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    SubjectRe: [PATCH] binder: prevent transactions to context manager from its own process.
    On Mon, Jul 15, 2019 at 9:18 PM Hridya Valsaraju <hridya@google.com> wrote:
    > Currently, a transaction to context manager from its own process
    > is prevented by checking if its binder_proc struct is the same as
    > that of the sender. However, this would not catch cases where the
    > process opens the binder device again and uses the new fd to send
    > a transaction to the context manager.
    >
    > Reported-by: syzbot+8b3c354d33c4ac78bfad@syzkaller.appspotmail.com
    > Signed-off-by: Hridya Valsaraju <hridya@google.com>
    > ---
    > drivers/android/binder.c | 2 +-
    > 1 file changed, 1 insertion(+), 1 deletion(-)
    >
    > diff --git a/drivers/android/binder.c b/drivers/android/binder.c
    > index e4d25ebec5be..89b9cedae088 100644
    > --- a/drivers/android/binder.c
    > +++ b/drivers/android/binder.c
    > @@ -3138,7 +3138,7 @@ static void binder_transaction(struct binder_proc *proc,
    > else
    > return_error = BR_DEAD_REPLY;
    > mutex_unlock(&context->context_mgr_node_lock);
    > - if (target_node && target_proc == proc) {
    > + if (target_node && target_proc->pid == proc->pid) {
    > binder_user_error("%d:%d got transaction to context manager from process owning it\n",
    > proc->pid, thread->pid);
    > return_error = BR_FAILED_REPLY;

    This isn't a valid fix.

    For context, the syzkaller report at
    <https://lore.kernel.org/lkml/000000000000afe2c70589526668@google.com/>
    triggered this WARN_ON() in binder_transaction_buffer_release() in the
    BINDER_TYPE_FD case, which Todd added in 44d8047f1d87 ("binder: use
    standard functions to allocate fds"):

    case BINDER_TYPE_FD: {
    /*
    * No need to close the file here since user-space
    * closes it for for successfully delivered
    * transactions. For transactions that weren't
    * delivered, the new fd was never allocated so
    * there is no need to close and the fput on the
    * file is done when the transaction is torn
    * down.
    */
    WARN_ON(failed_at &&
    proc->tsk == current->group_leader);
    } break;

    That check seems to be attempting to detect cases where
    binder_transaction() fails and rolls back a partial transaction sent
    by a process to itself. I think the intent there is probably to catch
    cases that would cause the check in the BINDER_TYPE_FDA case below to
    trip up?

    About this fix: This prevents a task from sending binder transactions
    to the context manager if they're running in the same process. (By the
    way, I don't understand why that's a problem, conceptually.) But you
    can still open a binder device twice (binder_proc instances A and B)
    from a process that does not own the context manager instance, pass a
    binder object from A to the context manager, let the context manager
    pass it to B, and then A can transact with the same-process B. So this
    merely looks fixed because syzkaller isn't able to construct such a
    complicated testcase. (I think you could also let A receive a handle
    to itself and then transact with itself, but I haven't tested that.)


    I think this fix should probably be reverted (unless you actually want
    to prevent intra-process transactions, which would probably require a
    bunch of ugly extra checks), the WARN_ON() should be removed, and the
    BINDER_TYPE_FDA case should be adjusted to make its decision based on
    a flag passed from its parent instead of guessing based on what
    `current` is. Since it looks like because of this bug, an aborted
    intra-process transaction containing BINDER_TYPE_FDA (e.g. via the
    err_translate_failed or err_dead_proc_or_thread cases) will cause file
    descriptors to unexpectedly be released in the caller, leading to a
    file-descriptor use-after-free in userspace, the fix should probably
    also be stable-backported. (It's probably not a huge problem in
    practice though, given that only hwbinder uses BINDER_TYPE_FDA and you
    need to have an intra-process transaction at the same time as
    something like a thread going away, or something like that? I don't
    fully understand the failure conditions for binder transactions.)


    Here's a reproducer for triggering the WARN_ON() on git master. The
    helper files binder.c and binder.h are attached.

    =================
    #define _GNU_SOURCE
    #include <unistd.h>
    #include <stdio.h>
    #include <stdint.h>
    #include <err.h>
    #include <stdlib.h>
    #include <sys/signal.h>
    #include <sys/prctl.h>
    #include "binder.h"

    #define BINDER_PATH "/dev/binder/binder"

    static void do_exit(int dummy) {
    _exit(1);
    }

    static uint32_t ref_a_from_manager;

    int my_handler(struct binder_state *bs, struct binder_transaction_data *txn,
    struct binder_io *msg, struct binder_io *reply) {
    if (txn->code == 1) {
    ref_a_from_manager = bio_get_ref(msg);
    if (ref_a_from_manager == 0)
    errx(1, "manager received bogus message 1");
    binder_acquire(bs, ref_a_from_manager);
    printf("manager received handle 0x%x from A\n", ref_a_from_manager);
    return 0;
    } else if (txn->code == 2) {
    if (ref_a_from_manager == 0)
    errx(1, "B asked too early");
    bio_put_ref(reply, ref_a_from_manager);
    printf("manager is sending handle to B\n");
    return 0;
    } else {
    errx(1, "manager got unexpected message");
    }
    }

    int main(void) {
    if (signal(SIGCHLD, do_exit))
    err(1, "signal");

    struct binder_state *bs_mgr = binder_open(BINDER_PATH, 0x400000);
    if (bs_mgr == NULL)
    err(1, "binder_open()");
    if (binder_become_context_manager(bs_mgr))
    err(1, "become mgr");

    pid_t child = fork();
    if (child == -1)
    err(1, "fork");
    if (child == 0) {
    prctl(PR_SET_PDEATHSIG, SIGKILL);
    if (getppid() == 1) exit(0);

    /* create endpoint A and send message with handle to manager */
    {
    struct binder_state *bs_a = binder_open(BINDER_PATH, 0x400000);
    if (bs_a == NULL) err(1, "binder_open()");

    struct binder_io msg;
    struct binder_io reply;
    char data[0x1000];
    bio_init(&msg, data, sizeof(data), 4);
    bio_put_obj(&msg, (void*)1);
    if (binder_call(bs_a, &msg, &reply, 0, 1/*code*/))
    errx(1, "binder_call");
    binder_done(bs_a, &msg, &reply);
    }

    /* create endpoint B and retrieve handle from manager */
    struct binder_state *bs_b;
    uint32_t ref_a_from_b;
    {
    bs_b = binder_open(BINDER_PATH, 0x400000);
    if (bs_b == NULL) err(1, "binder_open()");

    struct binder_io msg;
    struct binder_io reply;
    char data[0x1000];
    bio_init(&msg, data, sizeof(data), 4);
    if (binder_call(bs_b, &msg, &reply, 0, 2/*code*/))
    errx(1, "binder_call");
    ref_a_from_b = bio_get_ref(&reply);
    if (ref_a_from_b == 0)
    errx(1, "B received bogus reply");
    binder_acquire(bs_b, ref_a_from_b);
    printf("B received handle 0x%x from manager\n", ref_a_from_b);
    binder_done(bs_b, &msg, &reply);
    }

    /* let B send a message with a valid FD and an invalid FD to A */
    {
    struct binder_io msg;
    struct binder_io reply;
    char data[0x1000];
    bio_init(&msg, data, sizeof(data), 4);
    bio_put_fd(&msg, 0); /*valid*/
    bio_put_fd(&msg, -1); /*invalid*/
    if (binder_call(bs_b, &msg, &reply, ref_a_from_b, 3/*code*/))
    errx(1, "binder_call");
    }

    exit(0);
    }

    binder_loop(bs_mgr, my_handler);
    }
    =================
    /* Copyright 2008 The Android Open Source Project
    */
    #ifndef _BINDER_H_
    #define _BINDER_H_

    #include <sys/ioctl.h>
    #include </h/aosp-walleye/bionic/libc/kernel/uapi/linux/android/binder.h>

    struct binder_state
    {
    int fd;
    void *mapped;
    size_t mapsize;
    };
    struct binder_io
    {
    char *data; /* pointer to read/write from */
    binder_size_t *offs; /* array of offsets */
    size_t data_avail; /* bytes available in data buffer */
    size_t offs_avail; /* entries available in offsets array */
    char *data0; /* start of data buffer */
    binder_size_t *offs0; /* start of offsets buffer */
    uint32_t flags;
    uint32_t unused;
    uint64_t buffers_size;
    };
    struct binder_death {
    void (*func)(struct binder_state *bs, void *ptr);
    void *ptr;
    };
    /* the one magic handle */
    #define BINDER_SERVICE_MANAGER 0U
    #define SVC_MGR_NAME "android.os.IServiceManager"
    enum {
    /* Must match definitions in IBinder.h and IServiceManager.h */
    PING_TRANSACTION = B_PACK_CHARS('_','P','N','G'),
    SVC_MGR_GET_SERVICE = 1,
    SVC_MGR_CHECK_SERVICE,
    SVC_MGR_ADD_SERVICE,
    SVC_MGR_LIST_SERVICES,
    };
    typedef int (*binder_handler)(struct binder_state *bs,
    struct binder_transaction_data *txn,
    struct binder_io *msg,
    struct binder_io *reply);
    struct binder_state *binder_open(char *device, size_t mapsize);
    void binder_close(struct binder_state *bs);
    /* initiate a blocking binder call
    * - returns zero on success
    */
    int binder_call(struct binder_state *bs,
    struct binder_io *msg, struct binder_io *reply,
    uint32_t target, uint32_t code);
    int binder_call_async(struct binder_state *bs,
    struct binder_io *msg,
    uint32_t target, uint32_t code);
    int binder_read_reply(struct binder_state* bs,
    struct binder_io* reply);
    int binder_read_reply_handler(struct binder_state* bs,
    struct binder_io* reply, binder_handler func);
    /* release any state associate with the binder_io
    * - call once any necessary data has been extracted from the
    * binder_io after binder_call() returns
    * - can safely be called even if binder_call() fails
    */
    void binder_done(struct binder_state *bs,
    struct binder_io *msg, struct binder_io *reply);

    /* manipulate strong references */
    void binder_acquire(struct binder_state *bs, uint32_t target);
    void binder_release(struct binder_state *bs, uint32_t target);
    void binder_increfs(struct binder_state *bs, uint32_t target);
    void binder_decrefs(struct binder_state *bs, uint32_t target);
    void binder_link_to_death(struct binder_state *bs, uint32_t target, struct binder_death *death);
    void binder_loop(struct binder_state *bs, binder_handler func);
    int binder_become_context_manager(struct binder_state *bs);
    /* allocate a binder_io, providing a stack-allocated working
    * buffer, size of the working buffer, and how many object
    * offset entries to reserve from the buffer
    */
    void bio_init(struct binder_io *bio, void *data,
    size_t maxdata, size_t maxobjects);
    void bio_put_obj(struct binder_io *bio, void *ptr);
    void bio_put_fd(struct binder_io *bio, int fd);
    void bio_put_ref(struct binder_io *bio, uint32_t handle);
    void bio_put_uint32(struct binder_io *bio, uint32_t n);
    void bio_put_string16(struct binder_io *bio, const uint16_t *str);
    void bio_put_string16_x(struct binder_io *bio, const char *_str);
    void bio_put_string8_x(struct binder_io *bio, const char *_str);
    void bio_put_cstring(struct binder_io *bio, const char *_str);
    uint32_t bio_get_uint32(struct binder_io *bio);
    uint16_t *bio_get_string16(struct binder_io *bio, size_t *sz);
    char *bio_get_string8(struct binder_io *bio, size_t *sz);
    uint32_t bio_get_ref(struct binder_io *bio);
    uint32_t bio_get_ref_cookie(struct binder_io *bio, uint64_t* cookie);
    void bio_put_buf(struct binder_io *bio, void *data, size_t len, int *buf_id);
    void bio_put_sub_buf(struct binder_io *bio, int parent_id, int parent_offset, void *data, size_t len, int *buf_id);

    int binder_write(struct binder_state *bs, void *data, size_t len);
    #endif/* Copyright 2008 The Android Open Source Project
    */
    #include <inttypes.h>
    #include <stdbool.h>
    #include <stdio.h>
    #include <stdlib.h>
    #include <string.h>
    #include <errno.h>
    #include <unistd.h>
    #include <fcntl.h>
    #include <err.h>
    #include <sys/mman.h>
    #include <sys/wait.h>
    #include "binder.h"
    #define MAX_BIO_SIZE (1 << 30)
    #define TRACE 0
    #define LOG_TAG "Binder"
    #define ALOGE(...)
    #define ALOGW(...)
    #define ALOGD(...)
    void bio_init_from_txn(struct binder_io *io, struct binder_transaction_data *txn);
    #if TRACE
    void hexdump(void *_data, size_t len)
    {
    unsigned char *data = _data;
    size_t count;
    for (count = 0; count < len; count++) {
    if ((count & 15) == 0)
    fprintf(stderr,"%04zu:", count);
    fprintf(stderr," %02x %c", *data,
    (*data < 32) || (*data > 126) ? '.' : *data);
    data++;
    if ((count & 15) == 15)
    fprintf(stderr,"\n");
    }
    if ((count & 15) != 0)
    fprintf(stderr,"\n");
    }
    void binder_dump_txn(struct binder_transaction_data *txn)
    {
    struct flat_binder_object *obj;
    binder_size_t *offs = (binder_size_t *)(uintptr_t)txn->data.ptr.offsets;
    size_t count = txn->offsets_size / sizeof(binder_size_t);
    fprintf(stderr," target %016"PRIx64" cookie %016"PRIx64" code %08x flags %08x\n",
    (uint64_t)txn->target.ptr, (uint64_t)txn->cookie, txn->code, txn->flags);
    fprintf(stderr," pid %8d uid %8d data %"PRIu64" offs %"PRIu64"\n",
    txn->sender_pid, txn->sender_euid, (uint64_t)txn->data_size, (uint64_t)txn->offsets_size);
    hexdump((void *)(uintptr_t)txn->data.ptr.buffer, txn->data_size);
    while (count--) {
    obj = (struct flat_binder_object *) (((char*)(uintptr_t)txn->data.ptr.buffer) + *offs++);
    fprintf(stderr," - type %08x flags %08x ptr %016"PRIx64" cookie %016"PRIx64"\n",
    obj->hdr.type, obj->flags, (uint64_t)obj->binder, (uint64_t)obj->cookie);
    }
    }
    #define NAME(n) case n: return #n
    const char *cmd_name(uint32_t cmd)
    {
    switch(cmd) {
    NAME(BR_NOOP);
    NAME(BR_TRANSACTION_COMPLETE);
    NAME(BR_INCREFS);
    NAME(BR_ACQUIRE);
    NAME(BR_RELEASE);
    NAME(BR_DECREFS);
    NAME(BR_TRANSACTION);
    NAME(BR_REPLY);
    NAME(BR_FAILED_REPLY);
    NAME(BR_DEAD_REPLY);
    NAME(BR_DEAD_BINDER);
    default: return "???";
    }
    }
    #else
    #define hexdump(a,b) do{} while (0)
    #define binder_dump_txn(txn) do{} while (0)
    #endif
    #define BIO_F_SHARED 0x01 /* needs to be buffer freed */
    #define BIO_F_OVERFLOW 0x02 /* ran out of space */
    #define BIO_F_IOERROR 0x04
    #define BIO_F_MALLOCED 0x08 /* needs to be free()'d */
    struct binder_state *binder_open(char *device, size_t mapsize)
    {
    struct binder_state *bs;
    struct binder_version vers;
    bs = malloc(sizeof(*bs));
    if (!bs) {
    errno = ENOMEM;
    return NULL;
    }
    bs->fd = open(device, O_RDWR | O_CLOEXEC);
    if (bs->fd < 0) {
    fprintf(stderr,"binder: cannot open device (%s)\n",
    strerror(errno));
    goto fail_open;
    }
    if ((ioctl(bs->fd, BINDER_VERSION, &vers) == -1) ||
    (vers.protocol_version != BINDER_CURRENT_PROTOCOL_VERSION)) {
    fprintf(stderr,
    "binder: kernel driver version (%d) differs from user space version (%d)\n",
    vers.protocol_version, BINDER_CURRENT_PROTOCOL_VERSION);
    goto fail_open;
    }
    bs->mapsize = mapsize;
    bs->mapped = mmap(NULL, mapsize, PROT_READ, MAP_PRIVATE, bs->fd, 0);
    if (bs->mapped == MAP_FAILED) {
    fprintf(stderr,"binder: cannot map device (%s)\n",
    strerror(errno));
    goto fail_map;
    }
    if (madvise(bs->mapped, mapsize, MADV_DOFORK)) err(1, "MADV_DOFORK");
    return bs;
    fail_map:
    close(bs->fd);
    fail_open:
    free(bs);
    return NULL;
    }
    void binder_close(struct binder_state *bs)
    {
    munmap(bs->mapped, bs->mapsize);
    close(bs->fd);
    free(bs);
    }
    int binder_become_context_manager(struct binder_state *bs)
    {
    return ioctl(bs->fd, BINDER_SET_CONTEXT_MGR, 0);
    }
    int binder_write(struct binder_state *bs, void *data, size_t len)
    {
    struct binder_write_read bwr;
    int res;
    bwr.write_size = len;
    bwr.write_consumed = 0;
    bwr.write_buffer = (uintptr_t) data;
    bwr.read_size = 0;
    bwr.read_consumed = 0;
    bwr.read_buffer = 0;
    res = ioctl(bs->fd, BINDER_WRITE_READ, &bwr);
    if (res < 0) {
    fprintf(stderr,"binder_write: ioctl failed (%s)\n",
    strerror(errno));
    }
    return res;
    }
    void binder_send_reply(struct binder_state *bs,
    struct binder_io *reply,
    binder_uintptr_t buffer_to_free,
    int status)
    {
    printf("binder_send_reply(status=%d)\n", status);
    struct {
    uint32_t cmd_free;
    binder_uintptr_t buffer;
    uint32_t cmd_reply;
    struct binder_transaction_data_sg txn_sg;
    } __attribute__((packed)) data;
    data.cmd_free = BC_FREE_BUFFER;
    data.buffer = buffer_to_free;
    data.cmd_reply = BC_REPLY_SG;
    data.txn_sg.buffers_size = reply->buffers_size;
    data.txn_sg.transaction_data.target.ptr = 0;
    data.txn_sg.transaction_data.cookie = 0;
    data.txn_sg.transaction_data.code = 0;
    if (status) {
    data.txn_sg.transaction_data.flags = TF_STATUS_CODE;
    data.txn_sg.transaction_data.data_size = sizeof(int);
    data.txn_sg.transaction_data.offsets_size = 0;
    data.txn_sg.transaction_data.data.ptr.buffer = (uintptr_t)&status;
    data.txn_sg.transaction_data.data.ptr.offsets = 0;
    } else {
    data.txn_sg.transaction_data.flags = 0;
    data.txn_sg.transaction_data.data_size = reply->data - reply->data0;
    data.txn_sg.transaction_data.offsets_size = ((char*) reply->offs) - ((char*) reply->offs0);
    data.txn_sg.transaction_data.data.ptr.buffer = (uintptr_t)reply->data0;
    data.txn_sg.transaction_data.data.ptr.offsets = (uintptr_t)reply->offs0;
    if (data.txn_sg.transaction_data.offsets_size) {
    *(volatile unsigned long *)data.txn_sg.transaction_data.data.ptr.offsets;
    }
    printf("offsets=%p, offsets_size=%lu\n",
    reply->offs0,
    (unsigned long)data.txn_sg.transaction_data.offsets_size);
    }
    binder_write(bs, &data, sizeof(data));
    }
    int binder_parse(struct binder_state *bs, struct binder_io *bio,
    uintptr_t ptr, size_t size, binder_handler func)
    {
    int r = 1;
    uintptr_t end = ptr + (uintptr_t) size;
    while (ptr < end) {
    uint32_t cmd = *(uint32_t *) ptr;
    ptr += sizeof(uint32_t);
    #if TRACE
    fprintf(stderr,"%s:\n", cmd_name(cmd));
    #endif
    switch(cmd) {
    case BR_NOOP:
    break;
    case BR_TRANSACTION_COMPLETE:
    break;
    case BR_INCREFS:
    case BR_ACQUIRE:
    case BR_RELEASE:
    case BR_DECREFS:
    #if TRACE
    fprintf(stderr," %p, %p\n", (void *)ptr, (void *)(ptr + sizeof(void *)));
    #endif
    ptr += sizeof(struct binder_ptr_cookie);
    break;
    case BR_TRANSACTION: {
    struct binder_transaction_data *txn = (struct binder_transaction_data *) ptr;
    if ((end - ptr) < sizeof(*txn)) {
    ALOGE("parse: txn too small!\n");
    return -1;
    }
    binder_dump_txn(txn);
    if (func) {
    unsigned rdata[256/4];
    struct binder_io msg;
    struct binder_io reply;
    int res;
    bio_init(&reply, rdata, sizeof(rdata), 4);
    bio_init_from_txn(&msg, txn);
    res = func(bs, txn, &msg, &reply);
    if ((txn->flags & 1) == 0) {
    binder_send_reply(bs, &reply, txn->data.ptr.buffer, res);
    }
    }
    ptr += sizeof(*txn);
    break;
    }
    case BR_REPLY: {
    struct binder_transaction_data *txn = (struct binder_transaction_data *) ptr;
    if ((end - ptr) < sizeof(*txn)) {
    ALOGE("parse: reply too small!\n");
    return -1;
    }
    binder_dump_txn(txn);
    if (bio) {
    bio_init_from_txn(bio, txn);
    bio = 0;
    } else {
    /* todo FREE BUFFER */
    }
    ptr += sizeof(*txn);
    r = 0;
    break;
    }
    case BR_DEAD_BINDER: {
    struct binder_death *death = (struct binder_death *)(uintptr_t) *(binder_uintptr_t *)ptr;
    ptr += sizeof(binder_uintptr_t);
    death->func(bs, death->ptr);
    break;
    }
    case BR_FAILED_REPLY:
    r = -1;
    break;
    case BR_DEAD_REPLY:
    r = -1;
    break;
    default:
    ALOGE("parse: OOPS %d\n", cmd);
    return -1;
    }
    }
    return r;
    }
    void binder_acquire(struct binder_state *bs, uint32_t target)
    {
    uint32_t cmd[2];
    cmd[0] = BC_ACQUIRE;
    cmd[1] = target;
    binder_write(bs, cmd, sizeof(cmd));
    }
    void binder_release(struct binder_state *bs, uint32_t target)
    {
    uint32_t cmd[2];
    cmd[0] = BC_RELEASE;
    cmd[1] = target;
    binder_write(bs, cmd, sizeof(cmd));
    }
    void binder_increfs(struct binder_state *bs, uint32_t target)
    {
    uint32_t cmd[2];
    cmd[0] = BC_INCREFS;
    cmd[1] = target;
    binder_write(bs, cmd, sizeof(cmd));
    }
    void binder_decrefs(struct binder_state *bs, uint32_t target)
    {
    uint32_t cmd[2];
    cmd[0] = BC_DECREFS;
    cmd[1] = target;
    binder_write(bs, cmd, sizeof(cmd));
    }
    void binder_link_to_death(struct binder_state *bs, uint32_t target, struct binder_death *death)
    {
    struct {
    uint32_t cmd;
    struct binder_handle_cookie payload;
    } __attribute__((packed)) data;
    data.cmd = BC_REQUEST_DEATH_NOTIFICATION;
    data.payload.handle = target;
    data.payload.cookie = (uintptr_t) death;
    binder_write(bs, &data, sizeof(data));
    }
    int binder_call(struct binder_state *bs,
    struct binder_io *msg, struct binder_io *reply,
    uint32_t target, uint32_t code)
    {
    int res;
    struct binder_write_read bwr;
    struct {
    uint32_t cmd;
    struct binder_transaction_data_sg txn_sg;
    } __attribute__((packed)) writebuf;
    unsigned readbuf[32];
    if (msg->flags & BIO_F_OVERFLOW) {
    fprintf(stderr,"binder: txn buffer overflow\n");
    goto fail;
    }
    writebuf.cmd = BC_TRANSACTION_SG;
    writebuf.txn_sg.buffers_size = msg->buffers_size;
    writebuf.txn_sg.transaction_data.target.handle = target;
    writebuf.txn_sg.transaction_data.code = code;
    writebuf.txn_sg.transaction_data.flags = TF_ACCEPT_FDS;
    writebuf.txn_sg.transaction_data.data_size = msg->data - msg->data0;
    writebuf.txn_sg.transaction_data.offsets_size = ((char*) msg->offs) - ((char*) msg->offs0);
    writebuf.txn_sg.transaction_data.data.ptr.buffer = (uintptr_t)msg->data0;
    writebuf.txn_sg.transaction_data.data.ptr.offsets = (uintptr_t)msg->offs0;
    bwr.write_size = sizeof(writebuf);
    bwr.write_consumed = 0;
    bwr.write_buffer = (uintptr_t) &writebuf;
    hexdump(msg->data0, msg->data - msg->data0);
    bool first_iter = false;
    for (;;) {
    bwr.read_size = sizeof(readbuf);
    bwr.read_consumed = 0;
    bwr.read_buffer = (uintptr_t) readbuf;

    if (first_iter) {
    bwr.read_size = 0;
    printf("%d forking...\n", getpid());
    pid_t child = fork();
    if (child == -1) err(1, "fork");
    if (child == 0) {

    printf("entering child: %d\n", getpid());
    res = ioctl(bs->fd, BINDER_WRITE_READ, &bwr);
    if (res < 0) {
    fprintf(stderr,"binder: ioctl failed (%s)\n", strerror(errno));
    }
    if (bwr.write_consumed != bwr.write_size) {
    errx(1, "write_consumed != write_size");
    }

    printf("child exiting\n");
    exit(0);
    }
    int status;
    if (wait(&status) != child) err(1, "wait for child");
    bwr.write_consumed = bwr.write_size;
    printf("child is dead\n");
    } else {
    res = ioctl(bs->fd, BINDER_WRITE_READ, &bwr);
    if (res < 0) {
    fprintf(stderr,"binder: ioctl failed (%s)\n", strerror(errno));
    goto fail;
    }
    res = binder_parse(bs, reply, (uintptr_t) readbuf, bwr.read_consumed, 0);
    if (res == 0) return 0;
    if (res < 0) goto fail;
    }

    first_iter = false;
    }
    fail:
    memset(reply, 0, sizeof(*reply));
    reply->flags |= BIO_F_IOERROR;
    return -1;
    }
    int binder_call_async(struct binder_state *bs,
    struct binder_io *msg, uint32_t target, uint32_t code)
    {
    int res;
    struct binder_write_read bwr;
    struct {
    uint32_t cmd;
    struct binder_transaction_data txn;
    } __attribute__((packed)) writebuf;
    if (msg->flags & BIO_F_OVERFLOW) {
    fprintf(stderr,"binder: txn buffer overflow\n");
    goto fail;
    }
    writebuf.cmd = BC_TRANSACTION;
    writebuf.txn.target.handle = target;
    writebuf.txn.code = code;
    writebuf.txn.flags = TF_ACCEPT_FDS;
    writebuf.txn.data_size = msg->data - msg->data0;
    writebuf.txn.offsets_size = ((char*) msg->offs) - ((char*) msg->offs0);
    writebuf.txn.data.ptr.buffer = (uintptr_t)msg->data0;
    writebuf.txn.data.ptr.offsets = (uintptr_t)msg->offs0;
    bwr.write_size = sizeof(writebuf);
    bwr.write_consumed = 0;
    bwr.write_buffer = (uintptr_t) &writebuf;
    bwr.read_size = 0;
    bwr.read_buffer = 0;
    bwr.read_consumed = 0;
    hexdump(msg->data0, msg->data - msg->data0);
    res = ioctl(bs->fd, BINDER_WRITE_READ, &bwr);
    if (res < 0) {
    fprintf(stderr,"binder: ioctl failed (%s)\n", strerror(errno));
    goto fail;
    }
    return 0;
    fail:
    return -1;
    }


    int binder_read_reply(struct binder_state* bs,
    struct binder_io* reply)
    {
    int res;
    struct binder_write_read bwr;
    unsigned readbuf[32];
    bwr.write_size = 0;
    bwr.write_consumed = 0;
    bwr.write_buffer = 0;
    for (;;) {
    bwr.read_size = sizeof(readbuf);
    bwr.read_consumed = 0;
    bwr.read_buffer = (uintptr_t) readbuf;
    res = ioctl(bs->fd, BINDER_WRITE_READ, &bwr);
    if (res < 0) {
    fprintf(stderr,"binder: ioctl failed (%s)\n", strerror(errno));
    goto fail;
    }
    res = binder_parse(bs, reply, (uintptr_t) readbuf, bwr.read_consumed, 0);
    if (res == 0) return 0;
    if (res < 0) goto fail;
    }
    fail:
    memset(reply, 0, sizeof(*reply));
    reply->flags |= BIO_F_IOERROR;
    return -1;
    }

    int binder_read_reply_handler(struct binder_state* bs,
    struct binder_io* reply, binder_handler func)
    {
    int res;
    struct binder_write_read bwr;
    unsigned readbuf[32];
    bwr.write_size = 0;
    bwr.write_consumed = 0;
    bwr.write_buffer = 0;
    for (;;) {
    bwr.read_size = sizeof(readbuf);
    bwr.read_consumed = 0;
    bwr.read_buffer = (uintptr_t) readbuf;
    res = ioctl(bs->fd, BINDER_WRITE_READ, &bwr);
    if (res < 0) {
    fprintf(stderr,"binder: ioctl failed (%s)\n", strerror(errno));
    goto fail;
    }
    res = binder_parse(bs, reply, (uintptr_t) readbuf, bwr.read_consumed, func);
    if (res == 0) return 0;
    if (res < 0) goto fail;
    }
    fail:
    memset(reply, 0, sizeof(*reply));
    reply->flags |= BIO_F_IOERROR;
    return -1;
    }

    void binder_loop(struct binder_state *bs, binder_handler func)
    {
    int res;
    struct binder_write_read bwr;
    uint32_t readbuf[32];
    bwr.write_size = 0;
    bwr.write_consumed = 0;
    bwr.write_buffer = 0;
    readbuf[0] = BC_ENTER_LOOPER;
    binder_write(bs, readbuf, sizeof(uint32_t));
    for (;;) {
    bwr.read_size = sizeof(readbuf);
    bwr.read_consumed = 0;
    bwr.read_buffer = (uintptr_t) readbuf;
    res = ioctl(bs->fd, BINDER_WRITE_READ, &bwr);
    if (res < 0) {
    fprintf(stderr,"binder_loop: ioctl failed (%s)\n", strerror(errno));
    break;
    }
    res = binder_parse(bs, 0, (uintptr_t) readbuf, bwr.read_consumed, func);
    if (res == 0) {
    fprintf(stderr,"binder_loop: unexpected reply?!\n");
    break;
    }
    if (res < 0) {
    fprintf(stderr,"binder_loop: io error %d %s\n", res, strerror(errno));
    break;
    }
    }
    }
    void bio_init_from_txn(struct binder_io *bio, struct binder_transaction_data *txn)
    {
    bio->data = bio->data0 = (char *)(intptr_t)txn->data.ptr.buffer;
    bio->offs = bio->offs0 = (binder_size_t *)(intptr_t)txn->data.ptr.offsets;
    bio->data_avail = txn->data_size;
    bio->offs_avail = txn->offsets_size / sizeof(size_t);
    bio->flags = BIO_F_SHARED;
    }
    void bio_init(struct binder_io *bio, void *data,
    size_t maxdata, size_t maxoffs)
    {
    size_t n = maxoffs * sizeof(size_t);
    if (n > maxdata) {
    bio->flags = BIO_F_OVERFLOW;
    bio->data_avail = 0;
    bio->offs_avail = 0;
    return;
    }
    bio->data = bio->data0 = (char *) data + n;
    bio->offs = bio->offs0 = data;
    bio->data_avail = maxdata - n;
    bio->offs_avail = maxoffs;
    bio->flags = 0;
    bio->buffers_size = 0;
    }
    static void *bio_alloc(struct binder_io *bio, size_t size)
    {
    size = (size + 3) & (~3);
    if (size > bio->data_avail) {
    bio->flags |= BIO_F_OVERFLOW;
    return NULL;
    } else {
    void *ptr = bio->data;
    bio->data += size;
    bio->data_avail -= size;
    return ptr;
    }
    }
    void binder_done(struct binder_state *bs,
    struct binder_io *msg,
    struct binder_io *reply)
    {
    struct {
    uint32_t cmd;
    uintptr_t buffer;
    } __attribute__((packed)) data;
    if (reply->flags & BIO_F_SHARED) {
    printf("binder_done: freeing buffer\n");
    data.cmd = BC_FREE_BUFFER;
    data.buffer = (uintptr_t) reply->data0;
    binder_write(bs, &data, sizeof(data));
    reply->flags = 0;
    printf("binder_done: free done\n");
    }
    }
    static struct flat_binder_object *bio_alloc_obj(struct binder_io *bio)
    {
    struct flat_binder_object *obj;
    obj = bio_alloc(bio, sizeof(*obj));
    if (obj && bio->offs_avail) {
    bio->offs_avail--;
    *bio->offs++ = ((char*) obj) - ((char*) bio->data0);
    return obj;
    }
    bio->flags |= BIO_F_OVERFLOW;
    return NULL;
    }
    static struct binder_fd_array_object *bio_alloc_fda(struct binder_io *bio)
    {
    struct binder_fd_array_object *obj;
    obj = bio_alloc(bio, sizeof(*obj));
    if (obj && bio->offs_avail) {
    bio->offs_avail--;
    *bio->offs++ = ((char*) obj) - ((char*) bio->data0);
    return obj;
    }
    bio->flags |= BIO_F_OVERFLOW;
    return NULL;
    }
    static struct binder_buffer_object *bio_alloc_buf(struct binder_io *bio, int *buf_id)
    {
    struct binder_buffer_object *obj;
    obj = bio_alloc(bio, sizeof(*obj));
    if (obj && bio->offs_avail) {
    bio->offs_avail--;
    if (buf_id) *buf_id = bio->offs - bio->offs0;
    *bio->offs++ = ((char*) obj) - ((char*) bio->data0);
    return obj;
    }
    bio->flags |= BIO_F_OVERFLOW;
    return NULL;
    }
    void bio_put_uint32(struct binder_io *bio, uint32_t n)
    {
    uint32_t *ptr = bio_alloc(bio, sizeof(n));
    if (ptr)
    *ptr = n;
    }
    void bio_put_obj(struct binder_io *bio, void *ptr)
    {
    struct flat_binder_object *obj;
    obj = bio_alloc_obj(bio);
    if (!obj)
    return;
    obj->flags = 0x7f | FLAT_BINDER_FLAG_ACCEPTS_FDS;
    obj->hdr.type = BINDER_TYPE_BINDER;
    obj->binder = (uintptr_t)ptr;
    obj->cookie = 0;
    }
    void bio_put_fd(struct binder_io *bio, int fd)
    {
    struct flat_binder_object *obj;
    obj = bio_alloc_obj(bio);
    if (!obj)
    return;
    obj->flags = 0x7f | FLAT_BINDER_FLAG_ACCEPTS_FDS;
    obj->hdr.type = BINDER_TYPE_FD;
    obj->binder = (uintptr_t)fd;
    obj->cookie = 0;
    }

    void bio_put_buf(struct binder_io *bio, void *data, size_t len, int *buf_id) {
    struct binder_buffer_object *obj;
    obj = bio_alloc_buf(bio, buf_id);
    if (!obj)
    return;
    obj->hdr.type = BINDER_TYPE_PTR;
    obj->flags = 0;
    obj->buffer = (unsigned long)data;
    obj->length = len;
    obj->parent = 0; // unused
    obj->parent_offset = 0; // unused
    bio->buffers_size += (len+7)&~7UL; // TODO rounding blargh
    }

    void bio_put_sub_buf(struct binder_io *bio, int parent_id, int parent_offset, void *data, size_t len, int *buf_id) {
    struct binder_buffer_object *obj;
    obj = bio_alloc_buf(bio, buf_id);
    if (!obj)
    return;
    obj->hdr.type = BINDER_TYPE_PTR;
    obj->flags = BINDER_BUFFER_FLAG_HAS_PARENT;
    obj->buffer = (unsigned long)data;
    obj->length = len;
    obj->parent = parent_id;
    obj->parent_offset = parent_offset;
    bio->buffers_size += (len+7)&~7UL; // TODO rounding blargh
    }

    void bio_put_fda(struct binder_io *bio, int *fds, int fd_count) {
    int buf_id = -1;
    bio_put_buf(bio, fds, sizeof(int)*fd_count, &buf_id);
    if (buf_id == -1) errx(1, "bio_put_buf fail");
    struct binder_fd_array_object *obj;
    obj = bio_alloc_fda(bio);
    if (!obj)
    return;
    obj->hdr.type = BINDER_TYPE_FDA;
    obj->num_fds = fd_count;
    printf("fda->parent = %d\n", buf_id);
    obj->parent = buf_id;
    obj->parent_offset = 0;
    }

