- mbed-tls - lists.trustedfirmware.org

Custom PSA API Implementation for mbedTLS tests

by murat＠za-ya.co

Hi all, We have implemented the PSA Functional API for a custom secure environment which passes PSA Arch tests. Now we would like to run mbedtls tests (make check) on the PSA API if possible. When we run "make check", it includes and compiles library/psa_crypto.c file for mbedTLS's PSA API Implementation. Herein, we would like to compile our own psa_crypto.c implementation, does mbedtls build system allow us to include custom PSA API Implementation to run tests? Thank you. Murat

5 years, 8 months

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LTS roadmap and announcement channel?

by Simon Leet

Hi folks, I understand that https://tls.mbed.org/ has migrated under the umbrella of https://www.trustedfirmware.org/ but it's not clear where I should turn to for information about the updates to the LTS versions. The https://tls.mbed.org/tech-updates blog used to announce LTS branch updates but seems defunct as of 2.16.7, and I can't find equivalent information in https://developer.trustedfirmware.org/w/mbed-tls/roadmap/, https://github.com/ARMmbed/mbedtls/projects/2 or the generic https://www.trustedfirmware.org/blog/. Is there a new channel for information about upcoming LTS mbedtls releases so that users can plan their appropriate upgrade cycles? E.g. when is 2.16.8 roughly expected to be released? Is the new model for monitoring release announcements reliably going to be as a new tag on https://github.com/ARMmbed/mbedtls/tags? -Simon

5 years, 8 months

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Re: [mbed-tls] Diffie Hellman Key Exchange

by Gilles Peskine

Hello, The interface of the Diffie-Hellman (DHM) module is modeled on the way it's used in TLS, which is a bit different from the classical presentation. You can find code examples in programs/pkey/dh_client.c and programs/pkey/dh_server.c . Elliptic-curve Diffie-Hellman (provided by the ECDH module) has similar security properties and is significantly faster. If you don't need interoperability with legacy software that only supports classical (finite-field) Diffie-Hellman, you should use ECDH rather than DHM. With the ECDH module, you can use either the same TLS-inspired interface as the DHM module, or a more classical interface for which there is a usage example in psa_crypto.c in the function psa_key_agreement_ecdh. Hope this helps, -- Gilles Peskine Mbed TLS developer You can find an example of the TLS-like inter On 12/08/2020 14:02, youssouf sokhona via mbed-tls wrote: > > Hello, I hope you are going well during this Covid crisis. > > > > I'm sending you this message to find out how to generate a Diffie > Hellman key using MbedTLS. Indeed, with all the documentation, I'm a > bit lost. > > > > I think, you have to use the int mbedtls_dhm_set_group function to > create p and g. And then, I don't know how to use which function... > Moreover, I can't find any function that allows to set a and b, > whereas they are 2 fundamental elements > > Can you help me? Thank you! > > > > Best regards, YS > > >

5 years, 8 months

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Minimum Python version

by Gilles Peskine

Hello, Short version: to use the official tools to configure Mbed TLS, or to run the unit tests, you need Python. If we start requiring Python 3.5, is this going to be a problem? Detailed version: Mbed TLS includes four Python scripts that are of interest to users, with a fifth one in preparation: * scripts/config.py : compile-time configuration (unless you prefer to edit config.h directly). * scripts/generate_psa_constants.py : to build programs/psa/psa_constant_names (we have a pending task to commit the result instead of requiring it during the build). * tests/scripts/generate_test_code.py : necessary to build the unit tests. * tests/scripts/mbedtls_test.py : does anyone use this? It's for testing on platforms with Greentea, but some of the automation is missing. * upcoming: a script to generate glue code for accelerator and secure element drivers. We'll also provide a manual way, but it won't be as convenient. This is a question to everyone who's building Mbed TLS and using some of these scripts: is it ok if they require Python 3.5? Currently: * scripts/config.py requires Python 3.5. * scripts/generate_psa_constants.py requires Python 3.3. * tests/scripts/generate_test_code.py still works with Python 2.7. * tests/scripts/mbedtls_test.py still works with Python 2.7. * the driver glue code generation script will require Python 3.5, or Python 3.4 + typing. Is there any demand for versions of Python before 3.5? -- Gilles Peskine Mbed TLS developer

5 years, 8 months

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Diffie Hellman Key Exchange

by youssouf sokhona

Hello, I hope you are going well during this Covid crisis. I'm sending you this message to find out how to generate a Diffie Hellman key using MbedTLS. Indeed, with all the documentation, I'm a bit lost. I think, you have to use the int mbedtls_dhm_set_group function to create p and g. And then, I don't know how to use which function... Moreover, I can't find any function that allows to set a and b, whereas they are 2 fundamental elements Can you help me? Thank you! Best regards, YS

