Merge tag 'fbdev-for-7.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/linux-fbdev

Pull fbdev updates from Helge Deller:
 "The usual bunch of many small fixes in various fbdev drivers, but
  more interestingly the Vodoo3/4/5 cards will now be initialized even
  without PC BIOS support and vintage Atari computers gain more color
  depths and console acceleration on SuperVidel's SuperBlitter chips.

  New features:
   - Allow Vodoo3/4/5 card to be initialized without PC-BIOS (Daniel
     Palmer)
   - Add support for SuperVidel's SuperBlitter (Miro Kropacek)
   - Add further video bit depths (Miro Kropacek)
   - Detect default graphics card for console output on sticon/parisc
     (Helge Deller)

  Fixes:
   - kyro: Validate overlay viewport coordinates (Danila Chernetsov)
   - platinumfb: add error checking for ioremap calls (BingKun Yue)
   - ssd1307fb: damage callback fixes (Hui Su)
   - maxine: fix 64-bit build error and code cleanups (Randy Dunlap)
   - omapfb: panel-dsi-cm: initialize lock before registering display
     (Runyu Xiao)
   - core: Clamp total_size to smem_len in read/write functions
     (Mingyu Wang)
   - uvesafb, tdxfb: failure path cleanups (Myeonghun Pak)
   - udlfb: validate DisplayLink vendor descriptor items before usage
     (Pengpeng Hou)

  Cleanups:
   - Convert multiple drivers to managed PCI and ioremap API (Shixiong Ou)
   - Remove redundant dev_err() from multiple drivers (Pan Chuang)
   - omap2: do not copy isr table (Andreas Kemnade)
   - pvr2fb: correct user pointer annotation and sentinel initializer
     (Florian Fuchs)
   - mb862xxfb: silence possibly unused functions (Helge Deller)
   - au1100fb: drop unneeded semicolon (Julia Lawall)
   - clps711x-fb: remove unreachable code (Karl Mehltretter)
   - viafb: refactor strcpy call (Ajith P V)
   - sstfb: add missing MODULE_DEVICE_TABLE() (Pengpeng Hou)
   - mb862xx: replace dead Kconfig select with dependency (Julian Braha)

  Documentation fixes:
   - fonts: fixup font.h kernel-doc warnings (Randy Dunlap)"

* tag 'fbdev-for-7.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/linux-fbdev: (43 commits)
  fbdev: atafb: Add support for SuperVidel's SuperBlitter
  fbdev: atafb: Add support for further video bit depths on atafb:external
  fbdev: atafb: Give atafb proper parent
  fbdev: omapfb: panel-dsi-cm: initialize lock before registering display
  fbdev: viafb: refactor strcpy and viafb_name
  fbdev: platinumfb: add error checking for ioremap calls
  fbdev: maxine: use MODULE_LICENSE() unconditionally
  fbdev: maxine: fix maxinefb_init() return value
  fbdev: maxine: fix 64-bit build error
  fbdev: maxine: elide an unused function
  fbdev: maxine: make functions static
  fbdev: atyfb: Convert to managed PCI and ioremap API
  fbdev: matrox: Convert to managed PCI and ioremap API
  fbdev: savage: Convert to managed PCI and ioremap API
  fbdev: nvidia: Convert to managed PCI and ioremap API
  fbdev: aty128fb: Convert to managed PCI and ioremap API
  fbdev: clps711x-fb: Remove unreachable unregister_framebuffer() call
  fbdev: mb862xxfb: Silence possibly unused functions
  sticon/parisc: Detect default STI graphics card for console output
  fbdev: ssd1307fb: defer I2C transfers from damage callbacks
  ...

2 files changed, 32 insertions, 0 deletions

diff --git a/drivers/video/fbdev/core/fb_io_fops.c b/drivers/video/fbdev/core/fb_io_fops.c
index 7d16513690c3..545886cb3eeb 100644
--- a/drivers/video/fbdev/core/fb_io_fops.c
+++ b/drivers/video/fbdev/core/fb_io_fops.c
@@ -24,6 +24,14 @@ ssize_t fb_io_read(struct fb_info *info, char __user *buf, size_t count, loff_t
 	if (total_size == 0)
 		total_size = info->fix.smem_len;
 
+	/*
+	 * Security Hardening: Defend against buggy legacy drivers that may
+	 * calculate a malformed screen_size. Clamp total_size to the actual
+	 * hardware mapped memory limit (smem_len) to prevent OOB access.
+	 */
+	if (info->fix.smem_len && total_size > info->fix.smem_len)
+		total_size = info->fix.smem_len;
+
 	if (p >= total_size)
 		return 0;
 
@@ -96,6 +104,14 @@ ssize_t fb_io_write(struct fb_info *info, const char __user *buf, size_t count,
 	if (total_size == 0)
 		total_size = info->fix.smem_len;
 
+	/*
+	 * Security Hardening: Defend against buggy legacy drivers that may
+	 * calculate a malformed screen_size. Clamp total_size to the actual
+	 * hardware mapped memory limit (smem_len) to prevent OOB access.
+	 */
+	if (info->fix.smem_len && total_size > info->fix.smem_len)
+		total_size = info->fix.smem_len;
+
 	if (p > total_size)
 		return -EFBIG;
 
diff --git a/drivers/video/fbdev/core/fb_sys_fops.c b/drivers/video/fbdev/core/fb_sys_fops.c
index be96b3b3942e..e97cf02f7c70 100644
--- a/drivers/video/fbdev/core/fb_sys_fops.c
+++ b/drivers/video/fbdev/core/fb_sys_fops.c
@@ -35,6 +35,14 @@ ssize_t fb_sys_read(struct fb_info *info, char __user *buf, size_t count,
 	if (total_size == 0)
 		total_size = info->fix.smem_len;
 
+	/*
+	 * Security Hardening: Defend against buggy legacy drivers that may
+	 * calculate a malformed screen_size. Clamp total_size to the actual
+	 * hardware mapped memory limit (smem_len) to prevent OOB access.
+	 */
+	if (info->fix.smem_len && total_size > info->fix.smem_len)
+		total_size = info->fix.smem_len;
+
 	if (p >= total_size)
 		return 0;
 
@@ -80,6 +88,14 @@ ssize_t fb_sys_write(struct fb_info *info, const char __user *buf,
 	if (total_size == 0)
 		total_size = info->fix.smem_len;
 
+	/*
+	 * Security Hardening: Defend against buggy legacy drivers that may
+	 * calculate a malformed screen_size. Clamp total_size to the actual
+	 * hardware mapped memory limit (smem_len) to prevent OOB access.
+	 */
+	if (info->fix.smem_len && total_size > info->fix.smem_len)
+		total_size = info->fix.smem_len;
+
 	if (p > total_size)
 		return -EFBIG;