The patch below does not apply to the 6.11-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.11.y git checkout FETCH_HEAD git cherry-pick -x 5fe6e308abaea082c20fbf2aa5df8e14495622cf # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '2024100247-spray-enjoyable-b1d0@gregkh' --subject-prefix 'PATCH 6.11.y' HEAD^..

Possible dependencies:

5fe6e308abae ("bpf: Fix use-after-free in bpf_uprobe_multi_link_attach()") 3c83a9ad0295 ("uprobes: make uprobe_register() return struct uprobe *") e04332ebc8ac ("uprobes: kill uprobe_register_refctr()") db61e6a4eee5 ("selftests/bpf: fix uprobe.path leak in bpf_testmod")

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 5fe6e308abaea082c20fbf2aa5df8e14495622cf Mon Sep 17 00:00:00 2001 From: Oleg Nesterov oleg@redhat.com Date: Tue, 13 Aug 2024 17:25:24 +0200 Subject: [PATCH] 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@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

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);