| Message ID | 20200513062649.2100053-33-hch@lst.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [01/33] net: add sock_set_reuseaddr | expand |
On Wed, May 13, 2020 at 08:26:47AM +0200, Christoph Hellwig wrote: > Add a helper to directly get the SCTP_PRIMARY_ADDR sockopt from kernel > space without going through a fake uaccess. Same comment as on the other dlm/sctp patch. > > Signed-off-by: Christoph Hellwig <hch@lst.de> > --- > fs/dlm/lowcomms.c | 11 +++----- > include/net/sctp/sctp.h | 1 + > net/sctp/socket.c | 57 +++++++++++++++++++++++++---------------- > 3 files changed, 39 insertions(+), 30 deletions(-) > > diff --git a/fs/dlm/lowcomms.c b/fs/dlm/lowcomms.c > index 6fa45365666a8..46d2d71b62c57 100644 > --- a/fs/dlm/lowcomms.c > +++ b/fs/dlm/lowcomms.c > @@ -855,10 +855,9 @@ static int tcp_accept_from_sock(struct connection *con) > static int sctp_accept_from_sock(struct connection *con) > { > /* Check that the new node is in the lockspace */ > - struct sctp_prim prim; > + struct sctp_prim prim = { }; > int nodeid; > - int prim_len, ret; > - int addr_len; > + int addr_len, ret; > struct connection *newcon; > struct connection *addcon; > struct socket *newsock; > @@ -876,11 +875,7 @@ static int sctp_accept_from_sock(struct connection *con) > if (ret < 0) > goto accept_err; > > - memset(&prim, 0, sizeof(struct sctp_prim)); > - prim_len = sizeof(struct sctp_prim); > - > - ret = kernel_getsockopt(newsock, IPPROTO_SCTP, SCTP_PRIMARY_ADDR, > - (char *)&prim, &prim_len); > + ret = sctp_sock_get_primary_addr(con->sock->sk, &prim); > if (ret < 0) { > log_print("getsockopt/sctp_primary_addr failed: %d", ret); > goto accept_err; > diff --git a/include/net/sctp/sctp.h b/include/net/sctp/sctp.h > index b505fa082f254..c98b1d14db853 100644 > --- a/include/net/sctp/sctp.h > +++ b/include/net/sctp/sctp.h > @@ -618,5 +618,6 @@ static inline bool sctp_newsk_ready(const struct sock *sk) > int sctp_setsockopt_bindx(struct sock *sk, struct sockaddr *kaddrs, > int addrs_size, int op); > void sctp_sock_set_nodelay(struct sock *sk, bool val); > +int sctp_sock_get_primary_addr(struct sock *sk, struct sctp_prim *prim); > > #endif /* __net_sctp_h__ */ > diff --git a/net/sctp/socket.c b/net/sctp/socket.c > index 64c395f7a86d5..39bf8090dbe1e 100644 > --- a/net/sctp/socket.c > +++ b/net/sctp/socket.c > @@ -6411,6 +6411,35 @@ static int sctp_getsockopt_local_addrs(struct sock *sk, int len, > return err; > } > > +static int __sctp_sock_get_primary_addr(struct sock *sk, struct sctp_prim *prim) > +{ > + struct sctp_association *asoc; > + > + asoc = sctp_id2assoc(sk, prim->ssp_assoc_id); > + if (!asoc) > + return -EINVAL; > + if (!asoc->peer.primary_path) > + return -ENOTCONN; > + > + memcpy(&prim->ssp_addr, &asoc->peer.primary_path->ipaddr, > + asoc->peer.primary_path->af_specific->sockaddr_len); > + > + sctp_get_pf_specific(sk->sk_family)->addr_to_user(sctp_sk(sk), > + (union sctp_addr *)&prim->ssp_addr); > + return 0; > +} > + > +int sctp_sock_get_primary_addr(struct sock *sk, struct sctp_prim *prim) > +{ > + int ret; > + > + lock_sock(sk); > + ret = __sctp_sock_get_primary_addr(sk, prim); > + release_sock(sk); > + return ret; > +} > +EXPORT_SYMBOL(sctp_sock_get_primary_addr); > + > /* 7.1.10 Set Primary Address (SCTP_PRIMARY_ADDR) > * > * Requests that the local SCTP stack use the enclosed peer address as > @@ -6421,35 +6450,19 @@ static int sctp_getsockopt_primary_addr(struct sock *sk, int len, > char __user *optval, int __user *optlen) > { > struct sctp_prim prim; > - struct sctp_association *asoc; > - struct sctp_sock *sp = sctp_sk(sk); > + int ret; > > if (len < sizeof(struct sctp_prim)) > return -EINVAL; > - > - len = sizeof(struct sctp_prim); > - > - if (copy_from_user(&prim, optval, len)) > + if (copy_from_user(&prim, optval, sizeof(struct sctp_prim))) > return -EFAULT; > > - asoc = sctp_id2assoc(sk, prim.ssp_assoc_id); > - if (!asoc) > - return -EINVAL; > - > - if (!asoc->peer.primary_path) > - return -ENOTCONN; > - > - memcpy(&prim.ssp_addr, &asoc->peer.primary_path->ipaddr, > - asoc->peer.primary_path->af_specific->sockaddr_len); > - > - sctp_get_pf_specific(sk->sk_family)->addr_to_user(sp, > - (union sctp_addr *)&prim.ssp_addr); > + ret = __sctp_sock_get_primary_addr(sk, &prim); > + if (ret) > + return ret; > > - if (put_user(len, optlen)) > + if (put_user(len, optlen) || copy_to_user(optval, &prim, len)) > return -EFAULT; > - if (copy_to_user(optval, &prim, len)) > - return -EFAULT; > - > return 0; > } > > -- > 2.26.2 >