5 years, 8 months

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Re: [mbed-tls] Availability of 2.16.7 in download archive

by Janos Follath

Hi Frank, We have now updated the links both on the download-archive and releases site and now they point to https://github.com/ARMmbed/mbedtls/releases, where all the releases are available. We also have added checksums to the release notes on github and fixed the archive structure. Thank you very much for pointing these issues out! Cheers, Janos (Mbed TLS developer) On 04/08/2020, 19:06, "mbed-tls on behalf of Frank Bergmann via mbed-tls" <mbed-tls-bounces(a)lists.trustedfirmware.org on behalf of mbed-tls(a)lists.trustedfirmware.org> wrote: Hi, 2.16.7 was released on github more than one month ago (2020-07-01). But it is not listed on - download archive at https://tls.mbed.org/download-archive - release news at https://tls.mbed.org/tech-updates/releases Questions about that: - Is it an "official" release even if it is not mentioned on release news? - When will it be available in download archive? - If there will be no more addings to download archive because now we'll have to use github: * Will there be separate releases GPL/Apache available? * Will a signed/unsigned check sum be provided? * Will the "new structure" as provided by tarball on github be kept in future or was it just an accident? (e.g. main dir is named "mbedtls-mbedtls-2.16.7") I started using mbed TLS with 2.16.6 but now I am confused. ;-) cheers, Frank -- mbed-tls mailing list mbed-tls(a)lists.trustedfirmware.org https://lists.trustedfirmware.org/mailman/listinfo/mbed-tls

5 years, 8 months

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Re: [mbed-tls] Availability of 2.16.7 in download archive

by Gilles Peskine

Hi Frank, I confirm that 2.16.7 is an official release of the 2.16 long-time support branch of Mbed TLS, alongside 2.7.16 for the 2.7 branch and 2.23.0 for the latest features. Everyone should update to one of these versions since they fix security issues and other bugs. We're progressively transitioning the project from Arm infrastructure to TrustedFirmware infrastructure. Eventually we'll decommission the existing tls.mbed.org, and we intend to distribute releases via trustedfirmware.org. We no longer intend to reference new releases directly on https://tls.mbed.org/download-archive . For the time being, we're distributing via GitHub. However, it isn't right that https://tls.mbed.org/download-archive links to https://github.com/ARMmbed/mbedtls/releases/ which doesn't list LTS branches. We need to link from https://tls.mbed.org/download-archive to the place that has the latest LTS releases one way or the other. There are no longer separate archives with Apache and GPL licenses. These archives were always identical except for license headers. Now LTS releases are distributed as a single archive in which the files are dual-licensed. The naming with mbedtls-mbedtls- must be a bug in our release script. Thanks for noticing. I don't think we made a conscious decision not to provide official checksums. I can see the value of having them so let's try to incorporate those in our new release process. -- Gilles Peskine Mbed TLS developer On 04/08/2020 19:05, Frank Bergmann via mbed-tls wrote: > Hi, > > 2.16.7 was released on github more than one month ago (2020-07-01). > But it is not listed on > - download archive at https://tls.mbed.org/download-archive > - release news at https://tls.mbed.org/tech-updates/releases > > Questions about that: > - Is it an "official" release even if it is not mentioned on release news? > - When will it be available in download archive? > - If there will be no more addings to download archive because now we'll > have to use github: > * Will there be separate releases GPL/Apache available? > * Will a signed/unsigned check sum be provided? > * Will the "new structure" as provided by tarball on github be kept > in future or was it just an accident? (e.g. main dir is named > "mbedtls-mbedtls-2.16.7") > > I started using mbed TLS with 2.16.6 but now I am confused. ;-) > > cheers, > Frank > >

5 years, 8 months

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Availability of 2.16.7 in download archive

by Frank Bergmann

Hi, 2.16.7 was released on github more than one month ago (2020-07-01). But it is not listed on - download archive at https://tls.mbed.org/download-archive - release news at https://tls.mbed.org/tech-updates/releases Questions about that: - Is it an "official" release even if it is not mentioned on release news? - When will it be available in download archive? - If there will be no more addings to download archive because now we'll have to use github: * Will there be separate releases GPL/Apache available? * Will a signed/unsigned check sum be provided? * Will the "new structure" as provided by tarball on github be kept in future or was it just an accident? (e.g. main dir is named "mbedtls-mbedtls-2.16.7") I started using mbed TLS with 2.16.6 but now I am confused. ;-) cheers, Frank

5 years, 8 months

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Re: [mbed-tls] Entropy & TRNG on the BGM13P32

