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bpf: Fix use-after-free in bpf_uprobe_multi_link_attach()

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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
This commit is contained in:
Oleg Nesterov 2024-08-13 17:25:24 +02:00 committed by Peter Zijlstra
parent 62c0b10615
commit 5fe6e308ab
1 changed files with 6 additions and 3 deletions
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9
kernel/trace/bpf_trace.c
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@ -3484,17 +3484,20 @@ int bpf_uprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *pr
&uprobes[i].consumer); &uprobes[i].consumer);
if (IS_ERR(uprobes[i].uprobe)) { if (IS_ERR(uprobes[i].uprobe)) {
err = PTR_ERR(uprobes[i].uprobe); err = PTR_ERR(uprobes[i].uprobe);
bpf_uprobe_unregister(uprobes, i); link->cnt = i;
goto error_free; goto error_unregister;
} }
} }
err = bpf_link_prime(&link->link, &link_primer); err = bpf_link_prime(&link->link, &link_primer);
if (err) if (err)
goto error_free; goto error_unregister;
return bpf_link_settle(&link_primer); return bpf_link_settle(&link_primer);
error_unregister:
bpf_uprobe_unregister(uprobes, link->cnt);
error_free: error_free:
kvfree(uprobes); kvfree(uprobes);
kfree(link); kfree(link);