From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:60932) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Z4kxG-0004EB-Lc for qemu-devel@nongnu.org; Tue, 16 Jun 2015 03:06:43 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Z4kxC-0006nU-Ly for qemu-devel@nongnu.org; Tue, 16 Jun 2015 03:06:42 -0400 Received: from mail-la0-f43.google.com ([209.85.215.43]:35111) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Z4kxC-0006nN-Fl for qemu-devel@nongnu.org; Tue, 16 Jun 2015 03:06:38 -0400 Received: by labko7 with SMTP id ko7so4809725lab.2 for ; Tue, 16 Jun 2015 00:06:37 -0700 (PDT) From: riku.voipio@linaro.org Date: Tue, 16 Jun 2015 10:06:30 +0300 Message-Id: <876e23cb2e545148a0ee4effda5c63c861855941.1434438233.git.riku.voipio@linaro.org> In-Reply-To: References: Subject: [Qemu-devel] [PULL v2 4/6] linux-user: use __get_user and __put_user in cmsg conversions List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: peter.maydell@linaro.org From: Peter Maydell The target payloads in cmsg conversions may not have the alignment required by the host. Using the get_user and put_user functions is the easiest way to handle this and also do the byte-swapping we require. (Note that prior to this commit target_to_host_cmsg was incorrectly using __put_user() rather than __get_user() for the SCM_CREDENTIALS conversion, which meant it wasn't getting the benefit of the misalignment handling.) Signed-off-by: Peter Maydell Signed-off-by: Riku Voipio --- linux-user/syscall.c | 20 +++++++++++--------- 1 file changed, 11 insertions(+), 9 deletions(-) diff --git a/linux-user/syscall.c b/linux-user/syscall.c index 15b1e81..5cf265c 100644 --- a/linux-user/syscall.c +++ b/linux-user/syscall.c @@ -1228,17 +1228,18 @@ static inline abi_long target_to_host_cmsg(struct msghdr *msgh, int *target_fd = (int *)target_data; int i, numfds = len / sizeof(int); - for (i = 0; i < numfds; i++) - fd[i] = tswap32(target_fd[i]); + for (i = 0; i < numfds; i++) { + __get_user(fd[i], target_fd + i); + } } else if (cmsg->cmsg_level == SOL_SOCKET && cmsg->cmsg_type == SCM_CREDENTIALS) { struct ucred *cred = (struct ucred *)data; struct target_ucred *target_cred = (struct target_ucred *)target_data; - __put_user(target_cred->pid, &cred->pid); - __put_user(target_cred->uid, &cred->uid); - __put_user(target_cred->gid, &cred->gid); + __get_user(cred->pid, &target_cred->pid); + __get_user(cred->uid, &target_cred->uid); + __get_user(cred->gid, &target_cred->gid); } else { gemu_log("Unsupported ancillary data: %d/%d\n", cmsg->cmsg_level, cmsg->cmsg_type); @@ -1333,8 +1334,9 @@ static inline abi_long host_to_target_cmsg(struct target_msghdr *target_msgh, int *target_fd = (int *)target_data; int i, numfds = tgt_len / sizeof(int); - for (i = 0; i < numfds; i++) - target_fd[i] = tswap32(fd[i]); + for (i = 0; i < numfds; i++) { + __put_user(fd[i], target_fd + i); + } break; } case SO_TIMESTAMP: @@ -1349,8 +1351,8 @@ static inline abi_long host_to_target_cmsg(struct target_msghdr *target_msgh, } /* copy struct timeval to target */ - target_tv->tv_sec = tswapal(tv->tv_sec); - target_tv->tv_usec = tswapal(tv->tv_usec); + __put_user(tv->tv_sec, &target_tv->tv_sec); + __put_user(tv->tv_usec, &target_tv->tv_usec); break; } case SCM_CREDENTIALS: -- 2.1.4