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authorKai Kang <kai.kang@windriver.com>2019-03-15 04:01:19 -0400
committerRichard Purdie <richard.purdie@linuxfoundation.org>2019-03-19 10:46:15 +0000
commit489ece1aa90d8f76b4c1f009d837f82e38e11ba9 (patch)
tree4b1fcd47eaef0be15b2320e95ca2eb52452ffce0 /meta
parentf24178993e7b0830510900e80e879c7f9f8e28f0 (diff)
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qemu: backport patches to fix cves
CVE: CVE-2018-16872 CVE: CVE-2018-20124 CVE: CVE-2018-20125 CVE: CVE-2018-20126 CVE: CVE-2018-20191 CVE: CVE-2018-20216 Patches 0015-fix-CVE-2018-20124.patch and 0017-fix-CVE-2018-20126.patch are rebased on current source code. Others are not modified. Signed-off-by: Kai Kang <kai.kang@windriver.com> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
Diffstat (limited to 'meta')
-rw-r--r--meta/recipes-devtools/qemu/qemu.inc6
-rw-r--r--meta/recipes-devtools/qemu/qemu/0014-fix-CVE-2018-16872.patch85
-rw-r--r--meta/recipes-devtools/qemu/qemu/0015-fix-CVE-2018-20124.patch60
-rw-r--r--meta/recipes-devtools/qemu/qemu/0016-fix-CVE-2018-20125.patch54
-rw-r--r--meta/recipes-devtools/qemu/qemu/0017-fix-CVE-2018-20126.patch113
-rw-r--r--meta/recipes-devtools/qemu/qemu/0018-fix-CVE-2018-20191.patch47
-rw-r--r--meta/recipes-devtools/qemu/qemu/0019-fix-CVE-2018-20216.patch85
7 files changed, 450 insertions, 0 deletions
diff --git a/meta/recipes-devtools/qemu/qemu.inc b/meta/recipes-devtools/qemu/qemu.inc
index 985289f542..2babfe4c6f 100644
--- a/meta/recipes-devtools/qemu/qemu.inc
+++ b/meta/recipes-devtools/qemu/qemu.inc
@@ -23,6 +23,12 @@ SRC_URI = "https://download.qemu.org/${BPN}-${PV}.tar.xz \
file://0011-Revert-linux-user-fix-mmap-munmap-mprotect-mremap-sh.patch \
file://0001-Add-a-missing-X11-include.patch \
file://0001-egl-headless-add-egl_create_context.patch \
+ file://0014-fix-CVE-2018-16872.patch \
+ file://0015-fix-CVE-2018-20124.patch \
+ file://0016-fix-CVE-2018-20125.patch \
+ file://0017-fix-CVE-2018-20126.patch \
+ file://0018-fix-CVE-2018-20191.patch \
+ file://0019-fix-CVE-2018-20216.patch \
"
UPSTREAM_CHECK_REGEX = "qemu-(?P<pver>\d+(\.\d+)+)\.tar"
diff --git a/meta/recipes-devtools/qemu/qemu/0014-fix-CVE-2018-16872.patch b/meta/recipes-devtools/qemu/qemu/0014-fix-CVE-2018-16872.patch
new file mode 100644
index 0000000000..412aa16046
--- /dev/null
+++ b/meta/recipes-devtools/qemu/qemu/0014-fix-CVE-2018-16872.patch
@@ -0,0 +1,85 @@
+CVE: CVE-2018-16872
+Upstream-Status: Backport [https://git.qemu.org/?p=qemu.git;a=commit;h=bab9df35]
+
+Signed-off-by: Kai Kang <kai.kang@windriver.com>
+
+From bab9df35ce73d1c8e19a37e2737717ea1c984dc1 Mon Sep 17 00:00:00 2001
+From: Gerd Hoffmann <kraxel@redhat.com>
+Date: Thu, 13 Dec 2018 13:25:11 +0100
+Subject: [PATCH] usb-mtp: use O_NOFOLLOW and O_CLOEXEC.
