| Message ID | cover.1605642949.git.dxu@dxuuu.xyz (mailing list archive) |
|---|---|
| Headers | show |
| Series | Fix bpf_probe_read_user_str() overcopying | expand |
Hello: This series was applied to bpf/bpf.git (refs/heads/master): On Tue, 17 Nov 2020 12:05:44 -0800 you wrote: > 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. > > [...] Here is the summary with links: - [bpf,v7,1/2] lib/strncpy_from_user.c: Don't overcopy bytes after NUL terminator https://git.kernel.org/bpf/bpf/c/33b97ea52713 - [bpf,v7,2/2] selftest/bpf: Test bpf_probe_read_user_str() strips trailing bytes after NUL https://git.kernel.org/bpf/bpf/c/a8005439fc81 You are awesome, thank you! -- Deet-doot-dot, I am a bot. https://korg.docs.kernel.org/patchwork/pwbot.html
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. v6 -> v7: * Add comments v5 -> v6: * zero-pad up to sizeof(unsigned long) after NUL v4 -> v5: * don't read potentially uninitialized memory v3 -> v4: * directly pass userspace pointer to prog * test more strings of different length v2 -> v3: * set pid filter before attaching prog in selftest * use long instead of int as bpf_probe_read_user_str() retval * style changes v1 -> v2: * add Fixes: tag * add selftest 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 kernel/trace/bpf_trace.c | 10 +++ lib/strncpy_from_user.c | 19 ++++- .../bpf/prog_tests/probe_read_user_str.c | 71 +++++++++++++++++++ .../bpf/progs/test_probe_read_user_str.c | 25 +++++++ 4 files changed, 123 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