by Steven Cooreman

Hi Youssouf, This is Steven with Silicon Labs. It sounds like you have questions that are very device-specific, and relate to Silicon Labs products. We do provide TRNG drivers for mbed TLS through Simplicity Studio and our software SDK. Please contact our support staff at www.silabs.com/support<http://www.silabs.com/support>, and they’ll do their best to help you out with your questions. Regards, -- Steven From: mbed-tls <mbed-tls-bounces(a)lists.trustedfirmware.org> on behalf of youssouf sokhona via mbed-tls <mbed-tls(a)lists.trustedfirmware.org> Reply to: youssouf sokhona <youssouf.sokhona(a)hotmail.fr> Date: Tuesday, 4 August 2020 at 12:59 To: "mbed-tls(a)lists.trustedfirmware.org" <mbed-tls(a)lists.trustedfirmware.org> Subject: [mbed-tls] Entropy & TRNG on the BGM13P32 CAUTION: This email originated from outside of the organization. Do not click links or open attachments unless you recognize the sender and know the content is safe. Hi, everyone, First of all, I hope you are all healthy during this difficult time. I am working with Simplicity Studio IDE with MbedTLS and I am currently working on a project with a BGM13P32. I plan to perform a key exchange via bluetooth with the Diffie Hellman protocol. To start my project, I need an entropy source. I read the following on the BGM13P32 documentation "The TRNG is a non-deterministic random number generator based on a full hardware solution. The TRNG is validated with NIST800-22and AIS-31 test suites as well as being suitable for FIPS 140-2 certification (for the purposes of cryptographic key generation)." And I also read about the Random Number Generator "The Frame Controller (FRC) implements a random number generator that uses entropy gathered from noise in the RF receive chain.The data is suitable for use in cryptographic applications.Output from the random number generator can be used either directly or as a seed or entropy source for software-based random num-ber generator algorithms such as Fortuna" Knowing this, how can we use this to create entropy and then create a sequence of random numbers? I need to implement the MbedTLS_hardware_poll() function? Do I have to add another entropy, like real timing for example As you can see I am a bit confused actually. Can you help me out? Thanks in advance, and take care of yourself !

5 years, 8 months

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Entropy & TRNG on the BGM13P32

by youssouf sokhona

Hi, everyone, First of all, I hope you are all healthy during this difficult time. I am working with Simplicity Studio IDE with MbedTLS and I am currently working on a project with a BGM13P32. I plan to perform a key exchange via bluetooth with the Diffie Hellman protocol. To start my project, I need an entropy source. I read the following on the BGM13P32 documentation "The TRNG is a non-deterministic random number generator based on a full hardware solution. The TRNG is validated with NIST800-22and AIS-31 test suites as well as being suitable for FIPS 140-2 certification (for the purposes of cryptographic key generation)." And I also read about the Random Number Generator "The Frame Controller (FRC) implements a random number generator that uses entropy gathered from noise in the RF receive chain.The data is suitable for use in cryptographic applications.Output from the random number generator can be used either directly or as a seed or entropy source for software-based random num-ber generator algorithms such as Fortuna" Knowing this, how can we use this to create entropy and then create a sequence of random numbers? I need to implement the MbedTLS_hardware_poll() function? Do I have to add another entropy, like real timing for example As you can see I am a bit confused actually. Can you help me out? Thanks in advance, and take care of yourself !

5 years, 8 months

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Open & Read a file with a BGMQ

by youssouf sokhona

Morning, First of all, I hope you are all healthy during this difficult time. I am working with Simplicity Studio IDE and with Mbed TLS and I am currently working on a project with a BGM13P32. I plan to write in a file some parameters that will allow a key exchange by bluetooth (Diffie Hellman Protocol). I intend to make the BGM13P32 read this file, and these data to allow a key exchange. Is it possible to do that? If yes, how? Because I'm a total beginner Thank you, and take care of yourself !

5 years, 8 months

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DTS session resumption and fragmentation

by Fatima, Fariya

Hi all, I have configured the max fragment length at the client and server to both 512. With this setting when I try to reconnect using a saved session at the client side, the ssl handshake doesn’t seem to happen. Below is the comment in the server code. /* We don't support fragmentation of ClientHello (yet?) */ The mbedtls code I am using is version 2.16.6. Are there any plans to support fragmentation of clienthello? Do let me know Regards, Fariya

5 years, 8 months

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DTLS session resumption

by Fatima, Fariya

Hi, I do not quite have enough knowledge on DTLS session resumption .. nevertheless here's my question: a) Difference between the features: MBEDTLS_SSL_COOKIE_C and MBEDTLS_SSL_SESSION_TICKETS? b) Enabling the feature MBEDTLS_SSL_SESSION_TICKETS would be sufficient to resume an earlier established DTLS session quickly (i.e avoid the whole TLS handshake done the last time)? c) How do I test this - i.e initiate connection from client and server, break the connection and then make the client connect to the server again? Not sure what additional steps are required on client side. Any callbacks to be registered in the code? Regards, Fariya

5 years, 8 months

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Re: [mbed-tls] SSH client sample (Gilles Peskine)