From: Marcelo Ricardo Leitner > Sent: 13 May 2020 19:03 > > On Wed, May 13, 2020 at 08:26:47AM +0200, Christoph Hellwig wrote: > > Add a helper to directly get the SCTP_PRIMARY_ADDR sockopt from kernel > > space without going through a fake uaccess. > > Same comment as on the other dlm/sctp patch. Wouldn't it be best to write sctp_[gs]etsockotp() that use a kernel buffer and then implement the user-space calls using a wrapper that does the copies to an on-stack (or malloced if big) buffer. That will also simplify the code be removing all the copies and -EFAULT returns. Only the size checks will be needed and the code can assume the buffer is at least the size of the on-stack buffer. Our SCTP code uses SO_REUSADDR, SCTP_EVENTS, SCTP_NODELAY, SCTP_STATUS, SCTP_INITMSG, IPV6_ONLY, SCTP_SOCKOPT_BINDX_ADD and SO_LINGER. David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)
From: David Laight > Sent: 14 May 2020 10:51 > From: Marcelo Ricardo Leitner > > Sent: 13 May 2020 19:03 > > > > On Wed, May 13, 2020 at 08:26:47AM +0200, Christoph Hellwig wrote: > > > Add a helper to directly get the SCTP_PRIMARY_ADDR sockopt from kernel > > > space without going through a fake uaccess. > > > > Same comment as on the other dlm/sctp patch. > > Wouldn't it be best to write sctp_[gs]etsockotp() that > use a kernel buffer and then implement the user-space > calls using a wrapper that does the copies to an on-stack > (or malloced if big) buffer. Actually looking at __sys_setsockopt() it calls BPF_CGROUP_RUN_PROG_SETSOCKOPT() which (by the look of it) can copy the user buffer into malloc()ed memory and cause set_fs(KERNEL_DS) be called. The only way to get rid of that set_fs() is to always have the buffer in kernel memory when the underlying setsockopt() code is called. The comment above __sys_[sg]etsockopt() about not knowing the length is just wrong. It probably applied to getsockopt() in the dim and distant past before it was made read-update. David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)
From: David Laight > Sent: 14 May 2020 13:30 > Subject: RE: [PATCH 32/33] sctp: add sctp_sock_get_primary_addr > > From: David Laight > > Sent: 14 May 2020 10:51 > > From: Marcelo Ricardo Leitner > > > Sent: 13 May 2020 19:03 > > > > > > On Wed, May 13, 2020 at 08:26:47AM +0200, Christoph Hellwig wrote: > > > > Add a helper to directly get the SCTP_PRIMARY_ADDR sockopt from kernel > > > > space without going through a fake uaccess. > > > > > > Same comment as on the other dlm/sctp patch. > > > > Wouldn't it be best to write sctp_[gs]etsockotp() that > > use a kernel buffer and then implement the user-space > > calls using a wrapper that does the copies to an on-stack > > (or malloced if big) buffer. > > Actually looking at __sys_setsockopt() it calls > BPF_CGROUP_RUN_PROG_SETSOCKOPT() which (by the look of it) > can copy the user buffer into malloc()ed memory and > cause set_fs(KERNEL_DS) be called. > > The only way to get rid of that set_fs() is to always > have the buffer in kernel memory when the underlying > setsockopt() code is called. And having started to try coding __sys_setsockopt() and then found the compat code I suspect that would be a whole lot more sane if the buffer was in kernel and it knew that at least (say) 64 bytes were allocated. The whole compat_alloc_user_space() 'crap' could probably go. Actually it looks like an application can avoid whatever checks BPF_CGROUP_RUN_PROG_SETSOCKOPT() is trying to do by using the 32bit compat ioctls. David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)
