Currently each received Ident Resp triggers an Attach Accept/Reject
if IMSI and IMEI are known. This has led to duplicated Attach Accept
messages when used with the gbproxy (IMSI acquisition active) and
with certain mobile equipment (iOS).
This patch modifies gsm48_rx_gmm_id_resp to discard Ident Resp messages
if all required information (IMEI and IMSI) has been gathered.
Ticket: OW#1322
Sponsored-by: On-Waves ehf
Currently the P-TMSI IE in PAGING_PS is not patched.
This commit adds code to patch BSSGP P-TMSI IE in
gbproxy_patch_bssgp independently from the P-TMSI patching at the LLC
layer. It also extends gbproxy_update_link_state_dl to use the IMSI
to find the link_info if the TLLI is not present in the message.
Note that the spec (GSM 08.18, 7.2) requires to use of the P-TMSI
instead of the IMSI to select the MS if that IE is available.
Nevertheless as long as the IMSI is always present in downlink BSSGP
messages and as long as the optional P-TMSI refers to the same MS
(which is the case currently), this is not an issue.
Sponsored-by: On-Waves ehf
Currently, when P-TMSI patching is enabled, a new BSS P-TMSI is
generated for each Attach Accept. So two duplicated, subsequent
Attach Accept messages will be mapped to different BSS side P-TMSI.
Because the last one will replace former ones in the link_info
struct, the MS will fail to access the SGSN if it uses the former
P-TMSI to derive the new TLLI.
This patch checks the SGSN P-TMSI already assigned to the link_info
and only generates a new BSS P-TMSI on mismatch (or if the BSS P-TMSI
hasn't been set yet).
Ticket: OW#1322
Sponsored-by: On-Waves ehf
This adds a test case to check gbproxy's behaviour when processing
two subsequent but identical Attach Accept messages.
Ticket: OW#1322
Sponsored-by: On-Waves ehf
This patch adds assertions to check the LLC/GMM message received from
the gbproxy by the test framework within the function
test_gbproxy_keep_info.
It also fixes the source address of the DETACH ACC messages.
Sponsored-by: On-Waves ehf
The osmo-sgsn sends Status messages (or nothing in case of non
GMM/GSM) when the TLLI is unknown. This prevents the MS from
reconnecting.
This patch adds the initiation of an MT detach procedure to force a
re-attach to set up a valid LLE context if an LLE or an MM context
cannot be found. Since this can also be triggered by non-GMM SAPI
messages, a GPRS application callback sgsn_force_reattach_oldmsg is
added which in turn calls the GMM layer to generate the GSM 04.08
specific messages.
Note that the MS can be left in REGISTERED state after initially
wanting to detach itself, since it will receive a Detach Req
(re-attach) when sending a DEACT PDP CTX REQ after the SGSN or
gbproxy (P-TMSI patching enabled) has been restarted. This same
behaviour has been observed with another SGSN.
Sponsored-by: On-Waves ehf
Currently the PDP contexts are hard freed (via sgsn_pdp_ctx_free)
at some places in gprs_gmm.c on the reception of a Detach Req and on
re-use of an IMSI that is already associated with an MM context. This
can lead to segfaults when there is a pending request or a data
indication at libgtp.
This patch add a new function sgsn_pdp_ctx_terminate that de-associates
the PTP context from the MM context, deactivates SNDCP, sets pdp->mm
to NULL and then calls sgsn_delete_pdp_ctx. sgsn_libgtp is updated to
check for pdp->mm being non-NULL before dereferencing it. The
sgsn_pdp_ctx_terminate function will be called for each PDP context of
an MM context before this context is going to be deleted via
sgsn_mm_ctx_free. To ensure, that the ctx->llme (which is accessed
during the deactivation of SNDCP) remains valid, the call to
gprs_llgmm_assign is moved after the call to sgsn_mm_ctx_free. The
handling of re-used IMSIs is changed to mimic the processing of a
Detach Req.
Addresses:
<0002> gprs_gmm.c:654 MM(/f6b31ab0) Deleting old MM Context for same
IMSI p_tmsi_old=0xc6f19134
<000f> gprs_sgsn.c:259 PDP freeing PDP context that still has a
libgtp handle attached to it, this shouldn't happen!
[...]
SEGFAULT
Ticket: OW#1311
Sponsored-by: On-Waves ehf
Currently the timer is not stopped before the MM context is freed
which can lead to failure if sgsn_mm_ctx_free is called while timer
protected procedures are active.
This patch add code to cancel the timer if necessary from within
sgsn_mm_ctx_free.
Ticket: OW#1322
Sponsored-by: On-Waves ehf
Currently the code segfaults when the link shall be deleted by IMSI
when the IMSI has not been set yet.