+
+Open files and directories with O_NOFOLLOW to avoid symlinks attacks.
+While being at it also add O_CLOEXEC.
+
+usb-mtp only handles regular files and directories and ignores
+everything else, so users should not see a difference.
+
+Because qemu ignores symlinks, carrying out a successful symlink attack
+requires swapping an existing file or directory below rootdir for a
+symlink and winning the race against the inotify notification to qemu.
+
+Fixes: CVE-2018-16872
+Cc: Prasad J Pandit <ppandit@redhat.com>
+Cc: Bandan Das <bsd@redhat.com>
+Reported-by: Michael Hanselmann <public@hansmi.ch>
+Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
+Reviewed-by: Michael Hanselmann <public@hansmi.ch>
+Message-id: 20181213122511.13853-1-kraxel@redhat.com
+---
+ hw/usb/dev-mtp.c | 13 +++++++++----
+ 1 file changed, 9 insertions(+), 4 deletions(-)
+
+diff --git a/hw/usb/dev-mtp.c b/hw/usb/dev-mtp.c
+index 100b7171f4..36c43b8c20 100644
+--- a/hw/usb/dev-mtp.c
++++ b/hw/usb/dev-mtp.c
+@@ -653,13 +653,18 @@ static void usb_mtp_object_readdir(MTPState *s, MTPObject *o)
+ {
+ struct dirent *entry;
+ DIR *dir;
++ int fd;
+
+ if (o->have_children) {
+ return;
+ }
+ o->have_children = true;
+
+- dir = opendir(o->path);
++ fd = open(o->path, O_DIRECTORY | O_CLOEXEC | O_NOFOLLOW);
++ if (fd < 0) {
++ return;
++ }
++ dir = fdopendir(fd);
+ if (!dir) {
+ return;
+ }
+@@ -1007,7 +1012,7 @@ static MTPData *usb_mtp_get_object(MTPState *s, MTPControl *c,
+
+ trace_usb_mtp_op_get_object(s->dev.addr, o->handle, o->path);
+
+- d->fd = open(o->path, O_RDONLY);
++ d->fd = open(o->path, O_RDONLY | O_CLOEXEC | O_NOFOLLOW);
+ if (d->fd == -1) {
+ usb_mtp_data_free(d);
+ return NULL;
+@@ -1031,7 +1036,7 @@ static MTPData *usb_mtp_get_partial_object(MTPState *s, MTPControl *c,
+ c->argv[1], c->argv[2]);
+
+ d = usb_mtp_data_alloc(c);
+- d->fd = open(o->path, O_RDONLY);
++ d->fd = open(o->path, O_RDONLY | O_CLOEXEC | O_NOFOLLOW);
+ if (d->fd == -1) {
+ usb_mtp_data_free(d);
+ return NULL;
+@@ -1658,7 +1663,7 @@ static void usb_mtp_write_data(MTPState *s)
+ 0, 0, 0, 0);
+ goto done;
+ }
+- d->fd = open(path, O_CREAT | O_WRONLY, mask);
++ d->fd = open(path, O_CREAT | O_WRONLY | O_CLOEXEC | O_NOFOLLOW, mask);
+ if (d->fd == -1) {
+ usb_mtp_queue_result(s, RES_STORE_FULL, d->trans,
+ 0, 0, 0, 0);
+--
+2.20.1
+
diff --git a/meta/recipes-devtools/qemu/qemu/0015-fix-CVE-2018-20124.patch b/meta/recipes-devtools/qemu/qemu/0015-fix-CVE-2018-20124.patch
new file mode 100644
index 0000000000..ad846958a7
--- /dev/null
+++ b/meta/recipes-devtools/qemu/qemu/0015-fix-CVE-2018-20124.patch
@@ -0,0 +1,60 @@
+CVE: CVE-2018-20124
+Upstream-Status: Backport [https://git.qemu.org/?p=qemu.git;a=commit;h=0e68373]
+
+Backport patch to fix CVE-2018-20124. Update context and stay with current
+function comp_handler() which has been replaced with complete_work() in latest
+git repo.
