* [RFC PATCH-for-7.2 v3 0/5] hw/display/qxl: Avoid buffer overrun in qxl_phys2virt()
@ 2022-11-28 20:27 Philippe Mathieu-Daudé
2022-11-28 20:27 ` [PATCH-for-7.2 v3 1/5] hw/display/qxl: Have qxl_log_command Return early if no log_cmd handler Philippe Mathieu-Daudé
` (5 more replies)
0 siblings, 6 replies; 8+ messages in thread
From: Philippe Mathieu-Daudé @ 2022-11-28 20:27 UTC (permalink / raw)
To: qemu-devel, Marc-André Lureau
Cc: Alexander Bulekov, Paolo Bonzini, Gerd Hoffmann, Peter Maydell,
Mauro Matteo Cascella, Philippe Mathieu-Daudé
Since v2:
- Do not abort checking guest-provided addresses (Stefan)
- Handle chunked QEMUCursor (Gerd)
Since v1:
- Moved overrun check in qxl_get_check_slot_offset (Marc-André)
memory_region_get_ram_ptr() returns a host pointer for a
MemoryRegion. Sometimes we do offset calculation using this
pointer without checking the underlying MemoryRegion size.
Wenxu Yin reported a buffer overrun in QXL. This series
aims to fix it. I haven't audited the other _get_ram_ptr()
uses (yet). Eventually we could rename it _get_ram_ptr_unsafe
and add a safer helper which checks for overrun.
Worth considering for 7.2?
Regards,
Phil.
Philippe Mathieu-Daudé (5):
hw/display/qxl: Have qxl_log_command Return early if no log_cmd
handler
hw/display/qxl: Document qxl_phys2virt()
hw/display/qxl: Pass requested buffer size to qxl_phys2virt()
hw/display/qxl: Avoid buffer overrun in qxl_phys2virt (CVE-2022-4144)
hw/display/qxl: Assert memory slot fits in preallocated MemoryRegion
hw/display/qxl-logger.c | 22 ++++++++++++++++++---
hw/display/qxl-render.c | 20 ++++++++++++++++----
hw/display/qxl.c | 42 ++++++++++++++++++++++++++++++++---------
hw/display/qxl.h | 23 +++++++++++++++++++++-
4 files changed, 90 insertions(+), 17 deletions(-)
--
2.38.1
^ permalink raw reply [flat|nested] 8+ messages in thread
* [PATCH-for-7.2 v3 1/5] hw/display/qxl: Have qxl_log_command Return early if no log_cmd handler
2022-11-28 20:27 [RFC PATCH-for-7.2 v3 0/5] hw/display/qxl: Avoid buffer overrun in qxl_phys2virt() Philippe Mathieu-Daudé
@ 2022-11-28 20:27 ` Philippe Mathieu-Daudé
2022-11-28 20:27 ` [PATCH-for-7.2 v3 2/5] hw/display/qxl: Document qxl_phys2virt() Philippe Mathieu-Daudé
` (4 subsequent siblings)
5 siblings, 0 replies; 8+ messages in thread
From: Philippe Mathieu-Daudé @ 2022-11-28 20:27 UTC (permalink / raw)
To: qemu-devel, Marc-André Lureau
Cc: Alexander Bulekov, Paolo Bonzini, Gerd Hoffmann, Peter Maydell,
Mauro Matteo Cascella, Philippe Mathieu-Daudé
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>
---
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;
}
--
2.38.1
^ permalink raw reply related [flat|nested] 8+ messages in thread
* [PATCH-for-7.2 v3 2/5] hw/display/qxl: Document qxl_phys2virt()
2022-11-28 20:27 [RFC PATCH-for-7.2 v3 0/5] hw/display/qxl: Avoid buffer overrun in qxl_phys2virt() Philippe Mathieu-Daudé
2022-11-28 20:27 ` [PATCH-for-7.2 v3 1/5] hw/display/qxl: Have qxl_log_command Return early if no log_cmd handler Philippe Mathieu-Daudé
@ 2022-11-28 20:27 ` Philippe Mathieu-Daudé
2022-11-28 20:27 ` [RFC PATCH-for-7.2 v3 3/5] hw/display/qxl: Pass requested buffer size to qxl_phys2virt() Philippe Mathieu-Daudé
` (3 subsequent siblings)
5 siblings, 0 replies; 8+ messages in thread
From: Philippe Mathieu-Daudé @ 2022-11-28 20:27 UTC (permalink / raw)
To: qemu-devel, Marc-André Lureau
Cc: Alexander Bulekov, Paolo Bonzini, Gerd Hoffmann, Peter Maydell,
Mauro Matteo Cascella, Philippe Mathieu-Daudé
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <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 e74de9579d..78b3a6c9ba 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, ...)
