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 DA01214D705; Wed, 19 Jun 2024 13:03:07 +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=1718802187; cv=none; b=j8A3VC4+ABKn4JwFAza93qZ0YsiV4MaZL0027JCZzh9lt9eCHZr2GLmFCxZlOcWB0sxzWQ7Ijny6hzGiqvP3JHVNz8eWClfAtUls5u8GW5e/Zdk0P/2VTUGZYTIJsCKR3PjvVM1zrXBMEFRjz4M6uq+Hs7KEOTIkBGcxvn4vb90= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1718802187; c=relaxed/simple; bh=KGv0OALaU2lTNwp2EZemZw1F8NLflFe94MBWUPIsYa8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=jHV7UMXqz2nJHZdHT3NOTuXUup4QiW138Vtpw45Pyud7ts7mPFfYzUp8QWtmGJ6D3LQE9lsrTDX+BI9sdtNtJ5LHeih6xcdG0K466aw/j8aKohmHDDUEU5l1wdaqcA1cxzvvEKUPaMcFukKZYsyrxdi0bpjReDxly2GMqtzdJm0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=f0d3BFKq; 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="f0d3BFKq" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 15BA1C2BBFC; Wed, 19 Jun 2024 13:03:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1718802187; bh=KGv0OALaU2lTNwp2EZemZw1F8NLflFe94MBWUPIsYa8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=f0d3BFKqRppOj8jjlepdRVbfDvWpBnGmxMTGFE1oPDqymy+E2z4mqAIBcqBfgssey 9lciS2NZ3s6kFk5C/SdRYpiNRKAdQVUrhdWZ67tiAhUn+bzFiWu5H+M7uM11jH9quA wxYjBTmXKFouAWv3Y4I6+NJG5yKcd3pTz5PwHGo0= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Baokun Li , Jeff Layton , Jia Zhu , Jingbo Xu , Christian Brauner , Sasha Levin Subject: [PATCH 6.6 111/267] cachefiles: fix slab-use-after-free in cachefiles_ondemand_daemon_read() Date: Wed, 19 Jun 2024 14:54:22 +0200 Message-ID: <20240619125610.613663584@linuxfoundation.org> X-Mailer: git-send-email 2.45.2 In-Reply-To: <20240619125606.345939659@linuxfoundation.org> References: <20240619125606.345939659@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Baokun Li [ Upstream commit da4a827416066191aafeeccee50a8836a826ba10 ] We got the following issue in a fuzz test of randomly issuing the restore command: ================================================================== BUG: KASAN: slab-use-after-free in cachefiles_ondemand_daemon_read+0xb41/0xb60 Read of size 8 at addr ffff888122e84088 by task ondemand-04-dae/963 CPU: 13 PID: 963 Comm: ondemand-04-dae Not tainted 6.8.0-dirty #564 Call Trace: kasan_report+0x93/0xc0 cachefiles_ondemand_daemon_read+0xb41/0xb60 vfs_read+0x169/0xb50 ksys_read+0xf5/0x1e0 Allocated by task 116: kmem_cache_alloc+0x140/0x3a0 cachefiles_lookup_cookie+0x140/0xcd0 fscache_cookie_state_machine+0x43c/0x1230 [...] Freed by task 792: kmem_cache_free+0xfe/0x390 cachefiles_put_object+0x241/0x480 fscache_cookie_state_machine+0x5c8/0x1230 [...] ================================================================== Following is the process that triggers the issue: mount | daemon_thread1 | daemon_thread2 ------------------------------------------------------------ cachefiles_withdraw_cookie cachefiles_ondemand_clean_object(object) cachefiles_ondemand_send_req REQ_A = kzalloc(sizeof(*req) + data_len) wait_for_completion(&REQ_A->done) cachefiles_daemon_read cachefiles_ondemand_daemon_read REQ_A = cachefiles_ondemand_select_req msg->object_id = req->object->ondemand->ondemand_id ------ restore ------ cachefiles_ondemand_restore