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Message-ID: <20141118194206.GC14641@ZenIV.linux.org.uk>
Date: Tue, 18 Nov 2014 19:42:06 +0000
From: Al Viro <viro@...IV.linux.org.uk>
To: netdev@...r.kernel.org
Cc: Linus Torvalds <torvalds@...ux-foundation.org>,
David Miller <davem@...emloft.net>,
linux-kernel@...r.kernel.org
Subject: [PATCH 2/5] {compat_,}verify_iovec(): switch to generic copying of
iovecs
use {compat_,}rw_copy_check_uvector(). As the result, we are
guaranteed that all iovecs seen in ->msg_iov by ->sendmsg()
and ->recvmsg() will pass access_ok(). The next commit removes
now redundant checks in callees...
Signed-off-by: Al Viro <viro@...iv.linux.org.uk>
---
net/compat.c | 51 +++++++++++++++------------------------------------
net/core/iovec.c | 37 ++++++++++++++-----------------------
net/socket.c | 38 ++++++++------------------------------
3 files changed, 37 insertions(+), 89 deletions(-)
diff --git a/net/compat.c b/net/compat.c
index 562e920..7b4b6ad 100644
--- a/net/compat.c
+++ b/net/compat.c
@@ -31,33 +31,6 @@
#include <asm/uaccess.h>
#include <net/compat.h>
-static inline int iov_from_user_compat_to_kern(struct iovec *kiov,
- struct compat_iovec __user *uiov32,
- int niov)
-{
- int tot_len = 0;
-
- while (niov > 0) {
- compat_uptr_t buf;
- compat_size_t len;
-
- if (get_user(len, &uiov32->iov_len) ||
- get_user(buf, &uiov32->iov_base))
- return -EFAULT;
-
- if (len > INT_MAX - tot_len)
- len = INT_MAX - tot_len;
-
- tot_len += len;
- kiov->iov_base = compat_ptr(buf);
- kiov->iov_len = (__kernel_size_t) len;
- uiov32++;
- kiov++;
- niov--;
- }
- return tot_len;
-}
-
int get_compat_msghdr(struct msghdr *kmsg, struct compat_msghdr __user *umsg)
{
compat_uptr_t tmp1, tmp2, tmp3;
@@ -80,13 +53,15 @@ int get_compat_msghdr(struct msghdr *kmsg, struct compat_msghdr __user *umsg)
}
/* I've named the args so it is easy to tell whose space the pointers are in. */
-int verify_compat_iovec(struct msghdr *kern_msg, struct iovec *kern_iov,
+int verify_compat_iovec(struct msghdr *kern_msg, struct iovec *iov,
struct sockaddr_storage *kern_address, int mode)
{
- int tot_len;
+ struct compat_iovec __user *p;
+ struct iovec *res;
+ int err;
if (kern_msg->msg_name && kern_msg->msg_namelen) {
- if (mode == VERIFY_READ) {
+ if (mode == WRITE) {
int err = move_addr_to_kernel(kern_msg->msg_name,
kern_msg->msg_namelen,
kern_address);
@@ -99,13 +74,17 @@ int verify_compat_iovec(struct msghdr *kern_msg, struct iovec *kern_iov,
kern_msg->msg_namelen = 0;
}
- tot_len = iov_from_user_compat_to_kern(kern_iov,
- (struct compat_iovec __user *)kern_msg->msg_iov,
- kern_msg->msg_iovlen);
- if (tot_len >= 0)
- kern_msg->msg_iov = kern_iov;
+ if (kern_msg->msg_iovlen > UIO_MAXIOV)
+ return -EMSGSIZE;
- return tot_len;
+ p = (struct compat_iovec __user *)kern_msg->msg_iov;
+ err = compat_rw_copy_check_uvector(mode, p, kern_msg->msg_iovlen,
+ UIO_FASTIOV, iov, &res);
+ if (err >= 0)
+ kern_msg->msg_iov = res;
+ else if (res != iov)
+ kfree(res);
+ return err;
}
/* Bleech... */
diff --git a/net/core/iovec.c b/net/core/iovec.c
index e1ec45a..86beeea 100644
--- a/net/core/iovec.c
+++ b/net/core/iovec.c
@@ -37,13 +37,13 @@
int verify_iovec(struct msghdr *m, struct iovec *iov, struct sockaddr_storage *address, int mode)
{
- int size, ct, err;
+ struct iovec *res;
+ int err;
