From 61c34fc194b776ecadc39fb26b061331107e5599 Mon Nov 28 21:27:37 2022
From: =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= <philmd@linaro.org>
Date: Mon, 28 Nov 2022 21:27:37 +0100
Subject: [PATCH] hw/display/qxl: Have qxl_log_command Return early if no
log_cmd handler
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
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Only 3 command types are logged: no need to call qxl_phys2virt()
for the other types. Using different cases will help to pass
different structure sizes to qxl_phys2virt() in a pair of commits.
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20221128202741.4945-2-philmd@linaro.org>
---
hw/display/qxl-logger.c | 11 +++++++++++
1 file changed, 11 insertions(+)
diff --git a/hw/display/qxl-logger.c b/hw/display/qxl-logger.c
index 68bfa47568..1bcf803db6 100644
--- a/hw/display/qxl-logger.c
+++ b/hw/display/qxl-logger.c
@@ -247,6 +247,16 @@ int qxl_log_command(PCIQXLDevice *qxl, const char *ring, QXLCommandExt *ext)
qxl_name(qxl_type, ext->cmd.type),
compat ? "(compat)" : "");
+ switch (ext->cmd.type) {
+ case QXL_CMD_DRAW:
+ break;
+ case QXL_CMD_SURFACE:
+ break;
+ case QXL_CMD_CURSOR:
+ break;
+ default:
+ goto out;
+ }
data = qxl_phys2virt(qxl, ext->cmd.data, ext->group_id);
if (!data) {
return 1;
@@ -269,6 +279,7 @@ int qxl_log_command(PCIQXLDevice *qxl, const char *ring, QXLCommandExt *ext)
qxl_log_cmd_cursor(qxl, data, ext->group_id);
break;
}
+out:
fprintf(stderr, "\n");
return 0;
}
From b1901de83a9456cde26fc755f71ca2b7b3ef50fc Mon Nov 28 21:27:37 2022
From: =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= <philmd@linaro.org>
Date: Mon, 28 Nov 2022 21:27:38 +0100
Subject: [PATCH] hw/display/qxl: Document qxl_phys2virt()
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20221128202741.4945-3-philmd@linaro.org>
---
hw/display/qxl.h | 19 +++++++++++++++++++
1 file changed, 19 insertions(+)
diff --git a/hw/display/qxl.h b/hw/display/qxl.h
index 30d21f4d0b..c938f88a2f 100644
--- a/hw/display/qxl.h
+++ b/hw/display/qxl.h
@@ -147,6 +147,25 @@ OBJECT_DECLARE_SIMPLE_TYPE(PCIQXLDevice, PCI_QXL)
#define QXL_DEFAULT_REVISION (QXL_REVISION_STABLE_V12 + 1)
/* qxl.c */
+/**
+ * qxl_phys2virt: Get a pointer within a PCI VRAM memory region.
+ *
+ * @qxl: QXL device
+ * @phys: physical offset of buffer within the VRAM
+ * @group_id: memory slot group
+ *
+ * Returns a host pointer to a buffer placed at offset @phys within the
+ * active slot @group_id of the PCI VGA RAM memory region associated with
+ * the @qxl device. If the slot is inactive, or the offset is out
+ * of the memory region, returns NULL.
+ *
+ * Use with care; by the time this function returns, the returned pointer is
+ * not protected by RCU anymore. If the caller is not within an RCU critical
+ * section and does not hold the iothread lock, it must have other means of
+ * protecting the pointer, such as a reference to the region that includes
+ * the incoming ram_addr_t.
+ *
+ */
void *qxl_phys2virt(PCIQXLDevice *qxl, QXLPHYSICAL phys, int group_id);
void qxl_set_guest_bug(PCIQXLDevice *qxl, const char *msg, ...)
GCC_FMT_ATTR(2, 3);
From 8efec0ef8bbc1e75a7ebf6e325a35806ece9b39f Mon Nov 28 21:27:37 2022
From: =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= <philmd@linaro.org>
Date: Mon, 28 Nov 2022 21:27:39 +0100
Subject: [PATCH] hw/display/qxl: Pass requested buffer size to qxl_phys2virt()
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Currently qxl_phys2virt() doesn't check for buffer overrun.
