reintroduce accept4
Introduce a new accept4() system call. The addition of this system call matches analogous changes in 2.6.27 (dup3(), evenfd2(), signalfd4(), inotify_init1(), epoll_create1(), pipe2()) which added new system calls that differed from analogous traditional system calls in adding a flags argument that can be used to access additional functionality. The accept4() system call is exactly the same as accept(), except that it adds a flags bit-mask argument. Two flags are initially implemented. (Most of the new system calls in 2.6.27 also had both of these flags.) SOCK_CLOEXEC causes the close-on-exec (FD_CLOEXEC) flag to be enabled for the new file descriptor returned by accept4(). This is a useful security feature to avoid leaking information in a multithreaded program where one thread is doing an accept() at the same time as another thread is doing a fork() plus exec(). More details here: http://udrepper.livejournal.com/20407.html "Secure File Descriptor Handling", Ulrich Drepper). The other flag is SOCK_NONBLOCK, which causes the O_NONBLOCK flag to be enabled on the new open file description created by accept4(). (This flag is merely a convenience, saving the use of additional calls fcntl(F_GETFL) and fcntl (F_SETFL) to achieve the same result. Here's a test program. Works on x86-32. Should work on x86-64, but I (mtk) don't have a system to hand to test with. It tests accept4() with each of the four possible combinations of SOCK_CLOEXEC and SOCK_NONBLOCK set/clear in 'flags', and verifies that the appropriate flags are set on the file descriptor/open file description returned by accept4(). I tested Ulrich's patch in this thread by applying against 2.6.28-rc2, and it passes according to my test program. /* test_accept4.c Copyright (C) 2008, Linux Foundation, written by Michael Kerrisk <mtk.manpages@gmail.com> Licensed under the GNU GPLv2 or later. */ #define _GNU_SOURCE #include <unistd.h> #include <sys/syscall.h> #include <sys/socket.h> #include <netinet/in.h> #include <stdlib.h> #include <fcntl.h> #include <stdio.h> #include <string.h> #define PORT_NUM 33333 #define die(msg) do { perror(msg); exit(EXIT_FAILURE); } while (0) /**********************************************************************/ /* The following is what we need until glibc gets a wrapper for accept4() */ /* Flags for socket(), socketpair(), accept4() */ #ifndef SOCK_CLOEXEC #define SOCK_CLOEXEC O_CLOEXEC #endif #ifndef SOCK_NONBLOCK #define SOCK_NONBLOCK O_NONBLOCK #endif #ifdef __x86_64__ #define SYS_accept4 288 #elif __i386__ #define USE_SOCKETCALL 1 #define SYS_ACCEPT4 18 #else #error "Sorry -- don't know the syscall # on this architecture" #endif static int accept4(int fd, struct sockaddr *sockaddr, socklen_t *addrlen, int flags) { printf("Calling accept4(): flags = %x", flags); if (flags != 0) { printf(" ("); if (flags & SOCK_CLOEXEC) printf("SOCK_CLOEXEC"); if ((flags & SOCK_CLOEXEC) && (flags & SOCK_NONBLOCK)) printf(" "); if (flags & SOCK_NONBLOCK) printf("SOCK_NONBLOCK"); printf(")"); } printf("\n"); #if USE_SOCKETCALL long args[6]; args[0] = fd; args[1] = (long) sockaddr; args[2] = (long) addrlen; args[3] = flags; return syscall(SYS_socketcall, SYS_ACCEPT4, args); #else return syscall(SYS_accept4, fd, sockaddr, addrlen, flags); #endif } /**********************************************************************/ static int do_test(int lfd, struct sockaddr_in *conn_addr, int closeonexec_flag, int nonblock_flag) { int connfd, acceptfd; int fdf, flf, fdf_pass, flf_pass; struct sockaddr_in claddr; socklen_t