From nobody Sat Nov 8 06:05:22 2025 Delivered-To: importer@patchew.org Received-SPF: temperror (zoho.com: Error in retrieving data from DNS) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zohomail.com; spf=temperror (zoho.com: Error in retrieving data from DNS) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org Return-Path: Received: from lists.gnu.org (209.51.188.17 [209.51.188.17]) by mx.zohomail.com with SMTPS id 15501447013571011.9836275496316; Thu, 14 Feb 2019 03:45:01 -0800 (PST) Received: from localhost ([127.0.0.1]:47051 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1guFRp-00067f-4n for importer@patchew.org; Thu, 14 Feb 2019 06:44:57 -0500 Received: from eggs.gnu.org ([209.51.188.92]:35579) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1guFQy-0005o5-LR for qemu-devel@nongnu.org; Thu, 14 Feb 2019 06:44:05 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1guFQx-0005MQ-8z for qemu-devel@nongnu.org; Thu, 14 Feb 2019 06:44:04 -0500 Received: from mx2.suse.de ([195.135.220.15]:42968 helo=mx1.suse.de) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1guFQv-0005AG-24 for qemu-devel@nongnu.org; Thu, 14 Feb 2019 06:44:03 -0500 Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 6F850ADFF; Thu, 14 Feb 2019 11:43:41 +0000 (UTC) X-Virus-Scanned: by amavisd-new at test-mx.suse.de From: Andreas Schwab To: Laurent Vivier References: <3c8aca9d-e47e-04a7-1e6a-a65deab125ce@vivier.eu> X-Yow: I want a WESSON OIL lease!! Date: Thu, 14 Feb 2019 12:43:40 +0100 In-Reply-To: <3c8aca9d-e47e-04a7-1e6a-a65deab125ce@vivier.eu> (Laurent Vivier's message of "Thu, 14 Feb 2019 10:17:39 +0100") Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.1.91 (gnu/linux) MIME-Version: 1.0 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x (no timestamps) [generic] X-Received-From: 195.135.220.15 Subject: [Qemu-devel] [PATCH] linux-user: fix emulation of accept4/getpeername/getsockname/recvfrom syscalls X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Riku Voipio , qemu-devel@nongnu.org Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" System calls that return a socket address do so by writing the (possibly truncated) address into the provided buffer space, but setting the addrlen parameter to the actual size of the address. To determine how much to copy back to the target memory the emulation needs to remember the incoming value of the addrlen parameter, so that it doesn't write past the buffer limits. Signed-off-by: Andreas Schwab --- linux-user/syscall.c | 41 +++++++++++++++++++++++++---------------- 1 file changed, 25 insertions(+), 16 deletions(-) diff --git a/linux-user/syscall.c b/linux-user/syscall.c index 4a320850bb..f24743a2b2 100644 --- a/linux-user/syscall.c +++ b/linux-user/syscall.c @@ -2885,7 +2885,7 @@ static abi_long do_sendrecvmmsg(int fd, abi_ulong tar= get_msgvec, static abi_long do_accept4(int fd, abi_ulong target_addr, abi_ulong target_addrlen_addr, int flags) { - socklen_t addrlen; + socklen_t addrlen, ret_addrlen; void *addr; abi_long ret; int host_flags; @@ -2909,11 +2909,13 @@ static abi_long do_accept4(int fd, abi_ulong target= _addr, =20 addr =3D alloca(addrlen); =20 - ret =3D