G_GNUC_PRINTF(2, 3);
--
2.38.1
^ permalink raw reply related [flat|nested] 8+ messages in thread
* [RFC PATCH-for-7.2 v3 3/5] hw/display/qxl: Pass requested buffer size to qxl_phys2virt()
2022-11-28 20:27 [RFC PATCH-for-7.2 v3 0/5] hw/display/qxl: Avoid buffer overrun in qxl_phys2virt() Philippe Mathieu-Daudé
2022-11-28 20:27 ` [PATCH-for-7.2 v3 1/5] hw/display/qxl: Have qxl_log_command Return early if no log_cmd handler Philippe Mathieu-Daudé
2022-11-28 20:27 ` [PATCH-for-7.2 v3 2/5] hw/display/qxl: Document qxl_phys2virt() Philippe Mathieu-Daudé
@ 2022-11-28 20:27 ` Philippe Mathieu-Daudé
2022-11-29 7:09 ` Gerd Hoffmann
2022-11-28 20:27 ` [RFC PATCH-for-7.2 v3 4/5] hw/display/qxl: Avoid buffer overrun in qxl_phys2virt (CVE-2022-4144) Philippe Mathieu-Daudé
` (2 subsequent siblings)
5 siblings, 1 reply; 8+ messages in thread
From: Philippe Mathieu-Daudé @ 2022-11-28 20:27 UTC (permalink / raw)
To: qemu-devel, Marc-André Lureau
Cc: Alexander Bulekov, Paolo Bonzini, Gerd Hoffmann, Peter Maydell,
Mauro Matteo Cascella, Philippe Mathieu-Daudé
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>
---
Except the QXLCursor changes, v2 had:
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
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 ca217004bf..fcfd40c3ac 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;
}
@@ -295,7 +298,8 @@ 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;
@@ -314,7 +318,15 @@ 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 5b10f697f1..231d733250 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;
@@ -1456,7 +1459,8 @@ 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;
@@ -1964,7 +1968,7 @@ 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 78b3a6c9ba..bf03138ab4 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, ...)
G_GNUC_PRINTF(2, 3);
--
2.38.1
^ permalink raw reply related [flat|nested] 8+ messages in thread
* [RFC PATCH-for-7.2 v3 4/5] hw/display/qxl: Avoid buffer overrun in qxl_phys2virt (CVE-2022-4144)
2022-11-28 20:27 [RFC PATCH-for-7.2 v3 0/5] hw/display/qxl: Avoid buffer overrun in qxl_phys2virt() Philippe Mathieu-Daudé
` (2 preceding siblings ...)
2022-11-28 20:27 ` [RFC PATCH-for-7.2 v3 3/5] hw/display/qxl: Pass requested buffer size to qxl_phys2virt() Philippe Mathieu-Daudé
@ 2022-11-28 20:27 ` Philippe Mathieu-Daudé
2022-11-28 20:27 ` [PATCH-for-8.0 v3 5/5] hw/display/qxl: Assert memory slot fits in preallocated MemoryRegion Philippe Mathieu-Daudé
2022-11-30 19:45 ` [RFC PATCH-for-7.2 v3 0/5] hw/display/qxl: Avoid buffer overrun in qxl_phys2virt() Stefan Hajnoczi
5 siblings, 0 replies; 8+ messages in thread
From: Philippe Mathieu-Daudé @ 2022-11-28 20:27 UTC (permalink / raw)
To: qemu-devel, Marc-André Lureau
Cc: Alexander Bulekov, Paolo Bonzini, Gerd Hoffmann, Peter Maydell,
Mauro Matteo Cascella, Philippe Mathieu-Daudé
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>
---
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 231d733250..0b21626aad 100644
--- a/hw/display/qxl.c
+++ b/hw/display/qxl.c
@@ -1424,11 +1424,13 @@ 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,
@@ -1452,6 +1454,23 @@ 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;
@@ -1471,7 +1490,7 @@ 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);
@@ -1937,9 +1956,9 @@ 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 bf03138ab4..7894bd5134 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
--
2.38.1
^ permalink raw reply related [flat|nested] 8+ messages in thread
* [PATCH-for-8.0 v3 5/5] hw/display/qxl: Assert memory slot fits in preallocated MemoryRegion
2022-11-28 20:27 [RFC PATCH-for-7.2 v3 0/5] hw/display/qxl: Avoid buffer overrun in qxl_phys2virt() Philippe Mathieu-Daudé
` (3 preceding siblings ...)
