Messages in this thread Patch in this message | | | From | Andrey Strachuk <> | Subject | [PATCH] drm/fb-helper: add virtual screen size check to drm_fb_helper_check_var() | Date | Thu, 11 Aug 2022 13:23:04 +0300 |
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Add virtual screen size check to drm_fb_helper_check_var() in order to validate userspace input.
Found by Linux Verification Center (linuxtesting.org) with syzkaller.
Signed-off-by: Andrey Strachuk <strochuk@ispras.ru> Fixes: 6c11df58fd1a ("fbmem: Check virtual screen sizes in fb_set_var()") --- drivers/gpu/drm/drm_fb_helper.c | 10 ++++++++++ 1 file changed, 10 insertions(+)
diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c index 2d4cee6a10ff..d21fe89358af 100644 --- a/drivers/gpu/drm/drm_fb_helper.c +++ b/drivers/gpu/drm/drm_fb_helper.c @@ -1355,6 +1355,16 @@ int drm_fb_helper_check_var(struct fb_var_screeninfo *var, (drm_format_info_block_height(fb->format, 0) > 1)) return -EINVAL; + /* verify that virtual resolution >= physical resolution */ + if (var->xres_virtual < var->xres || + var->yres_virtual < var->yres) { + drm_dbg_kms(dev, "requested virtual screen size that is " + "below the physical size(%ux%u vs. %ux%u)\n", + var->xres_virtual, var->yres_virtual, + var->xres, var->yres); + return -EINVAL; + } + /* * Changes struct fb_var_screeninfo are currently not pushed back * to KMS, hence fail if different settings are requested. -- 2.25.1
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