linux-kernel - Re: [PATCH bpf v4 1/2] lib/strncpy_from_user.c: Don't overcopy bytes after NUL terminator

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Message-Id: <160493940533.2913.16972160195346742271.git-patchwork-notify@kernel.org>
Date:   Mon, 09 Nov 2020 16:30:05 +0000
From:   patchwork-bot+netdevbpf@...nel.org
To:     Daniel Xu <dxu@...uu.xyz>
Cc:     bpf@...r.kernel.org, linux-kernel@...r.kernel.org, ast@...nel.org,
        daniel@...earbox.net, songliubraving@...com,
        andrii.nakryiko@...il.com, kernel-team@...com
Subject: Re: [PATCH bpf v4 1/2] lib/strncpy_from_user.c: Don't overcopy bytes
 after NUL terminator

Hello:

This series was applied to bpf/bpf.git (refs/heads/master):

On Thu,  5 Nov 2020 16:06:34 -0800 you wrote:
> do_strncpy_from_user() may copy some extra bytes after the NUL
> terminator into the destination buffer. This usually does not matter for
> normal string operations. However, when BPF programs key BPF maps with
> strings, this matters a lot.
> 
> A BPF program may read strings from user memory by calling the
> bpf_probe_read_user_str() helper which eventually calls
> do_strncpy_from_user(). The program can then key a map with the
> resulting string. BPF map keys are fixed-width and string-agnostic,
> meaning that map keys are treated as a set of bytes.
> 
> [...]

Here is the summary with links:
  - [bpf,v4,1/2] lib/strncpy_from_user.c: Don't overcopy bytes after NUL terminator
    https://git.kernel.org/bpf/bpf/c/baca7f1c1c1e
  - [bpf,v4,2/2] selftest/bpf: Test bpf_probe_read_user_str() strips trailing bytes after NUL
    https://git.kernel.org/bpf/bpf/c/d18b184127de

You are awesome, thank you!
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