1813424 - (CVE-2023-25742) Web Crypto ImportKey crashes tab

Status: RESOLVED FIXED

(Core :: DOM: Web Crypto, defect)

Description

[Francesco Gorini]

Attachment: WebCrypto-crash-ff.png

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:105.0) Gecko/20100101 Firefox/105.0

Steps to reproduce:

Import an SPKI RSA Public Key but specify the type of the key as ECDSA P-256.

try {
await crypto.subtle.importKey(
"spki",
Buffer.from(pem, 'base64'),
{
name: "ECDSA",
namedCurve: curve
},
false,
["verify"]
);
} catch (err) {
console.error(err);
}

Contents of the pem variable:

MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAs6kchlNLKPbvVTJrAhPP
B+b1JMODYEmVLS6jBBltlN4asrVzUIxstVzbmhElDBkWnqM0VsCqrgTGK/iCu4Hd
/Io8oABQlWvH+M/2Pync7HBtvXZcGCz9RXRTBaTlpAe8eR6CJjT0YmQOOFUXxUsf
95/hLOf2hSryelC+kIf0nCRCkHEUqpNdc8YUXDLnzoMWyClfsisn0lwmVWweWIuK
3CjmiDUP5O9zh7fiZpCRerr3emYCYjLtZfw3qeweDclSmVwErS2qPXgQw4L8DV5D
8oZZT01ckLZGIs3OTYxiUDvsHxLaNdmN0WnbsDiKBcqj7A3uMN6MkrWW/2d0uEwN
swIDAQAB

Actual results:

The tab crashed (as per screenshot).

Expected results:

I understand that this is caused by a misuse of the Webcrypto library.
However I believe an Error or Exception should be thrown instead of a crash.

Comment 1

[Dana Keeler (she/her) (use needinfo) [:keeler] (on leave)]

Attachment: Bug 1813424 - webcrypto: check decoded key type before using r?jschanck

Comment 2

[Sebastian Hengst [:aryx] (needinfo me if it's about an intermittent or backout)]

webcrypto: check decoded key type before using r=jschanck
https://hg.mozilla.org/integration/autoland/rev/8bd422f4177126ef4249894d0124c40a34f1b022
https://hg.mozilla.org/mozilla-central/rev/8bd422f41771

Comment 3

[Ryan VanderMeulen [:RyanVM]]

Is the S1 severity on this bug correct? From the docs:

(Catastrophic) Blocks development/testing, may impact more than 25% of users, causes data loss, likely dot release driver, and no workaround available

Also, please nominate this for uplift if this is something you thing we need to fix across other branches as well. It grafts cleanly.

Comment 4

[Dana Keeler (she/her) (use needinfo) [:keeler] (on leave)]

No - I set that out of an abundance of caution. Somewhere between S2/3 is appropriate - it's mostly a denial-of-service issue, although there's a slight chance it could be exploited for something more serious, like an attacker reading memory they're not supposed to be able to.

Comment 5

[Dana Keeler (she/her) (use needinfo) [:keeler] (on leave)]

Comment on attachment 9315250 [details]
Bug 1813424 - webcrypto: check decoded key type before using r?jschanck

Beta/Release Uplift Approval Request

• User impact if declined: Mostly looks like a potential denial-of-service (crashing tabs). There's a possibility it could be used to read memory that otherwise wouldn't be accessible.
• Is this code covered by automated tests?: Yes
• Has the fix been verified in Nightly?: Yes
• Needs manual test from QE?: No
• If yes, steps to reproduce:
• List of other uplifts needed: None
• Risk to taking this patch: Low
• Why is the change risky/not risky? (and alternatives if risky): The changes are very minimal, localized, and fairly clearly correct.
• String changes made/needed: none
• Is Android affected?: Yes

ESR Uplift Approval Request

• If this is not a sec:{high,crit} bug, please state case for ESR consideration: Mostly looks like a potential denial-of-service (crashing tabs). There's a possibility it could be used to read memory that otherwise wouldn't be accessible.
• User impact if declined: ^
• Fix Landed on Version: 111
• Risk to taking this patch: Low
• Why is the change risky/not risky? (and alternatives if risky): The changes are very minimal, localized, and fairly clearly correct.

Comment 6

[Pascal Chevrel:pascalc (PTO until April 26)]

Comment on attachment 9315250 [details]
Bug 1813424 - webcrypto: check decoded key type before using r?jschanck

Approved for our last 110 beta, thanks.

Comment 7

[Pascal Chevrel:pascalc (PTO until April 26)]

https://hg.mozilla.org/releases/mozilla-beta/rev/ec02782eba77

Comment 8

[Pascal Chevrel:pascalc (PTO until April 26)]

Comment on attachment 9315250 [details]
Bug 1813424 - webcrypto: check decoded key type before using r?jschanck

Approved for ESR 102.8.0, thanks.

Comment 9

[Pascal Chevrel:pascalc (PTO until April 26)]

https://hg.mozilla.org/releases/mozilla-esr102/rev/e31f59bc107f

Comment 10

[Tom Ritter [:tjr] (OOTO until 4/30 at least)]

Attachment: advisory.txt