Merge branch 'Fix bpf_probe_read_user_str() overcopying'
Daniel Xu says: ==================== 6ae08ae3 ("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 ==================== Signed-off-by:Alexei Starovoitov <ast@kernel.org>
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