diff options
| author | Peter Maydell <peter.maydell@linaro.org> | 2016-09-06 10:36:40 +0100 |
|---|---|---|
| committer | Peter Maydell <peter.maydell@linaro.org> | 2016-09-06 10:36:40 +0100 |
| commit | 6534b8565e152f398d7ae3e3d58f8a6d6311efb0 (patch) | |
| tree | e121ec4d2291f7d827ab9a64a4968b2ef59d4738 | |
| parent | 9b46645ca4cec642404ceb85ba42f5a148e03860 (diff) | |
linux-user: Allow bad msg_name for recvfrom on connected socket
The POSIX standard mandates that for a connected socket recvfrom()
must ignore the msg_name and msg_namelen fields. This is awkward
for QEMU because we will attempt to copy them from guest address
space. Handle this by not immediately returning a TARGET_EFAULT
if the copy failed, but instead passing a known-bad address
to the host kernel, which can then return EFAULT or ignore the
value appropriately.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
| -rw-r--r-- | linux-user/syscall.c | 11 |
1 files changed, 9 insertions, 2 deletions
diff --git a/linux-user/syscall.c b/linux-user/syscall.c index 69c187fcda..acb037a97b 100644 --- a/linux-user/syscall.c +++ b/linux-user/syscall.c @@ -3472,7 +3472,14 @@ static abi_long do_sendrecvmsg_locked(int fd, struct target_msghdr *msgp, ret = target_to_host_sockaddr(fd, msg.msg_name, tswapal(msgp->msg_name), msg.msg_namelen); - if (ret) { + if (ret == -TARGET_EFAULT) { + /* For connected sockets msg_name and msg_namelen must + * be ignored, so returning EFAULT immediately is wrong. + * Instead, pass a bad msg_name to the host kernel, and + * let it decide whether to return EFAULT or not. + */ + msg.msg_name = (void *)-1; + } else if (ret) { goto out2; } } else { @@ -3534,7 +3541,7 @@ static abi_long do_sendrecvmsg_locked(int fd, struct target_msghdr *msgp, } if (!is_error(ret)) { msgp->msg_namelen = tswap32(msg.msg_namelen); - if (msg.msg_name != NULL) { + if (msg.msg_name != NULL && msg.msg_name != (void *)-1) { ret = host_to_target_sockaddr(tswapal(msgp->msg_name), msg.msg_name, msg.msg_namelen); if (ret) { |