| Message ID | 20230628115329.248450-9-laoar.shao@gmail.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | bpf: Support ->fill_link_info for kprobe_multi and perf_event links | expand |
On Wed, Jun 28, 2023 at 4:53 AM Yafang Shao <laoar.shao@gmail.com> wrote: > > Add a new helper bpf_perf_link_fill_common(), which will be used by > perf_link based tracepoint, kprobe and uprobe. > > Signed-off-by: Yafang Shao <laoar.shao@gmail.com> > --- > kernel/bpf/syscall.c | 34 ++++++++++++++++++++++++++++++++++ > 1 file changed, 34 insertions(+) > > diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c > index 4aa6e5776a04..72de91beabbc 100644 > --- a/kernel/bpf/syscall.c > +++ b/kernel/bpf/syscall.c > @@ -3364,6 +3364,40 @@ static void bpf_perf_link_dealloc(struct bpf_link *link) > kfree(perf_link); > } > > +static int bpf_perf_link_fill_common(const struct perf_event *event, > + char __user *uname, u32 ulen, > + u64 *probe_offset, u64 *probe_addr, > + u32 *fd_type) > +{ > + const char *buf; > + u32 prog_id; > + size_t len; > + int err; > + > + if (!ulen ^ !uname) > + return -EINVAL; > + if (!uname) > + return 0; > + > + err = bpf_get_perf_event_info(event, &prog_id, fd_type, &buf, > + probe_offset, probe_addr); > + if (err) > + return err; > + > + len = strlen(buf); > + if (buf) { if buf is NULL, strlen above will crash, so you need to calculate len inside this if branch > + err = bpf_copy_to_user(uname, buf, ulen, len); > + if (err) > + return err; > + } else { > + char zero = '\0'; > + > + if (put_user(zero, uname)) > + return -EFAULT; > + } > + return 0; > +} > + > static const struct bpf_link_ops bpf_perf_link_lops = { > .release = bpf_perf_link_release, > .dealloc = bpf_perf_link_dealloc, > -- > 2.39.3 >
On Fri, Jul 7, 2023 at 6:00 AM Andrii Nakryiko <andrii.nakryiko@gmail.com> wrote: > > On Wed, Jun 28, 2023 at 4:53 AM Yafang Shao <laoar.shao@gmail.com> wrote: > > > > Add a new helper bpf_perf_link_fill_common(), which will be used by > > perf_link based tracepoint, kprobe and uprobe. > > > > Signed-off-by: Yafang Shao <laoar.shao@gmail.com> > > --- > > kernel/bpf/syscall.c | 34 ++++++++++++++++++++++++++++++++++ > > 1 file changed, 34 insertions(+) > > > > diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c > > index 4aa6e5776a04..72de91beabbc 100644 > > --- a/kernel/bpf/syscall.c > > +++ b/kernel/bpf/syscall.c > > @@ -3364,6 +3364,40 @@ static void bpf_perf_link_dealloc(struct bpf_link *link) > > kfree(perf_link); > > } > > > > +static int bpf_perf_link_fill_common(const struct perf_event *event, > > + char __user *uname, u32 ulen, > > + u64 *probe_offset, u64 *probe_addr, > > + u32 *fd_type) > > +{ > > + const char *buf; > > + u32 prog_id; > > + size_t len; > > + int err; > > + > > + if (!ulen ^ !uname) > > + return -EINVAL; > > + if (!uname) > > + return 0; > > + > > + err = bpf_get_perf_event_info(event, &prog_id, fd_type, &buf, > > + probe_offset, probe_addr); > > + if (err) > > + return err; > > + > > + len = strlen(buf); > > + if (buf) { > > if buf is NULL, strlen above will crash, so you need to calculate len > inside this if branch Nice catch. Will fix it.
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 4aa6e5776a04..72de91beabbc 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -3364,6 +3364,40 @@ static void bpf_perf_link_dealloc(struct bpf_link *link) kfree(perf_link); } +static int bpf_perf_link_fill_common(const struct perf_event *event, + char __user *uname, u32 ulen, + u64 *probe_offset, u64 *probe_addr, + u32 *fd_type) +{ + const char *buf; + u32 prog_id; + size_t len; + int err; + + if (!ulen ^ !uname) + return -EINVAL; + if (!uname) + return 0; + + err = bpf_get_perf_event_info(event, &prog_id, fd_type, &buf, + probe_offset, probe_addr); + if (err) + return err; + + len = strlen(buf); + if (buf) { + err = bpf_copy_to_user(uname, buf, ulen, len); + if (err) + return err; + } else { + char zero = '\0'; + + if (put_user(zero, uname)) + return -EFAULT; + } + return 0; +} + static const struct bpf_link_ops bpf_perf_link_lops = { .release = bpf_perf_link_release, .dealloc = bpf_perf_link_dealloc,
Add a new helper bpf_perf_link_fill_common(), which will be used by perf_link based tracepoint, kprobe and uprobe. Signed-off-by: Yafang Shao <laoar.shao@gmail.com> --- kernel/bpf/syscall.c | 34 ++++++++++++++++++++++++++++++++++ 1 file changed, 34 insertions(+)