Ensure to honor the 'first_kex_packet_follow' field when processing
KEXINIT messages in the 'ssh_packet_kexinit' callback. Until now
libssh would assume that this field is always unset (zero). But
some clients may set this (dropbear at or beyond version 2013.57),
and it needs to be included when computing the session ID.
Also include logic for handling wrongly-guessed key exchange algorithms.
Save whether a client's guess is wrong in a new field in the session
struct: when set, the next KEX_DHINIT message to be processed will be
ignored per RFC 4253, 7.1.
While here, update both 'ssh_packet_kexinit' and 'make_sessionid' to
use softabs with a 4 space indent level throughout, and also convert
various error-checking to store intermediate values into an explicit
'rc'.
Patch adjusted from original to ensure that client tests remain passing
(ie 'torture_connect'): restrict the changes in 'ssh_packet_kexinit'
only for the 'server_kex' case.
Signed-off-by: Jon Simons <jon@jonsimons.org>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
Ensure to honor the 'first_kex_packet_follow' field when processing
KEXINIT messages in the 'ssh_packet_kexinit' callback. Until now
libssh would assume that this field is always unset (zero). But
some clients may set this (dropbear at or beyond version 2013.57),
and it needs to be included when computing the session ID.
Also include logic for handling wrongly-guessed key exchange algorithms.
Save whether a client's guess is wrong in a new field in the session
struct: when set, the next KEX_DHINIT message to be processed will be
ignored per RFC 4253, 7.1.
While here, update both 'ssh_packet_kexinit' and 'make_sessionid' to
use softabs with a 4 space indent level throughout, and also convert
various error-checking to store intermediate values into an explicit
'rc'.
Signed-off-by: Jon Simons <jon@jonsimons.org>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
Enable retrieving the "ecdsa-sha2-nistpNNN" name of ECDSA keys with a
new 'ssh_pki_key_ecdsa_name' API. This gives more information than the
'ssh_key_type_to_char' API, which yields "ssh-ecdsa" for ECDSA keys.
The motivation is that this info is useful to have in a server context.
The torture_pki unit test is updated to include the new API, and a few
more passes are added to additionally test 384 and 521-bit keys.
Signed-off-by: Jon Simons <jon@jonsimons.org>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
SSH_BIND_OPTIONS_HOSTKEY will now load host keys of any supported type
rather than set the algorithms that the server permits (which seems
like an unhelpful option anyway; it seems you can always control this
by just loading the right keys).
This option has slightly different semantics than the
SSH_BIND_OPTIONS_<x>KEY options because it requires the key file to
exist immediately rather than on ssh_bind_listen or
ssh_bind_accept_fd. The semantics of this option makes more sense to
me.
We also eliminate ssh_bind_options_set_algo, since it is no longer
used.
Signed-off-by: Alan Dunn <amdunn@gmail.com>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
In packet_send2, rather than issue two separate buffer_prepend_data calls
(each of which may entail realloc + memmove + memcpy), elide the prepend
work into a single buffer_prepend_data: the header information is computed
locally, and a single 5 byte prepend operation is now done instead of
prepending 1, then 4 bytes.
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
If the sockets are created manually and passed to libssh the internal session
state is set to SSH_SESSION_STATE_SOCKET_CONNECTED. Result of this fix can be
verified by running torture_connect test (torture_connect_socket) with -vvvv
flags.
Signed-off-by: Luka Perkov <luka.perkov@sartura.hr>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
On Mar 16, 09:41, Aris Adamantiadis wrote:
> Hi Petar,
> I agree with the principle, but I don't think this code can work...
> RSA_generate_key takes an RSA* as parameter and in our code we probably
> have key->rsa==NULL. (if we don't then the old code had a memory leak).
>
> Does the test case work ?
>
> Aris
>
Yes, you are right. This works, tested with tests/unittests/torture_pki
Signed-off-by: Petar Koretic <petar.koretic@sartura.hr>
The commit fixes this build warning:
====
src/server.c:223:8: warning: ‘privkey’ may be used uninitialized in this function [-Wmaybe-uninitialized]
rc = ssh_pki_export_privkey_to_pubkey(*privkey, &pubkey);
^
src/server.c:243:11: note: ‘privkey’ was declared here
ssh_key privkey;
====
Signed-off-by: Luka Perkov <luka.perkov@sartura.hr>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
In 'ssh_bind_listen', move setting of 'sshbind->bindfd' to only happen after
the listen call: otherwise 'bindfd' can be set to a bogus descriptor for the
case that listen fails.
