or not-yet-valid errors
on client certificate:
bind 0.0.0.0:443 ssl crt crt.pem verify required
cafile ca.pem ca-ignore-err all crt-ignore-err 10,9
Add keyword 'verify' on bind:
'verify none': authentication disabled (default)
'verify optional': accept connection without certificate
and process a verify if the client sent a certificate
'verify required': reject connection without certificate
and process a verify if the client send a certificate
Add keyword 'cafile' on bind:
'cafile <path>' path to a client CA file used to verify.
'crlfile <path>' path to a client CRL file used to verify.
It's better to set all listeners to ssl_sock when seeing the "ssl"
keyword that to loop on all of them afterwards just for this. This
also removes some #ifdefs.
Navigating through listeners was very inconvenient and error-prone. Not to
mention that listeners were linked in reverse order and reverted afterwards.
In order to definitely get rid of these issues, we now do the following :
- frontends have a dual-linked list of bind_conf
- frontends have a dual-linked list of listeners
- bind_conf have a dual-linked list of listeners
- listeners have a pointer to their bind_conf
This way we can now navigate from anywhere to anywhere and always find the
proper bind_conf for a given listener, as well as find the list of listeners
for a current bind_conf.
Registering new SSL bind keywords was not particularly handy as it required
many #ifdef in cfgparse.c. Now the code has moved to ssl_sock.c which calls
a register function for all the keywords.
Error reporting was also improved by this move, because the called functions
build an error message using memprintf(), which can span multiple lines if
needed, and each of these errors will be displayed indented in the context of
the bind line being processed. This is important when dealing with certificate
directories which can report multiple errors.
Some settings need to be merged per-bind config line and are not necessarily
SSL-specific. It becomes quite inconvenient to have this ssl_conf SSL-specific,
so let's replace it with something more generic.
Baptiste Assmann observed a crash of 1.5-dev12 occuring when the ssl_sni
fetch was used with no SNI on the input connection and without a prior
has_sni check. A code review revealed several issues :
1) it was possible to call the has_sni and ssl_sni fetch functions with
a NULL data_ctx if the handshake fails or if the connection is aborted
during the handshake.
2) when no SNI is present, strlen() was called with a NULL parameter in
smp_fetch_ssl_sni().
Really, the quality of their code deserves it, it would have been much
harder to figure how to get all the things right at once without looking
there from time to time !
A side effect of this change is that the "ssl" keyword on "bind" lines is now
just a boolean and that "crt" is needed to designate certificate files or
directories.
Note that much refcounting was needed to have the free() work correctly due to
the number of cert aliases which can make a context be shared by multiple names.
SSL config holds many parameters which are per bind line and not per
listener. Let's use a per-bind line config instead of having it
replicated for each listener.
At the moment we only do this for the SSL part but this should probably
evolved to handle more of the configuration and maybe even the state per
bind line.
SSL connections take a huge amount of memory, and unfortunately openssl
does not check malloc() returns and easily segfaults when too many
connections are used.
The only solution against this is to provide a global maxsslconn setting
to reject SSL connections above the limit in order to avoid reaching
unsafe limits.
The WAIT_L6_CONN was designed especially to ensure that the connection
was not marked ready before the SSL layer was OK, but we forgot to set
the flag, resulting in a rejected handshake when ssl was combined with
accept-proxy because accept-proxy would validate the connection alone
and the SSL handshake would then believe in a client-initiated reneg
and kill it.
CVE-2009-3555 suggests that client-initiated renegociation should be
prevented in the middle of data. The workaround here consists in having
the SSL layer notify our callback about a handshake occurring, which in
turn causes the connection to be marked in the error state if it was
already considered established (which means if a previous handshake was
completed). The result is that the connection with the client is immediately
aborted and any pending data are dropped.
This data layer supports socket-to-buffer and buffer-to-socket operations.
No sock-to-pipe nor pipe-to-sock functions are provided, since splicing does
not provide any benefit with data transformation. At best it could save a
memcpy() and avoid keeping a buffer allocated but that does not seem very
useful.
An init function and a close function are provided because the SSL context
needs to be allocated/freed.
A data-layer shutw() function is also provided because upon successful
shutdown, we want to store the SSL context in the cache in order to reuse
it for future connections and avoid a new key generation.
The handshake function is directly called from the connection handler.
At this point it is not certain whether this will remain this way or
if a new ->handshake callback will be added to the data layer so that
the connection handler doesn't care about SSL.
The sock-to-buf and buf-to-sock functions are all capable of enabling
the SSL handshake at any time. This also implies polling in the opposite
direction to what was expected. The upper layers must take that into
account (it is OK right now with the stream interface).