by Christie Su

Hi Gilles, I checked one you recommended and looks like it is very complicated. Do you have any sample project(SSH client) based on MbedTLS+LWIP? Thanks, Christie -----Original Message----- From: mbed-tls <mbed-tls-bounces(a)lists.trustedfirmware.org> On Behalf Of mbed-tls-request(a)lists.trustedfirmware.org Sent: July-22-20 11:35 AM To: mbed-tls(a)lists.trustedfirmware.org Subject: mbed-tls Digest, Vol 5, Issue 15 Send mbed-tls mailing list submissions to mbed-tls(a)lists.trustedfirmware.org To subscribe or unsubscribe via the World Wide Web, visit https://lists.trustedfirmware.org/mailman/listinfo/mbed-tls or, via email, send a message with subject or body 'help' to mbed-tls-request(a)lists.trustedfirmware.org You can reach the person managing the list at mbed-tls-owner(a)lists.trustedfirmware.org When replying, please edit your Subject line so it is more specific than "Re: Contents of mbed-tls digest..." Today's Topics: 1. Problem with decrypt aes 128 in ecb mode. HELP ME! (dany_banik2000(a)yahoo.com) 2. Re: SSH client sample (Gilles Peskine) 3. Re: patches for low memory (Gilles Peskine) ---------------------------------------------------------------------- Message: 1 Date: Wed, 22 Jul 2020 14:42:33 +0000 (UTC) From: "dany_banik2000(a)yahoo.com" <dany_banik2000(a)yahoo.com> To: mbed-tls(a)lists.trustedfirmware.org Subject: [mbed-tls] Problem with decrypt aes 128 in ecb mode. HELP ME! Message-ID: <1371131400.5486983.1595428953399(a)mail.yahoo.com> Content-Type: text/plain; charset="utf-8" I developed a server application that obtains the data from a dht11 sensor, I encrypt it with aes 128 and publish it on the server. The client application makes a request to the server, and I would like to decrypt the answer. When I want to display decrypted message, it shows garbage The message retrieved from the server is in hex. I think that must to convert hex in binary, but i don’t know how can do it… -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.trustedfirmware.org/pipermail/mbed-tls/attachments/20200722/a5…> ------------------------------ Message: 2 Date: Wed, 22 Jul 2020 17:10:18 +0200 From: Gilles Peskine <gilles.peskine(a)arm.com> To: mbed-tls(a)lists.trustedfirmware.org Subject: Re: [mbed-tls] SSH client sample Message-ID: <4a7265ac-7b3e-33ef-7222-4cd29c3cda08(a)arm.com> Content-Type: text/plain; charset=windows-1252 Hi Christie, Libssh2 (https://github.com/libssh2/libssh2) supports Mbed TLS. I've never used it or investigated it, so I can't vouch for it, I just know that it's there. -- Gilles Peskine Mbed TLS developer On 21/07/2020 18:40, Christie Su via mbed-tls wrote: > > Hi, > > ï¿½ > > I am using FRDM-K64F with LWIP+mbedTLS for our control system. Now, I > want to develop the SSH client(or telnet 22) to access my SSH server. > > ï¿½ > > Could you give me some indications how to do it? Or do you have any > sample project? > > ï¿½ > > Thanks, > > ï¿½ > > Christie > > ------------------------------ Message: 3 Date: Wed, 22 Jul 2020 17:34:44 +0200 From: Gilles Peskine <gilles.peskine(a)arm.com> To: mbed-tls(a)lists.trustedfirmware.org Subject: Re: [mbed-tls] patches for low memory Message-ID: <152f6571-6972-8262-c38d-d200dcc7c0b7(a)arm.com> Content-Type: text/plain; charset=utf-8 Hi Nick, A TLS stack in 6kB of RAM sounds impressive, congratulations! We'd certainly be interested in all the improvements you can contribute. The process is documented in CONTRIBUTING.md (https://github.com/ARMmbed/mbedtls/blob/development/CONTRIBUTING.md). I just need to warn you that the limiting factor is reviewers' time. For a significant contribution, it may take a while before the Mbed TLS team can look at it in detail. Small patches are usually easier than large ones: if something only takes half an hour to review, someone will probably do it when they're stuck on some other task. If a review takes several days, it needs to be scheduled. It would probably be better to discuss the general nature of the changes on this mailing list first. Is a new compilation option needed? Is an API change needed? What is the risk that the change might break existing code? How is the new code tested? etc. Which version of Mbed TLS have you been using? We've made a few changes that are of interest to low-memory platforms recently, such as the option MBEDTLS_SSL_VARIABLE_BUFFER_LENGTH to resize SSL buffers after the handshake (new in 2.22). I don't know what the issue with the incoming SSL packet header length could be. If you could give precise steps to reproduce the issue, this would be very helpful. Eventually we'd want to construct a test in tests/ssl-opt.sh for this. -- Gilles Peskine Mbed TLS developer On 17/07/2020 21:00, Nick Setzer via mbed-tls wrote: > > Hi, I have been working with Mbed TLS for the last 6 months in an > extremely low memory use case. This library has been an absolute joy > to work with because of how flexible it is. I have an interesting use > case with how little RAM I have to work with (around 6kb on one > microprocessor) and I have made some changes that I thought would be > of interest. I'm not sure if I should submit them as a single > changeset or a set of changes. I'll describe the changes and if there > is interest I can clean them up for submission. > > The first change that I made was for a scenario with two > microprocessors communicating over a UART. I was already using TLS > offloading so that the private key was on one processor (with only 6kb > of RAM free) and the SSL context stored on the other. I required > generating a CSR and thus made some changes to the CSR code to be able > to generate the CSR using a similar private key offloading strategy. > > I found an issue with downloading firmware for OTA from openssl web > servers. This is a little tricky to describe. The server was not > responsive to requests for reducing the max fragment length, which > forced me to use MBEDTLS_SSL_MAX_CONTENT_LEN set to 16384. But I > needed to have multiple ssl sessions open for other activities and did > not have enough RAM to hold multiple large buffers. I have made a set > of changes to allow setting the content length when the ssl context is > initialized, as well as setting different IN and OUT content lengths > to save memory. This change allowed me to set up one session with 16kb > for the IN content length, and then 4kb for OUT content length, while > a second session could use 2kb for a total of 24kb instead of 64kb. > > Related to the openssl issue, I found that the incoming ssl packet > header length can sometimes be 8 or 16 bytes larger than expected > depending on which AES method is selected. I'm not actually sure what > the best way to solve this is. One way may be to change > MBEDTLS_SSL_HEADER_LEN from 13 to 29 bytes. However I ended up solving > it by adding 16 to both MBEDTLS_SSL_IN_BUFFER_LEN and > MBEDTLS_SSL_OUT_BUFFER_LEN. This way I could handle the larger ssl > header as well as receive the content body. > > If these three changes sound interesting I can start work on cleaning > up the code to be less specific to my company and then submit the > changes. Also I would like to know if there is any process I should be > following when submitting these changes. > > Thanks, > > Nick Setzer > SimpliSafe, Inc. > 294 Washington Street, 9th Floor > Boston, MA 02108 > ------------------------------ Subject: Digest Footer mbed-tls mailing list mbed-tls(a)lists.trustedfirmware.org https://lists.trustedfirmware.org/mailman/listinfo/mbed-tls ------------------------------ End of mbed-tls Digest, Vol 5, Issue 15 ***************************************

