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[Qemu-devel] [PATCH v3 22/40] ivshmem: Simplify rejection of invalid pee
From: |
Markus Armbruster |
Subject: |
[Qemu-devel] [PATCH v3 22/40] ivshmem: Simplify rejection of invalid peer ID from server |
Date: |
Tue, 15 Mar 2016 19:34:37 +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>
---
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] [PATCH v3 09/40] ivshmem-test: Improve test cases /ivshmem/server-*, (continued)
- [Qemu-devel] [PATCH v3 09/40] ivshmem-test: Improve test cases /ivshmem/server-*, Markus Armbruster, 2016/03/15
- [Qemu-devel] [PATCH v3 03/40] ivshmem-server: Don't overload POSIX shmem and file name, Markus Armbruster, 2016/03/15
- [Qemu-devel] [PATCH v3 13/40] ivshmem: Clean up after commit 9940c32, Markus Armbruster, 2016/03/15
- [Qemu-devel] [PATCH v3 17/40] ivshmem: Failed realize() can leave migration blocker behind, Markus Armbruster, 2016/03/15
- [Qemu-devel] [PATCH v3 20/40] ivshmem: Leave INTx alone when using MSI-X, Markus Armbruster, 2016/03/15
- [Qemu-devel] [PATCH v3 25/40] ivshmem: Receive shared memory synchronously in realize(), Markus Armbruster, 2016/03/15
- [Qemu-devel] [PATCH v3 18/40] ivshmem: Clean up register callbacks, Markus Armbruster, 2016/03/15
- [Qemu-devel] [PATCH v3 11/40] ivshmem: Add missing newlines to debug printfs, Markus Armbruster, 2016/03/15
- [Qemu-devel] [PATCH v3 23/40] ivshmem: Disentangle ivshmem_read(), Markus Armbruster, 2016/03/15
- [Qemu-devel] [PATCH v3 22/40] ivshmem: Simplify rejection of invalid peer ID from server,
Markus Armbruster <=
- [Qemu-devel] [PATCH v3 35/40] ivshmem: Replace int role_val by OnOffAuto master, Markus Armbruster, 2016/03/15
- [Qemu-devel] [PATCH v3 15/40] ivshmem: Don't destroy the chardev on version mismatch, Markus Armbruster, 2016/03/15
- [Qemu-devel] [PATCH v3 21/40] ivshmem: Assert interrupts are set up once, Markus Armbruster, 2016/03/15
- [Qemu-devel] [PATCH v3 33/40] ivshmem: Inline check_shm_size() into its only caller, Markus Armbruster, 2016/03/15
- [Qemu-devel] [PATCH v3 40/40] contrib/ivshmem-server: Print "not for production" warning, Markus Armbruster, 2016/03/15
- [Qemu-devel] [PATCH v3 27/40] ivshmem: Rely on server sending the ID right after the version, Markus Armbruster, 2016/03/15
- [Qemu-devel] [PATCH v3 26/40] ivshmem: Propagate errors through ivshmem_recv_setup(), Markus Armbruster, 2016/03/15