In order to do so in the next commit, pass the buffer size
as argument.
For QXLCursor in qxl_render_cursor() -> qxl_cursor() we
verify the size of the chunked data ahead, checking we can
access 'sizeof(QXLCursor) + chunk->data_size' bytes.
Since in the SPICE_CURSOR_TYPE_MONO case the cursor is
assumed to fit in one chunk, no change are required.
In SPICE_CURSOR_TYPE_ALPHA the ahead read is handled in
qxl_unpack_chunks().
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20221128202741.4945-4-philmd@linaro.org>
---
hw/display/qxl-logger.c | 11 ++++++++---
hw/display/qxl-render.c | 20 ++++++++++++++++----
hw/display/qxl.c | 14 +++++++++-----
hw/display/qxl.h | 4 +++-
4 files changed, 36 insertions(+), 13 deletions(-)
diff --git a/hw/display/qxl-logger.c b/hw/display/qxl-logger.c
index 1bcf803db6..35c38f6252 100644
--- a/hw/display/qxl-logger.c
+++ b/hw/display/qxl-logger.c
@@ -106,7 +106,7 @@ static int qxl_log_image(PCIQXLDevice *qxl, QXLPHYSICAL addr, int group_id)
QXLImage *image;
QXLImageDescriptor *desc;
- image = qxl_phys2virt(qxl, addr, group_id);
+ image = qxl_phys2virt(qxl, addr, group_id, sizeof(QXLImage));
if (!image) {
return 1;
}
@@ -214,7 +214,8 @@ int qxl_log_cmd_cursor(PCIQXLDevice *qxl, QXLCursorCmd *cmd, int group_id)
cmd->u.set.position.y,
cmd->u.set.visible ? "yes" : "no",
cmd->u.set.shape);
- cursor = qxl_phys2virt(qxl, cmd->u.set.shape, group_id);
+ cursor = qxl_phys2virt(qxl, cmd->u.set.shape, group_id,
+ sizeof(QXLCursor));
if (!cursor) {
return 1;
}
@@ -236,6 +237,7 @@ int qxl_log_command(PCIQXLDevice *qxl, const char *ring, QXLCommandExt *ext)
{
bool compat = ext->flags & QXL_COMMAND_FLAG_COMPAT;
void *data;
+ size_t datasz;
int ret;
if (!qxl->cmdlog) {
@@ -249,15 +251,18 @@ int qxl_log_command(PCIQXLDevice *qxl, const char *ring, QXLCommandExt *ext)
switch (ext->cmd.type) {
case QXL_CMD_DRAW:
+ datasz = compat ? sizeof(QXLCompatDrawable) : sizeof(QXLDrawable);
break;
case QXL_CMD_SURFACE:
+ datasz = sizeof(QXLSurfaceCmd);
break;
case QXL_CMD_CURSOR:
+ datasz = sizeof(QXLCursorCmd);
break;
default:
goto out;
}
- data = qxl_phys2virt(qxl, ext->cmd.data, ext->group_id);
+ data = qxl_phys2virt(qxl, ext->cmd.data, ext->group_id, datasz);
if (!data) {
return 1;
}
diff --git a/hw/display/qxl-render.c b/hw/display/qxl-render.c
index d28849b121..3daf960191 100644
--- a/hw/display/qxl-render.c
+++ b/hw/display/qxl-render.c
@@ -107,7 +107,9 @@ static void qxl_render_update_area_unlocked(PCIQXLDevice *qxl)
qxl->guest_primary.resized = 0;
qxl->guest_primary.data = qxl_phys2virt(qxl,
qxl->guest_primary.surface.mem,
- MEMSLOT_GROUP_GUEST);
+ MEMSLOT_GROUP_GUEST,
+ qxl->guest_primary.abs_stride
+ * height);
if (!qxl->guest_primary.data) {
goto end;
}
@@ -228,7 +230,8 @@ static void qxl_unpack_chunks(void *dest, size_t size, PCIQXLDevice *qxl,
if (offset == size) {
return;
}
