The following commit has been merged into the perf/core branch of tip: Commit-ID: 5fe6e308abaea082c20fbf2aa5df8e14495622cf Gitweb: https://git.kernel.org/tip/5fe6e308abaea082c20fbf2aa5df8e14495622cf Author: Oleg Nesterov <oleg@xxxxxxxxxx> AuthorDate: Tue, 13 Aug 2024 17:25:24 +02:00 Committer: Peter Zijlstra <peterz@xxxxxxxxxxxxx> CommitterDate: Thu, 05 Sep 2024 16:56:13 +02:00 bpf: Fix use-after-free in bpf_uprobe_multi_link_attach() 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@xxxxxxxxxx/ Reported-by: syzbot+f7a1c2c2711e4a780f19@xxxxxxxxxxxxxxxxxxxxxxxxx Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx> Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx> Acked-by: Andrii Nakryiko <andrii@xxxxxxxxxx> Acked-by: Jiri Olsa <jolsa@xxxxxxxxxx> Tested-by: syzbot+f7a1c2c2711e4a780f19@xxxxxxxxxxxxxxxxxxxxxxxxx Cc: stable@xxxxxxxxxxxxxxx Link: https://lore.kernel.org/r/20240813152524.GA7292@xxxxxxxxxx --- 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 4e391da..90cd30e 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);
