fbdev: improve fb_mmap bounds checks

Improve fb_mmap bounds checks in gbefb, smscufx, udlfb and vfb drivers to
prevent possible uint overflows.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: Steve Glendinning <steve.glendinning@smsc.com>
Cc: Bernie Thompson <bernie@plugable.com>

diff --git a/drivers/video/gbefb.c b/drivers/video/gbefb.c
index bda5e39..ceab370 100644 (file)
--- a/drivers/video/gbefb.c
+++ b/drivers/video/gbefb.c
@@ -1016,7 +1016,9 @@ static int gbefb_mmap(struct fb_info *info,
        /* check range */
        if (vma->vm_pgoff > (~0UL >> PAGE_SHIFT))
                return -EINVAL;
-       if (offset + size > gbe_mem_size)
+       if (size > gbe_mem_size)
+               return -EINVAL;
+       if (offset > gbe_mem_size - size)
                return -EINVAL;
 
        /* remap using the fastest write-through mode on architecture */

diff --git a/drivers/video/smscufx.c b/drivers/video/smscufx.c
index 97bd662..b2b33fc 100644 (file)
--- a/drivers/video/smscufx.c
+++ b/drivers/video/smscufx.c
@@ -782,7 +782,11 @@ static int ufx_ops_mmap(struct fb_info *info, struct vm_area_struct *vma)
        unsigned long offset = vma->vm_pgoff << PAGE_SHIFT;
        unsigned long page, pos;
 
-       if (offset + size > info->fix.smem_len)
+       if (vma->vm_pgoff > (~0UL >> PAGE_SHIFT))
+               return -EINVAL;
+       if (size > info->fix.smem_len)
+               return -EINVAL;
+       if (offset > info->fix.smem_len - size)
                return -EINVAL;
 
        pos = (unsigned long)info->fix.smem_start + offset;

diff --git a/drivers/video/udlfb.c b/drivers/video/udlfb.c
index 86d449e..ec03e72 100644 (file)
--- a/drivers/video/udlfb.c
+++ b/drivers/video/udlfb.c
@@ -324,7 +324,11 @@ static int dlfb_ops_mmap(struct fb_info *info, struct vm_area_struct *vma)
        unsigned long offset = vma->vm_pgoff << PAGE_SHIFT;
        unsigned long page, pos;
 
-       if (offset + size > info->fix.smem_len)
+       if (vma->vm_pgoff > (~0UL >> PAGE_SHIFT))
+               return -EINVAL;
+       if (size > info->fix.smem_len)
+               return -EINVAL;
+       if (offset > info->fix.smem_len - size)
                return -EINVAL;
 
        pos = (unsigned long)info->fix.smem_start + offset;

diff --git a/drivers/video/vfb.c b/drivers/video/vfb.c
index 8bc1f93..ee5985e 100644 (file)
--- a/drivers/video/vfb.c
+++ b/drivers/video/vfb.c
@@ -420,9 +420,12 @@ static int vfb_mmap(struct fb_info *info,
        unsigned long offset = vma->vm_pgoff << PAGE_SHIFT;
        unsigned long page, pos;
 
-       if (offset + size > info->fix.smem_len) {
+       if (vma->vm_pgoff > (~0UL >> PAGE_SHIFT))
+               return -EINVAL;
+       if (size > info->fix.smem_len)
+               return -EINVAL;
+       if (offset > info->fix.smem_len - size)
                return -EINVAL;
-       }
 
        pos = (unsigned long)info->fix.smem_start + offset;