- chunk = qxl_phys2virt(qxl, chunk->next_chunk, group_id);
+ chunk = qxl_phys2virt(qxl, chunk->next_chunk, group_id,
+ sizeof(QXLDataChunk) + chunk->data_size);
if (!chunk) {
return;
}
@@ -288,7 +291,8 @@ fail:
/* called from spice server thread context only */
int qxl_render_cursor(PCIQXLDevice *qxl, QXLCommandExt *ext)
{
- QXLCursorCmd *cmd = qxl_phys2virt(qxl, ext->cmd.data, ext->group_id);
+ QXLCursorCmd *cmd = qxl_phys2virt(qxl, ext->cmd.data, ext->group_id,
+ sizeof(QXLCursorCmd));
QXLCursor *cursor;
QEMUCursor *c;
@@ -307,7 +311,15 @@ int qxl_render_cursor(PCIQXLDevice *qxl, QXLCommandExt *ext)
}
switch (cmd->type) {
case QXL_CURSOR_SET:
- cursor = qxl_phys2virt(qxl, cmd->u.set.shape, ext->group_id);
+ /* First read the QXLCursor to get QXLDataChunk::data_size ... */
+ cursor = qxl_phys2virt(qxl, cmd->u.set.shape, ext->group_id,
+ sizeof(QXLCursor));
+ if (!cursor) {
+ return 1;
+ }
+ /* Then read including the chunked data following QXLCursor. */
+ cursor = qxl_phys2virt(qxl, cmd->u.set.shape, ext->group_id,
+ sizeof(QXLCursor) + cursor->chunk.data_size);
if (!cursor) {
return 1;
}
diff --git a/hw/display/qxl.c b/hw/display/qxl.c
index 29c80b4289..aa9065183e 100644
--- a/hw/display/qxl.c
+++ b/hw/display/qxl.c
@@ -274,7 +274,8 @@ static void qxl_spice_monitors_config_async(PCIQXLDevice *qxl, int replay)
QXL_IO_MONITORS_CONFIG_ASYNC));
}
- cfg = qxl_phys2virt(qxl, qxl->guest_monitors_config, MEMSLOT_GROUP_GUEST);
+ cfg = qxl_phys2virt(qxl, qxl->guest_monitors_config, MEMSLOT_GROUP_GUEST,
+ sizeof(QXLMonitorsConfig));
if (cfg != NULL && cfg->count == 1) {
qxl->guest_primary.resized = 1;
qxl->guest_head0_width = cfg->heads[0].width;
@@ -459,7 +460,8 @@ static int qxl_track_command(PCIQXLDevice *qxl, struct QXLCommandExt *ext)
switch (le32_to_cpu(ext->cmd.type)) {
case QXL_CMD_SURFACE:
{
- QXLSurfaceCmd *cmd = qxl_phys2virt(qxl, ext->cmd.data, ext->group_id);
+ QXLSurfaceCmd *cmd = qxl_phys2virt(qxl, ext->cmd.data, ext->group_id,
+ sizeof(QXLSurfaceCmd));
if (!cmd) {
return 1;
@@ -494,7 +496,8 @@ static int qxl_track_command(PCIQXLDevice *qxl, struct QXLCommandExt *ext)
}
case QXL_CMD_CURSOR:
{
- QXLCursorCmd *cmd = qxl_phys2virt(qxl, ext->cmd.data, ext->group_id);
+ QXLCursorCmd *cmd = qxl_phys2virt(qxl, ext->cmd.data, ext->group_id,
+ sizeof(QXLCursorCmd));
if (!cmd) {
return 1;
@@ -1444,7 +1447,8 @@ static bool qxl_get_check_slot_offset(PCIQXLDevice *qxl, QXLPHYSICAL pqxl,
}
/* can be also called from spice server thread context */
-void *qxl_phys2virt(PCIQXLDevice *qxl, QXLPHYSICAL pqxl, int group_id)
+void *qxl_phys2virt(PCIQXLDevice *qxl, QXLPHYSICAL pqxl, int group_id,
+ size_t size)
{
uint64_t offset;
uint32_t slot;
@@ -1952,7 +1956,7 @@ static void qxl_dirty_surfaces(PCIQXLDevice *qxl)
}
cmd = qxl_phys2virt(qxl, qxl->guest_surfaces.cmds[i],
- MEMSLOT_GROUP_GUEST);
+ MEMSLOT_GROUP_GUEST, sizeof(QXLSurfaceCmd));
