From 5dae773138986901a3578d35c5138b1416e1d1b1 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Mon, 10 Aug 2020 18:42:14 +0200 Subject: [PATCH] net: Revert "net: optimize the sockptr_t for unified kernel/user address spaces" This reverts commits d238c60e3a7dd82f15f62de7828f3e0a8cb3900e and e8bb81db6b359a8361cb6eba29431e98b2a1a42d. 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: d238c60e3a7d ("net: optimize the sockptr_t for unified kernel/user address spaces") Reported-by: Eric Dumazet Reported-by: John Stultz Signed-off-by: Christoph Hellwig Signed-off-by: David S. Miller --- include/linux/sockptr.h | 26 ++------------------------ net/ipv4/bpfilter/sockopt.c | 14 ++++++-------- net/socket.c | 6 +----- 3 files changed, 9 insertions(+), 37 deletions(-) diff --git a/include/linux/sockptr.h b/include/linux/sockptr.h index 96840def9d69c..ea193414298b7 100644 --- a/include/linux/sockptr.h +++ b/include/linux/sockptr.h @@ -8,26 +8,9 @@ #ifndef _LINUX_SOCKPTR_H #define _LINUX_SOCKPTR_H -#include #include #include -#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) diff --git a/net/ipv4/bpfilter/sockopt.c b/net/ipv4/bpfilter/sockopt.c index 545b2640f0194..1b34cb9a7708e 100644 --- a/net/ipv4/bpfilter/sockopt.c +++ b/net/ipv4/bpfilter/sockopt.c @@ -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) diff --git a/net/socket.c b/net/socket.c index f4d5998bdcbad..dbbe8ea7d395d 100644 --- a/net/socket.c +++ b/net/socket.c @@ -2095,7 +2095,7 @@ 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; @@ -2103,10 +2103,6 @@ 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; -- 2.39.5