+
+Signed-off-by: Kai Kang <kai.kang@windriver.com>
+
+From 0e68373cc2b3a063ce067bc0cc3edaf370752890 Mon Sep 17 00:00:00 2001
+From: Prasad J Pandit <pjp@fedoraproject.org>
+Date: Thu, 13 Dec 2018 01:00:34 +0530
+Subject: [PATCH] rdma: check num_sge does not exceed MAX_SGE
+
+rdma back-end has scatter/gather array ibv_sge[MAX_SGE=4] set
+to have 4 elements. A guest could send a 'PvrdmaSqWqe' ring element
+with 'num_sge' set to > MAX_SGE, which may lead to OOB access issue.
+Add check to avoid it.
+
+Reported-by: Saar Amar <saaramar5@gmail.com>
+Signed-off-by: Prasad J Pandit <pjp@fedoraproject.org>
+Reviewed-by: Yuval Shaia <yuval.shaia@oracle.com>
+Signed-off-by: Marcel Apfelbaum <marcel.apfelbaum@gmail.com>
+---
+ hw/rdma/rdma_backend.c | 12 ++++++------
+ 1 file changed, 6 insertions(+), 6 deletions(-)
+
+diff --git a/hw/rdma/rdma_backend.c b/hw/rdma/rdma_backend.c
+index d7a4bbd9..7f8028f8 100644
+--- a/hw/rdma/rdma_backend.c
++++ b/hw/rdma/rdma_backend.c
+@@ -311,9 +311,9 @@ void rdma_backend_post_send(RdmaBackendDev *backend_dev,
+ }
+
+ pr_dbg("num_sge=%d\n", num_sge);
+- if (!num_sge) {
+- pr_dbg("num_sge=0\n");
+- comp_handler(IBV_WC_GENERAL_ERR, VENDOR_ERR_NO_SGE, ctx);
++ if (!num_sge || num_sge > MAX_SGE) {
++ pr_dbg("invalid num_sge=%d\n", num_sge);
++ comp_handler(IBV_WC_GENERAL_ERR, VENDOR_ERR_INV_NUM_SGE, ctx);
+ return;
+ }
+
+@@ -390,9 +390,9 @@ void rdma_backend_post_recv(RdmaBackendDev *backend_dev,
+ }
+
+ pr_dbg("num_sge=%d\n", num_sge);
+- if (!num_sge) {
+- pr_dbg("num_sge=0\n");
+- comp_handler(IBV_WC_GENERAL_ERR, VENDOR_ERR_NO_SGE, ctx);
++ if (!num_sge || num_sge > MAX_SGE) {
++ pr_dbg("invalid num_sge=%d\n", num_sge);
++ comp_handler(IBV_WC_GENERAL_ERR, VENDOR_ERR_INV_NUM_SGE, ctx);
+ return;
+ }
+
+--
+2.20.1
+
diff --git a/meta/recipes-devtools/qemu/qemu/0016-fix-CVE-2018-20125.patch b/meta/recipes-devtools/qemu/qemu/0016-fix-CVE-2018-20125.patch
new file mode 100644
index 0000000000..56559c8388
--- /dev/null
+++ b/meta/recipes-devtools/qemu/qemu/0016-fix-CVE-2018-20125.patch
@@ -0,0 +1,54 @@
+CVE: CVE-2018-20125
+Upstream-Status: Backport [https://git.qemu.org/?p=qemu.git;a=commit;h=2c858ce]
+
+Signed-off-by: Kai Kang <kai.kang@windriver.com>
+
+From 2c858ce5da8ae6689c75182b73bc455a291cad41 Mon Sep 17 00:00:00 2001
+From: Prasad J Pandit <pjp@fedoraproject.org>
+Date: Thu, 13 Dec 2018 01:00:36 +0530
+Subject: [PATCH] pvrdma: check number of pages when creating rings
+
+When creating CQ/QP rings, an object can have up to
+PVRDMA_MAX_FAST_REG_PAGES 8 pages. Check 'npages' parameter
+to avoid excessive memory allocation or a null dereference.