This patch adds a NULL check to skip the entry before calling
gsm48_mi_to_string,
Adresses:
Program received signal SIGSEGV, Segmentation fault.
0xb693af77 in gsm48_mi_to_string (string=0xbfffe020 "", str_len=200,
mi=0x0, mi_len=0) at gsm48.c:360
360 mi_type = mi[0] & GSM_MI_TYPE_MASK;
str_len=200, mi=0x0, mi_len=0) at gsm48.c:360
self=0x807c9a0 <delete_gb_link_by_id_cmd>, vty=0xb4303c70,
argc=3, argv=0xbfffe1c0) at gb_proxy_vty.c:670
...
Sponsored-by: On-Waves ehf
Coverity complains about having side effects in OSMO_ASSERT argument
expressions. This would be an issue in this case, because that
variable is only reference in other OSMO_ASSERT expressions.
Nevertheless this patch changes this to assign the variable outside
of OSMO_ASSERT.
Fixes: Coverity CID 1244239
Sponsored-by: On-Waves ehf
Currently all PTP messages are in general forwarded to the SGSN even
when the BVCI is not known to the gbproxy. Only if message patching
is active and the peer cannot be determined, a log message is
generated, a STATUS message returned, and the message discarded.
The intention for this was to keep the old gbproxy's behaviour if
patching is disabled. But the code gets much more complex this way.
Another drawback is that when the SGSN returns a corresponding STATUS
message, it cannot be routed to the BSS where the original message
came from.
This patch therefore changes the behaviour to reject BSSGP PTP uplink
messages immediately if the BVCI is not known.
Fixes: Coverity CID 1244240
Ticket: OW#1317
Sponsored-by: On-Waves ehf
This has been re-produced using the "osmo-pcu emulator" code
and a ping to force segmented SNDCP messages. When the NS link
enters the DEAD/BLOCKED state the msgb would be freed twice.
Once inside gprs_ns_sendmsg and once by the caller. Based on the
return one can not see if the parameter has been deleted.
I changed libosmocore/libosmogb to always free the msgb in case
of an error on the way to gprs_ns_sendmsg. Catch up, avoid the
double free and fix some memory leaks. In case the sending fails
assume the entire segmented message is at end and free the
original input data.
This has been tested by posix suspending/resuming the emulator
process to have the GPRS-NS link go to dead/blocked to alive
and unblocked. The ping recovers and "SIGUSR1" to the SGSN does
not show active memory allocations.
The SGSN calls bssgp_tx_dl_ud at the lowest level and has the
following callchains. Most of them allocate the msgb and have
no early return and transfer ownership already:
<- gprs_llc_tx_u
<- gprs_llc_tx_ui
<- gsm48_gmm_sendmsg (all callers sane)
<- _tx_status
<- _tx_detach_req
<- gprs_llc_tx_xid (all callers sane)
<- sndcp_unitdata_req
<- sndcp_send_ud_frag
To get a clue which message caused the error without having to enable
LOGL_DEBUG, information about how far the parser came (message name,
parsed fields) is logged with LOGL_NOTICE along with a full hexdump
of the message.
Ticket: OW#1307
Sponsored-by: On-Waves ehf
Currently, the log level is always LOGL_DEBUG. In case of errors it
would be helpful to use a higher log level.
This patch adds a log_level parameter to gprs_gb_log_parse_context to
let the caller decide about the level.
Ticket: OW#1307
Sponsored-by: On-Waves ehf
This function tries to get an accurate name for the message even if
the parsing has been aborted due to message errors.
The patch also moves the settings of the BSSGP related fields in
parse_ctx from behind to the front of bssgp_tlv_parse, to get more
information in the case of failure. This is now consistent with the
handling of the llc and g48_hdr fields.
Id addition, gprs_gb_log_parse_context now uses the new function to
derive a more accurate message name.
Ticket: OW#1307
Sponsored-by: On-Waves ehf
Currently it is possible to set the secondary SGSN NSEI to the same
value like the (primary) SGSN NSEI. This leads to undefined behaviour
and is hard to recognize.
This patch adds checks to either NSEI configuration command to refuse
conflicting values.
Ticket: OW#1306
Sponsored-by: On-Waves ehf
Currently, ptmsi_enc and new_ptmsi_enc point to the beginning of the
mobile identity. Since all P-TMSI in 04.08 (MM) are encoded this way (1
byte header + 4 byte P-TMSI value). This is different to the P-TMSI
encoding in 08.18 (BSSGP), where the P-TMSI is encoded into 4 byte
without MI header.
This patch changes the code to use pointers to the P-TMSI value,
which is encoded in the same way in both specifications.
Sponsored-by: On-Waves ehf
Currently BSSGP PTP messages are silently dropped when the BVCI is
not known and patching is enabled. The nanoBTS will not recognize
this and continue to send messages on the BVCI. If it receives a
STATUS(BVCI unknown) instead, it will start a BVC reset procedure
instead.