5 years, 8 months

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Re: [mbed-tls] [Mbed-tls-announce] Force push on the master branch

by Gilles Peskine

On 20/07/2020 12:21, Scott Branden via mbed-tls wrote: > Although this particular change doesn't affect me - rewriting history is a > bad idea. > > Why not simply commit a revert back to a cleaner point on "master" branch > and then commit the new changes you want from there? > > Then history is not lost on master branch. Mbed TLS used to follow the Git Flow model: day-to-day work happens on the 'development' branch, and there's a 'master' branch which always points to the latest commit on master that's a tagged release. A release is done by tagging a commit on 'development' and fast-forwarding 'master' to it. But after the 2.16 LTS release, we made 'master' follow the 2.16 LTS branch rather than 'development'. I think this was a mistake, but it's too late to change this, the question is what we do now with the existing situation. A force-push on 'master' would not erase history from the face of the world. The history is still there in 'mbedtls-2.16'. It is no longer possible to fast-forward 'master' to any commit on 'development'. No amount of revert or merge commits on 'master' will make it be the same commit as some a release made from 'development'. Without a force-push, all we can hope is to have 'master' have the same content as a release. This means that getting the same release would give you the same content, but different history, depending on whether tyou get it from 'master' or 'development'. This would also mean a more complicated release process. Another solution would be to do a merge of 'master' into 'development', ignoring all changes from the 'master' side. But this would mess up the history on 'development'. Is this more complicated release process, or this messy history, worth it, just to avoid a force-push? > Or, with the BLM movement some repos are stopping use of master branch. > github seems to be encourage it going forware: > https://www.zdnet.com/article/github-to-replace-master-with-alternative-ter… > > So another option: stop using "master" branch. You could even create a > tag/rename and then delete the branch name to avoid any confusions. History > won't be rewritten then, just a little "hidden". > And start using a new "main" branch. You can push you entire commit series > there without revering anything on master branch. Sure, we can create a new branch name. But then we'd still have to keep a branch with the old name, for the sake of existing setups that pull from 'master'. Or else we should make a commit on 'master' that removes every file and instead adds a README that says "pull from 'main' instead". -- Gilles Peskine Mbed TLS developer

5 years, 8 months

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Re: [mbed-tls] patches for low memory

by Gilles Peskine

On 22/07/2020 17:35, Gilles Peskine via mbed-tls wrote: > I just need to warn you that the limiting factor is reviewers' time. For a > significant contribution, it may take a while before the Mbed TLS team > can look at it in detail. Small patches are usually easier than large > ones: if something only takes half an hour to review, someone will > probably do it when they're stuck on some other task. If a review takes > several days, it needs to be scheduled. As an aside, Mbed TLS is under the governance of TrustedFirmware. Currently, only Arm employees are consider trusted reviewers, but this is not by policy, it's only due to the history of the project (until a few months ago, Mbed TLS was governed by Arm). We (as in, the Arm employees working on Mbed TLS) welcome design and code reviews from everyone. We don't yet have a formal process for becoming a “trusted” reviewer, beyond the general principles of TrustedFirmware. But a required part of that process will undoubtedly be to have done some reviews before. As every project, there is an informal, unwritten culture. If there's interest, we can try to document our review culture in writing. If I had to sum it up in one sentence, I'd say that if a reviewer should reject code that they don't understand: it's the job of the patch author to convince reviewers that the patch is good. “I don't see anything wrong” is not a good enough standard. -- Gilles Peskine Mbed TLS developer

