| Message ID | 20240813152524.GA7292@redhat.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | [tip/perf/core] bpf: fix use-after-free in bpf_uprobe_multi_link_attach() | expand |
On Tue, Aug 13, 2024 at 05:25:24PM +0200, Oleg Nesterov wrote: > If bpf_link_prime() fails, bpf_uprobe_multi_link_attach() goes to the > error_free label and frees the array of bpf_uprobe's without calling > bpf_uprobe_unregister(). > > This leaks bpf_uprobe->uprobe and worse, this frees bpf_uprobe->consumer > without removing it from the uprobe->consumers list. > > Cc: stable@vger.kernel.org > Fixes: 89ae89f53d20 ("bpf: Add multi uprobe link") > Reported-by: syzbot+f7a1c2c2711e4a780f19@syzkaller.appspotmail.com > Closes: https://lore.kernel.org/all/000000000000382d39061f59f2dd@google.com/ > Tested-by: syzbot+f7a1c2c2711e4a780f19@syzkaller.appspotmail.com > Acked-by: Andrii Nakryiko <andrii@kernel.org> > Signed-off-by: Oleg Nesterov <oleg@redhat.com> thanks for fixing this Acked-by: Jiri Olsa <jolsa@kernel.org> jirka > --- > kernel/trace/bpf_trace.c | 9 ++++++--- > 1 file changed, 6 insertions(+), 3 deletions(-) > > diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c > index 4e391daafa64..90cd30e9723e 100644 > --- a/kernel/trace/bpf_trace.c > +++ b/kernel/trace/bpf_trace.c > @@ -3484,17 +3484,20 @@ int bpf_uprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *pr > &uprobes[i].consumer); > if (IS_ERR(uprobes[i].uprobe)) { > err = PTR_ERR(uprobes[i].uprobe); > - bpf_uprobe_unregister(uprobes, i); > - goto error_free; > + link->cnt = i; > + goto error_unregister; > } > } > > err = bpf_link_prime(&link->link, &link_primer); > if (err) > - goto error_free; > + goto error_unregister; > > return bpf_link_settle(&link_primer); > > +error_unregister: > + bpf_uprobe_unregister(uprobes, link->cnt); > + > error_free: > kvfree(uprobes); > kfree(link); > -- > 2.25.1.362.g51ebf55 > >
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index 4e391daafa64..90cd30e9723e 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -3484,17 +3484,20 @@ int bpf_uprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *pr &uprobes[i].consumer); if (IS_ERR(uprobes[i].uprobe)) { err = PTR_ERR(uprobes[i].uprobe); - bpf_uprobe_unregister(uprobes, i); - goto error_free; + link->cnt = i; + goto error_unregister; } } err = bpf_link_prime(&link->link, &link_primer); if (err) - goto error_free; + goto error_unregister; return bpf_link_settle(&link_primer); +error_unregister: + bpf_uprobe_unregister(uprobes, link->cnt); + error_free: kvfree(uprobes); kfree(link);
If bpf_link_prime() fails, bpf_uprobe_multi_link_attach() goes to the error_free label and frees the array of bpf_uprobe's without calling bpf_uprobe_unregister(). This leaks bpf_uprobe->uprobe and worse, this frees bpf_uprobe->consumer without removing it from the uprobe->consumers list. Cc: stable@vger.kernel.org Fixes: 89ae89f53d20 ("bpf: Add multi uprobe link") Reported-by: syzbot+f7a1c2c2711e4a780f19@syzkaller.appspotmail.com Closes: https://lore.kernel.org/all/000000000000382d39061f59f2dd@google.com/ Tested-by: syzbot+f7a1c2c2711e4a780f19@syzkaller.appspotmail.com Acked-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Oleg Nesterov <oleg@redhat.com> --- kernel/trace/bpf_trace.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-)