From 7f3d3ba1a61f28a951ca5fbe59ed15c7ce55219c Mon Sep 17 00:00:00 2001

From: David Herrmann <dh.herrmann@gmail.com>

Date: Mon, 22 Sep 2014 12:49:47 +0200

Subject: [PATCH] bus: align kdbus ioctl parameters to 8byte

All kdbus ioctl arguments must be 8byte aligned. Make sure we use

alloca_align() and _alignas_(8) in all situations where gcc doesn't

guarantee 8-byte alignment.

Note that objects on the stack are always 8byte aligned as we put

_alignas_(8) into the structure definition in kdbus.h.

---

 src/libsystemd/sd-bus/bus-control.c | 14 +++++++-------

 src/libsystemd/sd-bus/bus-kernel.c  | 26 ++++++++++++++------------

 src/libsystemd/sd-bus/bus-message.c |  2 +-

 3 files changed, 22 insertions(+), 20 deletions(-)

diff --git a/src/libsystemd/sd-bus/bus-control.c b/src/libsystemd/sd-bus/bus-control.c

index ad372f6772..5ac48c081f 100644

--- a/src/libsystemd/sd-bus/bus-control.c

+++ b/src/libsystemd/sd-bus/bus-control.c

@@ -60,7 +60,7 @@ static int bus_request_name_kernel(sd_bus *bus, const char *name, uint64_t flags

         l = strlen(name);

         size = offsetof(struct kdbus_cmd_name, name) + l + 1;

-        n = alloca0(size);

+        n = alloca0_align(size, 8);

         n->size = size;

         kdbus_translate_request_name_flags(flags, (uint64_t *) &n->flags);

         memcpy(n->name, name, l+1);

@@ -151,7 +151,7 @@ static int bus_release_name_kernel(sd_bus *bus, const char *name) {

         assert(name);

         l = strlen(name);

-        n = alloca0(offsetof(struct kdbus_cmd_name, name) + l + 1);

+        n = alloca0_align(offsetof(struct kdbus_cmd_name, name) + l + 1, 8);

         n->size = offsetof(struct kdbus_cmd_name, name) + l + 1;

         memcpy(n->name, name, l+1);

@@ -376,11 +376,11 @@ static int bus_get_owner_kdbus(

                 return r;

         if (r > 0) {

                 size = offsetof(struct kdbus_cmd_conn_info, name);

-                cmd = alloca0(size);

+                cmd = alloca0_align(size, 8);

                 cmd->id = id;

         } else {

                 size = offsetof(struct kdbus_cmd_conn_info, name) + strlen(name) + 1;

-                cmd = alloca0(size);

+                cmd = alloca0_align(size, 8);

                 strcpy(cmd->name, name);

         }

@@ -827,7 +827,7 @@ static int add_name_change_match(sd_bus *bus,

                             offsetof(struct kdbus_notify_name_change, name) +

                             l);

-                m = alloca0(sz);

+                m = alloca0_align(sz, 8);

                 m->size = sz;

                 m->cookie = cookie;

@@ -887,7 +887,7 @@ static int add_name_change_match(sd_bus *bus,

                             offsetof(struct kdbus_item, id_change) +

                             sizeof(struct kdbus_notify_id_change));

-                m = alloca0(sz);

+                m = alloca0_align(sz, 8);

                 m->size = sz;

                 m->cookie = cookie;

@@ -1057,7 +1057,7 @@ int bus_add_match_internal_kernel(

         if (using_bloom)

                 sz += ALIGN8(offsetof(struct kdbus_item, data64) + bus->bloom_size);

-        m = alloca0(sz);

+        m = alloca0_align(sz, 8);

         m->size = sz;

         m->cookie = cookie;

diff --git a/src/libsystemd/sd-bus/bus-kernel.c b/src/libsystemd/sd-bus/bus-kernel.c

index b3cc996b1e..c30491e687 100644

--- a/src/libsystemd/sd-bus/bus-kernel.c

+++ b/src/libsystemd/sd-bus/bus-kernel.c

@@ -709,7 +709,7 @@ int bus_kernel_take_fd(sd_bus *b) {

                 sz += ALIGN8(offsetof(struct kdbus_item, str) + l + 1);

