1630688 - For emails with two nested S/MIME signatures the inner signed data isn't shown (e.g. PEC email).

Status: RESOLVED FIXED

(Thunderbird :: Message Reader UI, defect)

Description

[massimo marin]

Attachment: POSTA CERTIFICATA Messaggio PEC inoltrato [POSTA CERTIFICATA x max].eml

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:75.0) Gecko/20100101 Firefox/75.0

Steps to reproduce:

• i open the new email and read body of email
• i open "postacert.eml" attachment and read body of email
• i open "copia.eml" attachment but it's shown as empty boby/attachment

Actual results:

"copia.email" is shown as empty body/attachment but by "view source" it's not empty so i need to save "copia.eml" on disk and then i can read the body and attachment of orginal email forwarded

Expected results:

"copia.eml" should be shown with body and attachments right not blank

Comment 1

[Firefox Bug Husbandry Bot]

Resetting severity to default of --.

Comment 2

[Firefox Bug Husbandry Bot]

Because this bug's Severity has not been changed from the default since it was filed, and it's Priority is -- (Backlog,) indicating it has has not been previously triaged, the bug's Severity is being updated to -- (default, untriaged.)

Comment 3

[Wayne Mery (:wsmwk)]

Reporter, do. you still see this when using version 78?

Comment 4

[Phoenix]

Resolved per whiteboard

Comment 5

[Luca]

Hi,
I am having the same issue with others Italian PEC and confirm the above attachment "POSTA CERTIFICATA Messaggio PEC inoltrato [POSTA CERTIFICATA x max].eml" still have the issue with

Thunderbird 78.14.0 debian stable
Thunderbird-91.1_20210924213438.AppImage downloaded from https://github.com/srevinsaju/thunderbird-appimage/releases

I try to explain again the steps:

• Open POSTA CERTIFICATA Messaggio PEC inoltrato [POSTA CERTIFICATA x max].eml
  Here only 2 attachments are shown (postacert.eml and copia.eml, total size 2.5 kB) and the body text of copia.eml is empty.
  Opening copia.eml shows an empty message (no attachments and inline text)
• Save postacert.eml to disk and open it from there.
  postacert.eml now shows 4 attachments (one is a RN-TB.pdf, total size 1.1 MB)

I also attach some screenshots

Only few of these email have this issue, but in Italy they are considered "Registered mail" with legal value as soon as they are received (so even if you do not open or read)

Thanks

Comment 6

[Luca]

Attachment: 1_not every attachments is shown

Comment 7

[Luca]

Attachment: 2_opening copia.eml show an empy body and no attachments

Comment 8

[Luca]

Attachment: 3_after saving to disk and opening it, full boby and attachments are present

Comment 9

[Wayne Mery (:wsmwk)]

luca are you able to reproduce using version 91?

Comment 10

[massimo marin]

hi

issue still present even with TB 91.4.1 (64 bit)

MM

Comment 11

[massimo marin]

Attachment: POSTA CERTIFICATA Messaggio PEC inoltrato [POSTA CERTIFICATA x max] - 'Per conto di [e-mail]' ([e-mail]) - 2022-01-05 0854.eml

Comment 12

[Luca]

(In reply to Wayne Mery (:wsmwk) from comment #9)

luca are you able to reproduce using version 91?

As for me the issue persist with Thunderbird-91.4_20211216022855.AppImage (it's 91.4.1 as previous report)

Comment 13

[Luca]

still present with Thuderdirb 102.3.0 (debian stable)

Comment 14

[Magnus Melin [:mkmelin]]

Perhaps Kai has some idea.

Comment 15

[Kai Engert [:KaiE:]]

I'm sorry that I haven't been able to investigate this bug earlier.
I've started to investigate today.

Comment 16

[Kai Engert [:KaiE:]]

In the given examples, an email has another email attached.
When trying to open the nested email, we don't show the message contents.

There are two S/MIME signatures involved here. A signature for the outer layer, and another signature for an inner layer.

I performed a few experiments by manually modifying the messages.

Experiment 1:
If I remove the outer S/MIME signature, and keep everything else, we correctly show all parts of the message.