addrlen; printf("=======================================\n"); connfd = socket(AF_INET, SOCK_STREAM, 0); if (connfd == -1) die("socket"); if (connect(connfd, (struct sockaddr *) conn_addr, sizeof(struct sockaddr_in)) == -1) die("connect"); addrlen = sizeof(struct sockaddr_in); acceptfd = accept4(lfd, (struct sockaddr *) &claddr, &addrlen, closeonexec_flag | nonblock_flag); if (acceptfd == -1) { perror("accept4()"); close(connfd); return 0; } fdf = fcntl(acceptfd, F_GETFD); if (fdf == -1) die("fcntl:F_GETFD"); fdf_pass = ((fdf & FD_CLOEXEC) != 0) == ((closeonexec_flag & SOCK_CLOEXEC) != 0); printf("Close-on-exec flag is %sset (%s); ", (fdf & FD_CLOEXEC) ? "" : "not ", fdf_pass ? "OK" : "failed"); flf = fcntl(acceptfd, F_GETFL); if (flf == -1) die("fcntl:F_GETFD"); flf_pass = ((flf & O_NONBLOCK) != 0) == ((nonblock_flag & SOCK_NONBLOCK) !=0); printf("nonblock flag is %sset (%s)\n", (flf & O_NONBLOCK) ? "" : "not ", flf_pass ? "OK" : "failed"); close(acceptfd); close(connfd); printf("Test result: %s\n", (fdf_pass && flf_pass) ? "PASS" : "FAIL"); return fdf_pass && flf_pass; } static int create_listening_socket(int port_num) { struct sockaddr_in svaddr; int lfd; int optval; memset(&svaddr, 0, sizeof(struct sockaddr_in)); svaddr.sin_family = AF_INET; svaddr.sin_addr.s_addr = htonl(INADDR_ANY); svaddr.sin_port = htons(port_num); lfd = socket(AF_INET, SOCK_STREAM, 0); if (lfd == -1) die("socket"); optval = 1; if (setsockopt(lfd, SOL_SOCKET, SO_REUSEADDR, &optval, sizeof(optval)) == -1) die("setsockopt"); if (bind(lfd, (struct sockaddr *) &svaddr, sizeof(struct sockaddr_in)) == -1) die("bind"); if (listen(lfd, 5) == -1) die("listen"); return lfd; } int main(int argc, char *argv[]) { struct sockaddr_in conn_addr; int lfd; int port_num; int passed; passed = 1; port_num = (argc > 1) ? atoi(argv[1]) : PORT_NUM; memset(&conn_addr, 0, sizeof(struct sockaddr_in)); conn_addr.sin_family = AF_INET; conn_addr.sin_addr.s_addr = htonl(INADDR_LOOPBACK); conn_addr.sin_port = htons(port_num); lfd = create_listening_socket(port_num); if (!do_test(lfd, &conn_addr, 0, 0)) passed = 0; if (!do_test(lfd, &conn_addr, SOCK_CLOEXEC, 0)) passed = 0; if (!do_test(lfd, &conn_addr, 0, SOCK_NONBLOCK)) passed = 0; if (!do_test(lfd, &conn_addr, SOCK_CLOEXEC, SOCK_NONBLOCK)) passed = 0; close(lfd); exit(passed ? EXIT_SUCCESS : EXIT_FAILURE); } [mtk.manpages@gmail.com: rewrote changelog, updated test program] Signed-off-by: Ulrich Drepper <drepper@redhat.com> Tested-by: Michael Kerrisk <mtk.manpages@gmail.com> Acked-by: Michael Kerrisk <mtk.manpages@gmail.com> Cc: <linux-api@vger.kernel.org> Cc: <linux-arch@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Ulrich Drepper
Linus Torvalds
Родитель
cf7ee554f3
Коммит
de11defebf
|
|
@ -639,8 +639,8 @@ __SYSCALL(__NR_fallocate, sys_fallocate)
|
|||
__SYSCALL(__NR_timerfd_settime, sys_timerfd_settime)
|
||||
#define __NR_timerfd_gettime 287
|
||||
__SYSCALL(__NR_timerfd_gettime, sys_timerfd_gettime)
|
||||
#define __NR_paccept 288
|
||||
__SYSCALL(__NR_paccept, sys_paccept)
|
||||
#define __NR_accept4 288
|
||||
__SYSCALL(__NR_accept4, sys_accept4)
|
||||
#define __NR_signalfd4 289
|
||||
__SYSCALL(__NR_signalfd4, sys_signalfd4)
|
||||
#define __NR_eventfd2 290
|
||||
|
|
|
|||
|
|
@ -40,7 +40,7 @@
|
|||
#define SYS_GETSOCKOPT 15 /* sys_getsockopt(2) */
|
||||
#define SYS_SENDMSG 16 /* sys_sendmsg(2) */
|
||||
#define SYS_RECVMSG 17 /* sys_recvmsg(2) */
|
||||
#define SYS_PACCEPT 18 /* sys_paccept(2) */
|
||||
#define SYS_ACCEPT4 18 /* sys_accept4(2) */
|
||||
|
||||
typedef enum {
|
||||
