netdev - Re: [PATCH] net/handshake: Fix sock->file allocation

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Date: Fri, 19 May 2023 17:13:17 +0000
From: Chuck Lever III <chuck.lever@...cle.com>
To: Chuck Lever <cel@...nel.org>
CC: Dan Carpenter <dan.carpenter@...aro.org>, Netdev <netdev@...r.kernel.org>,
        "kernel-tls-handshake@...ts.linux.dev" <kernel-tls-handshake@...ts.linux.dev>
Subject: Re: [PATCH] net/handshake: Fix sock->file allocation



> On May 19, 2023, at 1:08 PM, Chuck Lever <cel@...nel.org> wrote:
> 
> From: Chuck Lever <chuck.lever@...cle.com>
> 
> sock->file = sock_alloc_file(sock, O_NONBLOCK, NULL);
> ^^^^                         ^^^^
> 
> sock_alloc_file() calls release_sock() on error but the left hand
> side of the assignment dereferences "sock".  This isn't the bug and
> I didn't report this earlier because there is an assert that it
> doesn't fail.
> 
> net/handshake/handshake-test.c:221 handshake_req_submit_test4() error: dereferencing freed memory 'sock'
> net/handshake/handshake-test.c:233 handshake_req_submit_test4() warn: 'req' was already freed.
> net/handshake/handshake-test.c:254 handshake_req_submit_test5() error: dereferencing freed memory 'sock'
> net/handshake/handshake-test.c:290 handshake_req_submit_test6() error: dereferencing freed memory 'sock'
> net/handshake/handshake-test.c:321 handshake_req_cancel_test1() error: dereferencing freed memory 'sock'
> net/handshake/handshake-test.c:355 handshake_req_cancel_test2() error: dereferencing freed memory 'sock'
> net/handshake/handshake-test.c:367 handshake_req_cancel_test2() warn: 'req' was already freed.
> net/handshake/handshake-test.c:395 handshake_req_cancel_test3() error: dereferencing freed memory 'sock'
> net/handshake/handshake-test.c:407 handshake_req_cancel_test3() warn: 'req' was already freed.
> net/handshake/handshake-test.c:451 handshake_req_destroy_test1() error: dereferencing freed memory 'sock'
> net/handshake/handshake-test.c:463 handshake_req_destroy_test1() warn: 'req' was already freed.
> 
> Reported-by: Dan Carpenter <dan.carpenter@...aro.org>

Fixes: 88232ec1ec5e ("net/handshake: Add Kunit tests for the handshake consumer API")

