From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:45016) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ee1Bj-00086n-Ij for qemu-devel@nongnu.org; Tue, 23 Jan 2018 11:12:44 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ee1Bi-0005Nu-Cy for qemu-devel@nongnu.org; Tue, 23 Jan 2018 11:12:43 -0500 References: <20180123145222.2487-1-f4bug@amsat.org> <20180123152339.GA23245@bogon.m.sigxcpu.org> From: Laurent Vivier Message-ID: <6d55a3e7-9d70-1ea1-2d22-65e136bda06b@vivier.eu> Date: Tue, 23 Jan 2018 17:12:26 +0100 MIME-Version: 1.0 In-Reply-To: <20180123152339.GA23245@bogon.m.sigxcpu.org> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Subject: Re: [Qemu-devel] [PATCH] linux-user/syscall: let recvfrom(struct sockaddr *) use abi_ulong List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: =?UTF-8?Q?Guido_G=c3=bcnther?= , =?UTF-8?Q?Philippe_Mathieu-Daud=c3=a9?= Cc: Riku Voipio , qemu-devel@nongnu.org, qemu-arm@nongnu.org Le 23/01/2018 à 16:23, Guido Günther a écrit : > Hi, > Thanks for having a look! > > On Tue, Jan 23, 2018 at 11:52:22AM -0300, Philippe Mathieu-Daudé wrote: >> Currently recvfrom() is restricted to handle 32-bit pointers, >> remove this limit for 64-bit hosts. >> >> This fixes: >> >> 31572 socket(AF_NETLINK, SOCK_RAW, NETLINK_AUDIT) = 3 >> ... >> 31572 sendto(3, {{len=124, type=0x454 /* NLMSG_??? */, flags=NLM_F_REQUEST|NLM_F_ACK, seq=1, pid=0}, "op=test:message acct=\"?\" exe=\"/tmp/nl-bad-addr\" hostname=localhost addr=? terminal=/dev/pts/2 res=success\0\0\0"}, 124, 0, 0xfffffa3897d0, 0) = 124 >> 31572 ppoll([{fd=3, events=POLLIN}], 1, {tv_sec=0, tv_nsec=500000000}, NULL, 0) = 1 ([{fd=3, revents=POLLIN}], left {tv_sec=0, tv_nsec=499993180}) >> 31572 recvfrom(3, 0x112a50eb4, 8988, MSG_PEEK|MSG_DONTWAIT, 0xfffffa3897e0, 0x42) = -1 EFAULT (Bad address) >> >> Reported-by: Guido Günther >> Message-id: 20180123120541.GA14216@bogon.m.sigxcpu.org >> Signed-off-by: Philippe Mathieu-Daudé >> --- >> linux-user/syscall.c | 4 ++-- >> 1 file changed, 2 insertions(+), 2 deletions(-) >> >> diff --git a/linux-user/syscall.c b/linux-user/syscall.c >> index 11c9116c4a..28805b1785 100644 >> --- a/linux-user/syscall.c >> +++ b/linux-user/syscall.c >> @@ -4032,7 +4032,7 @@ static abi_long do_recvfrom(int fd, abi_ulong msg, size_t len, int flags, >> if (!host_msg) >> return -TARGET_EFAULT; >> if (target_addr) { >> - if (get_user_u32(addrlen, target_addrlen)) { >> + if (get_user_ual(addrlen, target_addrlen)) { >> ret = -TARGET_EFAULT; >> goto fail; >> } >> @@ -4053,7 +4053,7 @@ static abi_long do_recvfrom(int fd, abi_ulong msg, size_t len, int flags, >> } >> if (target_addr) { >> host_to_target_sockaddr(target_addr, addr, addrlen); >> - if (put_user_u32(addrlen, target_addrlen)) { >> + if (put_user_ual(addrlen, target_addrlen)) { >> ret = -TARGET_EFAULT; >> goto fail; >> } > > Ahh...I saw these and was wondering how this would work on > 64bit. Unfortunately the patch doesn't change things: > > 4824 recvfrom(3, 0x1401f8eb4, 8988, MSG_PEEK|MSG_DONTWAIT, 0xffffe10a8620, 0x42) = -1 EFAULT (Bad address) > > If you want me to report qemu -strace or s.th. please let me know. > Cheers, > -- Guido > Could you try: strace -f chroot . /usr/bin/qemu-arm-static tmp/nl-bad-addr to see if the fault comes from the kernel or from QEMU. Thanks, Laurent