From: Oleg Nesterov Date: Thu, 19 Sep 2024 13:28:53 +0000 (+0200) Subject: bpf: Fix use-after-free in bpf_uprobe_multi_link_attach() X-Git-Tag: v6.10.13~3 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=7c1d782e5afbf7c50ba74ecc4ddc18a05d63e5ee;p=thirdparty%2Fkernel%2Fstable.git bpf: Fix use-after-free in bpf_uprobe_multi_link_attach() 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 Signed-off-by: Peter Zijlstra (Intel) Acked-by: Andrii Nakryiko Acked-by: Jiri Olsa 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 --- diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index f0b7e9eb81729..433be6bc8b778 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].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);