[tbb-bugs] #21448 [Applications/Tor Browser]: Identify what build flags we should be using for security, and use them

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#21448: Identify what build flags we should be using for security, and use them
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 Reporter:  arthuredelstein           |          Owner:  tbb-team
     Type:  defect                    |         Status:  new
 Priority:  Medium                    |      Milestone:
Component:  Applications/Tor Browser  |        Version:
 Severity:  Normal                    |     Resolution:
 Keywords:  tbb-security              |  Actual Points:
Parent ID:                            |         Points:
 Reviewer:                            |        Sponsor:
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Old description:

> I think we may be able to add some configure/compiler/linker flags in Tor
> Browser that can improve security without many downsides. Let's figure
> out what those are and add them. I would suggest child tickets for each
> new flag, so we can do this step by step.

New description:

 I think we may be able to add some configure/compiler/linker flags in Tor
 Browser that can improve security without many downsides. Let's figure out
 what those are and add them.

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Comment (by arthuredelstein):

 Here are my thoughts for flags we can add to the gcc-based builds (Linux
 and mingw). (I think we should be able to add similar flags to the clang
 based builds -- I will look into that after we settle on flags to add to
 gcc.)
 {{{
 -Werror=format
 -Werror=format-security
 -fstack-protector-strong
 --param ssp-buffer-size=4
 -pie -fPIE
 -D_FORTIFY_SOURCE=2 -O1
 -Wl,-z,relro,-z,now
 -ftrapv
 }}}

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/21448#comment:6>
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