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 B77021C3C00; Wed, 19 Feb 2025 09:11:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739956286; cv=none; b=S+AnfuWftOREfAKphRTNcWHZwjZ0imYXO6fR46xUw/qMaD265YfTE0rCNdo0pNcRtX1+cDhH+9t2F+qIl5tVcSyhgkDiWsx74ByTIHiTkWqJXeXnBZtEJVVGsX8C5ZxXqNMCkJL8C+zfyPZ0Y3jUUW2zvXOxLtj5pSQJiXUQVlA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739956286; c=relaxed/simple; bh=u+Hhpkju9BEy3djWwReFqDOHOhL4ETJKSugEwnb/IyQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Noy5FZT6FTpIXN3iGxFxyeLEFKZwrubekO6aijScZEuuvikHklnMANJney7k38nKVhsqEA4oIHqNKdVgbiv9Q1C73r59u3ignli9eZxzYIcNHW1MjAnlNWWlvXCocUbbYHohO2C9R9OP1jgtPXVXW4vZftnxY7VwR/nHWKTVzpU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=NOmblBG1; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="NOmblBG1" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C47E7C4CED1; Wed, 19 Feb 2025 09:11:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1739956286; bh=u+Hhpkju9BEy3djWwReFqDOHOhL4ETJKSugEwnb/IyQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=NOmblBG1libpdzF/7w6cg4A5UGLuHhRu7Gdg8SXiz3mXX0iFidz3iDC/oXv1ZSmUE 7c1CaIluc0wHQnsHtH29ajYsopnqdcFrcUit4e0QGeD0L/Tr91hyZYZZ1FQr4GeW/m fP4DCd6ed+iPpTKWYbU3aK15S2dVSgQ7fTk/9Gps= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Chen Ridong , Qu Zicheng , Daniel Jordan , Herbert Xu , Sasha Levin Subject: [PATCH 6.1 128/578] padata: fix UAF in padata_reorder Date: Wed, 19 Feb 2025 09:22:12 +0100 Message-ID: <20250219082658.023572412@linuxfoundation.org> X-Mailer: git-send-email 2.48.1 In-Reply-To: <20250219082652.891560343@linuxfoundation.org> References: <20250219082652.891560343@linuxfoundation.org> User-Agent: quilt/0.68 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 6.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Chen Ridong [ Upstream commit e01780ea4661172734118d2a5f41bc9720765668 ] A bug was found when run ltp test: BUG: KASAN: slab-use-after-free in padata_find_next+0x29/0x1a0 Read of size 4 at addr ffff88bbfe003524 by task kworker/u113:2/3039206 CPU: 0 PID: 3039206 Comm: kworker/u113:2 Kdump: loaded Not tainted 6.6.0+ Workqueue: pdecrypt_parallel padata_parallel_worker Call Trace: dump_stack_lvl+0x32/0x50 print_address_description.constprop.0+0x6b/0x3d0 print_report+0xdd/0x2c0 kasan_report+0xa5/0xd0 padata_find_next+0x29/0x1a0 padata_reorder+0x131/0x220 padata_parallel_worker+0x3d/0xc0 process_one_work+0x2ec/0x5a0 If 'mdelay(10)' is added before calling 'padata_find_next' in the 'padata_reorder' function, this issue could be reproduced easily with ltp test (pcrypt_aead01). This can be explained as bellow: pcrypt_aead_encrypt ... padata_do_parallel refcount_inc(&pd->refcnt); // add refcnt ... padata_do_serial padata_reorder // pd while (1) { padata_find_next(pd, true); // using pd queue_work_on ... padata_serial_worker crypto_del_alg padata_put_pd_cnt // sub refcnt padata_free_shell padata_put_pd(ps->pd); // pd is freed // loop again, but pd is freed // call padata_find_next, UAF } In the padata_reorder function, when it loops in 'while', if the alg is deleted, the refcnt may be decreased to 0 before entering 'padata_find_next', which leads to UAF. As mentioned in [1], do_serial is supposed to be called with BHs disabled and always happen under RCU protection, to address this issue, add synchronize_rcu() in 'padata_free_shell' wait for all _do_serial calls to finish. [1] https://lore.kernel.org/all/20221028160401.cccypv4euxikusiq@parnassus.localdomain/ [2] https://lore.kernel.org/linux-kernel/jfjz5d7zwbytztackem7ibzalm5lnxldi2eofeiczqmqs2m7o6@fq426cwnjtkm/ Fixes: b128a3040935 ("padata: allocate workqueue internally") Signed-off-by: Chen Ridong Signed-off-by: Qu Zicheng Acked-by: Daniel Jordan Signed-off-by: Herbert Xu Signed-off-by: Sasha Levin --- kernel/padata.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/kernel/padata.c b/kernel/padata.c index 46b75d6b3618c..5f3069907d497 100644 --- a/kernel/padata.c +++ b/kernel/padata.c @@ -1110,6 +1110,12 @@ void padata_free_shell(struct padata_shell *ps) if (!ps) return; + /* + * Wait for all _do_serial calls to finish to avoid touching + * freed pd's and ps's. + */ + synchronize_rcu(); + mutex_lock(&ps->pinst->lock); list_del(&ps->list); pd = rcu_dereference_protected(ps->pd, 1); -- 2.39.5