From: Yann Droneaud <ydrone...@opteya.com> This patch makes socketpair() use error paths which do not rely on heavy-weight call to sys_close(): it's better to try to push the file descriptor to userspace before installing the socket file to the file descriptor, so that errors are catched earlier and being easier to handle.
Using sys_close() seems to be the exception, while writing the file descriptor before installing it look like it's more or less the norm: eg. except for code used in init/, error handling involve fput() and put_unused_fd(), but not sys_close(). This make socketpair() usage of sys_close() quite unusual. So it deserves to be replaced by the common pattern relying on fput() and put_unused_fd() just like, for example, the one used in pipe(2) or recvmsg(2). Three distinct error paths are still needed since calling fput() on file structure returned by sock_alloc_file() will implicitly call sock_release() on the associated socket structure. Cc: David S. Miller <da...@davemloft.net> Cc: Al Viro <v...@zeniv.linux.org.uk> Signed-off-by: Yann Droneaud <ydrone...@opteya.com> Link: http://marc.info/?i=1385979146-13825-1-git-send-email-ydrone...@opteya.com Signed-off-by: David S. Miller <da...@davemloft.net> (cherry-picked from commit d73aa2867f33582314f098277421ded65f5745a9) https://syzkaller.appspot.com/bug?id=23d0799f98b7c8c4bc3f5ecff7c28a87c64e40e8 https://jira.sw.ru/browse/PSBM-123046 Signed-off-by: Vasily Averin <v...@virtuozzo.com> --- net/socket.c | 49 +++++++++++++++++++++++++++++++------------------ 1 file changed, 31 insertions(+), 18 deletions(-) diff --git a/net/socket.c b/net/socket.c index 22acff9..dd8fa2d 100644 --- a/net/socket.c +++ b/net/socket.c @@ -1533,48 +1533,61 @@ SYSCALL_DEFINE4(socketpair, int, family, int, type, int, protocol, err = fd1; goto out_release_both; } + fd2 = get_unused_fd_flags(flags); if (unlikely(fd2 < 0)) { err = fd2; - put_unused_fd(fd1); - goto out_release_both; + goto out_put_unused_1; } newfile1 = sock_alloc_file(sock1, flags, NULL); if (IS_ERR(newfile1)) { err = PTR_ERR(newfile1); - put_unused_fd(fd1); - put_unused_fd(fd2); - goto out_release_both; + goto out_put_unused_both; } newfile2 = sock_alloc_file(sock2, flags, NULL); if (IS_ERR(newfile2)) { err = PTR_ERR(newfile2); - fput(newfile1); - put_unused_fd(fd1); - put_unused_fd(fd2); - sock_release(sock2); - goto out; + goto out_fput_1; } + err = put_user(fd1, &usockvec[0]); + if (err) + goto out_fput_both; + + err = put_user(fd2, &usockvec[1]); + if (err) + goto out_fput_both; + audit_fd_pair(fd1, fd2); + fd_install(fd1, newfile1); fd_install(fd2, newfile2); /* fd1 and fd2 may be already another descriptors. * Not kernel problem. */ - err = put_user(fd1, &usockvec[0]); - if (!err) - err = put_user(fd2, &usockvec[1]); - if (!err) - return 0; + return 0; - sys_close(fd2); - sys_close(fd1); - return err; +out_fput_both: + fput(newfile2); + fput(newfile1); + put_unused_fd(fd2); + put_unused_fd(fd1); + goto out; +out_fput_1: + fput(newfile1); + put_unused_fd(fd2); + put_unused_fd(fd1); + sock_release(sock2); + goto out; + +out_put_unused_both: + put_unused_fd(fd2); +out_put_unused_1: + put_unused_fd(fd1); out_release_both: sock_release(sock2); out_release_1: -- 1.8.3.1 _______________________________________________ Devel mailing list Devel@openvz.org https://lists.openvz.org/mailman/listinfo/devel
