Messages in this thread | | | From | David Laight <> | Subject | RE: [PATCH 0/3] Prevent out-of-bounds access for built-in font data buffers | Date | Thu, 24 Sep 2020 14:42:18 +0000 |
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> On Thu, Sep 24, 2020 at 09:38:22AM -0400, Peilin Ye wrote: > > Hi all, > > > > syzbot has reported [1] a global out-of-bounds read issue in > > fbcon_get_font(). A malicious user may resize `vc_font.height` to a large > > value in vt_ioctl(), causing fbcon_get_font() to overflow our built-in > > font data buffers, declared in lib/fonts/font_*.c: ... > > (drivers/video/fbdev/core/fbcon.c) > > if (font->width <= 8) { > > j = vc->vc_font.height; > > + if (font->charcount * j > FNTSIZE(fontdata)) > > + return -EINVAL;
Can that still go wrong because the multiply wraps?
David
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