2022-11-28 20:27 ` [RFC PATCH-for-7.2 v3 4/5] hw/display/qxl: Avoid buffer overrun in qxl_phys2virt (CVE-2022-4144) Philippe Mathieu-Daudé
@ 2022-11-28 20:27 ` Philippe Mathieu-Daudé
2022-11-30 19:45 ` [RFC PATCH-for-7.2 v3 0/5] hw/display/qxl: Avoid buffer overrun in qxl_phys2virt() Stefan Hajnoczi
5 siblings, 0 replies; 8+ messages in thread
From: Philippe Mathieu-Daudé @ 2022-11-28 20:27 UTC (permalink / raw)
To: qemu-devel, Marc-André Lureau
Cc: Alexander Bulekov, Paolo Bonzini, Gerd Hoffmann, Peter Maydell,
Mauro Matteo Cascella, Philippe Mathieu-Daudé
Signed-off-by: Philippe Mathieu-Daudé <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 0b21626aad..6772849dec 100644
--- a/hw/display/qxl.c
+++ b/hw/display/qxl.c
@@ -1384,6 +1384,7 @@ 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;
--
2.38.1
^ permalink raw reply related [flat|nested] 8+ messages in thread
* Re: [RFC PATCH-for-7.2 v3 3/5] hw/display/qxl: Pass requested buffer size to qxl_phys2virt()
2022-11-28 20:27 ` [RFC PATCH-for-7.2 v3 3/5] hw/display/qxl: Pass requested buffer size to qxl_phys2virt() Philippe Mathieu-Daudé
@ 2022-11-29 7:09 ` Gerd Hoffmann
0 siblings, 0 replies; 8+ messages in thread
From: Gerd Hoffmann @ 2022-11-29 7:09 UTC (permalink / raw)
To: Philippe Mathieu-Daudé
Cc: qemu-devel, Marc-André Lureau, Alexander Bulekov,
Paolo Bonzini, Peter Maydell, Mauro Matteo Cascella
> @@ -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;
> }
Not checking the first chunk?
> @@ -314,7 +318,15 @@ 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;
> }
Ah, you do it here. Good.
Series:
Acked-by: Gerd Hoffmann <kraxel@redhat.com>
take care,
Gerd
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [RFC PATCH-for-7.2 v3 0/5] hw/display/qxl: Avoid buffer overrun in qxl_phys2virt()
2022-11-28 20:27 [RFC PATCH-for-7.2 v3 0/5] hw/display/qxl: Avoid buffer overrun in qxl_phys2virt() Philippe Mathieu-Daudé
` (4 preceding siblings ...)
2022-11-28 20:27 ` [PATCH-for-8.0 v3 5/5] hw/display/qxl: Assert memory slot fits in preallocated MemoryRegion Philippe Mathieu-Daudé
@ 2022-11-30 19:45 ` Stefan Hajnoczi
5 siblings, 0 replies; 8+ messages in thread
From: Stefan Hajnoczi @ 2022-11-30 19:45 UTC (permalink / raw)
To: Philippe Mathieu-Daudé
Cc: qemu-devel, Marc-André Lureau, Alexander Bulekov,
Paolo Bonzini, Gerd Hoffmann, Peter Maydell,
Mauro Matteo Cascella
On Mon, 28 Nov 2022 at 15:30, Philippe Mathieu-Daudé <philmd@linaro.org> wrote:
>
> Since v2:
> - Do not abort checking guest-provided addresses (Stefan)
> - Handle chunked QEMUCursor (Gerd)
>
> Since v1:
> - Moved overrun check in qxl_get_check_slot_offset (Marc-André)
>
> memory_region_get_ram_ptr() returns a host pointer for a
> MemoryRegion. Sometimes we do offset calculation using this
> pointer without checking the underlying MemoryRegion size.
>
> Wenxu Yin reported a buffer overrun in QXL. This series
> aims to fix it. I haven't audited the other _get_ram_ptr()
> uses (yet). Eventually we could rename it _get_ram_ptr_unsafe
> and add a safer helper which checks for overrun.
>
> Worth considering for 7.2?
Merged, thanks!
Stefan
^ permalink raw reply [flat|nested] 8+ messages in thread
end of thread, other threads:[~2022-11-30 19:47 UTC | newest]
Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-11-28 20:27 [RFC PATCH-for-7.2 v3 0/5] hw/display/qxl: Avoid buffer overrun in qxl_phys2virt() Philippe Mathieu-Daudé
2022-11-28 20:27 ` [PATCH-for-7.2 v3 1/5] hw/display/qxl: Have qxl_log_command Return early if no log_cmd handler Philippe Mathieu-Daudé
2022-11-28 20:27 ` [PATCH-for-7.2 v3 2/5] hw/display/qxl: Document qxl_phys2virt() Philippe Mathieu-Daudé
2022-11-28 20:27 ` [RFC PATCH-for-7.2 v3 3/5] hw/display/qxl: Pass requested buffer size to qxl_phys2virt() Philippe Mathieu-Daudé
2022-11-29 7:09 ` Gerd Hoffmann
2022-11-28 20:27 ` [RFC PATCH-for-7.2 v3 4/5] hw/display/qxl: Avoid buffer overrun in qxl_phys2virt (CVE-2022-4144) Philippe Mathieu-Daudé
2022-11-28 20:27 ` [PATCH-for-8.0 v3 5/5] hw/display/qxl: Assert memory slot fits in preallocated MemoryRegion Philippe Mathieu-Daudé
2022-11-30 19:45 ` [RFC PATCH-for-7.2 v3 0/5] hw/display/qxl: Avoid buffer overrun in qxl_phys2virt() Stefan Hajnoczi
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