Experiment 2:
If I remove the inner S/MIME signature, and keep everything else, we also correctly show all parts of the message.

I need to investigate how the presence of more than one S/MIME signature causes the incorrect message processing.

Comment 17

[Kai Engert [:KaiE:]]

Attachment: 1630688-repro.eml

Minimal testcase.

The text "level 2" from the attached message is not shown.
The text should be shown after we fix the bug.

Comment 18

[Kai Engert [:KaiE:]]

Attachment: 1630688-no-inner-sig.eml

This is a modified version of the minimal testcase.
The inner S/MIME signature layer is removed.
The "level 2" text is shown.

This demonstrates that we can show the contents of nested messages in general, but this bug (triggered by the second signature) prevents it from being shown.

Comment 19

[Kai Engert [:KaiE:]]

Attachment: Bug 1630688 - Better handling of nested S/MIME signatures. r=mkmelin

Comment 20

[Kai Engert [:KaiE:]]

I have a fix. It works on the esr102 branch.
I'll test comm-central soon, too.

Comment 21

[Kai Engert [:KaiE:]]

TODO. Turn the attached testcase into an automated test (check that text "level 2" is shown).

Comment 22

[Kai Engert [:KaiE:]]

Attachment: Bug 1630688 - Test rendering of nested message with nested S/MIME signature. r=mkmelin

Comment 23

[Kai Engert [:KaiE:]]

Test is trivial. Maybe we can get both fix and test checked in before the Monday merge?

Comment 24

[Kai Engert [:KaiE:]]

I was too optimistic, test doesn't work on comm-central.

Comment 25

[Kai Engert [:KaiE:]]

Ok, test patch updated to work on c-c.

Comment 26

[Kai Engert [:KaiE:]]

Attachment: 1630688-test-esr102.patch

Comment 27

[Kai Engert [:KaiE:]]

This missed the merge, I'd like to nominate for beta once landed.

Comment 28

[Kai Engert [:KaiE:]]

(In reply to Kai Engert (:KaiE:) from comment #27)

This missed the merge, I'd like to nominate for beta once landed.

Well, we're close to the next beta cycle, so probably sufficient to have it ride the train to beta.

Comment 29

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/comm-central/rev/dbe439ccd783
Better handling of nested S/MIME signatures. r=mkmelin
https://hg.mozilla.org/comm-central/rev/1574b0e6b27d
Test rendering of nested message with nested S/MIME signature. r=mkmelin

Comment 30

[Kai Engert [:KaiE:]]

This breaks existing S/MIME unit tests.
We should back out, I need to carefully review how the existing tests should be adjusted.

Comment 31

[Pulsebot]

Backout by [e-mail]:
https://hg.mozilla.org/comm-central/rev/682d2ef4f057
Backed out changeset 1574b0e6b27d for causing test failures. r=backout DONTBUILD
https://hg.mozilla.org/comm-central/rev/34c8f6c951c0
Backed out changeset dbe439ccd783 for causing test failures. r=backout DONTBUILD

Comment 32

[Kai Engert [:KaiE:]]

https://hg.mozilla.org/comm-central/rev/dbe439ccd783
Better handling of nested S/MIME signatures. r=mkmelin

This revision (now backed out) had caused an unwanted change of behavior in some scenarios.

If a message contained two S/MIME signatures (outer and inner), we had always reported the message as having an invalid signature.
(This makes sense, if an attacker wraps their own signature around encrypted contents they cannot read, the attacker's signature shouldn't be shown as valid on the decrypted contents.)

However, the above revision would allow exactly that to happen, so I'm glad the test caught that change in behavior.

I'll update the patch to always report a broken signature status for the nested scenarios.

Comment 33

[Kai Engert [:KaiE:]]

If this try run works we can land again.
https://treeherder.mozilla.org/jobs?repo=try-comm-central&revision=5249ac353e464233bd31c42be09ccedce12ef51c

Comment 34

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/comm-central/rev/e3bf99432ff8
Better handling of nested S/MIME signatures. r=mkmelin
https://hg.mozilla.org/comm-central/rev/e14039312c0a
Test rendering of nested message with nested S/MIME signature. r=mkmelin