get_errno(safe_accept4(fd, addr, &addrlen, host_flags)); + ret_addrlen =3D addrlen; + ret =3D get_errno(safe_accept4(fd, addr, &ret_addrlen, host_flags)); if (!is_error(ret)) { - host_to_target_sockaddr(target_addr, addr, addrlen); - if (put_user_u32(addrlen, target_addrlen_addr)) + host_to_target_sockaddr(target_addr, addr, MIN(addrlen, ret_addrle= n)); + if (put_user_u32(ret_addrlen, target_addrlen_addr)) { ret =3D -TARGET_EFAULT; + } } return ret; } @@ -2922,7 +2924,7 @@ static abi_long do_accept4(int fd, abi_ulong target_a= ddr, static abi_long do_getpeername(int fd, abi_ulong target_addr, abi_ulong target_addrlen_addr) { - socklen_t addrlen; + socklen_t addrlen, ret_addrlen; void *addr; abi_long ret; =20 @@ -2938,11 +2940,13 @@ static abi_long do_getpeername(int fd, abi_ulong ta= rget_addr, =20 addr =3D alloca(addrlen); =20 - ret =3D get_errno(getpeername(fd, addr, &addrlen)); + ret_addrlen =3D addrlen; + ret =3D get_errno(getpeername(fd, addr, &ret_addrlen)); if (!is_error(ret)) { - host_to_target_sockaddr(target_addr, addr, addrlen); - if (put_user_u32(addrlen, target_addrlen_addr)) + host_to_target_sockaddr(target_addr, addr, MIN(addrlen, ret_addrle= n)); + if (put_user_u32(ret_addrlen, target_addrlen_addr)) { ret =3D -TARGET_EFAULT; + } } return ret; } @@ -2951,7 +2955,7 @@ static abi_long do_getpeername(int fd, abi_ulong targ= et_addr, static abi_long do_getsockname(int fd, abi_ulong target_addr, abi_ulong target_addrlen_addr) { - socklen_t addrlen; + socklen_t addrlen, ret_addrlen; void *addr; abi_long ret; =20 @@ -2967,11 +2971,13 @@ static abi_long do_getsockname(int fd, abi_ulong ta= rget_addr, =20 addr =3D alloca(addrlen); =20 - ret =3D get_errno(getsockname(fd, addr, &addrlen)); + ret_addrlen =3D addrlen; + ret =3D get_errno(getsockname(fd, addr, &ret_addrlen)); if (!is_error(ret)) { - host_to_target_sockaddr(target_addr, addr, addrlen); - if (put_user_u32(addrlen, target_addrlen_addr)) + host_to_target_sockaddr(target_addr, addr, MIN(addrlen, ret_addrle= n)); + if (put_user_u32(ret_addrlen, target_addrlen_addr)) { ret =3D -TARGET_EFAULT; + } } return ret; } @@ -3043,7 +3049,7 @@ static abi_long do_recvfrom(int fd, abi_ulong msg, si= ze_t len, int flags, abi_ulong target_addr, abi_ulong target_addrlen) { - socklen_t addrlen; + socklen_t addrlen, ret_addrlen; void *addr; void *host_msg; abi_long ret; @@ -3061,10 +3067,12 @@ static abi_long do_recvfrom(int fd, abi_ulong msg, = size_t len, int flags, goto fail; } addr =3D alloca(addrlen); + ret_addrlen =3D addrlen; ret =3D get_errno(safe_recvfrom(fd, host_msg, len, flags, - addr, &addrlen)); + addr, &ret_addrlen)); } else { addr =3D NULL; /* To keep compiler quiet. */ + addrlen =3D 0; /* To keep compiler quiet. */ ret =3D get_errno(safe_recvfrom(fd, host_msg, len, flags, NULL, 0)= ); } if (!is_error(ret)) { @@ -3077,8 +3085,9 @@ static abi_long do_recvfrom(int fd, abi_ulong msg, si= ze_t len, int flags, } } if (target_addr) { - host_to_target_sockaddr(target_addr, addr, addrlen); - if (put_user_u32(addrlen, target_addrlen)) { + host_to_target_sockaddr(target_addr, addr, + MIN(addrlen, ret_addrlen)); + if (put_user_u32(ret_addrlen, target_addrlen)) { ret =3D -TARGET_EFAULT; goto fail; } --=20 2.20.1