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FROMGIT: net: Revert "net: optimize the sockptr_t for unified kernel/user address spaces"

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This reverts commits 6d04fe15f7 and
a31edb2059.

It turns out the idea to share a single pointer for both kernel and user
space address causes various kinds of problems.  So use the slightly less
optimal version that uses an extra bit, but which is guaranteed to be safe
everywhere.

Fixes: 6d04fe15f7 ("net: optimize the sockptr_t for unified kernel/user address spaces")
Reported-by: Eric Dumazet <edumazet@google.com>
Reported-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
(cherry picked from commit 519a8a6cf9
 https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net.git master)
Signed-off-by: John Stultz <john.stultz@linaro.org>
Change-Id: I645a8226be732b72cf8a404957754e3408dfc4bc
This commit is contained in:
Christoph Hellwig
2020-08-10 18:42:14 +02:00
committed by Greg Kroah-Hartman
parent ad29e85a9d
commit 0895708c5c
3 changed files with 9 additions and 37 deletions
Download Patch File Download Diff File Expand all files Collapse all files

26
include/linux/sockptr.h
View File

@@ -8,26 +8,9 @@
#ifndef _LINUX_SOCKPTR_H
#define _LINUX_SOCKPTR_H
#include <linux/compiler.h>
#include <linux/slab.h>
#include <linux/uaccess.h>
#ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
typedef union {
void *kernel;
void __user *user;
} sockptr_t;
static inline bool sockptr_is_kernel(sockptr_t sockptr)
{
return (unsigned long)sockptr.kernel >= TASK_SIZE;
}
static inline sockptr_t KERNEL_SOCKPTR(void *p)
{
return (sockptr_t) { .kernel = p };
}
#else /* CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE */
typedef struct {
union {
void *kernel;
@@ -45,15 +28,10 @@ static inline sockptr_t KERNEL_SOCKPTR(void *p)
{
return (sockptr_t) { .kernel = p, .is_kernel = true };
}
#endif /* CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE */
static inline int __must_check init_user_sockptr(sockptr_t *sp, void __user *p,
size_t size)
static inline sockptr_t USER_SOCKPTR(void __user *p)
{
if (!access_ok(p, size))
return -EFAULT;
*sp = (sockptr_t) { .user = p };
return 0;
return (sockptr_t) { .user = p };
}
static inline bool sockptr_is_null(sockptr_t sockptr)

14
net/ipv4/bpfilter/sockopt.c
View File

@@ -57,18 +57,16 @@ int bpfilter_ip_set_sockopt(struct sock *sk, int optname, sockptr_t optval,
return bpfilter_mbox_request(sk, optname, optval, optlen, true);
}
int bpfilter_ip_get_sockopt(struct sock *sk, int optname,
char __user *user_optval, int __user *optlen)
int bpfilter_ip_get_sockopt(struct sock *sk, int optname, char __user *optval,
int __user *optlen)
{
sockptr_t optval;
int err, len;
int len;
if (get_user(len, optlen))
return -EFAULT;
err = init_user_sockptr(&optval, user_optval, len);
if (err)
return err;
return bpfilter_mbox_request(sk, optname, optval, len, false);
return bpfilter_mbox_request(sk, optname, USER_SOCKPTR(optval), len,
false);
}
static int __init bpfilter_sockopt_init(void)

6
net/socket.c
View File

@@ -2098,7 +2098,7 @@ static bool sock_use_custom_sol_socket(const struct socket *sock)
int __sys_setsockopt(int fd, int level, int optname, char __user *user_optval,
int optlen)
{
sockptr_t optval;
sockptr_t optval = USER_SOCKPTR(user_optval);
char *kernel_optval = NULL;
int err, fput_needed;
struct socket *sock;
@@ -2106,10 +2106,6 @@ int __sys_setsockopt(int fd, int level, int optname, char __user *user_optval,
if (optlen < 0)
return -EINVAL;
err = init_user_sockptr(&optval, user_optval, optlen);
if (err)
return err;
sock = sockfd_lookup_light(fd, &err, &fput_needed);
if (!sock)
return err;