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[Qemu-devel] [PULL 22/40] ivshmem: Simplify rejection of invalid peer ID
From: |
Markus Armbruster |
Subject: |
[Qemu-devel] [PULL 22/40] ivshmem: Simplify rejection of invalid peer ID from server |
Date: |
Fri, 18 Mar 2016 18:01:09 +0100 |
ivshmem_read() processes server messages. These are 64 bit signed
integers. -1 is shared memory setup, 16 bit unsigned is a peer ID,
anything else is invalid.
ivshmem_read() rejects invalid negative messages right away, silently.
Invalid positive messages get rejected only in resize_peers(), and
ivshmem_read() then prints the rather cryptic message "failed to
resize peers array".
Extend the first check to cover all invalid messages, make it report
"server sent invalid message", and drop the second check.
Now resize_peers() can't fail anymore; simplify.
Signed-off-by: Markus Armbruster <address@hidden>
Reviewed-by: Marc-André Lureau <address@hidden>
Message-Id: <address@hidden>
---
hw/misc/ivshmem.c | 61 ++++++++++++++++++++-----------------------------------
1 file changed, 22 insertions(+), 39 deletions(-)
diff --git a/hw/misc/ivshmem.c b/hw/misc/ivshmem.c
index 61e21cd..703b3bf 100644
--- a/hw/misc/ivshmem.c
+++ b/hw/misc/ivshmem.c
@@ -39,7 +39,7 @@
#define PCI_VENDOR_ID_IVSHMEM PCI_VENDOR_ID_REDHAT_QUMRANET
#define PCI_DEVICE_ID_IVSHMEM 0x1110
-#define IVSHMEM_MAX_PEERS G_MAXUINT16
+#define IVSHMEM_MAX_PEERS UINT16_MAX
#define IVSHMEM_IOEVENTFD 0
#define IVSHMEM_MSI 1
@@ -93,7 +93,7 @@ typedef struct IVShmemState {
uint32_t ivshmem_64bit;
Peer *peers;
- int nb_peers; /* how many peers we have space for */
+ int nb_peers; /* space in @peers[] */
int vm_id;
uint32_t vectors;
@@ -451,34 +451,21 @@ static void close_peer_eventfds(IVShmemState *s, int posn)
s->peers[posn].nb_eventfds = 0;
}
-/* this function increase the dynamic storage need to store data about other
- * peers */
-static int resize_peers(IVShmemState *s, int new_min_size)
+static void resize_peers(IVShmemState *s, int nb_peers)
{
+ int old_nb_peers = s->nb_peers;
+ int i;
- int j, old_size;
+ assert(nb_peers > old_nb_peers);
+ IVSHMEM_DPRINTF("bumping storage to %d peers\n", nb_peers);
- /* limit number of max peers */
- if (new_min_size <= 0 || new_min_size > IVSHMEM_MAX_PEERS) {
- return -1;
- }
- if (new_min_size <= s->nb_peers) {
- return 0;
- }
-
- old_size = s->nb_peers;
- s->nb_peers = new_min_size;
+ s->peers = g_realloc(s->peers, nb_peers * sizeof(Peer));
+ s->nb_peers = nb_peers;
- IVSHMEM_DPRINTF("bumping storage to %d peers\n", s->nb_peers);
-
- s->peers = g_realloc(s->peers, s->nb_peers * sizeof(Peer));
-
- for (j = old_size; j < s->nb_peers; j++) {
- s->peers[j].eventfds = g_new0(EventNotifier, s->vectors);
- s->peers[j].nb_eventfds = 0;
+ for (i = old_nb_peers; i < nb_peers; i++) {
+ s->peers[i].eventfds = g_new0(EventNotifier, s->vectors);
+ s->peers[i].nb_eventfds = 0;
}
-
- return 0;
}
static bool fifo_update_and_get(IVShmemState *s, const uint8_t *buf, int size,
@@ -590,25 +577,21 @@ static void ivshmem_read(void *opaque, const uint8_t
*buf, int size)
return;
}
- if (incoming_posn < -1) {
- IVSHMEM_DPRINTF("invalid incoming_posn %" PRId64 "\n", incoming_posn);