diff --git a/fs/dlm/lowcomms.c b/fs/dlm/lowcomms.c index 6fa45365666a8..46d2d71b62c57 100644 --- a/fs/dlm/lowcomms.c +++ b/fs/dlm/lowcomms.c @@ -855,10 +855,9 @@ static int tcp_accept_from_sock(struct connection *con) static int sctp_accept_from_sock(struct connection *con) { /* Check that the new node is in the lockspace */ - struct sctp_prim prim; + struct sctp_prim prim = { }; int nodeid; - int prim_len, ret; - int addr_len; + int addr_len, ret; struct connection *newcon; struct connection *addcon; struct socket *newsock; @@ -876,11 +875,7 @@ static int sctp_accept_from_sock(struct connection *con) if (ret < 0) goto accept_err; - memset(&prim, 0, sizeof(struct sctp_prim)); - prim_len = sizeof(struct sctp_prim); - - ret = kernel_getsockopt(newsock, IPPROTO_SCTP, SCTP_PRIMARY_ADDR, - (char *)&prim, &prim_len); + ret = sctp_sock_get_primary_addr(con->sock->sk, &prim); if (ret < 0) { log_print("getsockopt/sctp_primary_addr failed: %d", ret); goto accept_err; diff --git a/include/net/sctp/sctp.h b/include/net/sctp/sctp.h index b505fa082f254..c98b1d14db853 100644 --- a/include/net/sctp/sctp.h +++ b/include/net/sctp/sctp.h @@ -618,5 +618,6 @@ static inline bool sctp_newsk_ready(const struct sock *sk) int sctp_setsockopt_bindx(struct sock *sk, struct sockaddr *kaddrs, int addrs_size, int op); void sctp_sock_set_nodelay(struct sock *sk, bool val); +int sctp_sock_get_primary_addr(struct sock *sk, struct sctp_prim *prim); #endif /* __net_sctp_h__ */ diff --git a/net/sctp/socket.c b/net/sctp/socket.c index 64c395f7a86d5..39bf8090dbe1e 100644 --- a/net/sctp/socket.c +++ b/net/sctp/socket.c @@ -6411,6 +6411,35 @@ static int sctp_getsockopt_local_addrs(struct sock *sk, int len, return err; } +static int __sctp_sock_get_primary_addr(struct sock *sk, struct sctp_prim *prim) +{ + struct sctp_association *asoc; + + asoc = sctp_id2assoc(sk, prim->ssp_assoc_id); + if (!asoc) + return -EINVAL; + if (!asoc->peer.primary_path) + return -ENOTCONN; + + memcpy(&prim->ssp_addr, &asoc->peer.primary_path->ipaddr, + asoc->peer.primary_path->af_specific->sockaddr_len); + + sctp_get_pf_specific(sk->sk_family)->addr_to_user(sctp_sk(sk), + (union sctp_addr *)&prim->ssp_addr); + return 0; +} + +int sctp_sock_get_primary_addr(struct sock *sk, struct sctp_prim *prim) +{ + int ret; + + lock_sock(sk); + ret = __sctp_sock_get_primary_addr(sk, prim); + release_sock(sk); + return ret; +} +EXPORT_SYMBOL(sctp_sock_get_primary_addr); + /* 7.1.10 Set Primary Address (SCTP_PRIMARY_ADDR) * * Requests that the local SCTP stack use the enclosed peer address as @@ -6421,35 +6450,19 @@ static int sctp_getsockopt_primary_addr(struct sock *sk, int len, char __user *optval, int __user *optlen) { struct sctp_prim prim; - struct sctp_association *asoc; - struct sctp_sock *sp = sctp_sk(sk); + int ret; if (len < sizeof(struct sctp_prim)) return -EINVAL; - - len = sizeof(struct sctp_prim); - - if (copy_from_user(&prim, optval, len)) + if (copy_from_user(&prim, optval, sizeof(struct sctp_prim))) return -EFAULT; - asoc = sctp_id2assoc(sk, prim.ssp_assoc_id); - if (!asoc) - return -EINVAL; - - if (!asoc->peer.primary_path) - return -ENOTCONN; - - memcpy(&prim.ssp_addr, &asoc->peer.primary_path->ipaddr, - asoc->peer.primary_path->af_specific->sockaddr_len); - - sctp_get_pf_specific(sk->sk_family)->addr_to_user(sp, - (union sctp_addr *)&prim.ssp_addr); + ret = __sctp_sock_get_primary_addr(sk, &prim); + if (ret) + return ret; - if (put_user(len, optlen)) + if (put_user(len, optlen) || copy_to_user(optval, &prim, len)) return -EFAULT; - if (copy_to_user(optval, &prim, len)) - return -EFAULT; - return 0; }
Add a helper to directly get the SCTP_PRIMARY_ADDR sockopt from kernel space without going through a fake uaccess. Signed-off-by: Christoph Hellwig <hch@lst.de> --- fs/dlm/lowcomms.c | 11 +++----- include/net/sctp/sctp.h | 1 + net/sctp/socket.c | 57 +++++++++++++++++++++++++---------------- 3 files changed, 39 insertions(+), 30 deletions(-)