From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 191E8455622; Sat, 12 Sep 2026 10:45:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789209930; cv=none; b=sytl1eeES5ltHd7a/R3hjsv7mK9IX8m5czdGPbi1Q2Z5TWxuPBJ6QQLLNQ5nW7ntV0ba9sqXdM0KQoqnatp4q+uuN81NDynBr52BlfRiE7JcJf3R7n44zZoGo5/6JmyKH6qn74gl3J2smomq46ZGhqGSsvYW8Wwj21Pec/EFWpU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789209930; c=relaxed/simple; bh=Uc4gbyPLxIdsAQVE8qaXOy7pqJKM36DNXu9xvN0jdAI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=OOoFyElG2p4ekua6oSYh9INDGC6gXyIwCdnPenTz5ykFYTTCrrAbIrpi6+yRTey7owdmXPLwN3LNkz6ajsCWlLCHBt5sHxsNegYiNaeer2M+5fDph+rGsofYJXI01S0oeTBlvDbrOsJsyQcg7+ywzBMphIxEjXY8JmsHsIQmW+Q= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=H45kCoLl; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="H45kCoLl" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 081111F00893; Sat, 12 Sep 2026 10:45:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789209928; bh=ee/VH4I64YoDuvvVKQtmYc8ykNJHJFTrPTWT0dSf8tI=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=H45kCoLluUauEYJR8qyiS2MlKcyvIfGJ09OvSshlisgGj6yrezTE/5R3XJN5ZQTHE gPyHXXpBZ/nLKhbFnrynsuldvmNiURbovMl/wKJWEOO21ZYOncS/G1DQo0MXel9VbC k2JP4QXIL6CwL0i+/oKJFtVow2TlMqDuro618xh4= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Sashiko , Pu Lehui , Andrii Nakryiko , Emil Tsalapatis , Sasha Levin Subject: [PATCH 6.18 0880/1518] bpf, cgroup: Fix invalid storage access after __cgroup_bpf_attach failed Date: Sat, 12 Sep 2026 08:50:49 +0200 Message-ID: <20260912065643.355643621@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260912065623.398859879@linuxfoundation.org> References: <20260912065623.398859879@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Pu Lehui [ Upstream commit 6655c409707ec8ce9ce0850ffe4fe02331fd4d9c ] A potential invalid storage access issue can occur after replacing a cgroup bpf prog. This occurs in the following scenario: 1. prog1 with storage is attached to a cgroup in multi-attach mode. 2. prog1 is replaced with prog2 using BPF_F_REPLACE in multi-attach mode, but fails midway (e.g. in bpf_trampoline_link_cgroup_shim or update_effective_progs). 3. A new prog3 is attached to the cgroup in multi-attach mode. The reason is that __cgroup_bpf_attach overwrites pl->storage with the new storage prior to attachment completion. When attachment fails midway, the cleanup path calls bpf_cgroup_storages_free(new_storage) to free the newly allocated storage, but fails to restore pl->storage back to old_storage. Consequently, the still-active prog1 holds invalid or dangling storage pointers, leading to an invalid memory access when prog1 executes and calls bpf_get_local_storage. Additionally, original pl->flags and cgrp->bpf.flags[atype] are left unrestored. Fix this by saving old_pl_flags, old_storage, and old_flags prior to the update, and properly restoring all of them in the cleanup path on error. Fixes: 7d9c3427894f ("bpf: Make cgroup storages shared between programs on the same cgroup") Reported-by: Sashiko Signed-off-by: Pu Lehui Signed-off-by: Andrii Nakryiko Reviewed-by: Emil Tsalapatis Link: https://lore.kernel.org/bpf/20260803013934.4036646-1-pulehui@huaweicloud.com Signed-off-by: Sasha Levin --- kernel/bpf/cgroup.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/kernel/bpf/cgroup.c b/kernel/bpf/cgroup.c index fc2f44b60a551..e5fa91515c563 100644 --- a/kernel/bpf/cgroup.c +++ b/kernel/bpf/cgroup.c @@ -813,8 +813,10 @@ static int __cgroup_bpf_attach(struct cgroup *cgrp, struct bpf_prog *old_prog = NULL; struct bpf_cgroup_storage *storage[MAX_BPF_CGROUP_STORAGE_TYPE] = {}; struct bpf_cgroup_storage *new_storage[MAX_BPF_CGROUP_STORAGE_TYPE] = {}; + struct bpf_cgroup_storage *old_storage[MAX_BPF_CGROUP_STORAGE_TYPE] = {}; struct bpf_prog *new_prog = prog ? : link->link.prog; enum cgroup_bpf_attach_type atype; + u32 old_flags, old_pl_flags; struct bpf_prog_list *pl; struct hlist_head *progs; int err; @@ -865,6 +867,8 @@ static int __cgroup_bpf_attach(struct cgroup *cgrp, if (pl) { old_prog = pl->prog; + old_pl_flags = pl->flags; + bpf_cgroup_storages_assign(old_storage, pl->storage); } else { pl = kmalloc(sizeof(*pl), GFP_KERNEL); if (!pl) { @@ -884,6 +888,7 @@ static int __cgroup_bpf_attach(struct cgroup *cgrp, pl->link = link; pl->flags = flags; bpf_cgroup_storages_assign(pl->storage, storage); + old_flags = cgrp->bpf.flags[atype]; cgrp->bpf.flags[atype] = saved_flags; if (type == BPF_LSM_CGROUP) { @@ -915,12 +920,15 @@ static int __cgroup_bpf_attach(struct cgroup *cgrp, if (old_prog) { pl->prog = old_prog; pl->link = NULL; + pl->flags = old_pl_flags; + bpf_cgroup_storages_assign(pl->storage, old_storage); } bpf_cgroup_storages_free(new_storage); if (!old_prog) { hlist_del(&pl->node); kfree(pl); } + cgrp->bpf.flags[atype] = old_flags; return err; } -- 2.53.0