From: Samuel Thibault <samuel.thibault@ens-lyon.org> To: gregkh@linuxfoundation.org, Daniel Vetter <daniel@ffwll.ch>, Helge Deller <deller@gmx.de> Cc: linux-fbdev@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org, Sanan Hasanov <sanan.hasanov@Knights.ucf.edu> Subject: [PATCHv2] fbcon: Check font dimension limits Date: Sun, 29 Jan 2023 16:17:40 +0100 [thread overview] Message-ID: <20230129151740.x5p7jj2pbuilpzzt@begin> (raw) blit_x and blit_y are u32, so fbcon currently cannot support fonts larger than 32x32. The 32x32 case also needs shifting an unsigned int, to properly set bit 31, otherwise we get "UBSAN: shift-out-of-bounds in fbcon_set_font", as reported on: http://lore.kernel.org/all/IA1PR07MB98308653E259A6F2CE94A4AFABCE9@IA1PR07MB9830.namprd07.prod.outlook.com Kernel Branch: 6.2.0-rc5-next-20230124 Kernel config: https://drive.google.com/file/d/1F-LszDAizEEH0ZX0HcSR06v5q8FPl2Uv/view?usp=sharing Reproducer: https://drive.google.com/file/d/1mP1jcLBY7vWCNM60OMf-ogw-urQRjNrm/view?usp=sharing Reported-by: Sanan Hasanov <sanan.hasanov@Knights.ucf.edu> Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org> Fixes: 2d2699d98492 ("fbcon: font setting should check limitation of driver") Cc: stable@vger.kernel.org --- v1 -> v2: - Use BIT macro instead of fixing bit test by hand. - Add Fixes and Cc: stable headers. Index: linux-6.0/drivers/video/fbdev/core/fbcon.c =================================================================== --- linux-6.0.orig/drivers/video/fbdev/core/fbcon.c +++ linux-6.0/drivers/video/fbdev/core/fbcon.c @@ -2489,9 +2489,12 @@ static int fbcon_set_font(struct vc_data h > FBCON_SWAP(info->var.rotate, info->var.yres, info->var.xres)) return -EINVAL; + if (font->width > 32 || font->height > 32) + return -EINVAL; + /* Make sure drawing engine can handle the font */ - if (!(info->pixmap.blit_x & (1 << (font->width - 1))) || - !(info->pixmap.blit_y & (1 << (font->height - 1)))) + if (!(info->pixmap.blit_x & BIT(font->width - 1)) || + !(info->pixmap.blit_y & BIT(font->height - 1))) return -EINVAL; /* Make sure driver can handle the font length */
WARNING: multiple messages have this Message-ID (diff)
From: Samuel Thibault <samuel.thibault@ens-lyon.org> To: gregkh@linuxfoundation.org, Daniel Vetter <daniel@ffwll.ch>, Helge Deller <deller@gmx.de> Cc: Sanan Hasanov <sanan.hasanov@Knights.ucf.edu>, stable@vger.kernel.org, linux-fbdev@vger.kernel.org, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org Subject: [PATCHv2] fbcon: Check font dimension limits Date: Sun, 29 Jan 2023 16:17:40 +0100 [thread overview] Message-ID: <20230129151740.x5p7jj2pbuilpzzt@begin> (raw) blit_x and blit_y are u32, so fbcon currently cannot support fonts larger than 32x32. The 32x32 case also needs shifting an unsigned int, to properly set bit 31, otherwise we get "UBSAN: shift-out-of-bounds in fbcon_set_font", as reported on: http://lore.kernel.org/all/IA1PR07MB98308653E259A6F2CE94A4AFABCE9@IA1PR07MB9830.namprd07.prod.outlook.com Kernel Branch: 6.2.0-rc5-next-20230124 Kernel config: https://drive.google.com/file/d/1F-LszDAizEEH0ZX0HcSR06v5q8FPl2Uv/view?usp=sharing Reproducer: https://drive.google.com/file/d/1mP1jcLBY7vWCNM60OMf-ogw-urQRjNrm/view?usp=sharing Reported-by: Sanan Hasanov <sanan.hasanov@Knights.ucf.edu> Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org> Fixes: 2d2699d98492 ("fbcon: font setting should check limitation of driver") Cc: stable@vger.kernel.org --- v1 -> v2: - Use BIT macro instead of fixing bit test by hand. - Add Fixes and Cc: stable headers. Index: linux-6.0/drivers/video/fbdev/core/fbcon.c =================================================================== --- linux-6.0.orig/drivers/video/fbdev/core/fbcon.c +++ linux-6.0/drivers/video/fbdev/core/fbcon.c @@ -2489,9 +2489,12 @@ static int fbcon_set_font(struct vc_data h > FBCON_SWAP(info->var.rotate, info->var.yres, info->var.xres)) return -EINVAL; + if (font->width > 32 || font->height > 32) + return -EINVAL; + /* Make sure drawing engine can handle the font */ - if (!(info->pixmap.blit_x & (1 << (font->width - 1))) || - !(info->pixmap.blit_y & (1 << (font->height - 1)))) + if (!(info->pixmap.blit_x & BIT(font->width - 1)) || + !(info->pixmap.blit_y & BIT(font->height - 1))) return -EINVAL; /* Make sure driver can handle the font length */
next reply other threads:[~2023-01-29 15:17 UTC|newest] Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top 2023-01-29 15:17 Samuel Thibault [this message] 2023-01-29 15:17 ` [PATCHv2] fbcon: Check font dimension limits Samuel Thibault 2023-01-29 17:09 ` Miko Larsson 2023-01-29 17:09 ` Miko Larsson 2023-01-31 14:51 ` Greg KH 2023-02-04 13:31 ` Helge Deller
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