assert(cmd);
assert(cmd->type == QXL_SURFACE_CMD_CREATE);
qxl_dirty_one_surface(qxl, cmd->u.surface_create.data,
diff --git a/hw/display/qxl.h b/hw/display/qxl.h
index c938f88a2f..c784315daa 100644
--- a/hw/display/qxl.h
+++ b/hw/display/qxl.h
@@ -153,6 +153,7 @@ OBJECT_DECLARE_SIMPLE_TYPE(PCIQXLDevice, PCI_QXL)
* @qxl: QXL device
* @phys: physical offset of buffer within the VRAM
* @group_id: memory slot group
+ * @size: size of the buffer
*
* Returns a host pointer to a buffer placed at offset @phys within the
* active slot @group_id of the PCI VGA RAM memory region associated with
@@ -166,7 +167,8 @@ OBJECT_DECLARE_SIMPLE_TYPE(PCIQXLDevice, PCI_QXL)
* the incoming ram_addr_t.
*
*/
-void *qxl_phys2virt(PCIQXLDevice *qxl, QXLPHYSICAL phys, int group_id);
+void *qxl_phys2virt(PCIQXLDevice *qxl, QXLPHYSICAL phys, int group_id,
+ size_t size);
void qxl_set_guest_bug(PCIQXLDevice *qxl, const char *msg, ...)
GCC_FMT_ATTR(2, 3);
From 6dbbf055148c6f1b7d8a3251a65bd6f3d1e1f62 Mon Nov 28 21:27:37 20222
From: =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= <philmd@linaro.org>
Date: Mon, 28 Nov 2022 21:27:40 +0100
Subject: [PATCH] hw/display/qxl: Avoid buffer overrun in qxl_phys2virt
(CVE-2022-4144)
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Have qxl_get_check_slot_offset() return false if the requested
buffer size does not fit within the slot memory region.
Similarly qxl_phys2virt() now returns NULL in such case, and
qxl_dirty_one_surface() aborts.
This avoids buffer overrun in the host pointer returned by
memory_region_get_ram_ptr().
Fixes: CVE-2022-4144 (out-of-bounds read)
Reported-by: Wenxu Yin (@awxylitol)
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1336
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20221128202741.4945-5-philmd@linaro.org>
---
hw/display/qxl.c | 27 +++++++++++++++++++++++----
hw/display/qxl.h | 2 +-
2 files changed, 24 insertions(+), 5 deletions(-)
diff --git a/hw/display/qxl.c b/hw/display/qxl.c
index aa9065183e..2a4b2d4158 100644
--- a/hw/display/qxl.c
+++ b/hw/display/qxl.c
@@ -1412,11 +1412,13 @@ static void qxl_reset_surfaces(PCIQXLDevice *d)
/* can be also called from spice server thread context */
static bool qxl_get_check_slot_offset(PCIQXLDevice *qxl, QXLPHYSICAL pqxl,
- uint32_t *s, uint64_t *o)
+ uint32_t *s, uint64_t *o,
+ size_t size_requested)
{
uint64_t phys = le64_to_cpu(pqxl);
uint32_t slot = (phys >> (64 - 8)) & 0xff;
uint64_t offset = phys & 0xffffffffffff;
+ uint64_t size_available;
if (slot >= NUM_MEMSLOTS) {
qxl_set_guest_bug(qxl, "slot too large %d >= %d", slot,
@@ -1440,6 +1442,23 @@ static bool qxl_get_check_slot_offset(PCIQXLDevice *qxl, QXLPHYSICAL pqxl,
slot, offset, qxl->guest_slots[slot].size);
return false;
}
+ size_available = memory_region_size(qxl->guest_slots[slot].mr);
+ if (qxl->guest_slots[slot].offset + offset >= size_available) {