         }

-        hello = alloca0(sz);

+        hello = alloca0_align(sz, 8);

         hello->size = sz;

         hello->conn_flags = b->hello_flags;

         hello->attach_flags = b->attach_flags;

@@ -796,7 +796,7 @@ int bus_kernel_connect(sd_bus *b) {

 }

 static void close_kdbus_msg(sd_bus *bus, struct kdbus_msg *k) {

-        uint64_t off;

+        uint64_t off _alignas_(8);

         struct kdbus_item *d;

         assert(bus);

@@ -1268,10 +1268,11 @@ int bus_kernel_create_bus(const char *name, bool world, char **s) {

         if (fd < 0)

                 return -errno;

-        make = alloca0(ALIGN8(offsetof(struct kdbus_cmd_make, items) +

-                              offsetof(struct kdbus_item, data64) + sizeof(uint64_t) +

-                              offsetof(struct kdbus_item, str) +

-                              DECIMAL_STR_MAX(uid_t) + 1 + strlen(name) + 1));

+        make = alloca0_align(ALIGN8(offsetof(struct kdbus_cmd_make, items) +

+                                    offsetof(struct kdbus_item, data64) + sizeof(uint64_t) +

+                                    offsetof(struct kdbus_item, str) +

+                                    DECIMAL_STR_MAX(uid_t) + 1 + strlen(name) + 1),

+                             8);

         make->size = offsetof(struct kdbus_cmd_make, items);

@@ -1423,7 +1424,7 @@ int bus_kernel_create_endpoint(const char *bus_name, const char *ep_name, char *

         size = ALIGN8(offsetof(struct kdbus_cmd_make, items));

         size += ALIGN8(offsetof(struct kdbus_item, str) + strlen(ep_name) + 1);

-        make = alloca0(size);

+        make = alloca0_align(size, 8);

         make->size = size;

         make->flags = KDBUS_MAKE_ACCESS_WORLD;

@@ -1472,7 +1473,7 @@ int bus_kernel_set_endpoint_policy(int fd, uid_t uid, BusEndpoint *ep) {

                 size += ALIGN8(offsetof(struct kdbus_item, policy_access) + sizeof(struct kdbus_policy_access));

         }

-        update = alloca0(size);

+        update = alloca0_align(size, 8);

         update->size = size;

         n = update->items;

@@ -1528,7 +1529,7 @@ int bus_kernel_make_starter(

                ALIGN8(offsetof(struct kdbus_item, str) + strlen(name) + 1) +

                policy_cnt * ALIGN8(offsetof(struct kdbus_item, policy_access) + sizeof(struct kdbus_policy_access));

-        hello = alloca0(size);

+        hello = alloca0_align(size, 8);

         n = hello->items;

         strcpy(n->str, name);

@@ -1588,9 +1589,10 @@ int bus_kernel_create_domain(const char *name, char **s) {

         if (fd < 0)

                 return -errno;

-        make = alloca0(ALIGN8(offsetof(struct kdbus_cmd_make, items) +

-                              offsetof(struct kdbus_item, str) +

-                              strlen(name) + 1));

+        make = alloca0_align(ALIGN8(offsetof(struct kdbus_cmd_make, items) +

+                                    offsetof(struct kdbus_item, str) +

+                                    strlen(name) + 1),

+                             8);

         n = make->items;

         strcpy(n->str, name);

diff --git a/src/libsystemd/sd-bus/bus-message.c b/src/libsystemd/sd-bus/bus-message.c

index 1fa3ad2611..400ba307bc 100644

--- a/src/libsystemd/sd-bus/bus-message.c

+++ b/src/libsystemd/sd-bus/bus-message.c

@@ -128,7 +128,7 @@ static void message_free(sd_bus_message *m) {

         message_reset_parts(m);

         if (m->release_kdbus) {

-                uint64_t off;

+                uint64_t off _alignas_(8);

                 off = (uint8_t *)m->kdbus - (uint8_t *)m->bus->kdbus_buffer;

                 ioctl(m->bus->input_fd, KDBUS_CMD_FREE, &off;;