+
+Reported-by: Li Qiang <liq3ea@163.com>
+Signed-off-by: Prasad J Pandit <pjp@fedoraproject.org>
+Reviewed-by: Yuval Shaia <yuval.shaia@oracle.com>
+Signed-off-by: Marcel Apfelbaum <marcel.apfelbaum@gmail.com>
+---
+ hw/rdma/vmw/pvrdma_cmd.c | 11 +++++++++++
+ 1 file changed, 11 insertions(+)
+
+diff --git a/hw/rdma/vmw/pvrdma_cmd.c b/hw/rdma/vmw/pvrdma_cmd.c
+index 3b94545761..f236ac4795 100644
+--- a/hw/rdma/vmw/pvrdma_cmd.c
++++ b/hw/rdma/vmw/pvrdma_cmd.c
+@@ -259,6 +259,11 @@ static int create_cq_ring(PCIDevice *pci_dev , PvrdmaRing **ring,
+ int rc = -EINVAL;
+ char ring_name[MAX_RING_NAME_SZ];
+
++ if (!nchunks || nchunks > PVRDMA_MAX_FAST_REG_PAGES) {
++ pr_dbg("invalid nchunks: %d\n", nchunks);
++ return rc;
++ }
++
+ pr_dbg("pdir_dma=0x%llx\n", (long long unsigned int)pdir_dma);
+ dir = rdma_pci_dma_map(pci_dev, pdir_dma, TARGET_PAGE_SIZE);
+ if (!dir) {
+@@ -372,6 +377,12 @@ static int create_qp_rings(PCIDevice *pci_dev, uint64_t pdir_dma,
+ char ring_name[MAX_RING_NAME_SZ];
+ uint32_t wqe_sz;
+
++ if (!spages || spages > PVRDMA_MAX_FAST_REG_PAGES
++ || !rpages || rpages > PVRDMA_MAX_FAST_REG_PAGES) {
++ pr_dbg("invalid pages: %d, %d\n", spages, rpages);
++ return rc;
++ }
++
+ pr_dbg("pdir_dma=0x%llx\n", (long long unsigned int)pdir_dma);
+ dir = rdma_pci_dma_map(pci_dev, pdir_dma, TARGET_PAGE_SIZE);
+ if (!dir) {
+--
+2.20.1
+
diff --git a/meta/recipes-devtools/qemu/qemu/0017-fix-CVE-2018-20126.patch b/meta/recipes-devtools/qemu/qemu/0017-fix-CVE-2018-20126.patch
new file mode 100644
index 0000000000..8329f2cfd0
--- /dev/null
+++ b/meta/recipes-devtools/qemu/qemu/0017-fix-CVE-2018-20126.patch
@@ -0,0 +1,113 @@
+CVE: CVE-2018-20126
+Upstream-Status: Backport [https://git.qemu.org/?p=qemu.git;a=commit;h=509f57c]
+
+Backport and rebase patch to fix CVE-2018-20126.
+
+Signed-off-by: Kai Kang <kai.kang@windriver.com>
+
+From 509f57c98e7536905bb4902363d0cba66ce7e089 Mon Sep 17 00:00:00 2001
+From: Prasad J Pandit <pjp@fedoraproject.org>
+Date: Thu, 13 Dec 2018 01:00:37 +0530
+Subject: [PATCH] pvrdma: release ring object in case of an error
+
+create_cq and create_qp routines allocate ring object, but it's
+not released in case of an error, leading to memory leakage.
