From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 D731911C88 for ; Mon, 12 Jun 2023 10:39:47 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5D65DC433D2; Mon, 12 Jun 2023 10:39:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1686566387; bh=zKysH0PqgO4ppCUgof0pBqkfcBmwRsnAPviQqMNILN0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=iflXxiOsBOfqEKnAgsOp3fJkFiXxx31hNvbEXjci0+AURKIlQEeuaVeNxDcJ/pInr 8DOb+tayPJuufn3vBBpWBBhF/RxBqG5m8G/cL/9vPW1TqV1WIkA3zD2zRI5V+3VR2K quC9b7AdqhLfXAYrirHeF85zKfExTSkLnp/0CEzM= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Kuba Piecuch , KP Singh , Song Liu , Martin KaFai Lau , Sasha Levin Subject: [PATCH 6.1 013/132] bpf: Fix UAF in task local storage Date: Mon, 12 Jun 2023 12:25:47 +0200 Message-ID: <20230612101710.884537100@linuxfoundation.org> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230612101710.279705932@linuxfoundation.org> References: <20230612101710.279705932@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: KP Singh [ Upstream commit b0fd1852bcc21accca6260ef245356d5c141ff66 ] When task local storage was generalized for tracing programs, the bpf_task_local_storage callback was moved from a BPF LSM hook callback for security_task_free LSM hook to it's own callback. But a failure case in bad_fork_cleanup_security was missed which, when triggered, led to a dangling task owner pointer and a subsequent use-after-free. Move the bpf_task_storage_free to the very end of free_task to handle all failure cases. This issue was noticed when a BPF LSM program was attached to the task_alloc hook on a kernel with KASAN enabled. The program used bpf_task_storage_get to copy the task local storage from the current task to the new task being created. Fixes: a10787e6d58c ("bpf: Enable task local storage for tracing programs") Reported-by: Kuba Piecuch Signed-off-by: KP Singh Acked-by: Song Liu Link: https://lore.kernel.org/r/20230602002612.1117381-1-kpsingh@kernel.org Signed-off-by: Martin KaFai Lau Signed-off-by: Sasha Levin --- kernel/fork.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/fork.c b/kernel/fork.c index ec913b13c5edb..6bb91fbbf73cc 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -559,6 +559,7 @@ void free_task(struct task_struct *tsk) arch_release_task_struct(tsk); if (tsk->flags & PF_KTHREAD) free_kthread_struct(tsk); + bpf_task_storage_free(tsk); free_task_struct(tsk); } EXPORT_SYMBOL(free_task); @@ -843,7 +844,6 @@ void __put_task_struct(struct task_struct *tsk) cgroup_free(tsk); task_numa_free(tsk, true); security_task_free(tsk); - bpf_task_storage_free(tsk); exit_creds(tsk); delayacct_tsk_free(tsk); put_signal_struct(tsk->signal); -- 2.39.2