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Commit 2727e165 authored by Stephen Crane's avatar Stephen Crane
Browse files

storageproxyd: Use alternate data path if in DSU state 

Adds a check for a DSU mode boot in storageproxyd. Changes path handling
so that storageproxyd will not allow opening a file in the root data
path in DSU mode. Instead, storageproxyd creates an "alternate/"
directory in the data directory and the TA must use this directory to
store its backing file.

Re-landing reverted change: Iad68872dc6915f64eaf26cd3c92c04d9071ef169

Test: Boot into DSU and inspect logs for "Cannot open root data file"
Test: Test that TD writes in DSU mode don't corrupt host image storage
when using a compatible storage TA that supports alternate data mode.
Bug: 203719297

Merged-In: I1d07e7c3d15dc1beba2d340181d1b11a7988f869
Change-Id: I1d07e7c3d15dc1beba2d340181d1b11a7988f869
parent 43752295

trusty/storage/proxy/Android.bp

+4 −1
Original line number Diff line number Diff line
@@ -35,7 +35,10 @@ cc_binary { 
        "liblog",

        "libhardware_legacy",

    ],

    header_libs: ["libcutils_headers"],

    header_libs: [

        "libcutils_headers",

        "libgsi_headers",

    ],



    static_libs: [

        "libfstab",

trusty/storage/proxy/checkpoint_handling.cpp

+15 −0
Original line number Diff line number Diff line
@@ -18,9 +18,12 @@ 
#include "log.h"



#include <fstab/fstab.h>

#include <unistd.h>

#include <cstring>

#include <string>



#include <libgsi/libgsi.h>



namespace {



bool checkpointingDoneForever = false;
@@ -75,3 +78,15 @@ int is_data_checkpoint_active(bool* active) { 


    return 0;

}



/**

 * is_gsi_running() - Check if a GSI image is running via DSU.

 *

 * This function is equivalent to android::gsi::IsGsiRunning(), but this API is

 * not yet vendor-accessible although the underlying metadata file is.

 *

 */

bool is_gsi_running() {

    /* TODO(b/210501710): Expose GSI image running state to vendor storageproxyd */

    return !access(android::gsi::kGsiBootedIndicatorFile, F_OK);

}

trusty/storage/proxy/checkpoint_handling.h

+2 −0
Original line number Diff line number Diff line
@@ -32,6 +32,8 @@ extern "C" { 
 */

int is_data_checkpoint_active(bool* active);



bool is_gsi_running();



#ifdef __cplusplus

}

#endif

trusty/storage/proxy/proxy.c

+5 −2
Original line number Diff line number Diff line
@@ -104,8 +104,11 @@ static int drop_privs(void) { 
        return -1;

    }



    /* no-execute for user, no access for group and other */

    umask(S_IXUSR | S_IRWXG | S_IRWXO);

    /*

     * No access for group and other. We need execute access for user to create

     * an accessible directory.

     */

    umask(S_IRWXG | S_IRWXO);



    return 0;

}

trusty/storage/proxy/storage.c

+45 −1
Original line number Diff line number Diff line
@@ -16,6 +16,7 @@ 
#include <errno.h>

#include <fcntl.h>

#include <inttypes.h>

#include <libgen.h>

#include <stdbool.h>

#include <stdlib.h>

#include <string.h>
@@ -24,13 +25,16 @@ 
#include <sys/types.h>

#include <unistd.h>



#include "log.h"

#include "checkpoint_handling.h"

#include "ipc.h"

#include "log.h"

#include "storage.h"



#define FD_TBL_SIZE 64

#define MAX_READ_SIZE 4096



#define ALTERNATE_DATA_DIR "alternate/"



enum sync_state {

    SS_UNUSED = -1,

    SS_CLEAN =  0,
@@ -44,6 +48,8 @@ static enum sync_state fs_state; 
static enum sync_state dir_state;

static enum sync_state fd_state[FD_TBL_SIZE];



static bool alternate_mode;



static struct {

   struct storage_file_read_resp hdr;

   uint8_t data[MAX_READ_SIZE];
@@ -216,6 +222,7 @@ int storage_file_open(struct storage_msg *msg, 
                      const void *r, size_t req_len)

{

    char *path = NULL;

    char* parent_path;

    const struct storage_file_open_req *req = r;

    struct storage_file_open_resp resp = {0};
@@ -234,6 +241,24 @@ int storage_file_open(struct storage_msg *msg, 
        goto err_response;

    }



    /*

     * TODO(b/210501710): Expose GSI image running state to vendor

     * storageproxyd. We want to control data file paths in vendor_init, but we

     * don't have access to the necessary property there yet. When we have

     * access to that property we can set the root data path read-only and only

     * allow creation of files in alternate/. Checking paths here temporarily

     * until that is fixed.

     *

     * We are just checking for "/" instead of "alternate/" because we still

     * want to still allow access to "persist/" in alternate mode (for now, this

     * may change in the future).

     */

    if (alternate_mode && !strchr(req->name, '/')) {

        ALOGE("%s: Cannot open root data file \"%s\" in alternate mode\n", __func__, req->name);

        msg->result = STORAGE_ERR_ACCESS;

        goto err_response;

    }



    int rc = asprintf(&path, "%s/%s", ssdir_name, req->name);

    if (rc < 0) {

        ALOGE("%s: asprintf failed\n", __func__);
@@ -246,7 +271,23 @@ int storage_file_open(struct storage_msg *msg, 
    if (req->flags & STORAGE_FILE_OPEN_TRUNCATE)

        open_flags |= O_TRUNC;



    parent_path = dirname(path);

    if (req->flags & STORAGE_FILE_OPEN_CREATE) {

        /*

         * Create the alternate parent dir if needed & allowed.

         *

         * TODO(b/210501710): Expose GSI image running state to vendor

         * storageproxyd. This directory should be created by vendor_init, once

         * it has access to the necessary bit of information.

         */

        if (strstr(req->name, ALTERNATE_DATA_DIR) == req->name) {

            rc = mkdir(parent_path, S_IRWXU);

            if (rc && errno != EEXIST) {

                ALOGE("%s: Could not create parent directory \"%s\": %s\n", __func__, parent_path,

                      strerror(errno));

            }

        }



        /* open or create */

        if (req->flags & STORAGE_FILE_OPEN_CREATE_EXCLUSIVE) {

            /* create exclusive */
@@ -467,6 +508,9 @@ err_response: 


int storage_init(const char *dirname)

{

    /* If there is an active DSU image, use the alternate fs mode. */

    alternate_mode = is_gsi_running();



    fs_state = SS_CLEAN;

    dir_state = SS_CLEAN;

    for (uint i = 0; i < FD_TBL_SIZE; i++) {