- return;
- }
-
- /* pick off s->server_chr->msgfd and store it, posn should accompany msg */
incoming_fd = qemu_chr_fe_get_msgfd(s->server_chr);
IVSHMEM_DPRINTF("posn is %" PRId64 ", fd is %d\n",
incoming_posn, incoming_fd);
- /* make sure we have enough space for this peer */
+ if (incoming_posn < -1 || incoming_posn > IVSHMEM_MAX_PEERS) {
+ error_report("server sent invalid message %" PRId64,
+ incoming_posn);
+ if (incoming_fd != -1) {
+ close(incoming_fd);
+ }
+ return;
+ }
+
if (incoming_posn >= s->nb_peers) {
- if (resize_peers(s, incoming_posn + 1) < 0) {
- error_report("failed to resize peers array");
- if (incoming_fd != -1) {
- close(incoming_fd);
- }
- return;
- }
+ resize_peers(s, incoming_posn + 1);
}
peer = &s->peers[incoming_posn];
--
2.4.3
- [Qemu-devel] [PULL 12/40] ivshmem: Compile debug prints unconditionally to prevent bit-rot, (continued)
- [Qemu-devel] [PULL 12/40] ivshmem: Compile debug prints unconditionally to prevent bit-rot, Markus Armbruster, 2016/03/18
- [Qemu-devel] [PULL 07/40] ivshmem-test: Improve test case /ivshmem/single, Markus Armbruster, 2016/03/18
- [Qemu-devel] [PULL 09/40] ivshmem-test: Improve test cases /ivshmem/server-*, Markus Armbruster, 2016/03/18
- [Qemu-devel] [PULL 06/40] tests/libqos/pci-pc: Fix qpci_pc_iomap() to map BARs aligned, Markus Armbruster, 2016/03/18
- [Qemu-devel] [PULL 03/40] ivshmem-server: Don't overload POSIX shmem and file name, Markus Armbruster, 2016/03/18
- [Qemu-devel] [PULL 08/40] ivshmem-test: Clean up wait for devices to become operational, Markus Armbruster, 2016/03/18
- [Qemu-devel] [PULL 01/40] target-ppc: Document TOCTTOU in hugepage support, Markus Armbruster, 2016/03/18
- [Qemu-devel] [PULL 05/40] event_notifier: Make event_notifier_init_fd() #ifdef CONFIG_EVENTFD, Markus Armbruster, 2016/03/18
- [Qemu-devel] [PULL 15/40] ivshmem: Don't destroy the chardev on version mismatch, Markus Armbruster, 2016/03/18
- [Qemu-devel] [PULL 11/40] ivshmem: Add missing newlines to debug printfs, Markus Armbruster, 2016/03/18
- [Qemu-devel] [PULL 22/40] ivshmem: Simplify rejection of invalid peer ID from server,
Markus Armbruster <=
- [Qemu-devel] [PULL 18/40] ivshmem: Clean up register callbacks, Markus Armbruster, 2016/03/18
- [Qemu-devel] [PULL 14/40] ivshmem: Drop ivshmem_event() stub, Markus Armbruster, 2016/03/18
- [Qemu-devel] [PULL 24/40] ivshmem: Plug leaks on unplug, fix peer disconnect, Markus Armbruster, 2016/03/18
- [Qemu-devel] [PULL 38/40] ivshmem: Drop ivshmem property x-memdev, Markus Armbruster, 2016/03/18
- [Qemu-devel] [PULL 20/40] ivshmem: Leave INTx alone when using MSI-X, Markus Armbruster, 2016/03/18
- [Qemu-devel] [PULL 39/40] ivshmem: Require master to have ID zero, Markus Armbruster, 2016/03/18
- [Qemu-devel] [PULL 33/40] ivshmem: Inline check_shm_size() into its only caller, Markus Armbruster, 2016/03/18
- [Qemu-devel] [PULL 26/40] ivshmem: Propagate errors through ivshmem_recv_setup(), Markus Armbruster, 2016/03/18
- [Qemu-devel] [PULL 10/40] ivshmem: Rewrite specification document, Markus Armbruster, 2016/03/18
- [Qemu-devel] [PULL 32/40] ivshmem: Simplify memory regions for BAR 2 (shared memory), Markus Armbruster, 2016/03/18