5 years, 8 months

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Re: [mbed-tls] patches for low memory

by Gilles Peskine

Hi Nick, A TLS stack in 6kB of RAM sounds impressive, congratulations! We'd certainly be interested in all the improvements you can contribute. The process is documented in CONTRIBUTING.md (https://github.com/ARMmbed/mbedtls/blob/development/CONTRIBUTING.md). I just need to warn you that the limiting factor is reviewers' time. For a significant contribution, it may take a while before the Mbed TLS team can look at it in detail. Small patches are usually easier than large ones: if something only takes half an hour to review, someone will probably do it when they're stuck on some other task. If a review takes several days, it needs to be scheduled. It would probably be better to discuss the general nature of the changes on this mailing list first. Is a new compilation option needed? Is an API change needed? What is the risk that the change might break existing code? How is the new code tested? etc. Which version of Mbed TLS have you been using? We've made a few changes that are of interest to low-memory platforms recently, such as the option MBEDTLS_SSL_VARIABLE_BUFFER_LENGTH to resize SSL buffers after the handshake (new in 2.22). I don't know what the issue with the incoming SSL packet header length could be. If you could give precise steps to reproduce the issue, this would be very helpful. Eventually we'd want to construct a test in tests/ssl-opt.sh for this. -- Gilles Peskine Mbed TLS developer On 17/07/2020 21:00, Nick Setzer via mbed-tls wrote: > > Hi, I have been working with Mbed TLS for the last 6 months in an > extremely low memory use case. This library has been an absolute joy > to work with because of how flexible it is. I have an interesting use > case with how little RAM I have to work with (around 6kb on one > microprocessor) and I have made some changes that I thought would be > of interest. I'm not sure if I should submit them as a single > changeset or a set of changes. I'll describe the changes and if there > is interest I can clean them up for submission. > > The first change that I made was for a scenario with two > microprocessors communicating over a UART. I was already using TLS > offloading so that the private key was on one processor (with only 6kb > of RAM free) and the SSL context stored on the other. I required > generating a CSR and thus made some changes to the CSR code to be able > to generate the CSR using a similar private key offloading strategy. > > I found an issue with downloading firmware for OTA from openssl web > servers. This is a little tricky to describe. The server was not > responsive to requests for reducing the max fragment length, which > forced me to use MBEDTLS_SSL_MAX_CONTENT_LEN set to 16384. But I > needed to have multiple ssl sessions open for other activities and did > not have enough RAM to hold multiple large buffers. I have made a set > of changes to allow setting the content length when the ssl context is > initialized, as well as setting different IN and OUT content lengths > to save memory. This change allowed me to set up one session with 16kb > for the IN content length, and then 4kb for OUT content length, while > a second session could use 2kb for a total of 24kb instead of 64kb. > > Related to the openssl issue, I found that the incoming ssl packet > header length can sometimes be 8 or 16 bytes larger than expected > depending on which AES method is selected. I'm not actually sure what > the best way to solve this is. One way may be to change > MBEDTLS_SSL_HEADER_LEN from 13 to 29 bytes. However I ended up solving > it by adding 16 to both MBEDTLS_SSL_IN_BUFFER_LEN and > MBEDTLS_SSL_OUT_BUFFER_LEN. This way I could handle the larger ssl > header as well as receive the content body. > > If these three changes sound interesting I can start work on cleaning > up the code to be less specific to my company and then submit the > changes. Also I would like to know if there is any process I should be > following when submitting these changes. > > Thanks, > > Nick Setzer > SimpliSafe, Inc. > 294 Washington Street, 9th Floor > Boston, MA 02108 >

5 years, 8 months

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Re: [mbed-tls] SSH client sample

by Gilles Peskine

Hi Christie, Libssh2 (https://github.com/libssh2/libssh2) supports Mbed TLS. I've never used it or investigated it, so I can't vouch for it, I just know that it's there. -- Gilles Peskine Mbed TLS developer On 21/07/2020 18:40, Christie Su via mbed-tls wrote: > > Hi, > > ï¿½ > > I am using FRDM-K64F with LWIP+mbedTLS for our control system. Now, I > want to develop the SSH client(or telnet 22) to access my SSH server. > > ï¿½ > > Could you give me some indications how to do it? Or do you have any > sample project? > > ï¿½ > > Thanks, > > ï¿½ > > Christie > >

5 years, 8 months

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Problem with decrypt aes 128 in ecb mode. HELP ME!

by dany_banik2000＠yahoo.com

I developed a server application that obtains the data from a dht11 sensor, I encrypt it with aes 128 and publish it on the server. The client application makes a request to the server, and I would like to decrypt the answer. When I want to display decrypted message, it shows garbage The message retrieved from the server is in hex. I think that must to convert hex in binary, but i don’t know how can do it…

5 years, 8 months

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SSH client sample

by Christie Su

Hi, I am using FRDM-K64F with LWIP+mbedTLS for our control system. Now, I want to develop the SSH client(or telnet 22) to access my SSH server. Could you give me some indications how to do it? Or do you have any sample project? Thanks, Christie