SS_FREE = 0, /* not allocated */
|
||||
|
|
@ -100,7 +100,7 @@ enum sock_type {
|
|||
* remaining bits are used as flags. */
|
||||
#define SOCK_TYPE_MASK 0xf
|
||||
|
||||
/* Flags for socket, socketpair, paccept */
|
||||
/* Flags for socket, socketpair, accept4 */
|
||||
#define SOCK_CLOEXEC O_CLOEXEC
|
||||
#ifndef SOCK_NONBLOCK
|
||||
#define SOCK_NONBLOCK O_NONBLOCK
|
||||
|
|
@ -223,8 +223,6 @@ extern int sock_map_fd(struct socket *sock, int flags);
|
|||
extern struct socket *sockfd_lookup(int fd, int *err);
|
||||
#define sockfd_put(sock) fput(sock->file)
|
||||
extern int net_ratelimit(void);
|
||||
extern long do_accept(int fd, struct sockaddr __user *upeer_sockaddr,
|
||||
int __user *upeer_addrlen, int flags);
|
||||
|
||||
#define net_random() random32()
|
||||
#define net_srandom(seed) srandom32((__force u32)seed)
|
||||
|
|
|
|||
|
|
@ -410,8 +410,7 @@ asmlinkage long sys_getsockopt(int fd, int level, int optname,
|
|||
asmlinkage long sys_bind(int, struct sockaddr __user *, int);
|
||||
asmlinkage long sys_connect(int, struct sockaddr __user *, int);
|
||||
asmlinkage long sys_accept(int, struct sockaddr __user *, int __user *);
|
||||
asmlinkage long sys_paccept(int, struct sockaddr __user *, int __user *,
|
||||
const __user sigset_t *, size_t, int);
|
||||
asmlinkage long sys_accept4(int, struct sockaddr __user *, int __user *, int);
|
||||
asmlinkage long sys_getsockname(int, struct sockaddr __user *, int __user *);
|
||||
asmlinkage long sys_getpeername(int, struct sockaddr __user *, int __user *);
|
||||
asmlinkage long sys_send(int, void __user *, size_t, unsigned);
|
||||
|
|
|
|||
|
|
@ -31,7 +31,7 @@ cond_syscall(sys_socketpair);
|
|||
cond_syscall(sys_bind);
|
||||
cond_syscall(sys_listen);
|
||||
cond_syscall(sys_accept);
|
||||
cond_syscall(sys_paccept);
|
||||
cond_syscall(sys_accept4);
|
||||
cond_syscall(sys_connect);
|
||||
cond_syscall(sys_getsockname);
|
||||
cond_syscall(sys_getpeername);
|
||||
|
|
|
|||
50
net/compat.c
50
net/compat.c
|
|
@ -725,7 +725,7 @@ EXPORT_SYMBOL(compat_mc_getsockopt);
|
|||
static unsigned char nas[19]={AL(0),AL(3),AL(3),AL(3),AL(2),AL(3),
|
||||
AL(3),AL(3),AL(4),AL(4),AL(4),AL(6),
|
||||
AL(6),AL(2),AL(5),AL(5),AL(3),AL(3),
|
||||
AL(6)};
|
||||
AL(4)};
|
||||
#undef AL
|
||||
|
||||
asmlinkage long compat_sys_sendmsg(int fd, struct compat_msghdr __user *msg, unsigned flags)
|
||||
|
|
@ -738,52 +738,13 @@ asmlinkage long compat_sys_recvmsg(int fd, struct compat_msghdr __user *msg, uns
|
|||
return sys_recvmsg(fd, (struct msghdr __user *)msg, flags | MSG_CMSG_COMPAT);
|
||||
}
|
||||
|
||||
asmlinkage long compat_sys_paccept(int fd, struct sockaddr __user *upeer_sockaddr,
|
||||
int __user *upeer_addrlen,
|
||||
const compat_sigset_t __user *sigmask,
|
||||
compat_size_t sigsetsize, int flags)
|
||||
{
|
||||
compat_sigset_t ss32;
|
||||
sigset_t ksigmask, sigsaved;
|
||||
int ret;
|
||||
|
||||
if (sigmask) {
|
||||
if (sigsetsize != sizeof(compat_sigset_t))
|
||||
return -EINVAL;
|
||||
if (copy_from_user(&ss32, sigmask, sizeof(ss32)))
|
||||
return -EFAULT;
|
||||
sigset_from_compat(&ksigmask, &ss32);
|
||||
|
||||
sigdelsetmask(&ksigmask, sigmask(SIGKILL)|sigmask(SIGSTOP));
|
||||
sigprocmask(SIG_SETMASK, &ksigmask, &sigsaved);
|
||||
}
|
||||
|
||||
ret = do_accept(fd, upeer_sockaddr, upeer_addrlen, flags);
|
||||
|
||||
if (ret == -ERESTARTNOHAND) {
|
||||
/*
|
||||
* Don't restore the signal mask yet. Let do_signal() deliver
|
||||
* the signal on the way back to userspace, before the signal
|
||||
* mask is restored.
