From: =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= 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 Content-Transfer-Encoding: 8bit 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 Signed-off-by: Philippe Mathieu-Daudé Signed-off-by: Stefan Hajnoczi 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: =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= 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 Signed-off-by: Philippe Mathieu-Daudé Signed-off-by: Stefan Hajnoczi 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 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); From: =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= 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 Acked-by: Gerd Hoffmann Signed-off-by: Stefan Hajnoczi 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 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 adbdbcaeb6..c1ab202f98 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); From: =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= 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 Signed-off-by: Stefan Hajnoczi 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 c1ab202f98..91c0fe698c 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 From: =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= 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 Signed-off-by: Stefan Hajnoczi 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 91c0fe698c..8fe4e6b8cd 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;