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x86/fsgsbase/64: Fix NULL deref in 86_fsgsbase_read_task]

PATCH In review Ingo Molnar 2 participants 2 messages Aug 15, 2020 – Aug 16, 2020 Stable branch

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Ingo Molnar

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PATCH 1/1 x86/fsgsbase/64: Fix NULL deref in 86_fsgsbase_read_task]

hi Greg,

Please apply upstream 8ab49526b53d to all stable kernels containing 07e1d88adaae, which should be v4.20 and higher stable kernels.

Thanks,

Ingo

----- Forwarded message from Eric Dumazet <[email protected]> -----

Date: Sat, 15 Aug 2020 10:38:58 -0700
From: Eric Dumazet <[email protected]>
To: Ingo Molnar <[email protected]>
Cc: linux-kernel <[email protected]>, Eric Dumazet <[email protected]>, Jann Horn <[email protected]>, syzbot <[email protected]>, Andy Lutomirski <[email protected]>, "Chang S . Bae" <[email protected]>, Andy Lutomirski <[email protected]>,
Borislav Petkov <[email protected]>, Brian Gerst <[email protected]>, Dave Hansen <[email protected]>, Denys Vlasenko <[email protected]>, "H . Peter Anvin" <[email protected]>, Linus Torvalds <[email protected]>, Markus T Metzger <[email protected]>, Peter Zijlstra <[email protected]>, Ravi Shankar <[email protected]>, Rik van Riel <[email protected]>, Thomas Gleixner <[email protected]>
Subject: Re: [PATCH] x86/fsgsbase/64: Fix NULL deref in 86_fsgsbase_read_task

Quoted 8 lines · Ingo Molnar
Quoted 3 lines · Eric Dumazet

syzbot found its way in 86_fsgsbase_read_task() [1]

Fix is to make sure ldt pointer is not NULL.

Quoted 8 lines

Thanks for this fix. Linus has picked it up (inclusive the typos to the x86_fsgsbase_read_task() function name ;-), it's now upstream under:

8ab49526b53d: ("x86/fsgsbase/64: Fix NULL deref in 86_fsgsbase_read_task")

By the fixes tag it looks like this should probably be backported all the way back to ~v4.20 or so?

This is absolutely right, sorry about the lack of a stable tag.

Most of my patches usually land into David Miller trees, where the stable tag is not welcomed.
We use Fixes: tags to convey the exact information needed for stable backports.

Thanks.

----- End forwarded message -----

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Quoted 5 lines · Ingo Molnar

hi Greg,

Please apply upstream 8ab49526b53d to all stable kernels containing 07e1d88adaae, which should be v4.20 and higher stable kernels.

I've picked it all the way up to 4.14, as 07e1d88adaae was backported that far.

Signature · 2 lines
Thanks,
Sasha