|
||||
*/
|
||||
if (sigmask) {
|
||||
memcpy(¤t->saved_sigmask, &sigsaved,
|
||||
sizeof(sigsaved));
|
||||
set_restore_sigmask();
|
||||
}
|
||||
} else if (sigmask)
|
||||
sigprocmask(SIG_SETMASK, &sigsaved, NULL);
|
||||
|
||||
return ret;
|
||||
}
|
||||
|
||||
asmlinkage long compat_sys_socketcall(int call, u32 __user *args)
|
||||
{
|
||||
int ret;
|
||||
u32 a[6];
|
||||
u32 a0, a1;
|
||||
|
||||
if (call < SYS_SOCKET || call > SYS_PACCEPT)
|
||||
if (call < SYS_SOCKET || call > SYS_ACCEPT4)
|
||||
return -EINVAL;
|
||||
if (copy_from_user(a, args, nas[call]))
|
||||
return -EFAULT;
|
||||
|
|
@ -804,7 +765,7 @@ asmlinkage long compat_sys_socketcall(int call, u32 __user *args)
|
|||
ret = sys_listen(a0, a1);
|
||||
break;
|
||||
case SYS_ACCEPT:
|
||||
ret = do_accept(a0, compat_ptr(a1), compat_ptr(a[2]), 0);
|
||||
ret = sys_accept4(a0, compat_ptr(a1), compat_ptr(a[2]), 0);
|
||||
break;
|
||||
case SYS_GETSOCKNAME:
|
||||
ret = sys_getsockname(a0, compat_ptr(a1), compat_ptr(a[2]));
|
||||
|
|
@ -844,9 +805,8 @@ asmlinkage long compat_sys_socketcall(int call, u32 __user *args)
|
|||
case SYS_RECVMSG:
|
||||
ret = compat_sys_recvmsg(a0, compat_ptr(a1), a[2]);
|
||||
break;
|
||||
case SYS_PACCEPT:
|
||||
ret = compat_sys_paccept(a0, compat_ptr(a1), compat_ptr(a[2]),
|
||||
compat_ptr(a[3]), a[4], a[5]);
|
||||
case SYS_ACCEPT4:
|
||||
ret = sys_accept4(a0, compat_ptr(a1), compat_ptr(a[2]), a[3]);
|
||||
break;
|
||||
default:
|
||||
ret = -EINVAL;
|
||||
|
|
|
|||
80
net/socket.c
80
net/socket.c
|
|
@ -1426,8 +1426,8 @@ asmlinkage long sys_listen(int fd, int backlog)
|
|||
* clean when we restucture accept also.
|
||||
*/
|
||||
|
||||
long do_accept(int fd, struct sockaddr __user *upeer_sockaddr,
|
||||
int __user *upeer_addrlen, int flags)
|
||||
asmlinkage long sys_accept4(int fd, struct sockaddr __user *upeer_sockaddr,
|
||||
int __user *upeer_addrlen, int flags)
|
||||
{
|
||||
struct socket *sock, *newsock;
|
||||
struct file *newfile;
|
||||
|
|
@ -1510,66 +1510,10 @@ out_fd:
|
|||
goto out_put;
|
||||
}
|
||||
|
||||
#if 0
|
||||
#ifdef HAVE_SET_RESTORE_SIGMASK
|
||||
asmlinkage long sys_paccept(int fd, struct sockaddr __user *upeer_sockaddr,
|
||||
int __user *upeer_addrlen,
|
||||
const sigset_t __user *sigmask,
|
||||
size_t sigsetsize, int flags)
|
||||
{
|
||||
sigset_t ksigmask, sigsaved;
|
||||
int ret;
|
||||
|
||||
if (sigmask) {
|
||||
/* XXX: Don't preclude handling different sized sigset_t's. */
|
||||
if (sigsetsize != sizeof(sigset_t))
|
||||
return -EINVAL;
|
||||
if (copy_from_user(&ksigmask, sigmask, sizeof(ksigmask)))
|
||||
return -EFAULT;
|
||||
|
||||
sigdelsetmask(&ksigmask, sigmask(SIGKILL)|sigmask(SIGSTOP));
|
||||
sigprocmask(SIG_SETMASK, &ksigmask, &sigsaved);
|
||||
}
|
||||
|
||||
ret = do_accept(fd, upeer_sockaddr, upeer_addrlen, flags);
|
||||
|
||||
if (ret < 0 && signal_pending(current)) {
|
||||
/*
|
||||
* Don't restore the signal mask yet. Let do_signal() deliver
|
||||
* the signal on the way back to userspace, before the signal
|
||||
* mask is restored.