This patch modifies gbprox_rx_ptp_from_bss() to return a
STATUS(BVCI unknown) to the BSS instead of dropping the message.
Sponsored-by: On-Waves ehf
Currently the parse expects a 'MS network capability' IE with
2 <= length <= 3 which is compliant to GSM 04.08, 9.4.1 but not to
GSM 24.008, 9.4.1 which specifies 3 <= length <= 9. Thus the parser
rejects messages with a length >= 4 (including length field).
This patch relaxes the length check to accept either range by
requiring 2 <= length <= 9.
Ticket: OW#1258
Sponsored-by: On-Waves ehf
Currently one regexp ('patching') is used for all matching.
This patch adds a second category 'routing' which is exclusively used
for SGSN selection. It also adds a corresponding VTY command:
- match-imsi patching RE : MS related patching (currently APN)
- match-imsi routing RE : Select secondary SGSN on match only
- no match-imsi : Clear all filter expressions
Ticket: OW#1258
Sponsored-by: On-Waves ehf
This patch modifies the match-imsi command to allow for different
match categories (currently only 'patching' is provided).
- match-imsi patching RE : Filter APN patching and routing
- no match-imsi : Clear all filter expressions
Sponsored-by: On-Waves ehf
Currently, patch filter configurations are leaking between tests.
This adds a call to gbproxy_clear_patch_filter() to the end of each
test that calls gbproxy_set_patch_filter().
Sponsored-by: On-Waves ehf
The current implementation makes it difficult to add further match
expressions.
This patch adds a new struct gbproxy_match that contains the fields
needed for each match expression. The matches (config) and the
results (link_info) are stored in arrays. All related functions are
updated to use them. The old fields in the config structure are
removed.
Sponsored-by: On-Waves ehf
This patch adds assertions to check the LLC/GMM message received from
the gbproxy by the test framework within the function
test_gbproxy_ra_patching.
Sponsored-by: On-Waves ehf
Currently the only way to check, whether the right message have been
generated is to look into the generated text output. This is
error-prone if there are many messages.
This patch adds a way to optionally store all received messages into
a FIFO. They can then be checked by calling expect_msg() which
removes the first message from the FIFO and returns a pointer to it
or NULL if there is none. The pointer is only valid until the next
call to this function.
A few convenience functions are added to check for common message
types:
- expect_gmm_msg checks for certain GSM 04.08 messages in LLC/GMM
- expect_llc_msg checks for arbitrary LLC messages in BSSGP/UD
- expect_bssgp_msg checks for arbitrary BSSG messages
Each of their arguments can be set by MATCH_ANY to ignore it while
matching. On success, they return a pointer to a statically
allocated struct containing the pointer to the msg and the full parse
context.
Recording is enabled by setting the global variable received_messages
to a pointer to a struct llist_head. It can be disabled again by
setting it to NULL.
Sponsored-by: On-Waves ehf
Currently the pointers are computed by adding an offset to the new
message's _data pointer even when the original pointer is NULL.
This leads to invalid pointers in the copied msgb.
This patch adds a NULL check to each computation such that NULL
pointers are not adjusted.
Sponsored-by: On-Waves ehf
This patch adds und uses the function gbproxy_gsm48_to_peer() which
takes a GSM 04.08 message, encapsulates it in BSSGP and LLC, and
sends it to the BSS peer. This function increments vu_gen_tx_bss
which is now used instead of imsi_acq_retries to set the N(U) of the
outgoing message.
Since imsi_acq_retries isn't currently incremented before a Detach
Accept is generated, this patch also fixes the N(U) of such messages.
Sponsored-by: On-Waves ehf
Currently then link_info is not cleaned up completely, when
gbproxy_unregister_link_info is called.
This patch adds a function gbproxy_reset_link that must be defined
externally. This is done in gb_proxy.c, where it resets the IMSI
acquisition.
Sponsored-by: On-Waves ehf
That message is currently ignored but should invalidate the TLLI and
de-register the logical link instead.
This patch extends the parser to recognize such messages and to set
the invalidate_tlli flag.
Sponsored-by: On-Waves ehf
The TLLI should also be invalidated:
- when an Attach Reject info is received from the SGSN
- when an Attach Req is immediately followed by a Detach Req
- when an Attach Req is immediately followed by an MT detach
procedure
To verify that, this patch adds corresponding message sequences to
the test.
Sponsored-by: On-Waves ehf
This fixes the IMSI length assertion, which currently uses a
greater-or-equal than zero comparison which always yields true. It is
replaced by a greater than zero check.
Fixes: Coverity CID 1239442
Sponsored-by: On-Waves ehf
A single test case still uses time() to obtain the reference time.