+
+Reported-by: Li Qiang <liq3ea@163.com>
+Signed-off-by: Prasad J Pandit <pjp@fedoraproject.org>
+Reviewed-by: Yuval Shaia <yuval.shaia@oracle.com>
+Signed-off-by: Marcel Apfelbaum <marcel.apfelbaum@gmail.com>
+---
+ hw/rdma/vmw/pvrdma_cmd.c | 41 ++++++++++++++++++++++++++++++-----------
+ 1 file changed, 30 insertions(+), 11 deletions(-)
+
+diff --git a/hw/rdma/vmw/pvrdma_cmd.c b/hw/rdma/vmw/pvrdma_cmd.c
+index 4faeb21..9b6796f 100644
+--- a/hw/rdma/vmw/pvrdma_cmd.c
++++ b/hw/rdma/vmw/pvrdma_cmd.c
+@@ -310,6 +310,14 @@ out:
+ return rc;
+ }
+
++static void destroy_cq_ring(PvrdmaRing *ring)
++{
++ pvrdma_ring_free(ring);
++ /* ring_state was in slot 1, not 0 so need to jump back */
++ rdma_pci_dma_unmap(ring->dev, --ring->ring_state, TARGET_PAGE_SIZE);
++ g_free(ring);
++}
++
+ static int create_cq(PVRDMADev *dev, union pvrdma_cmd_req *req,
+ union pvrdma_cmd_resp *rsp)
+ {
+@@ -333,6 +341,10 @@ static int create_cq(PVRDMADev *dev, union pvrdma_cmd_req *req,
+
+ resp->hdr.err = rdma_rm_alloc_cq(&dev->rdma_dev_res, &dev->backend_dev,
+ cmd->cqe, &resp->cq_handle, ring);
++ if (resp->hdr.err) {
++ destroy_cq_ring(ring);
++ }
++
+ resp->cqe = cmd->cqe;
+
+ out:
+@@ -356,10 +368,7 @@ static int destroy_cq(PVRDMADev *dev, union pvrdma_cmd_req *req,
+ }
+
+ ring = (PvrdmaRing *)cq->opaque;
+- pvrdma_ring_free(ring);
+- /* ring_state was in slot 1, not 0 so need to jump back */
+- rdma_pci_dma_unmap(PCI_DEVICE(dev), --ring->ring_state, TARGET_PAGE_SIZE);
+- g_free(ring);
++ destroy_cq_ring(ring);
+
+ rdma_rm_dealloc_cq(&dev->rdma_dev_res, cmd->cq_handle);
+
+@@ -451,6 +460,17 @@ out:
+ return rc;
+ }
+
++static void destroy_qp_rings(PvrdmaRing *ring)
++{
++ pr_dbg("sring=%p\n", &ring[0]);
++ pvrdma_ring_free(&ring[0]);
++ pr_dbg("rring=%p\n", &ring[1]);
++ pvrdma_ring_free(&ring[1]);
++
++ rdma_pci_dma_unmap(ring->dev, ring->ring_state, TARGET_PAGE_SIZE);
++ g_free(ring);
++}
++
+ static int create_qp(PVRDMADev *dev, union pvrdma_cmd_req *req,
+ union pvrdma_cmd_resp *rsp)
+ {
+@@ -482,6 +502,11 @@ static int create_qp(PVRDMADev *dev, union pvrdma_cmd_req *req,
+ cmd->max_recv_wr, cmd->max_recv_sge,
+ cmd->recv_cq_handle, rings, &resp->qpn);
+
++ if (resp->hdr.err) {
++ destroy_qp_rings(rings);
++ return resp->hdr.err;
++ }
++
+ resp->max_send_wr = cmd->max_send_wr;
+ resp->max_recv_wr = cmd->max_recv_wr;
+ resp->max_send_sge = cmd->max_send_sge;
+@@ -555,13 +580,7 @@ static int destroy_qp(PVRDMADev *dev, union pvrdma_cmd_req *req,
+ rdma_rm_dealloc_qp(&dev->rdma_dev_res, cmd->qp_handle);
+
+ ring = (PvrdmaRing *)qp->opaque;
+- pr_dbg("sring=%p\n", &ring[0]);
+- pvrdma_ring_free(&ring[0]);
+- pr_dbg("rring=%p\n", &ring[1]);
+- pvrdma_ring_free(&ring[1]);
+-