|
||||
*/
|
||||
if (sigmask) {
|
||||
memcpy(¤t->saved_sigmask, &sigsaved,
|
||||
sizeof(sigsaved));
|
||||
set_restore_sigmask();
|
||||
}
|
||||
} else if (sigmask)
|
||||
sigprocmask(SIG_SETMASK, &sigsaved, NULL);
|
||||
|
||||
return ret;
|
||||
}
|
||||
#else
|
||||
asmlinkage long sys_paccept(int fd, struct sockaddr __user *upeer_sockaddr,
|
||||
int __user *upeer_addrlen,
|
||||
const sigset_t __user *sigmask,
|
||||
size_t sigsetsize, int flags)
|
||||
{
|
||||
/* The platform does not support restoring the signal mask in the
|
||||
* return path. So we do not allow using paccept() with a signal
|
||||
* mask. */
|
||||
if (sigmask)
|
||||
return -EINVAL;
|
||||
|
||||
return do_accept(fd, upeer_sockaddr, upeer_addrlen, flags);
|
||||
}
|
||||
#endif
|
||||
#endif
|
||||
|
||||
asmlinkage long sys_accept(int fd, struct sockaddr __user *upeer_sockaddr,
|
||||
int __user *upeer_addrlen)
|
||||
{
|
||||
return do_accept(fd, upeer_sockaddr, upeer_addrlen, 0);
|
||||
return sys_accept4(fd, upeer_sockaddr, upeer_addrlen, 0);
|
||||
}
|
||||
|
||||
/*
|
||||
|
|
@ -2096,7 +2040,7 @@ static const unsigned char nargs[19]={
|
|||
AL(0),AL(3),AL(3),AL(3),AL(2),AL(3),
|
||||
AL(3),AL(3),AL(4),AL(4),AL(4),AL(6),
|
||||
AL(6),AL(2),AL(5),AL(5),AL(3),AL(3),
|
||||
AL(6)
|
||||
AL(4)
|
||||
};
|
||||
|
||||
#undef AL
|
||||
|
|
@ -2115,7 +2059,7 @@ asmlinkage long sys_socketcall(int call, unsigned long __user *args)
|
|||
unsigned long a0, a1;
|
||||
int err;
|
||||
|
||||
if (call < 1 || call > SYS_PACCEPT)
|
||||
if (call < 1 || call > SYS_ACCEPT4)
|
||||
return -EINVAL;
|
||||
|
||||
/* copy_from_user should be SMP safe. */
|
||||
|
|
@ -2143,9 +2087,8 @@ asmlinkage long sys_socketcall(int call, unsigned long __user *args)
|
|||
err = sys_listen(a0, a1);
|
||||
break;
|
||||
case SYS_ACCEPT:
|
||||
err =
|
||||
do_accept(a0, (struct sockaddr __user *)a1,
|
||||
(int __user *)a[2], 0);
|
||||
err = sys_accept4(a0, (struct sockaddr __user *)a1,
|
||||
(int __user *)a[2], 0);
|
||||
break;
|
||||
case SYS_GETSOCKNAME:
|
||||
err =
|
||||
|
|
@ -2192,12 +2135,9 @@ asmlinkage long sys_socketcall(int call, unsigned long __user *args)
|
|||
case SYS_RECVMSG:
|
||||
err = sys_recvmsg(a0, (struct msghdr __user *)a1, a[2]);
|
||||
break;
|
||||
case SYS_PACCEPT:
|
||||
err =
|
||||
sys_paccept(a0, (struct sockaddr __user *)a1,
|
||||
(int __user *)a[2],
|
||||
(const sigset_t __user *) a[3],
|
||||
a[4], a[5]);
|
||||
case SYS_ACCEPT4:
|
||||
err = sys_accept4(a0, (struct sockaddr __user *)a1,
|
||||
(int __user *)a[2], a[3]);
|
||||
break;
|
||||
default:
|
||||
err = -EINVAL;
|
||||
|
|
|
|||
Загрузка…
Ссылка в новой задаче