5 years, 8 months

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patches for low memory

by Nick Setzer

Hi, I have been working with Mbed TLS for the last 6 months in an extremely low memory use case. This library has been an absolute joy to work with because of how flexible it is. I have an interesting use case with how little RAM I have to work with (around 6kb on one microprocessor) and I have made some changes that I thought would be of interest. I'm not sure if I should submit them as a single changeset or a set of changes. I'll describe the changes and if there is interest I can clean them up for submission. The first change that I made was for a scenario with two microprocessors communicating over a UART. I was already using TLS offloading so that the private key was on one processor (with only 6kb of RAM free) and the SSL context stored on the other. I required generating a CSR and thus made some changes to the CSR code to be able to generate the CSR using a similar private key offloading strategy. I found an issue with downloading firmware for OTA from openssl web servers. This is a little tricky to describe. The server was not responsive to requests for reducing the max fragment length, which forced me to use MBEDTLS_SSL_MAX_CONTENT_LEN set to 16384. But I needed to have multiple ssl sessions open for other activities and did not have enough RAM to hold multiple large buffers. I have made a set of changes to allow setting the content length when the ssl context is initialized, as well as setting different IN and OUT content lengths to save memory. This change allowed me to set up one session with 16kb for the IN content length, and then 4kb for OUT content length, while a second session could use 2kb for a total of 24kb instead of 64kb. Related to the openssl issue, I found that the incoming ssl packet header length can sometimes be 8 or 16 bytes larger than expected depending on which AES method is selected. I'm not actually sure what the best way to solve this is. One way may be to change MBEDTLS_SSL_HEADER_LEN from 13 to 29 bytes. However I ended up solving it by adding 16 to both MBEDTLS_SSL_IN_BUFFER_LEN and MBEDTLS_SSL_OUT_BUFFER_LEN. This way I could handle the larger ssl header as well as receive the content body. If these three changes sound interesting I can start work on cleaning up the code to be less specific to my company and then submit the changes. Also I would like to know if there is any process I should be following when submitting these changes. Thanks, Nick Setzer SimpliSafe, Inc. 294 Washington Street, 9th Floor Boston, MA 02108

5 years, 9 months

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Re: [mbed-tls] [Mbed-tls-announce] Force push on the master branch

by Scott Branden

Although this particular change doesn't affect me - rewriting history is a bad idea. Why not simply commit a revert back to a cleaner point on "master" branch and then commit the new changes you want from there? Then history is not lost on master branch. Or, with the BLM movement some repos are stopping use of master branch. github seems to be encourage it going forware: https://www.zdnet.com/article/github-to-replace-master-with-alternative-ter… So another option: stop using "master" branch. You could even create a tag/rename and then delete the branch name to avoid any confusions. History won't be rewritten then, just a little "hidden". And start using a new "main" branch. You can push you entire commit series there without revering anything on master branch. Regards, Scott -----Original Message----- From: Mbed-tls-announce [mailto:mbed-tls-announce-bounces@lists.trustedfirmware.org] On Behalf Of Janos Follath via Mbed-tls-announce Sent: Thursday, July 16, 2020 4:09 AM To: mbed-tls-announce(a)lists.trustedfirmware.org Cc: nd <nd(a)arm.com> Subject: [Mbed-tls-announce] Force push on the master branch Hi All, The master branch used to track the latest development release. This changed in early 2019 after the 2.16 LTS branch was released. Around this time the cryptography library of Mbed TLS was moved to a separate repository and since then it was used as a submodule. This was one of the main reasons behind the decision to keep master pointing to the 2.16 LTS releases. Recently we have merged the cryptography library back into Mbed TLS. We don't have any reasons any more to keep master tracking the 2.16 LTS release. Therefore we intend to update master to the latest development release. This will happen on 3rd August. The update will involve a force push, which can be disruptive to those users who take Mbed TLS from master. We would like to give such users enough time to adapt to this change. If you are relying on the master branch in a way that this force push affects you, please let us know on the developer mailing list<https://lists.trustedfirmware.org/mailman/listinfo/mbed-tls> and we will do our best to accommodate your needs. Thanks and regards, Janos (on behalf of the Mbed TLS maintainer team) -- Mbed-tls-announce mailing list Mbed-tls-announce(a)lists.trustedfirmware.org https://lists.trustedfirmware.org/mailman/listinfo/mbed-tls-announce

