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On Monday, December 19, 2016 3:35:24 PM EST Ian Zimmerman wrote: |
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> On 2016-12-18 22:43, Ian Zimmerman wrote: |
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> > But now I hit the error chronicled at [2]. A look at kernel source, in |
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> > drivers/gpu/drm/drm_ioctl.c, shows that the relevant kernel ioctl is |
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> > |
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> > declared thus: |
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> > DRM_IOCTL_DEF(DRM_IOCTL_SET_MASTER, drm_setmaster_ioctl, DRM_ROOT_ONLY), |
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> |
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> And the answer is .. OF COURSE!! .. systemd. |
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> |
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> With systemd integration, the get_drm_info() function in xorg source file |
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> hw/xfree86/os-support/linux/lnx_platform.c sets the server_fd flag, |
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> which makes it do this later: |
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> |
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> if (server_fd) |
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> xf86_platform_devices[delayed_index].flags |= XF86_PDEV_SERVER_FD; |
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> |
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> .. which makes the radeon_set_drm_master() function in xf86-video-ati |
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> file src/radeon_kms.c immediately return TRUE and bypass the failing |
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> ioctl(DRM_IOCTL_SET_MASTER). |
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> |
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> So now I know that my only way to non-suid (and anyone else with similar |
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> hardware and without systemd) is to patch the X source, and/or the |
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> kernel source. I'll probably take a few days break from this issue |
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> pondering if it's worth it. |
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|
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Patch it, test it, file a bug report and supply your patch. Seems to me you |
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found a legitimate bug. |
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