From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:56850) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XHHDQ-0003dc-KF for qemu-devel@nongnu.org; Tue, 12 Aug 2014 14:54:45 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1XHHDH-00078n-K2 for qemu-devel@nongnu.org; Tue, 12 Aug 2014 14:54:36 -0400 From: Tom Musta Date: Tue, 12 Aug 2014 13:53:33 -0500 Message-Id: <1407869623-11185-3-git-send-email-tommusta@gmail.com> In-Reply-To: <1407869623-11185-1-git-send-email-tommusta@gmail.com> References: <1407869623-11185-1-git-send-email-tommusta@gmail.com> Subject: [Qemu-devel] [V2 PATCH 02/12] linux-user: Dereference Pointer Argument to ipc/semctl Sys Call List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org, qemu-ppc@nongnu.org Cc: peter.maydell@linaro.org, riku.voipio@linaro.org, agraf@suse.de, Tom Musta When the ipc system call is used to wrap a semctl system call, the ptr argument to ipc needs to be dereferenced prior to passing it to the semctl handler. This is because the fourth argument to semctl is a union and not a pointer to a union. Signed-off-by: Tom Musta --- V2: This is unchanged from V1. I briefly reviewew the QEMU, glibc and kernel code looking for some problems but did not find anything. I also did fairly comprehesive testing of semctl on 4 targets (ppc-linux-user, ppc64-linux-user, ppc64le-linux-user, x86_64-linux-user) on 3 different host platforms (x86-64 Ubuntu, PPC64 RHEL 6 (BE) and PPC64 Ubuntu 14.04 (LE)); this provided a broad coverage of co-endian and cross endian situations. linux-user/syscall.c | 10 ++++++++-- 1 files changed, 8 insertions(+), 2 deletions(-) diff --git a/linux-user/syscall.c b/linux-user/syscall.c index 540001c..229c482 100644 --- a/linux-user/syscall.c +++ b/linux-user/syscall.c @@ -3135,9 +3135,15 @@ static abi_long do_ipc(unsigned int call, int first, ret = get_errno(semget(first, second, third)); break; - case IPCOP_semctl: - ret = do_semctl(first, second, third, (union target_semun)(abi_ulong) ptr); + case IPCOP_semctl: { + /* The semun argument to semctl is passed by value, so dereference the + * ptr argument. */ + abi_ulong atptr; + get_user_ual(atptr, (abi_ulong)ptr); + ret = do_semctl(first, second, third, + (union target_semun)(abi_ulong) atptr); break; + } case IPCOP_msgget: ret = get_errno(msgget(first, second)); -- 1.7.1