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ivshmem: Check ivshmem_read() size argument

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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>
This commit is contained in:
Stefan Hajnoczi 2014-09-15 18:40:05 +02:00 committed by Paolo Bonzini
parent e64e353590
commit a2e9011b41
1 changed files with 28 additions and 2 deletions
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30
hw/misc/ivshmem.c
View file

@ -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[] = {