> Signed-off-by: Chuck Lever <chuck.lever@...cle.com>
> ---
> net/handshake/handshake-test.c |   42 +++++++++++++++++++++++++++-------------
> 1 file changed, 28 insertions(+), 14 deletions(-)
> 
> diff --git a/net/handshake/handshake-test.c b/net/handshake/handshake-test.c
> index e6adc5dec11a..daa1779063ed 100644
> --- a/net/handshake/handshake-test.c
> +++ b/net/handshake/handshake-test.c
> @@ -209,6 +209,7 @@ static void handshake_req_submit_test4(struct kunit *test)
> {
> struct handshake_req *req, *result;
> struct socket *sock;
> + struct file *filp;
> int err;
> 
> /* Arrange */
> @@ -218,9 +219,10 @@ static void handshake_req_submit_test4(struct kunit *test)
> err = __sock_create(&init_net, PF_INET, SOCK_STREAM, IPPROTO_TCP,
>    &sock, 1);
> KUNIT_ASSERT_EQ(test, err, 0);
> - sock->file = sock_alloc_file(sock, O_NONBLOCK, NULL);
> - KUNIT_ASSERT_NOT_ERR_OR_NULL(test, sock->file);
> + filp = sock_alloc_file(sock, O_NONBLOCK, NULL);
> + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, filp);
> KUNIT_ASSERT_NOT_NULL(test, sock->sk);
> + sock->file = filp;
> 
> err = handshake_req_submit(sock, req, GFP_KERNEL);
> KUNIT_ASSERT_EQ(test, err, 0);
> @@ -241,6 +243,7 @@ static void handshake_req_submit_test5(struct kunit *test)
> struct handshake_req *req;
> struct handshake_net *hn;
> struct socket *sock;
> + struct file *filp;
> struct net *net;
> int saved, err;
> 
> @@ -251,9 +254,10 @@ static void handshake_req_submit_test5(struct kunit *test)
> err = __sock_create(&init_net, PF_INET, SOCK_STREAM, IPPROTO_TCP,
>    &sock, 1);
> KUNIT_ASSERT_EQ(test, err, 0);
> - sock->file = sock_alloc_file(sock, O_NONBLOCK, NULL);
> - KUNIT_ASSERT_NOT_ERR_OR_NULL(test, sock->file);
> + filp = sock_alloc_file(sock, O_NONBLOCK, NULL);
> + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, filp);
> KUNIT_ASSERT_NOT_NULL(test, sock->sk);
> + sock->file = filp;
> 
> net = sock_net(sock->sk);
> hn = handshake_pernet(net);
> @@ -276,6 +280,7 @@ static void handshake_req_submit_test6(struct kunit *test)
> {
> struct handshake_req *req1, *req2;
> struct socket *sock;
> + struct file *filp;
> int err;
> 
> /* Arrange */
> @@ -287,9 +292,10 @@ static void handshake_req_submit_test6(struct kunit *test)
> err = __sock_create(&init_net, PF_INET, SOCK_STREAM, IPPROTO_TCP,
>    &sock, 1);
> KUNIT_ASSERT_EQ(test, err, 0);
> - sock->file = sock_alloc_file(sock, O_NONBLOCK, NULL);
> - KUNIT_ASSERT_NOT_ERR_OR_NULL(test, sock->file);
> + filp = sock_alloc_file(sock, O_NONBLOCK, NULL);
> + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, filp);
> KUNIT_ASSERT_NOT_NULL(test, sock->sk);
> + sock->file = filp;
> 
> /* Act */
> err = handshake_req_submit(sock, req1, GFP_KERNEL);
> @@ -307,6 +313,7 @@ static void handshake_req_cancel_test1(struct kunit *test)
> {
> struct handshake_req *req;
> struct socket *sock;
> + struct file *filp;
> bool result;
> int err;
> 
> @@ -318,8 +325,9 @@ static void handshake_req_cancel_test1(struct kunit *test)
>    &sock, 1);
> KUNIT_ASSERT_EQ(test, err, 0);
> 
> - sock->file = sock_alloc_file(sock, O_NONBLOCK, NULL);
> - KUNIT_ASSERT_NOT_ERR_OR_NULL(test, sock->file);
> + filp = sock_alloc_file(sock, O_NONBLOCK, NULL);
> + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, filp);
> + sock->file = filp;
> 
> err = handshake_req_submit(sock, req, GFP_KERNEL);
> KUNIT_ASSERT_EQ(test, err, 0);
> @@ -340,6 +348,7 @@ static void handshake_req_cancel_test2(struct kunit *test)
> struct handshake_req *req, *next;
> struct handshake_net *hn;
> struct socket *sock;
> + struct file *filp;
> struct net *net;
> bool result;
> int err;
> @@ -352,8 +361,9 @@ static void handshake_req_cancel_test2(struct kunit *test)
>    &sock, 1);
> KUNIT_ASSERT_EQ(test, err, 0);
> 
> - sock->file = sock_alloc_file(sock, O_NONBLOCK, NULL);
> - KUNIT_ASSERT_NOT_ERR_OR_NULL(test, sock->file);
> + filp = sock_alloc_file(sock, O_NONBLOCK, NULL);
> + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, filp);
> + sock->file = filp;
> 
> err = handshake_req_submit(sock, req, GFP_KERNEL);
> KUNIT_ASSERT_EQ(test, err, 0);
> @@ -380,6 +390,7 @@ static void handshake_req_cancel_test3(struct kunit *test)
> struct handshake_req *req, *next;
> struct handshake_net *hn;
> struct socket *sock;
> + struct file *filp;
> struct net *net;
> bool result;
> int err;
> @@ -392,8 +403,9 @@ static void handshake_req_cancel_test3(struct kunit *test)
>    &sock, 1);
> KUNIT_ASSERT_EQ(test, err, 0);
> 
> - sock->file = sock_alloc_file(sock, O_NONBLOCK, NULL);
> - KUNIT_ASSERT_NOT_ERR_OR_NULL(test, sock->file);
> + filp = sock_alloc_file(sock, O_NONBLOCK, NULL);
> + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, filp);
> + sock->file = filp;
> 
> err = handshake_req_submit(sock, req, GFP_KERNEL);
> KUNIT_ASSERT_EQ(test, err, 0);
> @@ -436,6 +448,7 @@ static void handshake_req_destroy_test1(struct kunit *test)
> {
> struct handshake_req *req;
> struct socket *sock;
> + struct file *filp;
> int err;
> 
> /* Arrange */
> @@ -448,8 +461,9 @@ static void handshake_req_destroy_test1(struct kunit *test)
>    &sock, 1);
> KUNIT_ASSERT_EQ(test, err, 0);
> 
> - sock->file = sock_alloc_file(sock, O_NONBLOCK, NULL);
> - KUNIT_ASSERT_NOT_ERR_OR_NULL(test, sock->file);
> + filp = sock_alloc_file(sock, O_NONBLOCK, NULL);
> + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, filp);
> + sock->file = filp;
> 
> err = handshake_req_submit(sock, req, GFP_KERNEL);
> KUNIT_ASSERT_EQ(test, err, 0);
> 
> 

--
Chuck Lever