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Subject[PATCH 2/4] sctp: refactor sctp_setsockopt_bindx
Date
Split out a sctp_setsockopt_bindx_kernel that takes a kernel pointer
to the sockaddr and make sctp_setsockopt_bindx a small wrapper around
it. This prepares for adding a new bind_add proto op.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
net/sctp/socket.c | 61 ++++++++++++++++++++++-------------------------
1 file changed, 28 insertions(+), 33 deletions(-)

diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index 827a9903ee288..6e745ac3c4a59 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -972,23 +972,22 @@ int sctp_asconf_mgmt(struct sctp_sock *sp, struct sctp_sockaddr_entry *addrw)
* it.
*
* sk The sk of the socket
- * addrs The pointer to the addresses in user land
+ * addrs The pointer to the addresses
* addrssize Size of the addrs buffer
* op Operation to perform (add or remove, see the flags of
* sctp_bindx)
*
* Returns 0 if ok, <0 errno code on error.
*/
-static int sctp_setsockopt_bindx(struct sock *sk,
- struct sockaddr __user *addrs,
- int addrs_size, int op)
+static int sctp_setsockopt_bindx_kernel(struct sock *sk,
+ struct sockaddr *addrs, int addrs_size,
+ int op)
{
- struct sockaddr *kaddrs;
int err;
int addrcnt = 0;
int walk_size = 0;
struct sockaddr *sa_addr;
- void *addr_buf;
+ void *addr_buf = addrs;
struct sctp_af *af;

pr_debug("%s: sk:%p addrs:%p addrs_size:%d opt:%d\n",
@@ -997,17 +996,10 @@ static int sctp_setsockopt_bindx(struct sock *sk,
if (unlikely(addrs_size <= 0))
return -EINVAL;

- kaddrs = memdup_user(addrs, addrs_size);
- if (IS_ERR(kaddrs))
- return PTR_ERR(kaddrs);
-
/* Walk through the addrs buffer and count the number of addresses. */
- addr_buf = kaddrs;
while (walk_size < addrs_size) {
- if (walk_size + sizeof(sa_family_t) > addrs_size) {
- kfree(kaddrs);
+ if (walk_size + sizeof(sa_family_t) > addrs_size)
return -EINVAL;
- }

sa_addr = addr_buf;
af = sctp_get_af_specific(sa_addr->sa_family);
@@ -1015,10 +1007,8 @@ static int sctp_setsockopt_bindx(struct sock *sk,
/* If the address family is not supported or if this address
* causes the address buffer to overflow return EINVAL.
*/
- if (!af || (walk_size + af->sockaddr_len) > addrs_size) {
- kfree(kaddrs);
+ if (!af || (walk_size + af->sockaddr_len) > addrs_size)
return -EINVAL;
- }
addrcnt++;
addr_buf += af->sockaddr_len;
walk_size += af->sockaddr_len;
@@ -1029,31 +1019,36 @@ static int sctp_setsockopt_bindx(struct sock *sk,
case SCTP_BINDX_ADD_ADDR:
/* Allow security module to validate bindx addresses. */
err = security_sctp_bind_connect(sk, SCTP_SOCKOPT_BINDX_ADD,
- (struct sockaddr *)kaddrs,
- addrs_size);
+ addrs, addrs_size);
if (err)
- goto out;
- err = sctp_bindx_add(sk, kaddrs, addrcnt);
+ return err;
+ err = sctp_bindx_add(sk, addrs, addrcnt);
if (err)
- goto out;
- err = sctp_send_asconf_add_ip(sk, kaddrs, addrcnt);
- break;
-
+ return err;
+ return sctp_send_asconf_add_ip(sk, addrs, addrcnt);
case SCTP_BINDX_REM_ADDR:
- err = sctp_bindx_rem(sk, kaddrs, addrcnt);
+ err = sctp_bindx_rem(sk, addrs, addrcnt);
if (err)
- goto out;
- err = sctp_send_asconf_del_ip(sk, kaddrs, addrcnt);
- break;
+ return err;
+ return sctp_send_asconf_del_ip(sk, addrs, addrcnt);

default:
- err = -EINVAL;
- break;
+ return -EINVAL;
}
+}

-out:
- kfree(kaddrs);
+static int sctp_setsockopt_bindx(struct sock *sk,
+ struct sockaddr __user *addrs,
+ int addrs_size, int op)
+{
+ struct sockaddr *kaddrs;
+ int err;

+ kaddrs = memdup_user(addrs, addrs_size);
+ if (IS_ERR(kaddrs))
+ return PTR_ERR(kaddrs);
+ err = sctp_setsockopt_bindx_kernel(sk, kaddrs, addrs_size, op);
+ kfree(kaddrs);
return err;
}

--
2.26.2
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