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authorStefan Hajnoczi <stefanha@redhat.com>2014-09-15 18:40:05 +0200
committerPaolo Bonzini <pbonzini@redhat.com>2014-10-31 17:01:44 +0100
commita2e9011b4164894594bf0b2a2a59e9c55c58c17b (patch)
tree944ce67af7f759c6fa731e9d15c85385ef8e2c0d /hw/misc/ivshmem.c
parente64e353590c2584b41cd1db925f67042a05f4250 (diff)
ivshmem: Check ivshmem_read() size argument
The third argument to the fd_read() callback implemented by ivshmem_read() is the number of bytes, not a flags field. Fix this and check we received enough bytes before accessing the buffer pointer. Cc: Cam Macdonell <cam@cs.ualberta.ca> Reported-by: Sebastian Krahmer <krahmer@suse.de> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> [AF: Handle partial reads via FIFO] Reported-by: Peter Maydell <peter.maydell@linaro.org> Cc: qemu-stable@nongnu.org Signed-off-by: Andreas Färber <afaerber@suse.de> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'hw/misc/ivshmem.c')
-rw-r--r--hw/misc/ivshmem.c30
1 files changed, 28 insertions, 2 deletions
diff --git a/hw/misc/ivshmem.c b/hw/misc/ivshmem.c
index bd9d7182af..caeee1ebf5 100644
--- a/hw/misc/ivshmem.c
+++ b/hw/misc/ivshmem.c
@@ -24,6 +24,7 @@
#include "migration/migration.h"
#include "qapi/qmp/qerror.h"
#include "qemu/event_notifier.h"
+#include "qemu/fifo8.h"
#include "sysemu/char.h"
#include <sys/mman.h>
@@ -73,6 +74,7 @@ typedef struct IVShmemState {
CharDriverState **eventfd_chr;
CharDriverState *server_chr;
+ Fifo8 incoming_fifo;
MemoryRegion ivshmem_mmio;
/* We might need to register the BAR before we actually have the memory.
@@ -424,14 +426,35 @@ static void increase_dynamic_storage(IVShmemState *s, int new_min_size) {
}
}
-static void ivshmem_read(void *opaque, const uint8_t * buf, int flags)
+static void ivshmem_read(void *opaque, const uint8_t *buf, int size)
{
IVShmemState *s = opaque;
int incoming_fd, tmp_fd;
int guest_max_eventfd;
long incoming_posn;
- memcpy(&incoming_posn, buf, sizeof(long));
+ if (fifo8_is_empty(&s->incoming_fifo) && size == sizeof(incoming_posn)) {
+ memcpy(&incoming_posn, buf, size);
+ } else {
+ const uint8_t *p;
+ uint32_t num;
+
+ IVSHMEM_DPRINTF("short read of %d bytes\n", size);
+ num = MAX(size, sizeof(long) - fifo8_num_used(&s->incoming_fifo));
+ fifo8_push_all(&s->incoming_fifo, buf, num);
+ if (fifo8_num_used(&s->incoming_fifo) < sizeof(incoming_posn)) {
+ return;
+ }
+ size -= num;
+ buf += num;
+ p = fifo8_pop_buf(&s->incoming_fifo, sizeof(incoming_posn), &num);
+ g_assert(num == sizeof(incoming_posn));
+ memcpy(&incoming_posn, p, sizeof(incoming_posn));
+ if (size > 0) {
+ fifo8_push_all(&s->incoming_fifo, buf, size);
+ }
+ }
+
/* pick off s->server_chr->msgfd and store it, posn should accompany msg */
tmp_fd = qemu_chr_fe_get_msgfd(s->server_chr);
IVSHMEM_DPRINTF("posn is %ld, fd is %d\n", incoming_posn, tmp_fd);
@@ -663,6 +686,8 @@ static int pci_ivshmem_init(PCIDevice *dev)
s->ivshmem_size = ivshmem_get_size(s);
}
+ fifo8_create(&s->incoming_fifo, sizeof(long));
+
register_savevm(DEVICE(dev), "ivshmem", 0, 0, ivshmem_save, ivshmem_load,
dev);
@@ -796,6 +821,7 @@ static void pci_ivshmem_uninit(PCIDevice *dev)
memory_region_del_subregion(&s->bar, &s->ivshmem);
vmstate_unregister_ram(&s->ivshmem, DEVICE(dev));
unregister_savevm(DEVICE(dev), "ivshmem", s);
+ fifo8_destroy(&s->incoming_fifo);
}
static Property ivshmem_properties[] = {