This commit fixes this by using the 'now' variable instead, that
contains a fixed time value and does therefore not depend on when the
test is executed.
Sponsored-by: On-Waves ehf
Currently time() is used for age calculations. This time source
may jump either forwards or backwards in time (NTP update, leap
seconds).
This patch replaces the use of time() by using
clock_gettime(CLOCK_MONOTONIC) instead.
Sponsored-by: On-Waves ehf
Don't return a link_info if TLLI is 0 resp. P-TMSI is 0xffff. These
values are used for uninitialised or cleared fields and can possibly
match several entries.
Sponsored-by: On-Waves ehf
Since the (former) TLLI list has developed into a logical link list,
related commands are renamed accordingly.
- tlli-list * -> link-list *
- delete-gbproxy-tlli * -> delete-gbproxy-link *
- show gbproxy tllis -> show gbproxy links
Sponsored-by: On-Waves ehf
This field in struct gbproxy_patch_state has involved and holds a
list of all tracked logical links now. Thus the name is modified
accordingly.
Sponsored-by: On-Waves ehf
Currently in many places where 'tlli' (Temporary Logical Link
Identifier) within identifiers is used, the logical link itself is
meant instead. For instance, the tlli_info contain information about
an LLC logical link including up to four individual TLLI.
To avoid confusion between these concepts, this patch replaces all
'tlli_info' by 'link_info' and a few 'tlli' by 'link'.
Sponsored-by: On-Waves ehf
This patch replaces 'tlli' by 'tlli_info' within the following
function identifiers:
- gbproxy_delete_tlli
- gbproxy_delete_tllis
- gbproxy_remove_stale_tllis
- gbproxy_touch_tlli
- gbproxy_unregister_tlli
- gbproxy_remove_matching_tllis
- gbproxy_find_tlli -> gbproxy_tlli_info_by_tlli
- gbproxy_find_tlli_by_* -> gbproxy_tlli_info_by_*
These functions refer to the whole logical link info rather than to a
certain TLLI. So they are renamed to be named consistently with
gbproxy_attach_tlli_info and others.
Sponsored-by: On-Waves ehf
The function gbproxy_imsi_acquisition() has a parameter sgsn_nsei
that is alyways equal to tlli_info->sgsn_nsei (if tlli_info is not
NULL).
This patch removes this parameter from gbproxy_imsi_acquisition() and
gbproxy_flush_stored_messages() and accesses tlli_info->sgsn_nsei
instead within these functions.
Sponsored-by: On-Waves ehf
This patch renames gbproxy_check_tlli() to
gbproxy_imsi_matches() and struct tlli_info's
enable_patching to imsi_matches.
It's meant to be more obvious and consistent this way.
Sponsored-by: On-Waves ehf
Currently the number of iterations when creating a P-TMSI/TLLI is not
limited. It is nevertheless very unlikely that the loop will not
terminate. On the other hand, the number of iterations of every loop
should have an upper bound (loop variant) which wouldn't be the case
here if an arbitrary random generator was used.
This patch limits the number of iterations to 23 and logs an error if
the creation of the indentifier was aborted due to this limit.
Sponsored-by: On-Waves ehf
Currently the IMSI acquisition is not restarted when a RA Update
Request is received. This leads to repeated N(U) in the generated
Ident Request message, which in turn causes the MS to drop the
second of these message. This is bad, when the first Ident Response
has been lost between MS and gbproxy.
This patch changes gbproxy_imsi_acquisition() to handle RA Update
Request messages like Attach Requests.
Sponsored-by: On-Waves ehf
When a MS is state GMM_REGISTERED enters a new RA, it sends a RA
Update Request which is then handled by a gbproxy that possibly
doesn't have a matching tlli_info. In this case, depending on the
configuration an identification procedure to acquire the IMSI must be
started.
This adds tests to test_gbproxy_imsi_acquisition():
- IMSI acquisition triggered by a RA Update Request message
- Reaction to repeated RA Update Request messages, like it could be
caused by packet loss between PCU and gbproxy.
Sponsored-by: On-Waves ehf
On a Detach/Re-attach cycle the Address Sanitizer detected a
use-after-free kind of problem. That is because we tried to
destroy the LLME twice. The first time it is destroyed as part
of the Detach handling ans the second time it is destroyed as
part of destroying the old MM context.
In case the GPRS GMM detach message is lost the SGSN needs
to reply besides not having a MM entry.
The alternative would have been to add NULL checks for all
usages of ctx->llme which would not have helped with the
readability.
Sponsored-by: On-Waves ehf
For jitter, transit and packet loss we should count the data
that arrived and not the data we send towards the remote. This
is changing the jitter timings to what they were before the
re-factoring.
For forced timing we might willingly add jumps in the sequence
number but for jitter and packet loss we are more interested
in the data that traveled through the wire/air.
Jacob Erlbeck