Re: [PATCH v4] xserver-kdrive: Fix X server on PowerPC when built with GCC 4.7.x

[Martin Jansa <martin.jansa@gmail.com>]

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On Wed, May 16, 2012 at 03:26:23PM -0600, Gary Thomas wrote:
> Newer versions of GCC uncovered illegal code practice which can cause
> runtime failures in the Xext/xace.c code.  This problem has been fixed upstream:
>   http://cgit.freedesktop.org/xorg/xserver/patch/Xext/xace.c?id=6dae7f3792611aace1df0cca63bf50c50d93de43
>   Subject: xace: Invalid reference to out-of-scope data.
> 
> Incorporate this patch into the recipe, with a PR bump.
> 
> Signed-off-by: Gary Thomas <gary@mlbassoc.com>
> ---
>  .../fix-bogus-stack-variables.patch                |  231 ++++++++++++++++++++
>  .../xorg-xserver/xserver-kdrive_1.7.99.2.bb        |    3 +-
>  2 files changed, 233 insertions(+), 1 deletions(-)
>  create mode 100644 meta/recipes-graphics/xorg-xserver/xserver-kdrive-1.7.99.2/fix-bogus-stack-variables.patch
> 
> diff --git a/meta/recipes-graphics/xorg-xserver/xserver-kdrive-1.7.99.2/fix-bogus-stack-variables.patch b/meta/recipes-graphics/xorg-xserver/xserver-kdrive-1.7.99.2/fix-bogus-stack-variables.patch
> new file mode 100644
> index 0000000..d900fc3
> --- /dev/null
> +++ b/meta/recipes-graphics/xorg-xserver/xserver-kdrive-1.7.99.2/fix-bogus-stack-variables.patch
> @@ -0,0 +1,233 @@
> +From 6dae7f3792611aace1df0cca63bf50c50d93de43 Mon Sep 17 00:00:00 2001
> +From: Chris Wilson <chris@chris-wilson.co.uk>
> +Date: Tue, 10 Aug 2010 18:30:20 +0000
> +Subject: xace: Invalid reference to out-of-scope data.
> +
> +The callback data passed by reference to the hook was allocated on stack
> +within the scope of the case statement. The compiler is free to reuse
> +any of that stack space whilst making the function call so we may end up
> +passing garbage into the callback.
> +
> +References:
> +
> +  Bug 18451 - Xorg server 1.5.2 SEGV during XFixesGetCursorImage()
> +  https://bugs.freedesktop.org/show_bug.cgi?id=18451
> +
> +v2: Drop the unrelated hunk that snuck in when ammending the commit
> +message.
> +
> +Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
> +Reviewed-by: Alan Coopersmith <alan.coopersmith@oracle.com>
> +Signed-off-by: Keith Packard <keithp@keithp.com>
> +
> +Upstream-Status: accepted

Shouldn't this ^ be "Backport" as in v3?

Probably not worth doing v5, just wondering why did you change that to "accepted".

