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| author |   Daniel Borkmann <daniel@iogearbox.net> | 2019-11-02 00:17:58 +0100 |
|---|---|---|
| committer |   Alexei Starovoitov <ast@kernel.org> | 2019-11-02 12:39:12 -0700 |
| commit | eb1b66887472eaa7342305b7890ae510dd9d1a79 (patch) | |
| tree | 33746a5e6c4bea68a4f2b8f91cf4b6c2e816608f /kernel | |
| parent | uaccess: Add strict non-pagefault kernel-space read function (diff) | |
| download | linux-dev-eb1b66887472eaa7342305b7890ae510dd9d1a79.tar.xz linux-dev-eb1b66887472eaa7342305b7890ae510dd9d1a79.zip | |
bpf: Make use of probe_user_write in probe write helper
Convert the bpf_probe_write_user() helper to probe_user_write() such that
writes are not attempted under KERNEL_DS anymore which is buggy as kernel
and user space pointers can have overlapping addresses. Also, given we have
the access_ok() check inside probe_user_write(), the helper doesn't need
to do it twice.
Fixes: 96ae52279594 ("bpf: Add bpf_probe_write_user BPF helper to be called in tracers")
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/841c461781874c07a0ee404a454c3bc0459eed30.1572649915.git.daniel@iogearbox.net
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/trace/bpf_trace.c | 6 |
1 files changed, 2 insertions, 4 deletions
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index f50bf19f7a05..2d87fcdcb19b 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -163,7 +163,7 @@ static const struct bpf_func_proto bpf_probe_read_proto = { .arg3_type = ARG_ANYTHING, }; -BPF_CALL_3(bpf_probe_write_user, void *, unsafe_ptr, const void *, src, +BPF_CALL_3(bpf_probe_write_user, void __user *, unsafe_ptr, const void *, src, u32, size) { /* @@ -186,10 +186,8 @@ BPF_CALL_3(bpf_probe_write_user, void *, unsafe_ptr, const void *, src, return -EPERM; if (unlikely(!nmi_uaccess_okay())) return -EPERM; - if (!access_ok(unsafe_ptr, size)) - return -EPERM; - return probe_kernel_write(unsafe_ptr, src, size); + return probe_user_write(unsafe_ptr, src, size); } static const struct bpf_func_proto bpf_probe_write_user_proto = { |