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[Pal/Linux-SGX] Allow to write/send from buffer in untrusted memory

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Previously, ocall_write() and ocall_sock_send() disallowed to write/send
data from a buffer allocated in untrusted memory (as it was considered
an impossible scenario). However, sendfile() logic may write an allowed
regular file (which is mmapped in untrusted memory) directly to a socket.
Thus, this commit allows such writes/sends.
This commit is contained in:
Dmitrii Kuvaiskii
2019-09-18 17:14:12 -07:00
parent 57d9e3347d
commit b3d00dc647
1 changed files with 36 additions and 18 deletions
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Pal/src/host/Linux-SGX/enclave_ocalls.c
+36 -18
View File
@@ -266,10 +266,21 @@ int ocall_write (int fd, const void * buf, unsigned int count)
void * obuf = NULL;
ms_ocall_write_t * ms;
if (count > PRESET_PAGESIZE) {
retval = ocall_alloc_untrusted(ALLOC_ALIGNUP(count), &obuf);
if (IS_ERR(retval))
return retval;
if (sgx_is_completely_outside_enclave(buf, count)) {
/* buf is in untrusted memory (e.g., allowed file mmaped in untrusted memory) */
obuf = (void*)buf;
} else if (sgx_is_completely_within_enclave(buf, count)) {
/* typical case of buf inside of enclave memory */
if (count > PRESET_PAGESIZE) {
/* buf is too big and may overflow untrusted stack, so use untrusted heap */
retval = ocall_alloc_untrusted(ALLOC_ALIGNUP(count), &obuf);
if (IS_ERR(retval))
return retval;
memcpy(obuf, buf, count);
}
} else {
/* buf is partially in/out of enclave memory */
return -EPERM;
}
ms = sgx_alloc_on_ustack(sizeof(*ms));
@@ -280,12 +291,10 @@ int ocall_write (int fd, const void * buf, unsigned int count)
ms->ms_fd = fd;
ms->ms_count = count;
if (obuf) {
if (obuf)
ms->ms_buf = obuf;
memcpy(obuf, buf, count);
} else {
else
ms->ms_buf = sgx_copy_to_ustack(buf, count);
}
if (!ms->ms_buf) {
retval = -EPERM;
@@ -296,7 +305,7 @@ int ocall_write (int fd, const void * buf, unsigned int count)
out:
sgx_reset_ustack();
if (obuf)
if (obuf && obuf != buf)
ocall_unmap_untrusted(obuf, ALLOC_ALIGNUP(count));
return retval;
}
@@ -791,10 +800,21 @@ int ocall_sock_send (int sockfd, const void * buf, unsigned int count,
void * obuf = NULL;
ms_ocall_sock_send_t * ms;
if ((count + addrlen) > PRESET_PAGESIZE) {
retval = ocall_alloc_untrusted(ALLOC_ALIGNUP(count), &obuf);
if (IS_ERR(retval))
return retval;
if (sgx_is_completely_outside_enclave(buf, count)) {
/* buf is in untrusted memory (e.g., allowed file mmaped in untrusted memory) */
obuf = (void*)buf;
} else if (sgx_is_completely_within_enclave(buf, count)) {
/* typical case of buf inside of enclave memory */
if ((count + addrlen) > PRESET_PAGESIZE) {
/* buf is too big and may overflow untrusted stack, so use untrusted heap */
retval = ocall_alloc_untrusted(ALLOC_ALIGNUP(count), &obuf);
if (IS_ERR(retval))
return retval;
memcpy(obuf, buf, count);
}
} else {
/* buf is partially in/out of enclave memory */
return -EPERM;
}
ms = sgx_alloc_on_ustack(sizeof(*ms));
@@ -807,12 +827,10 @@ int ocall_sock_send (int sockfd, const void * buf, unsigned int count,
ms->ms_count = count;
ms->ms_addrlen = addrlen;
ms->ms_addr = addr ? sgx_copy_to_ustack(addr, addrlen) : NULL;
if (obuf) {
if (obuf)
ms->ms_buf = obuf;
memcpy(obuf, buf, count);
} else {
else
ms->ms_buf = sgx_copy_to_ustack(buf, count);
}
if (!ms->ms_buf || (addr && !ms->ms_addr)) {
retval = -EPERM;
@@ -823,7 +841,7 @@ int ocall_sock_send (int sockfd, const void * buf, unsigned int count,
out:
sgx_reset_ustack();
if (obuf)
if (obuf && obuf != buf)
ocall_unmap_untrusted(obuf, ALLOC_ALIGNUP(count));
return retval;
}