| From magali.lemes@canonical.com Tue Mar 11 19:55:13 2025 |
| From: Magali Lemes <magali.lemes@canonical.com> |
| Date: Tue, 11 Mar 2025 15:54:27 -0300 |
| Subject: sctp: sysctl: auth_enable: avoid using current->nsproxy |
| To: gregkh@linuxfoundation.org, stable@vger.kernel.org |
| Cc: "Matthieu Baerts (NGI0)" <matttbe@kernel.org> |
| Message-ID: <20250311185427.1070104-5-magali.lemes@canonical.com> |
| |
| From: "Matthieu Baerts (NGI0)" <matttbe@kernel.org> |
| |
| commit 15649fd5415eda664ef35780c2013adeb5d9c695 upstream. |
| |
| As mentioned in a previous commit of this series, using the 'net' |
| structure via 'current' is not recommended for different reasons: |
| |
| - Inconsistency: getting info from the reader's/writer's netns vs only |
| from the opener's netns. |
| |
| - current->nsproxy can be NULL in some cases, resulting in an 'Oops' |
| (null-ptr-deref), e.g. when the current task is exiting, as spotted by |
| syzbot [1] using acct(2). |
| |
| The 'net' structure can be obtained from the table->data using |
| container_of(). |
| |
| Note that table->data could also be used directly, but that would |
| increase the size of this fix, while 'sctp.ctl_sock' still needs to be |
| retrieved from 'net' structure. |
| |
| Fixes: b14878ccb7fa ("net: sctp: cache auth_enable per endpoint") |
| Cc: stable@vger.kernel.org |
| Link: https://lore.kernel.org/67769ecb.050a0220.3a8527.003f.GAE@google.com [1] |
| Suggested-by: Al Viro <viro@zeniv.linux.org.uk> |
| Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org> |
| Link: https://patch.msgid.link/20250108-net-sysctl-current-nsproxy-v1-6-5df34b2083e8@kernel.org |
| Signed-off-by: Jakub Kicinski <kuba@kernel.org> |
| Signed-off-by: Magali Lemes <magali.lemes@canonical.com> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| --- |
| net/sctp/sysctl.c | 2 +- |
| 1 file changed, 1 insertion(+), 1 deletion(-) |
| |
| --- a/net/sctp/sysctl.c |
| +++ b/net/sctp/sysctl.c |
| @@ -442,7 +442,7 @@ static int proc_sctp_do_auth(struct ctl_ |
| void __user *buffer, size_t *lenp, |
| loff_t *ppos) |
| { |
| - struct net *net = current->nsproxy->net_ns; |
| + struct net *net = container_of(ctl->data, struct net, sctp.auth_enable); |
| struct ctl_table tbl; |
| int new_value, ret; |
| |
