From: Daniel Xu <dxu@dxuuu.xyz>
To: bpf@vger.kernel.org, linux-kernel@vger.kernel.org,
ast@kernel.org, daniel@iogearbox.net
Cc: Daniel Xu <dxu@dxuuu.xyz>, kernel-team@fb.com
Subject: [PATCH bpf v2 0/2] Fix bpf_probe_read_user_str() overcopying
Date: Wed, 4 Nov 2020 18:25:36 -0800 [thread overview]
Message-ID: <cover.1604542786.git.dxu@dxuuu.xyz> (raw)
6ae08ae3dea2 ("bpf: Add probe_read_{user, kernel} and probe_read_{user,
kernel}_str helpers") introduced a subtle bug where
bpf_probe_read_user_str() would potentially copy a few extra bytes after
the NUL terminator.
This issue is particularly nefarious when strings are used as map keys,
as seemingly identical strings can occupy multiple entries in a map.
This patchset fixes the issue and introduces a selftest to prevent
future regressions.
Daniel Xu (2):
lib/strncpy_from_user.c: Don't overcopy bytes after NUL terminator
selftest/bpf: Test bpf_probe_read_user_str() strips trailing bytes
after NUL
lib/strncpy_from_user.c | 9 ++-
.../bpf/prog_tests/probe_read_user_str.c | 60 +++++++++++++++++++
.../bpf/progs/test_probe_read_user_str.c | 34 +++++++++++
3 files changed, 101 insertions(+), 2 deletions(-)
create mode 100644 tools/testing/selftests/bpf/prog_tests/probe_read_user_str.c
create mode 100644 tools/testing/selftests/bpf/progs/test_probe_read_user_str.c
--
2.28.0
next reply other threads:[~2020-11-05 2:26 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-05 2:25 Daniel Xu [this message]
2020-11-05 2:25 ` [PATCH bpf v2 1/2] lib/strncpy_from_user.c: Don't overcopy bytes after NUL terminator Daniel Xu
2020-11-05 9:00 ` David Laight
2020-11-05 18:16 ` Song Liu
2020-11-05 18:18 ` Song Liu
2020-11-05 19:28 ` Daniel Xu
2020-11-05 2:25 ` [PATCH bpf v2 2/2] selftest/bpf: Test bpf_probe_read_user_str() strips trailing bytes after NUL Daniel Xu
2020-11-05 18:30 ` Song Liu
2020-11-05 19:27 ` Daniel Xu
2020-11-05 21:32 ` Andrii Nakryiko
2020-11-05 23:22 ` Daniel Xu
2020-11-05 23:31 ` Song Liu
2020-11-05 23:55 ` Daniel Xu
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