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sctp: use vmemdup_user() rather than badly open-coding memdup_user()

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Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2018-01-07 13:19:09 -05:00
parent 59aeaf3fef
commit c981f254cc
1 changed files with 11 additions and 48 deletions
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59
net/sctp/socket.c
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@ -970,13 +970,6 @@ int sctp_asconf_mgmt(struct sctp_sock *sp, struct sctp_sockaddr_entry *addrw)
* This is used for tunneling the sctp_bindx() request through sctp_setsockopt() * This is used for tunneling the sctp_bindx() request through sctp_setsockopt()
* from userspace. * from userspace.
* *
* We don't use copy_from_user() for optimization: we first do the
* sanity checks (buffer size -fast- and access check-healthy
* pointer); if all of those succeed, then we can alloc the memory
* (expensive operation) needed to copy the data to kernel. Then we do
* the copying without checking the user space area
* (__copy_from_user()).
*
* On exit there is no need to do sockfd_put(), sys_setsockopt() does * On exit there is no need to do sockfd_put(), sys_setsockopt() does
* it. * it.
* *
@ -1006,25 +999,15 @@ static int sctp_setsockopt_bindx(struct sock *sk,
if (unlikely(addrs_size <= 0)) if (unlikely(addrs_size <= 0))
return -EINVAL; return -EINVAL;
/* Check the user passed a healthy pointer. */ kaddrs = vmemdup_user(addrs, addrs_size);
if (unlikely(!access_ok(VERIFY_READ, addrs, addrs_size))) if (unlikely(IS_ERR(kaddrs)))
return -EFAULT; return PTR_ERR(kaddrs);
/* Alloc space for the address array in kernel memory. */
kaddrs = kmalloc(addrs_size, GFP_USER | __GFP_NOWARN);
if (unlikely(!kaddrs))
return -ENOMEM;
if (__copy_from_user(kaddrs, addrs, addrs_size)) {
kfree(kaddrs);
return -EFAULT;
}
/* Walk through the addrs buffer and count the number of addresses. */ /* Walk through the addrs buffer and count the number of addresses. */
addr_buf = kaddrs; addr_buf = kaddrs;
while (walk_size < addrs_size) { while (walk_size < addrs_size) {
if (walk_size + sizeof(sa_family_t) > addrs_size) { if (walk_size + sizeof(sa_family_t) > addrs_size) {
kfree(kaddrs); kvfree(kaddrs);
return -EINVAL; return -EINVAL;
} }
@ -1035,7 +1018,7 @@ static int sctp_setsockopt_bindx(struct sock *sk,
* causes the address buffer to overflow return EINVAL. * causes the address buffer to overflow return EINVAL.
*/ */
if (!af || (walk_size + af->sockaddr_len) > addrs_size) { if (!af || (walk_size + af->sockaddr_len) > addrs_size) {
kfree(kaddrs); kvfree(kaddrs);
return -EINVAL; return -EINVAL;
} }
addrcnt++; addrcnt++;
@ -1065,7 +1048,7 @@ static int sctp_setsockopt_bindx(struct sock *sk,
} }
out: out:
kfree(kaddrs); kvfree(kaddrs);
return err; return err;
} }
@ -1323,13 +1306,6 @@ out_free:
* land and invoking either sctp_connectx(). This is used for tunneling * land and invoking either sctp_connectx(). This is used for tunneling
* the sctp_connectx() request through sctp_setsockopt() from userspace. * the sctp_connectx() request through sctp_setsockopt() from userspace.
* *
* We don't use copy_from_user() for optimization: we first do the
* sanity checks (buffer size -fast- and access check-healthy
* pointer); if all of those succeed, then we can alloc the memory
* (expensive operation) needed to copy the data to kernel. Then we do
* the copying without checking the user space area
* (__copy_from_user()).
*
* On exit there is no need to do sockfd_put(), sys_setsockopt() does * On exit there is no need to do sockfd_put(), sys_setsockopt() does
* it. * it.
* *
@ -1345,7 +1321,6 @@ static int __sctp_setsockopt_connectx(struct sock *sk,
sctp_assoc_t *assoc_id) sctp_assoc_t *assoc_id)
{ {
struct sockaddr *kaddrs; struct sockaddr *kaddrs;
gfp_t gfp = GFP_KERNEL;
int err = 0; int err = 0;
pr_debug("%s: sk:%p addrs:%p addrs_size:%d\n", pr_debug("%s: sk:%p addrs:%p addrs_size:%d\n",
@ -1354,24 +1329,12 @@ static int __sctp_setsockopt_connectx(struct sock *sk,
if (unlikely(addrs_size <= 0)) if (unlikely(addrs_size <= 0))
return -EINVAL; return -EINVAL;
/* Check the user passed a healthy pointer. */ kaddrs = vmemdup_user(addrs, addrs_size);
if (unlikely(!access_ok(VERIFY_READ, addrs, addrs_size))) if (unlikely(IS_ERR(kaddrs)))
return -EFAULT; return PTR_ERR(kaddrs);
/* Alloc space for the address array in kernel memory. */ err = __sctp_connect(sk, kaddrs, addrs_size, assoc_id);
if (sk->sk_socket->file) kvfree(kaddrs);
gfp = GFP_USER | __GFP_NOWARN;
kaddrs = kmalloc(addrs_size, gfp);
if (unlikely(!kaddrs))
return -ENOMEM;
if (__copy_from_user(kaddrs, addrs, addrs_size)) {
err = -EFAULT;
} else {
err = __sctp_connect(sk, kaddrs, addrs_size, assoc_id);
}
kfree(kaddrs);
return err; return err;
} }