commit	3a17e02873fdf53898a2cfce894dcb36223d76d4	[log] [tgz]
author	Tim Lee <timlee660101@gmail.com>	Tue Oct 13 11:52:58 2020 +0800
committer	Gunnar Mills <gmills@us.ibm.com>	Thu Nov 12 15:05:58 2020 +0000
tree	f62a5b36748b1302223f99e0bc716a4a2490b6de
parent	83cf8189e5f9d414efb5c5fa73227e977cf5f84d [diff]

update_service: fix segmentation violation when updating images

Symptom:
Before repo this issue symptom, we need to enable bmcweb debug option.
Due to this issue is relevant to timing about callback function lifecycle.
Thus, enable debugging will increae issue repo rate almost 100%.

Bmcweb.service was terminated abnormal after updating images via Redfish curl command.
According debug log, bmcweb.service exited with status=11/SEGV (Segmentation Violation).
That's usually a bug in a program such as pointer, null pointer, arrays and so on.
The default action for a program upon receiving SIGSEGV is abnormal termination.

Coredump analysis:
From the backtrace result that is point to softwareInterfaceAdded() of caller:
at/home/tim/git/runbmc/openbmc/olympus-build/tmp/work/armv7a-openbmc-linux-gnueabi/bmcweb/
1.0+gitAUTOINC+72d566d9eb-r0/recipe-sysroot/usr/include/c++/10.1.0/bits/shared_ptr.h:149
at/home/tim/git/runbmc/openbmc/olympus-build/tmp/work/armv7a-openbmc-linux-gnueabi/bmcweb/
1.0+gitAUTOINC+72d566d9eb-r0/git/redfish-core/include/../lib/update_service.hpp:315

SEGV happen after executing line 84 in softwareInterfaceAdded()
line: 83 // Found our interface, disable callbacks
line: 84    fwUpdateMatcher = nullptr;
line: 86 // Retrieve service and activate
line: 87 crow::connections::systemBus->async_method_call(

Root cause:
From coredump and backtrace result that segmentation violation issue in softwareInterfaceAdded().
softwareInterfaceAdded() is a callback function will be called by monitorForSoftwareAvailable().
When there is a signal relate to member is InterfacesAdded in object path /xyz/operbmc_project/software.
However, this callback function pointer will set to NULL poniter in itself callback function.
Thus, there is possible to hit SEGV issue when accessing to NULL function pointer.

Solution:
Set fwUpdateMatcher as nullptr should remove it from softwareInterfaceAdded().
And that will be set as nullptr by call cleanUp() in monitorForSoftwareAvailable() after got response.
Thus, it save to remove this line and avoid this SEGV then cause bmcweb.service terminated abnormal.

Tested:
Update BMC image using UpdateService POST action:
curl -k -H "X-Auth-Token: $token" -H "Content-Type: application/octet-stream" -X POST -T
tim/obmc-phosphor-image-olympus-nuvoton-20200921031720.static.mtd.tar https://${bmc}/redfish/v1/UpdateService

Update BMC image using UpdateService.SimpleUpdate POST action:
curl -k -H "X-Auth-Token: $token" -X POST https://${bmc}/redfish/v1/UpdateService/Actions/UpdateService.SimpleUpdate
-d '{"ImageURI":"tftp://10.103.61.175/obmc-phosphor-image-olympus-nuvoton-20200921031720.static.mtd.tar"}'

Signed-off-by: Tim Lee <timlee660101@gmail.com>
Change-Id: I01dcf56893b5ca64fe1d45f29f3f858761ccf2a8

redfish-core/lib/update_service.hpp[diff]

1 file changed

tree: f62a5b36748b1302223f99e0bc716a4a2490b6de

README.md

OpenBMC webserver

This component attempts to be a "do everything" embedded webserver for openbmc.

Capabilities

At this time, the webserver implements a few interfaces:

Authentication middleware that supports cookie and token based authentication, as well as CSRF prevention backed by linux PAM authentication credentials.
An (incomplete) attempt at replicating phosphor-dbus-rest interfaces in C++. Right now, a few of the endpoint definitions work as expected, but there is still a lot of work to be done. The portions of the interface that are functional are designed to work correctly for phosphor-webui, but may not yet be complete.
Replication of the rest-dbus backend interfaces to allow bmc debug to logged in users.
An initial attempt at a read-only redfish interface. Currently the redfish interface targets ServiceRoot, SessionService, AccountService, Roles, and ManagersService. Some functionality here has been shimmed to make development possible. For example, there exists only a single user role.
SSL key generation at runtime. See the configuration section for details.
Static file hosting. Currently, static files are hosted from the fixed location at /usr/share/www. This is intended to allow loose coupling with yocto projects, and allow overriding static files at build time.
Dbus-monitor over websocket. A generic endpoint that allows UIs to open a websocket and register for notification of events to avoid polling in single page applications. (this interface may be modified in the future due to security concerns.

Configuration

BMCWeb is configured by setting -D flags that correspond to options in bmcweb/meson_options.txt and then compiling. For example, meson <builddir> -Dkvm=disabled ... followed by ninja in build directory. The option names become C++ preprocessor symbols that control which code is compiled into the program.

Compile bmcweb with default options:

meson builddir
ninja -C builddir

Compile bmcweb with yocto defaults:

meson builddir -Dbuildtype=minsize -Db_lto=true -Dtests=disabled
ninja -C buildir

If any of the dependencies are not found on the host system during configuration, meson automatically gets them via its wrap dependencies mentioned in bmcweb/subprojects.

Enable/Disable meson wrap feature

meson builddir -Dwrap_mode=nofallback
ninja -C builddir

Generate test coverage report:

meson builddir -Db_coverage=true -Dtests=enabled
ninja coverage -C builddir test

When BMCWeb starts running, it reads persistent configuration data (such as UUID and session data) from a local file. If this is not usable, it generates a new configuration.

When BMCWeb SSL support is enabled and a usable certificate is not found, it will generate a self-sign a certificate before launching the server. The keys are generated by the secp384r1 algorithm. The certificate

is issued by C=US, O=OpenBMC, CN=testhost,
is valid for 10 years,
has a random serial number, and
is signed using the SHA-256 algorithm.