if (m->msg_name && m->msg_namelen) {
- if (mode == VERIFY_READ) {
- void __user *namep;
- namep = (void __user __force *) m->msg_name;
- err = move_addr_to_kernel(namep, m->msg_namelen,
+ if (mode == WRITE) {
+ void __user *namep = (void __user __force *)m->msg_name;
+ int err = move_addr_to_kernel(namep, m->msg_namelen,
address);
if (err < 0)
return err;
@@ -53,24 +53,15 @@ int verify_iovec(struct msghdr *m, struct iovec *iov, struct sockaddr_storage *a
m->msg_name = NULL;
m->msg_namelen = 0;
}
-
- size = m->msg_iovlen * sizeof(struct iovec);
- if (copy_from_user(iov, (void __user __force *) m->msg_iov, size))
- return -EFAULT;
-
- m->msg_iov = iov;
- err = 0;
-
- for (ct = 0; ct < m->msg_iovlen; ct++) {
- size_t len = iov[ct].iov_len;
-
- if (len > INT_MAX - err) {
- len = INT_MAX - err;
- iov[ct].iov_len = len;
- }
- err += len;
- }
-
+ if (m->msg_iovlen > UIO_MAXIOV)
+ return -EMSGSIZE;
+
+ err = rw_copy_check_uvector(mode, (void __user __force *)m->msg_iov,
+ m->msg_iovlen, UIO_FASTIOV, iov, &res);
+ if (err >= 0)
+ m->msg_iov = res;
+ else if (res != iov)
+ kfree(res);
return err;
}
diff --git a/net/socket.c b/net/socket.c
index 0ae8147..59020f0 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -2032,24 +2032,14 @@ static int ___sys_sendmsg(struct socket *sock, struct user_msghdr __user *msg,
return err;
}
- if (msg_sys->msg_iovlen > UIO_FASTIOV) {
- err = -EMSGSIZE;
- if (msg_sys->msg_iovlen > UIO_MAXIOV)
- goto out;
- err = -ENOMEM;
- iov = kmalloc(msg_sys->msg_iovlen * sizeof(struct iovec),
- GFP_KERNEL);
- if (!iov)
- goto out;
- }
-
/* This will also move the address data into kernel space */
- if (MSG_CMSG_COMPAT & flags) {
- err = verify_compat_iovec(msg_sys, iov, &address, VERIFY_READ);
- } else
- err = verify_iovec(msg_sys, iov, &address, VERIFY_READ);
+ if (MSG_CMSG_COMPAT & flags)
+ err = verify_compat_iovec(msg_sys, iovstack, &address, WRITE);
+ else
+ err = verify_iovec(msg_sys, iovstack, &address, WRITE);
if (err < 0)
goto out_freeiov;
+ iov = msg_sys->msg_iov;
total_len = err;
err = -ENOBUFS;
@@ -2118,7 +2108,6 @@ out_freectl:
out_freeiov:
if (iov != iovstack)
kfree(iov);
-out:
return err;
}
@@ -2244,28 +2233,18 @@ static int ___sys_recvmsg(struct socket *sock, struct user_msghdr __user *msg,
return err;
}
- if (msg_sys->msg_iovlen > UIO_FASTIOV) {
- err = -EMSGSIZE;
- if (msg_sys->msg_iovlen > UIO_MAXIOV)
- goto out;
- err = -ENOMEM;
- iov = kmalloc(msg_sys->msg_iovlen * sizeof(struct iovec),
- GFP_KERNEL);
- if (!iov)
- goto out;
- }
-
/* Save the user-mode address (verify_iovec will change the
* kernel msghdr to use the kernel address space)
*/
uaddr = (__force void __user *)msg_sys->msg_name;
uaddr_len = COMPAT_NAMELEN(msg);
if (MSG_CMSG_COMPAT & flags)
- err = verify_compat_iovec(msg_sys, iov, &addr, VERIFY_WRITE);
+ err = verify_compat_iovec(msg_sys, iovstack, &addr, READ);
else
- err = verify_iovec(msg_sys, iov, &addr, VERIFY_WRITE);
+ err = verify_iovec(msg_sys, iovstack, &addr, READ);
if (err < 0)
goto out_freeiov;
+ iov = msg_sys->msg_iov;
total_len = err;
cmsg_ptr = (unsigned long)msg_sys->msg_control;
@@ -2306,7 +2285,6 @@ static int ___sys_recvmsg(struct socket *sock, struct user_msghdr __user *msg,
out_freeiov:
if (iov != iovstack)
kfree(iov);
-out:
return err;
}
--
1.7.10.4
--
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