5 years, 9 months

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[Mbed-tls-announce] Force push on the master branch

by Janos Follath via Mbed-tls-announce

Hi All, The master branch used to track the latest development release. This changed in early 2019 after the 2.16 LTS branch was released. Around this time the cryptography library of Mbed TLS was moved to a separate repository and since then it was used as a submodule. This was one of the main reasons behind the decision to keep master pointing to the 2.16 LTS releases. Recently we have merged the cryptography library back into Mbed TLS. We don't have any reasons any more to keep master tracking the 2.16 LTS release. Therefore we intend to update master to the latest development release. This will happen on 3rd August. The update will involve a force push, which can be disruptive to those users who take Mbed TLS from master. We would like to give such users enough time to adapt to this change. If you are relying on the master branch in a way that this force push affects you, please let us know on the developer mailing list<https://lists.trustedfirmware.org/mailman/listinfo/mbed-tls> and we will do our best to accommodate your needs. Thanks and regards, Janos (on behalf of the Mbed TLS maintainer team) -- Mbed-tls-announce mailing list Mbed-tls-announce(a)lists.trustedfirmware.org https://lists.trustedfirmware.org/mailman/listinfo/mbed-tls-announce

5 years, 9 months

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Re: [mbed-tls] Upgrading from 2.13.1.to ??.??.??

by Manuel Pegourie-Gonnard

Hi Jeff, > Given the age of the version of mbedTLS I’m using, which is 2.13.1, plus the recent security alert, I think I need to upgrade the version of mbedTLS we have. The question is, which version to use? Indeed upgrading to a maintained branch is very recommended! There are currently two actively maintained branches you could use: * 2.16.x, which is our latest LTS branch, currently at 2.16.7. As an LTS branch, it only receives bug fixes and security updates, so it's pretty stable. In particular, since it doesn't receive any new feature, its footprint (code size) should remain mostly stable as well. * 2.x.y, released from the development branch, currently at 2.23.0. This is the branch where new features land. Both of these have full API compatibility with 2.13.1. We take great care not to break API compatibility between major releases - we haven't broken it since Mbed TLS 2.0.0 (release 2015-07-13), and the next release to break API compatibility with be 3.0.0 (now planned for early 2021). Until then, upgrading should be a simple matter of replacing the mbedtls directory in your source tree with the version of your choice, then rebuilding your project. (Moreover in the LTS branches we actually try maintain ABI compatibility as far as possible - that is, unless there's a security issue that can only be fixed by changing the ABI.) Mbed TLS is designed bo be quite modular an integrate with the OS and networking stack via user-provided hooks and compile-time configuration (`include/mbedtls/config.h`). I'm not sure how the integration with LwIP and FreeRTOS was done by your MCU vendor, but I suggest you check: * is the mbedtls directory in your source tree identical to our upstream release? If yes, you should be able to just replace it with the release of your choice and things should work. * otherwise, what's the nature of the differences: are filed shuffled to a different directory structure? is the build system different? has the `mbedtls/config.h` file been modified? have other files been modified (which ideally really shouldn't be necessary)? In that case, you'll probably need to apply the same changes to the upgraded version of Mbed TLS. Hopefully the differences if any will be small, and otherwise perhaps you MCU vendor can provide documentation about it. So I can't really say for this specific integration, but in principle upgrading Mbed TLS should be really painless - precisely so that people can upgrade easily in case of security fixes. Hope this helps, and let us know how it went! Regards, Manuel. ________________________________ From: mbed-tls <mbed-tls-bounces(a)lists.trustedfirmware.org> on behalf of Thompson, Jeff via mbed-tls <mbed-tls(a)lists.trustedfirmware.org> Sent: 14 July 2020 22:11 To: mbed-tls(a)lists.trustedfirmware.org <mbed-tls(a)lists.trustedfirmware.org> Subject: [mbed-tls] Upgrading from 2.13.1.to ??.??.?? Given the age of the version of mbedTLS I’m using, which is 2.13.1, plus the recent security alert, I think I need to upgrade the version of mbedTLS we have. The question is, which version to use? Because we got mbedTLS as example code from the MCU vendor, it was already integrated with lwIP and FreeRTOS. I’m sure this will not be a trivial effort, but I do need to present my management with some idea of the time it could take. Does anyone have a rough estimate of what to expect? I’m thinking on the order of 2 to 4 weeks for someone who is an experienced C programmer, but unfamiliar with either mbedTLS or lwIP. Or is that a pipe dream, with the actual time being closer to 3 or 4 months? Jeff Thompson | Senior Electrical Engineer-Firmware +1 704 752 6513 x1394 www.invue.com [cid:image001.gif@01D659E2.BE6C0700]

5 years, 9 months

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Upgrading from 2.13.1.to ??.??.??

by Thompson, Jeff

Given the age of the version of mbedTLS I'm using, which is 2.13.1, plus the recent security alert, I think I need to upgrade the version of mbedTLS we have. The question is, which version to use? Because we got mbedTLS as example code from the MCU vendor, it was already integrated with lwIP and FreeRTOS. I'm sure this will not be a trivial effort, but I do need to present my management with some idea of the time it could take. Does anyone have a rough estimate of what to expect? I'm thinking on the order of 2 to 4 weeks for someone who is an experienced C programmer, but unfamiliar with either mbedTLS or lwIP. Or is that a pipe dream, with the actual time being closer to 3 or 4 months? Jeff Thompson | Senior Electrical Engineer-Firmware +1 704 752 6513 x1394 www.invue.com [cid:image001.gif@01D659E2.BE6C0700]

5 years, 9 months

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