+- rdma_pci_dma_unmap(PCI_DEVICE(dev), ring->ring_state, TARGET_PAGE_SIZE);
+- g_free(ring);
++ destroy_qp_rings(ring);
+
+ return 0;
+ }
+--
+2.20.1
+
diff --git a/meta/recipes-devtools/qemu/qemu/0018-fix-CVE-2018-20191.patch b/meta/recipes-devtools/qemu/qemu/0018-fix-CVE-2018-20191.patch
new file mode 100644
index 0000000000..8f8ff0567a
--- /dev/null
+++ b/meta/recipes-devtools/qemu/qemu/0018-fix-CVE-2018-20191.patch
@@ -0,0 +1,47 @@
+CVE: CVE-2018-20191
+Upstream-Status: Backport [https://git.qemu.org/?p=qemu.git;a=commit;h=2aa8645]
+
+Signed-off-by: Kai Kang <kai.kang@windriver.com>
+
+From 2aa86456fb938a11f2b7bd57c8643c213218681c Mon Sep 17 00:00:00 2001
+From: Prasad J Pandit <pjp@fedoraproject.org>
+Date: Thu, 13 Dec 2018 01:00:35 +0530
+Subject: [PATCH] pvrdma: add uar_read routine
+
+Define skeleton 'uar_read' routine. Avoid NULL dereference.
+
+Reported-by: Li Qiang <liq3ea@163.com>
+Signed-off-by: Prasad J Pandit <pjp@fedoraproject.org>
+Reviewed-by: Marcel Apfelbaum <marcel.apfelbaum@gmail.com>
+Signed-off-by: Marcel Apfelbaum <marcel.apfelbaum@gmail.com>
+---
+ hw/rdma/vmw/pvrdma_main.c | 6 ++++++
+ 1 file changed, 6 insertions(+)
+
+diff --git a/hw/rdma/vmw/pvrdma_main.c b/hw/rdma/vmw/pvrdma_main.c
+index 64de16fb52..838ad8a949 100644
+--- a/hw/rdma/vmw/pvrdma_main.c
++++ b/hw/rdma/vmw/pvrdma_main.c
+@@ -448,6 +448,11 @@ static const MemoryRegionOps regs_ops = {
+ },
+ };
+
++static uint64_t uar_read(void *opaque, hwaddr addr, unsigned size)
++{
++ return 0xffffffff;
++}
++
+ static void uar_write(void *opaque, hwaddr addr, uint64_t val, unsigned size)
+ {
+ PVRDMADev *dev = opaque;
+@@ -489,6 +494,7 @@ static void uar_write(void *opaque, hwaddr addr, uint64_t val, unsigned size)
+ }
+
+ static const MemoryRegionOps uar_ops = {
++ .read = uar_read,
+ .write = uar_write,
+ .endianness = DEVICE_LITTLE_ENDIAN,
+ .impl = {
+--
+2.20.1
+
diff --git a/meta/recipes-devtools/qemu/qemu/0019-fix-CVE-2018-20216.patch b/meta/recipes-devtools/qemu/qemu/0019-fix-CVE-2018-20216.patch
new file mode 100644
index 0000000000..c02bad3bb9
--- /dev/null
+++ b/meta/recipes-devtools/qemu/qemu/0019-fix-CVE-2018-20216.patch
@@ -0,0 +1,85 @@
+CVE: CVE-2018-20216
+Upstream-Status: Backport [https://git.qemu.org/?p=qemu.git;a=commit;h=f1e2e38]
+
+Signed-off-by: Kai Kang <kai.kang@windriver.com>
+
+From f1e2e38ee0136b7710a2caa347049818afd57a1b Mon Sep 17 00:00:00 2001
+From: Prasad J Pandit <pjp@fedoraproject.org>
+Date: Thu, 13 Dec 2018 01:00:39 +0530
+Subject: [PATCH] pvrdma: check return value from pvrdma_idx_ring_has_ routines
+
+pvrdma_idx_ring_has_[data/space] routines also return invalid
+index PVRDMA_INVALID_IDX[=-1], if ring has no data/space. Check
+return value from these routines to avoid plausible infinite loops.
