1141885 - Make readlink() fail instead of allowing it, for B2G content processes

Status: RESOLVED FIXED

(Core :: Security: Process Sandboxing, defect)

Description

[Jed Davis [:jld] ⟨⏰|UTC-7⟩ ⟦he/him⟧]

We're currently letting B2G content processes call readlink(), because WebRTC wants to do crypto in the content process, and NSS can't do that without trying to load a PKCS#11 library, and that wants to use readlink (misuse, really; it looks like it will fail entertainingly if it ever encounters relative symlinks).  And for some reason we can't easily get rid of the PKCS#11 thing, which very much does not belong in a content process under any circumstance, if I correctly understand what it is.

But it's not actually going to encounter a symlink, at least not on B2G.  So we can just have readlink always fail with EINVAL.  Empirically, WebRTC still works with this change; I'll also run Try.

It will save me some work if I don't actually have to remote readlink() in bug 930258.

Comment 1

[Jed Davis [:jld] ⟨⏰|UTC-7⟩ ⟦he/him⟧]

Attachment: bug1141885-fail-readlink-hg0.diff

Try run: https://treeherder.mozilla.org/#/jobs?repo=try&revision=069fb653a21f

Comment 2

[Guillaume Destuynder [:kang] [this account is no longer active]]

Comment on attachment 8576203 [details] [diff] [review]
bug1141885-fail-readlink-hg0.diff

Review of attachment 8576203 [details] [diff] [review]:
-----------------------------------------------------------------

more woohoo :)

Comment 3

[Jed Davis [:jld] ⟨⏰|UTC-7⟩ ⟦he/him⟧]

Attachment: bug1141885-fail-readlink-hg1.diff

Rebased (would conflict with bug 906996).  Carrying over r+.  Try run: https://treeherder.mozilla.org/#/jobs?repo=try&revision=374c094a84df

Also tested locally with an app that uses window.crypto.subtle.

Comment 4

[Jed Davis [:jld] ⟨⏰|UTC-7⟩ ⟦he/him⟧]

Try run in comment #3 seems to have passed as much as it can be expected to.

Comment 5

[Carsten Book [:Tomcat]]

https://hg.mozilla.org/integration/mozilla-inbound/rev/093b0a844c3b

Comment 6

[Carsten Book [:Tomcat]]

https://hg.mozilla.org/mozilla-central/rev/093b0a844c3b