+ qxl_set_guest_bug(qxl,
+ "slot %d offset %"PRIu64" > region size %"PRIu64"\n",
+ slot, qxl->guest_slots[slot].offset + offset,
+ size_available);
+ return false;
+ }
+ size_available -= qxl->guest_slots[slot].offset + offset;
+ if (size_requested > size_available) {
+ qxl_set_guest_bug(qxl,
+ "slot %d offset %"PRIu64" size %zu: "
+ "overrun by %"PRIu64" bytes\n",
+ slot, offset, size_requested,
+ size_requested - size_available);
+ return false;
+ }
*s = slot;
*o = offset;
@@ -1459,7 +1478,7 @@ void *qxl_phys2virt(PCIQXLDevice *qxl, QXLPHYSICAL pqxl, int group_id,
offset = le64_to_cpu(pqxl) & 0xffffffffffff;
return (void *)(intptr_t)offset;
case MEMSLOT_GROUP_GUEST:
- if (!qxl_get_check_slot_offset(qxl, pqxl, &slot, &offset)) {
+ if (!qxl_get_check_slot_offset(qxl, pqxl, &slot, &offset, size)) {
return NULL;
}
ptr = memory_region_get_ram_ptr(qxl->guest_slots[slot].mr);
@@ -1925,9 +1944,9 @@ static void qxl_dirty_one_surface(PCIQXLDevice *qxl, QXLPHYSICAL pqxl,
uint32_t slot;
bool rc;
- rc = qxl_get_check_slot_offset(qxl, pqxl, &slot, &offset);
- assert(rc == true);
size = (uint64_t)height * abs(stride);
+ rc = qxl_get_check_slot_offset(qxl, pqxl, &slot, &offset, size);
+ assert(rc == true);
trace_qxl_surfaces_dirty(qxl->id, offset, size);
qxl_set_dirty(qxl->guest_slots[slot].mr,
qxl->guest_slots[slot].offset + offset,
diff --git a/hw/display/qxl.h b/hw/display/qxl.h
index c784315daa..89ca832cf9 100644
--- a/hw/display/qxl.h
+++ b/hw/display/qxl.h
@@ -157,7 +157,7 @@ OBJECT_DECLARE_SIMPLE_TYPE(PCIQXLDevice, PCI_QXL)
*
* Returns a host pointer to a buffer placed at offset @phys within the
* active slot @group_id of the PCI VGA RAM memory region associated with
- * the @qxl device. If the slot is inactive, or the offset is out
+ * the @qxl device. If the slot is inactive, or the offset + size are out
* of the memory region, returns NULL.
*
* Use with care; by the time this function returns, the returned pointer is
From 86fdb0582c653a9824183679403a85f588260d62 Mon Nov 28 21:27:37 2022
From: =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= <philmd@linaro.org>
Date: Mon, 28 Nov 2022 21:27:41 +0100
Subject: [PATCH] hw/display/qxl: Assert memory slot fits in preallocated
MemoryRegion
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20221128202741.4945-6-philmd@linaro.org>
---
hw/display/qxl.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/hw/display/qxl.c b/hw/display/qxl.c
index 2a4b2d4158..bcd9e8716a 100644
--- a/hw/display/qxl.c
+++ b/hw/display/qxl.c
@@ -1372,6 +1372,7 @@ static int qxl_add_memslot(PCIQXLDevice *d, uint32_t slot_id, uint64_t delta,
qxl_set_guest_bug(d, "%s: pci_region = %d", __func__, pci_region);
return 1;
}
+ assert(guest_end - pci_start <= memory_region_size(mr));
virt_start = (intptr_t)memory_region_get_ram_ptr(mr);
memslot.slot_id = slot_id;