xas_for_each(&xas, req, ULONG_MAX) xas_set_mark(&xas, CACHEFILES_REQ_NEW) cachefiles_daemon_read cachefiles_ondemand_daemon_read REQ_A = cachefiles_ondemand_select_req copy_to_user(_buffer, msg, n) xa_erase(&cache->reqs, id) complete(&REQ_A->done) ------ close(fd) ------ cachefiles_ondemand_fd_release cachefiles_put_object cachefiles_put_object kmem_cache_free(cachefiles_object_jar, object) REQ_A->object->ondemand->ondemand_id // object UAF !!! When we see the request within xa_lock, req->object must not have been freed yet, so grab the reference count of object before xa_unlock to avoid the above issue. Fixes: 0a7e54c1959c ("cachefiles: resend an open request if the read request's object is closed") Signed-off-by: Baokun Li Link: https://lore.kernel.org/r/20240522114308.2402121-5-libaokun@huaweicloud.com Acked-by: Jeff Layton Reviewed-by: Jia Zhu Reviewed-by: Jingbo Xu Signed-off-by: Christian Brauner Stable-dep-of: 4b4391e77a6b ("cachefiles: defer exposing anon_fd until after copy_to_user() succeeds") Signed-off-by: Sasha Levin --- fs/cachefiles/ondemand.c | 3 +++ include/trace/events/cachefiles.h | 6 +++++- 2 files changed, 8 insertions(+), 1 deletion(-) diff --git a/fs/cachefiles/ondemand.c b/fs/cachefiles/ondemand.c index f8d0a01795702..fd73811c7ce4f 100644 --- a/fs/cachefiles/ondemand.c +++ b/fs/cachefiles/ondemand.c @@ -369,6 +369,7 @@ ssize_t cachefiles_ondemand_daemon_read(struct cachefiles_cache *cache, xas_clear_mark(&xas, CACHEFILES_REQ_NEW); cache->req_id_next = xas.xa_index + 1; refcount_inc(&req->ref); + cachefiles_grab_object(req->object, cachefiles_obj_get_read_req); xa_unlock(&cache->reqs); id = xas.xa_index; @@ -389,6 +390,7 @@ ssize_t cachefiles_ondemand_daemon_read(struct cachefiles_cache *cache, goto err_put_fd; } + cachefiles_put_object(req->object, cachefiles_obj_put_read_req); /* CLOSE request has no reply */ if (msg->opcode == CACHEFILES_OP_CLOSE) { xa_erase(&cache->reqs, id); @@ -402,6 +404,7 @@ ssize_t cachefiles_ondemand_daemon_read(struct cachefiles_cache *cache, if (msg->opcode == CACHEFILES_OP_OPEN) close_fd(((struct cachefiles_open *)msg->data)->fd); error: + cachefiles_put_object(req->object, cachefiles_obj_put_read_req); xas_reset(&xas); xas_lock(&xas); if (xas_load(&xas) == req) { diff --git a/include/trace/events/cachefiles.h b/include/trace/events/cachefiles.h index e3213af847cdf..7d931db02b934 100644 --- a/include/trace/events/cachefiles.h +++ b/include/trace/events/cachefiles.h @@ -33,6 +33,8 @@ enum cachefiles_obj_ref_trace { cachefiles_obj_see_withdrawal, cachefiles_obj_get_ondemand_fd, cachefiles_obj_put_ondemand_fd, + cachefiles_obj_get_read_req, + cachefiles_obj_put_read_req, }; enum fscache_why_object_killed { @@ -129,7 +131,9 @@ enum cachefiles_error_trace { EM(cachefiles_obj_see_withdraw_cookie, "SEE withdraw_cookie") \ EM(cachefiles_obj_see_withdrawal, "SEE withdrawal") \ EM(cachefiles_obj_get_ondemand_fd, "GET ondemand_fd") \ - E_(cachefiles_obj_put_ondemand_fd, "PUT ondemand_fd") + EM(cachefiles_obj_put_ondemand_fd, "PUT ondemand_fd") \ + EM(cachefiles_obj_get_read_req, "GET read_req") \ + E_(cachefiles_obj_put_read_req, "PUT read_req") #define cachefiles_coherency_traces \ EM(cachefiles_coherency_check_aux, "BAD aux ") \ -- 2.43.0