6.11-stable review patch. If anyone has any objections, please let me know.
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From: Oleg Nesterov oleg@redhat.com
commit 5fe6e308abaea082c20fbf2aa5df8e14495622cf upstream.
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.
Fixes: 89ae89f53d20 ("bpf: Add multi uprobe link") Closes: https://lore.kernel.org/all/000000000000382d39061f59f2dd@google.com/ Reported-by: syzbot+f7a1c2c2711e4a780f19@syzkaller.appspotmail.com Signed-off-by: Oleg Nesterov oleg@redhat.com Signed-off-by: Peter Zijlstra (Intel) peterz@infradead.org Acked-by: Andrii Nakryiko andrii@kernel.org Acked-by: Jiri Olsa jolsa@kernel.org Tested-by: syzbot+f7a1c2c2711e4a780f19@syzkaller.appspotmail.com Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20240813152524.GA7292@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- kernel/trace/bpf_trace.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-)
--- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -3487,17 +3487,20 @@ int bpf_uprobe_multi_link_attach(const u uprobes[i].ref_ctr_offset, &uprobes[i].consumer); if (err) { - bpf_uprobe_unregister(&path, 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(&path, uprobes, link->cnt); + error_free: kvfree(uprobes); kfree(link);