+
+Reported-by: Li Qiang <liq3ea@163.com>
+Signed-off-by: Prasad J Pandit <pjp@fedoraproject.org>
+Reviewed-by: Yuval Shaia <yuval.shaia@oracle.com>
+Signed-off-by: Marcel Apfelbaum <marcel.apfelbaum@gmail.com>
+---
+ hw/rdma/vmw/pvrdma_dev_ring.c | 29 +++++++++++------------------
+ 1 file changed, 11 insertions(+), 18 deletions(-)
+
+diff --git a/hw/rdma/vmw/pvrdma_dev_ring.c b/hw/rdma/vmw/pvrdma_dev_ring.c
+index 01247fc041..e8e5b502f6 100644
+--- a/hw/rdma/vmw/pvrdma_dev_ring.c
++++ b/hw/rdma/vmw/pvrdma_dev_ring.c
+@@ -73,23 +73,16 @@ out:
+
+ void *pvrdma_ring_next_elem_read(PvrdmaRing *ring)
+ {
++ int e;
+ unsigned int idx = 0, offset;
+
+- /*
+- pr_dbg("%s: t=%d, h=%d\n", ring->name, ring->ring_state->prod_tail,
+- ring->ring_state->cons_head);
+- */
+-
+- if (!pvrdma_idx_ring_has_data(ring->ring_state, ring->max_elems, &idx)) {
++ e = pvrdma_idx_ring_has_data(ring->ring_state, ring->max_elems, &idx);
++ if (e <= 0) {
+ pr_dbg("No more data in ring\n");
+ return NULL;
+ }
+
+ offset = idx * ring->elem_sz;
+- /*
+- pr_dbg("idx=%d\n", idx);
+- pr_dbg("offset=%d\n", offset);
+- */
+ return ring->pages[offset / TARGET_PAGE_SIZE] + (offset % TARGET_PAGE_SIZE);
+ }
+
+@@ -105,20 +98,20 @@ void pvrdma_ring_read_inc(PvrdmaRing *ring)
+
+ void *pvrdma_ring_next_elem_write(PvrdmaRing *ring)
+ {
+- unsigned int idx, offset, tail;
++ int idx;
++ unsigned int offset, tail;
+
+- /*
+- pr_dbg("%s: t=%d, h=%d\n", ring->name, ring->ring_state->prod_tail,
+- ring->ring_state->cons_head);
+- */
+-
+- if (!pvrdma_idx_ring_has_space(ring->ring_state, ring->max_elems, &tail)) {
++ idx = pvrdma_idx_ring_has_space(ring->ring_state, ring->max_elems, &tail);
++ if (idx <= 0) {
+ pr_dbg("CQ is full\n");
+ return NULL;
+ }
+
+ idx = pvrdma_idx(&ring->ring_state->prod_tail, ring->max_elems);
+- /* TODO: tail == idx */
++ if (idx < 0 || tail != idx) {
++ pr_dbg("invalid idx\n");
++ return NULL;
++ }
+
+ offset = idx * ring->elem_sz;
+ return ring->pages[offset / TARGET_PAGE_SIZE] + (offset % TARGET_PAGE_SIZE);
+--
+2.20.1
+