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drm: fix division-by-zero on dumb_create()
Kinda unexpected, but DIV_ROUND_UP() can overflow if passed an argument bigger than UINT_MAX - DIVISOR. Fix this by testing for "!cpp" before using it in the following division. Note that DIV_ROUND_UP() is defined as: #define DIV_ROUND_UP(n,d) (((n) + (d) - 1) / (d)) ..this will obviously overflow if (n + d - 1) is bigger than UINT_MAX. Reported-by: Tommi Rantala <tt.rantala@gmail.com> Signed-off-by: David Herrmann <dh.herrmann@gmail.com> Reviewed-by: Rob Clark <robdclark@gmail.com> Signed-off-by: Dave Airlie <airlied@redhat.com>
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1 changed files with 2 additions and 1 deletions
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@ -4696,8 +4696,9 @@ int drm_mode_create_dumb_ioctl(struct drm_device *dev,
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return -EINVAL;
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/* overflow checks for 32bit size calculations */
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/* NOTE: DIV_ROUND_UP() can overflow */
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cpp = DIV_ROUND_UP(args->bpp, 8);
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if (cpp > 0xffffffffU / args->width)
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if (!cpp || cpp > 0xffffffffU / args->width)
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return -EINVAL;
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stride = cpp * args->width;
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if (args->height > 0xffffffffU / stride)
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