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
When accepting a new connection, a forking server based on libssh forks
and the child process handles the request. The RAND_bytes() function of
openssl doesn't reset its state after the fork, but simply adds the
current process id (getpid) to the PRNG state, which is not guaranteed
to be unique.
This can cause several children to end up with same PRNG state which is
a security issue.
After discussion with Aris and it was not obvious enough to understand
the issue we decided to refactor it.
Reviewd-by: Aris Adamantiadis <aris@0xbadc0de.be>
Right now the behavior of packet_{en,de}crypt on len == 0 depends on
the behavior of malloc. Instead, make these consistently fail based
on what I assume the desired behavior is due to the first error
message in each.
Signed-off-by: Alan Dunn <amdunn@gmail.com>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
If we receive a packet of length exactly blocksize, then
packet_decrypt gets called on a buffer of size 0. The check at the
beginning of packet_decrypt indicates that the function should be
called on buffers of at least one blocksize, though the check allows
through zero length. As is packet_decrypt can return -1 when len is 0
because malloc can return NULL in this case: according to the ISO C
standard, malloc is free to return NULL or a pointer that can be freed
when size == 0, and uclibc by default will return NULL here (in
"non-glibc-compatible" mode). The net result is that when using
uclibc connections with libssh can anomalously fail.
Alternatively, packet_decrypt (and probably packet_encrypt for
consistency) could be made to always succeed on len == 0 without
depending on the behavior of malloc.
Thanks to Josh Berlin for bringing conneciton failures with uclibc to
my attention.
Signed-off-by: Alan Dunn <amdunn@gmail.com>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
Follow-up to 4e04ec8, which caused a regression on OS X.
Checking the value of CMAKE_THREAD_LIBS_INIT to decide whether any threading
library is present on a system turns out to be wrong -- in OS X, for
example, usage of pthreads does not depend on any additional linker or
compiler flags, so CMAKE_THREAD_LIBS_INIT is empty and our check in
src/CMakeLists.txt failed (it used to work before 4e04ec8 because
CMAKE_HAVE_THREADS_LIBRARY is set).
Instead, just look for Threads_FOUND, which FindThreads sets just like any
other Find module when it has found what it was looking for.
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
Fix bug #142
The mode does need to be an octal numeric string. Mode 0600 now gets sent on the wire as 0384, triggering a "scp: protocol error: bad mode" response, and an "scp status code 1d not valid" message from libssh.
As mentioned in the previous commit, there are cases where
CMAKE_HAVE_THREADS_LIBRARY is not set and pthreads _is_ being used: one can
pass -DTHREADS_HAVE_PTHREAD_ARG=1 to CMake directly so that it just passes
-pthread to the compiler/linker and does not set CMAKE_HAVE_THREADS_LIBRARY.
Since we are only interested in knowing whether any threading library has
been found, we should use CMAKE_THREAD_LIBS_INIT instead (Threads_FOUND
would also work).
Note that, at the moment, there is only a pthreads backend available in
threads/, so if it is not found configuration will fail because CMake will
try to create a library from an empty set of source files.
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
Ensure to check whether the socket at hand is indeed still connected
throughout POLLIN processing in ssh_socket_pollcallback.
Before this change, the POLLIN block in ssh_socket_pollcallback is
predicated against the condition (s->state == SSH_SOCKET_CONNECTED).
Once entered, data from the socket is consumed through the data
callback in this loop:
do {
r = s->callbacks->data(buffer_get_rest(s->in_buffer),
buffer_get_rest_len(s->in_buffer),
s->callbacks->userdata);
buffer_pass_bytes(s->in_buffer,r);
} while (r > 0);
However, it is possible for the socket data callback to change the
state of the socket (closing it, for example). Fix the loop to only
continue so long as the socket remains connected: this also entails
setting the ssh_socket state to SSH_SOCKET_CLOSED upon close.
The bug can be observed before the change by sending a bogus banner
to the server: 'echo -e "A\r\nB\r\n" | nc localhost 22'. Each of
'A' and 'B' will be processed by 'callback_receive_banner', even
though the client socket is closed after rejection of 'A'.
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
So that it would match ssh_channel_pty_request_callback as well as the documentation
Signed-off-by: Audrius Butkevicius <audrius.butkevicius@gmail.com>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
