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linux-user: use __get_user and __put_user in cmsg conversions 

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 <peter.maydell@linaro.org>
Signed-off-by: Riku Voipio <riku.voipio@linaro.org>
This commit is contained in:
Peter Maydell 2015-05-26 19:46:32 +01:00 committed by Riku Voipio
parent c2aeb2586b
commit 876e23cb2e
1 changed files with 11 additions and 9 deletions
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20
linux-user/syscall.c
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@ -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: