X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?a=blobdiff_plain;f=src%2Flibsystemd-bus%2Fbus-kernel.c;h=8ef5752b311ce5cd237f88c19f3fedc5f881b998;hb=66b26c5c9b02e787bc46db24daff04ad41e05ec5;hp=81469365f0ffdbd3ecae743e80a26feee3425d15;hpb=c91cb83c4dbc9a95a0a2a38e7028e0a7f4af3b35;p=elogind.git diff --git a/src/libsystemd-bus/bus-kernel.c b/src/libsystemd-bus/bus-kernel.c index 81469365f..8ef5752b3 100644 --- a/src/libsystemd-bus/bus-kernel.c +++ b/src/libsystemd-bus/bus-kernel.c @@ -65,19 +65,36 @@ static int parse_unique_name(const char *s, uint64_t *id) { static void append_payload_vec(struct kdbus_item **d, const void *p, size_t sz) { assert(d); - assert(p); assert(sz > 0); *d = ALIGN8_PTR(*d); + /* Note that p can be NULL, which encodes a region full of + * zeroes, which is useful to optimize certain padding + * conditions */ + (*d)->size = offsetof(struct kdbus_item, vec) + sizeof(struct kdbus_vec); (*d)->type = KDBUS_MSG_PAYLOAD_VEC; - (*d)->vec.address = (uint64_t) p; + (*d)->vec.address = PTR_TO_UINT64(p); (*d)->vec.size = sz; *d = (struct kdbus_item *) ((uint8_t*) *d + (*d)->size); } +static void append_payload_memfd(struct kdbus_item **d, int memfd, size_t sz) { + assert(d); + assert(memfd >= 0); + assert(sz > 0); + + *d = ALIGN8_PTR(*d); + (*d)->size = offsetof(struct kdbus_item, memfd) + sizeof(struct kdbus_memfd); + (*d)->type = KDBUS_MSG_PAYLOAD_MEMFD; + (*d)->memfd.fd = memfd; + (*d)->memfd.size = sz; + + *d = (struct kdbus_item *) ((uint8_t*) *d + (*d)->size); +} + static void append_destination(struct kdbus_item **d, const char *s, size_t length) { assert(d); assert(s); @@ -210,6 +227,9 @@ static int bus_message_setup_kmsg(sd_bus *b, sd_bus_message *m) { sz = offsetof(struct kdbus_msg, items); + assert_cc(ALIGN8(offsetof(struct kdbus_item, vec) + sizeof(struct kdbus_vec)) == + ALIGN8(offsetof(struct kdbus_item, memfd) + sizeof(struct kdbus_memfd))); + /* Add in fixed header, fields header and payload */ sz += (1 + m->n_body_parts) * ALIGN8(offsetof(struct kdbus_item, vec) + sizeof(struct kdbus_vec)); @@ -228,9 +248,12 @@ static int bus_message_setup_kmsg(sd_bus *b, sd_bus_message *m) { sz += ALIGN8(offsetof(struct kdbus_item, fds) + sizeof(int)*m->n_fds); m->kdbus = memalign(8, sz); - if (!m->kdbus) - return -ENOMEM; + if (!m->kdbus) { + r = -ENOMEM; + goto fail; + } + m->free_kdbus = true; memset(m->kdbus, 0, sz); m->kdbus->flags = @@ -250,19 +273,42 @@ static int bus_message_setup_kmsg(sd_bus *b, sd_bus_message *m) { append_destination(&d, m->destination, dl); append_payload_vec(&d, m->header, BUS_MESSAGE_BODY_BEGIN(m)); - MESSAGE_FOREACH_PART(part, i, m) + + MESSAGE_FOREACH_PART(part, i, m) { + if (part->is_zero) { + /* If this is padding then simply send a + * vector with a NULL data pointer which the + * kernel will just pass through. This is the + * most efficient way to encode zeroes */ + + append_payload_vec(&d, NULL, part->size); + continue; + } + + if (part->memfd >= 0 && part->sealed && m->destination) { + /* Try to send a memfd, if the part is + * sealed and this is not a broadcast. Since we can only */ + + append_payload_memfd(&d, part->memfd, part->size); + continue; + } + + /* Otherwise let's send a vector to the actual data, + * for that we need to map it first. */ + r = bus_body_part_map(part); + if (r < 0) + goto fail; + append_payload_vec(&d, part->data, part->size); + } if (m->kdbus->dst_id == KDBUS_DST_ID_BROADCAST) { void *p; p = append_bloom(&d, BLOOM_SIZE); r = bus_message_setup_bloom(m, p); - if (r < 0) { - free(m->kdbus); - m->kdbus = NULL; - return -r; - } + if (r < 0) + goto fail; } if (m->n_fds > 0) @@ -271,9 +317,11 @@ static int bus_message_setup_kmsg(sd_bus *b, sd_bus_message *m) { m->kdbus->size = (uint8_t*) d - (uint8_t*) m->kdbus; assert(m->kdbus->size <= sz); - m->free_kdbus = true; - return 0; + +fail: + m->poisoned = true; + return r; } int bus_kernel_take_fd(sd_bus *b) { @@ -387,17 +435,17 @@ static void close_kdbus_msg(sd_bus *bus, struct kdbus_msg *k) { KDBUS_ITEM_FOREACH(d, k) { - if (d->type != KDBUS_MSG_FDS) - continue; - - close_many(d->fds, (d->size - offsetof(struct kdbus_item, fds)) / sizeof(int)); + if (d->type == KDBUS_MSG_FDS) + close_many(d->fds, (d->size - offsetof(struct kdbus_item, fds)) / sizeof(int)); + else if (d->type == KDBUS_MSG_PAYLOAD_MEMFD) + close_nointr_nofail(d->memfd.fd); } } static int bus_kernel_make_message(sd_bus *bus, struct kdbus_msg *k, sd_bus_message **ret) { sd_bus_message *m = NULL; struct kdbus_item *d; - unsigned n_payload = 0, n_fds = 0; + unsigned n_fds = 0; _cleanup_free_ int *fds = NULL; struct bus_header *h = NULL; size_t total, n_bytes = 0, idx = 0; @@ -425,9 +473,15 @@ static int bus_kernel_make_message(sd_bus *bus, struct kdbus_msg *k, sd_bus_mess return -EBADMSG; } - n_payload++; n_bytes += d->vec.size; + } else if (d->type == KDBUS_MSG_PAYLOAD_MEMFD) { + + if (!h) + return -EBADMSG; + + n_bytes += d->memfd.size; + } else if (d->type == KDBUS_MSG_FDS) { int *f; unsigned j; @@ -441,9 +495,7 @@ static int bus_kernel_make_message(sd_bus *bus, struct kdbus_msg *k, sd_bus_mess memcpy(fds + n_fds, d->fds, sizeof(int) * j); n_fds += j; - } else if (d->type == KDBUS_MSG_DST_NAME) - destination = d->str; - else if (d->type == KDBUS_MSG_SRC_SECLABEL) + } else if (d->type == KDBUS_MSG_SRC_SECLABEL) seclabel = d->str; } @@ -478,22 +530,42 @@ static int bus_kernel_make_message(sd_bus *bus, struct kdbus_msg *k, sd_bus_mess part = message_append_part(m); if (!part) { - sd_bus_message_unref(m); - return -ENOMEM; + r = -ENOMEM; + goto fail; } if (idx >= begin_body) { part->data = UINT64_TO_PTR(d->vec.address); part->size = d->vec.size; } else { - part->data = (uint8_t*) UINT64_TO_PTR(d->vec.address) + (begin_body - idx); + part->data = d->vec.address != 0 ? (uint8_t*) UINT64_TO_PTR(d->vec.address) + (begin_body - idx) : NULL; part->size = d->vec.size - (begin_body - idx); } + part->is_zero = d->vec.address == 0; part->sealed = true; } idx += d->vec.size; + } else if (d->type == KDBUS_MSG_PAYLOAD_MEMFD) { + struct bus_body_part *part; + + if (idx < BUS_MESSAGE_BODY_BEGIN(m)) { + r = -EBADMSG; + goto fail; + } + + part = message_append_part(m); + if (!part) { + r = -ENOMEM; + goto fail; + } + + part->memfd = d->memfd.fd; + part->size = d->memfd.size; + part->sealed = true; + + idx += d->memfd.size; } else if (d->type == KDBUS_MSG_SRC_CREDS) { m->pid_starttime = d->creds.starttime / NSEC_PER_USEC; @@ -521,17 +593,16 @@ static int bus_kernel_make_message(sd_bus *bus, struct kdbus_msg *k, sd_bus_mess else if (d->type == KDBUS_MSG_SRC_CAPS) { m->capability = d->data; m->capability_size = l; - } else if (d->type != KDBUS_MSG_FDS && - d->type != KDBUS_MSG_DST_NAME && + } else if (d->type == KDBUS_MSG_DST_NAME) + destination = d->str; + else if (d->type != KDBUS_MSG_FDS && d->type != KDBUS_MSG_SRC_SECLABEL) log_debug("Got unknown field from kernel %llu", d->type); } r = bus_message_parse_fields(m); - if (r < 0) { - sd_bus_message_unref(m); - return r; - } + if (r < 0) + goto fail; if (k->src_id == KDBUS_SRC_ID_KERNEL) m->sender = "org.freedesktop.DBus"; @@ -560,6 +631,21 @@ static int bus_kernel_make_message(sd_bus *bus, struct kdbus_msg *k, sd_bus_mess *ret = m; return 1; + +fail: + if (m) { + struct bus_body_part *part; + unsigned i; + + /* Make sure the memfds are not freed twice */ + MESSAGE_FOREACH_PART(part, i, m) + if (part->memfd >= 0) + part->memfd = -1; + + sd_bus_message_unref(m); + } + + return r; } int bus_kernel_read_message(sd_bus *bus, sd_bus_message **m) { @@ -577,15 +663,6 @@ int bus_kernel_read_message(sd_bus *bus, sd_bus_message **m) { return -errno; } - -/* /\* Let's tell valgrind that there's really no need to */ -/* * initialize this fully. This should be removed again */ -/* * when valgrind learned the kdbus ioctls natively. *\/ */ -/* #ifdef HAVE_VALGRIND_MEMCHECK_H */ -/* VALGRIND_MAKE_MEM_DEFINED(k, sz); */ -/* #endif */ - - r = bus_kernel_make_message(bus, k, m); if (r <= 0) close_kdbus_msg(bus, k);