From 8cc425746fdee1a0dd3a4a1a74be6a6fb6e1a546 Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Tue, 17 Sep 2019 19:57:58 +0800 Subject: [PATCH] drm/i915: Sanity check mmap length against object size [ Upstream commit 000c4f90e3f0194eef218ff2c6a8fd8ca1de4313 ] We assumed that vm_mmap() would reject an attempt to mmap past the end of the filp (our object), but we were wrong. Applications that tried to use the mmap beyond the end of the object would be greeted by a SIGBUS. After this patch, those applications will be told about the error on creating the mmap, rather than at a random moment on later access. Reported-by: Antonio Argenziano Testcase: igt/gem_mmap/bad-size Signed-off-by: Chris Wilson Cc: Antonio Argenziano Cc: Joonas Lahtinen Cc: Tvrtko Ursulin Cc: stable@vger.kernel.org Reviewed-by: Tvrtko Ursulin Reviewed-by: Joonas Lahtinen Link: https://patchwork.freedesktop.org/patch/msgid/20190314075829.16838-1-chris@chris-wilson.co.uk (cherry picked from commit 794a11cb67201ad1bb61af510bb8460280feb3f3) Signed-off-by: Rodrigo Vivi Signed-off-by: Sasha Levin Signed-off-by: Yang Yingliang --- drivers/gpu/drm/i915/i915_gem.c | 15 +++++++++------ 1 file changed, 9 insertions(+), 6 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c index 2b939e8f066a..f50ccbf1cb1e 100644 --- a/drivers/gpu/drm/i915/i915_gem.c +++ b/drivers/gpu/drm/i915/i915_gem.c @@ -1871,8 +1871,13 @@ i915_gem_mmap_ioctl(struct drm_device *dev, void *data, * pages from. */ if (!obj->base.filp) { - i915_gem_object_put(obj); - return -ENXIO; + addr = -ENXIO; + goto err; + } + + if (range_overflows(args->offset, args->size, (u64)obj->base.size)) { + addr = -EINVAL; + goto err; } addr = vm_mmap(obj->base.filp, 0, args->size, @@ -1886,8 +1891,8 @@ i915_gem_mmap_ioctl(struct drm_device *dev, void *data, struct vm_area_struct *vma; if (down_write_killable(&mm->mmap_sem)) { - i915_gem_object_put(obj); - return -EINTR; + addr = -EINTR; + goto err; } vma = find_vma(mm, addr); if (vma && __vma_matches(vma, obj->base.filp, addr, args->size)) @@ -1905,12 +1910,10 @@ i915_gem_mmap_ioctl(struct drm_device *dev, void *data, i915_gem_object_put(obj); args->addr_ptr = (uint64_t) addr; - return 0; err: i915_gem_object_put(obj); - return addr; } -- GitLab