    void bio_put_ref(struct binder_io *bio, uint32_t handle)
    {
    struct flat_binder_object *obj;
    if (handle)
    obj = bio_alloc_obj(bio);
    else
    obj = bio_alloc(bio, sizeof(*obj));
    if (!obj)
    return;
    obj->flags = 0x7f | FLAT_BINDER_FLAG_ACCEPTS_FDS;
    obj->hdr.type = BINDER_TYPE_HANDLE;
    obj->handle = handle;
    obj->cookie = 0;
    }
    void bio_put_string16(struct binder_io *bio, const uint16_t *str)
    {
    size_t len;
    uint16_t *ptr;
    if (!str) {
    bio_put_uint32(bio, 0xffffffff);
    return;
    }
    len = 0;
    while (str[len]) len++;
    if (len >= (MAX_BIO_SIZE / sizeof(uint16_t))) {
    bio_put_uint32(bio, 0xffffffff);
    return;
    }
    /* Note: The payload will carry 32bit size instead of size_t */
    bio_put_uint32(bio, (uint32_t) len);
    len = (len + 1) * sizeof(uint16_t);
    ptr = bio_alloc(bio, len);
    if (ptr)
    memcpy(ptr, str, len);
    }

    void bio_put_cstring(struct binder_io *bio, const char *str)
    {
    char* ptr = NULL;
    size_t len = 0;

    len = strlen(str) + 1;
    ptr = bio_alloc(bio, len);
    if (ptr)
    memcpy(ptr, str, len);
    }

    void bio_put_string16_x(struct binder_io *bio, const char *_str)
    {
    unsigned char *str = (unsigned char*) _str;
    size_t len;
    uint16_t *ptr;
    if (!str) {
    bio_put_uint32(bio, 0xffffffff);
    return;
    }
    len = strlen(_str);
    if (len >= (MAX_BIO_SIZE / sizeof(uint16_t))) {
    bio_put_uint32(bio, 0xffffffff);
    return;
    }
    /* Note: The payload will carry 32bit size instead of size_t */
    bio_put_uint32(bio, len);
    ptr = bio_alloc(bio, (len + 1) * sizeof(uint16_t));
    if (!ptr)
    return;
    while (*str)
    *ptr++ = *str++;
    *ptr++ = 0;
    }

    void bio_put_string8_x(struct binder_io *bio, const char *_str)
    {
    unsigned char *str = (unsigned char*) _str;
    size_t len;
    uint8_t *ptr;
    if (!str) {
    bio_put_uint32(bio, 0xffffffff);
    return;
    }
    len = strlen(_str);
    if (len >= (MAX_BIO_SIZE / sizeof(uint8_t))) {
    bio_put_uint32(bio, 0xffffffff);
    return;
    }
    /* Note: The payload will carry 32bit size instead of size_t */
    bio_put_uint32(bio, len);
    ptr = bio_alloc(bio, (len + 1) * sizeof(uint8_t));
    if (!ptr)
    return;
    while (*str)
    *ptr++ = *str++;
    *ptr++ = 0;
    }
    static void *bio_get(struct binder_io *bio, size_t size)
    {
    size = (size + 3) & (~3);
    if (bio->data_avail < size){
    bio->data_avail = 0;
    bio->flags |= BIO_F_OVERFLOW;
    return NULL;
    } else {
    void *ptr = bio->data;
    bio->data += size;
    bio->data_avail -= size;
    return ptr;
    }
    }
    uint32_t bio_get_uint32(struct binder_io *bio)
    {
    uint32_t *ptr = bio_get(bio, sizeof(*ptr));
    return ptr ? *ptr : 0;
    }
    uint16_t *bio_get_string16(struct binder_io *bio, size_t *sz)
    {
    size_t len;
    /* Note: The payload will carry 32bit size instead of size_t */
    len = (size_t) bio_get_uint32(bio);
    if (sz)
    *sz = len;
    return bio_get(bio, (len + 1) * sizeof(uint16_t));
    }
    char *bio_get_string8(struct binder_io *bio, size_t *sz) {
    size_t len;
    /* Note: The payload will carry 32bit size instead of size_t */
    len = (size_t) bio_get_uint32(bio);
    if (sz)
    *sz = len;
    return bio_get(bio, len + 1);
    }
    static struct flat_binder_object *_bio_get_obj(struct binder_io *bio)
    {
    size_t n;
    size_t off = bio->data - bio->data0;
    /* TODO: be smarter about this? */
    for (n = 0; n < bio->offs_avail; n++) {
    if (bio->offs[n] == off)
    return bio_get(bio, sizeof(struct flat_binder_object));
    }
    bio->data_avail = 0;
    bio->flags |= BIO_F_OVERFLOW;
    return NULL;
    }
    uint32_t bio_get_ref(struct binder_io *bio)
    {
    struct flat_binder_object *obj;
    obj = _bio_get_obj(bio);
    if (!obj)
    return 0;
    if (obj->hdr.type == BINDER_TYPE_HANDLE)
    return obj->handle;
    return 0;
    }


    uint32_t bio_get_ref_cookie(struct binder_io *bio, uint64_t* cookie) {
    struct flat_binder_object *obj;
    obj = _bio_get_obj(bio);
    if (!obj)
    return 0;
    if (obj->hdr.type == BINDER_TYPE_HANDLE || obj->hdr.type == BINDER_TYPE_WEAK_HANDLE) {
    *cookie = obj->cookie;
    return obj->handle;
    }
    return 0;
    }
    \
     
     \ /
      Last update: 2019-10-12 00:01    [W:3.842 / U:1.128 seconds]
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