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Merge "Handle long responses by keymint IPC."

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This commit is contained in:
Treehugger Robot 2021-08-17 19:26:16 +00:00 • committed by Gerrit Code Review
commit 6809b6705f
1 changed files with 92 additions and 26 deletions
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118
trusty/keymaster/ipc/trusty_keymaster_ipc.cpp
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@ -25,6 +25,8 @@
#include <unistd.h>
#include <algorithm>
#include <variant>
#include <vector>
#include <log/log.h>
#include <trusty/tipc.h>
@ -46,8 +48,27 @@ int trusty_keymaster_connect() {
return 0;
}
int trusty_keymaster_call(uint32_t cmd, void* in, uint32_t in_size, uint8_t* out,
uint32_t* out_size) {
class VectorEraser {
public:
VectorEraser(std::vector<uint8_t>* v) : _v(v) {}
~VectorEraser() {
if (_v) {
std::fill(const_cast<volatile uint8_t*>(_v->data()),
const_cast<volatile uint8_t*>(_v->data() + _v->size()), 0);
}
}
void disarm() { _v = nullptr; }
VectorEraser(const VectorEraser&) = delete;
VectorEraser& operator=(const VectorEraser&) = delete;
VectorEraser(VectorEraser&& other) = delete;
VectorEraser& operator=(VectorEraser&&) = delete;
private:
std::vector<uint8_t>* _v;
};
std::variant<int, std::vector<uint8_t>> trusty_keymaster_call_2(uint32_t cmd, void* in,
uint32_t in_size) {
if (handle_ < 0) {
ALOGE("not connected\n");
return -EINVAL;
@ -70,15 +91,38 @@ int trusty_keymaster_call(uint32_t cmd, void* in, uint32_t in_size, uint8_t* out
ALOGE("failed to send cmd (%d) to %s: %s\n", cmd, KEYMASTER_PORT, strerror(errno));
return -errno;
}
size_t out_max_size = *out_size;
*out_size = 0;
std::vector<uint8_t> out(TRUSTY_KEYMASTER_RECV_BUF_SIZE);
VectorEraser out_eraser(&out);
uint8_t* write_pos = out.data();
uint8_t* out_end = out.data() + out.size();
struct iovec iov[2];
struct keymaster_message header;
iov[0] = {.iov_base = &header, .iov_len = sizeof(struct keymaster_message)};
while (true) {
iov[1] = {.iov_base = out + *out_size,
.iov_len = std::min<uint32_t>(KEYMASTER_MAX_BUFFER_LENGTH,
out_max_size - *out_size)};
if (out_end - write_pos < KEYMASTER_MAX_BUFFER_LENGTH) {
// In stead of using std::vector.resize(), allocate a new one to have chance
// at zeroing the old buffer.
std::vector<uint8_t> new_out(out.size() + KEYMASTER_MAX_BUFFER_LENGTH);
// After the swap below this erases the old out buffer.
VectorEraser new_out_eraser(&new_out);
std::copy(out.data(), write_pos, new_out.begin());
auto write_offset = write_pos - out.data();
std::swap(new_out, out);
write_pos = out.data() + write_offset;
out_end = out.data() + out.size();
}
size_t buffer_size = 0;
if (__builtin_sub_overflow(reinterpret_cast<uintptr_t>(out_end),
reinterpret_cast<uintptr_t>(write_pos), &buffer_size)) {
return -EOVERFLOW;
}
iov[1] = {.iov_base = write_pos, .iov_len = buffer_size};
rc = readv(handle_, iov, 2);
if (rc < 0) {
ALOGE("failed to retrieve response for cmd (%d) to %s: %s\n", cmd, KEYMASTER_PORT,
@ -95,13 +139,36 @@ int trusty_keymaster_call(uint32_t cmd, void* in, uint32_t in_size, uint8_t* out
ALOGE("invalid command (%d)", header.cmd);
return -EINVAL;
}
*out_size += ((size_t)rc - sizeof(struct keymaster_message));
write_pos += ((size_t)rc - sizeof(struct keymaster_message));
if (header.cmd & KEYMASTER_STOP_BIT) {
break;
}
}
return rc;
out.resize(write_pos - out.data());
out_eraser.disarm();
return out;
}
int trusty_keymaster_call(uint32_t cmd, void* in, uint32_t in_size, uint8_t* out,
uint32_t* out_size) {
auto result = trusty_keymaster_call_2(cmd, in, in_size);
if (auto out_buffer = std::get_if<std::vector<uint8_t>>(&result)) {
if (out_buffer->size() <= *out_size) {
std::copy(out_buffer->begin(), out_buffer->end(), out);
std::fill(const_cast<volatile uint8_t*>(&*out_buffer->begin()),
const_cast<volatile uint8_t*>(&*out_buffer->end()), 0);
*out_size = out_buffer->size();
return 0;
} else {
ALOGE("Message was to large (%zu) for the provided buffer (%u)", out_buffer->size(),
*out_size);
return -EMSGSIZE;
}
} else {
return std::get<int>(result);
}
}
void trusty_keymaster_disconnect() {
@ -155,28 +222,27 @@ keymaster_error_t trusty_keymaster_send(uint32_t command, const keymaster::Seria
req.Serialize(send_buf, send_buf + req_size);
// Send it
uint8_t recv_buf[TRUSTY_KEYMASTER_RECV_BUF_SIZE];
keymaster::Eraser recv_buf_eraser(recv_buf, TRUSTY_KEYMASTER_RECV_BUF_SIZE);
uint32_t rsp_size = TRUSTY_KEYMASTER_RECV_BUF_SIZE;
int rc = trusty_keymaster_call(command, send_buf, req_size, recv_buf, &rsp_size);
if (rc < 0) {
auto response = trusty_keymaster_call_2(command, send_buf, req_size);
if (auto response_buffer = std::get_if<std::vector<uint8_t>>(&response)) {
keymaster::Eraser response_buffer_erasor(response_buffer->data(), response_buffer->size());
ALOGV("Received %zu byte response\n", response_buffer->size());
const uint8_t* p = response_buffer->data();
if (!rsp->Deserialize(&p, p + response_buffer->size())) {
ALOGE("Error deserializing response of size %zu\n", response_buffer->size());
return KM_ERROR_UNKNOWN_ERROR;
} else if (rsp->error != KM_ERROR_OK) {
ALOGE("Response of size %zu contained error code %d\n", response_buffer->size(),
(int)rsp->error);
}
return rsp->error;
} else {
auto rc = std::get<int>(response);
// Reset the connection on tipc error
trusty_keymaster_disconnect();
trusty_keymaster_connect();
ALOGE("tipc error: %d\n", rc);
// TODO(swillden): Distinguish permanent from transient errors and set error_ appropriately.
return translate_error(rc);
} else {
ALOGV("Received %d byte response\n", rsp_size);
}
const uint8_t* p = recv_buf;
if (!rsp->Deserialize(&p, p + rsp_size)) {
ALOGE("Error deserializing response of size %d\n", (int)rsp_size);
return KM_ERROR_UNKNOWN_ERROR;
} else if (rsp->error != KM_ERROR_OK) {
ALOGE("Response of size %d contained error code %d\n", (int)rsp_size, (int)rsp->error);
return rsp->error;
}
return rsp->error;
}