> +---
> +(limited to 'Xext/xace.c')
> +
> +diff --git a/Xext/xace.c b/Xext/xace.c
> +index e10d837..c757cad 100644
> +--- a/Xext/xace.c
> ++++ b/Xext/xace.c
> +@@ -87,7 +87,18 @@ void XaceHookAuditEnd(ClientPtr ptr, int result)
> +  */
> + int XaceHook(int hook, ...)
> + {
> +-    pointer calldata;	/* data passed to callback */
> ++    union {
> ++	XaceResourceAccessRec res;
> ++	XaceDeviceAccessRec dev;
> ++	XaceSendAccessRec send;
> ++	XaceReceiveAccessRec recv;
> ++	XaceClientAccessRec client;
> ++	XaceExtAccessRec ext;
> ++	XaceServerAccessRec server;
> ++	XaceScreenAccessRec screen;
> ++	XaceAuthAvailRec auth;
> ++	XaceKeyAvailRec key;
> ++    } u;
> +     int *prv = NULL;	/* points to return value from callback */
> +     va_list ap;		/* argument list */
> +     va_start(ap, hook);
> +@@ -99,117 +110,86 @@ int XaceHook(int hook, ...)
> +      */
> +     switch (hook)
> +     {
> +-	case XACE_RESOURCE_ACCESS: {
> +-	    XaceResourceAccessRec rec;
> +-	    rec.client = va_arg(ap, ClientPtr);
> +-	    rec.id = va_arg(ap, XID);
> +-	    rec.rtype = va_arg(ap, RESTYPE);
> +-	    rec.res = va_arg(ap, pointer);
> +-	    rec.ptype = va_arg(ap, RESTYPE);
> +-	    rec.parent = va_arg(ap, pointer);
> +-	    rec.access_mode = va_arg(ap, Mask);
> +-	    rec.status = Success; /* default allow */
> +-	    calldata = &rec;
> +-	    prv = &rec.status;
> ++	case XACE_RESOURCE_ACCESS:
> ++	    u.res.client = va_arg(ap, ClientPtr);
> ++	    u.res.id = va_arg(ap, XID);
> ++	    u.res.rtype = va_arg(ap, RESTYPE);
> ++	    u.res.res = va_arg(ap, pointer);
> ++	    u.res.ptype = va_arg(ap, RESTYPE);
> ++	    u.res.parent = va_arg(ap, pointer);
> ++	    u.res.access_mode = va_arg(ap, Mask);
> ++	    u.res.status = Success; /* default allow */
> ++	    prv = &u.res.status;
> + 	    break;
> +-	}
> +-	case XACE_DEVICE_ACCESS: {
> +-	    XaceDeviceAccessRec rec;
> +-	    rec.client = va_arg(ap, ClientPtr);
> +-	    rec.dev = va_arg(ap, DeviceIntPtr);
> +-	    rec.access_mode = va_arg(ap, Mask);
> +-	    rec.status = Success; /* default allow */
> +-	    calldata = &rec;
> +-	    prv = &rec.status;
> ++	case XACE_DEVICE_ACCESS:
> ++	    u.dev.client = va_arg(ap, ClientPtr);
> ++	    u.dev.dev = va_arg(ap, DeviceIntPtr);
> ++	    u.dev.access_mode = va_arg(ap, Mask);
> ++	    u.dev.status = Success; /* default allow */
> ++	    prv = &u.dev.status;
> + 	    break;
> +-	}
> +-	case XACE_SEND_ACCESS: {
> +-	    XaceSendAccessRec rec;
> +-	    rec.client = va_arg(ap, ClientPtr);
> +-	    rec.dev = va_arg(ap, DeviceIntPtr);
> +-	    rec.pWin = va_arg(ap, WindowPtr);
> +-	    rec.events = va_arg(ap, xEventPtr);
> +-	    rec.count = va_arg(ap, int);
> +-	    rec.status = Success; /* default allow */
> +-	    calldata = &rec;
> +-	    prv = &rec.status;
> ++	case XACE_SEND_ACCESS:
> ++	    u.send.client = va_arg(ap, ClientPtr);
> ++	    u.send.dev = va_arg(ap, DeviceIntPtr);
> ++	    u.send.pWin = va_arg(ap, WindowPtr);
> ++	    u.send.events = va_arg(ap, xEventPtr);
> ++	    u.send.count = va_arg(ap, int);
> ++	    u.send.status = Success; /* default allow */
> ++	    prv = &u.send.status;
> + 	    break;
> +-	}
> +-	case XACE_RECEIVE_ACCESS: {
> +-	    XaceReceiveAccessRec rec;
> +-	    rec.client = va_arg(ap, ClientPtr);
> +-	    rec.pWin = va_arg(ap, WindowPtr);
> +-	    rec.events = va_arg(ap, xEventPtr);
> +-	    rec.count = va_arg(ap, int);
> +-	    rec.status = Success; /* default allow */
> +-	    calldata = &rec;
> +-	    prv = &rec.status;
> ++	case XACE_RECEIVE_ACCESS:
> ++	    u.recv.client = va_arg(ap, ClientPtr);
> ++	    u.recv.pWin = va_arg(ap, WindowPtr);
> ++	    u.recv.events = va_arg(ap, xEventPtr);
> ++	    u.recv.count = va_arg(ap, int);
> ++	    u.recv.status = Success; /* default allow */
> ++	    prv = &u.recv.status;
> + 	    break;
> +-	}
> +-	case XACE_CLIENT_ACCESS: {
> +-	    XaceClientAccessRec rec;
> +-	    rec.client = va_arg(ap, ClientPtr);
> +-	    rec.target = va_arg(ap, ClientPtr);
> +-	    rec.access_mode = va_arg(ap, Mask);
> +-	    rec.status = Success; /* default allow */
> +-	    calldata = &rec;
> +-	    prv = &rec.status;
> ++	case XACE_CLIENT_ACCESS:
> ++	    u.client.client = va_arg(ap, ClientPtr);
> ++	    u.client.target = va_arg(ap, ClientPtr);
> ++	    u.client.access_mode = va_arg(ap, Mask);
> ++	    u.client.status = Success; /* default allow */
> ++	    prv = &u.client.status;
> + 	    break;
> +-	}
> +-	case XACE_EXT_ACCESS: {
> +-	    XaceExtAccessRec rec;
> +-	    rec.client = va_arg(ap, ClientPtr);
> +-	    rec.ext = va_arg(ap, ExtensionEntry*);
> +-	    rec.access_mode = DixGetAttrAccess;
> +-	    rec.status = Success; /* default allow */
> +-	    calldata = &rec;
> +-	    prv = &rec.status;
> ++	case XACE_EXT_ACCESS:
> ++	    u.ext.client = va_arg(ap, ClientPtr);
> ++	    u.ext.ext = va_arg(ap, ExtensionEntry*);
> ++	    u.ext.access_mode = DixGetAttrAccess;
> ++	    u.ext.status = Success; /* default allow */
> ++	    prv = &u.ext.status;
> + 	    break;
> +-	}
> +-	case XACE_SERVER_ACCESS: {
> +-	    XaceServerAccessRec rec;
> +-	    rec.client = va_arg(ap, ClientPtr);
> +-	    rec.access_mode = va_arg(ap, Mask);
> +-	    rec.status = Success; /* default allow */
> +-	    calldata = &rec;
> +-	    prv = &rec.status;
> ++	case XACE_SERVER_ACCESS:
> ++	    u.server.client = va_arg(ap, ClientPtr);
> ++	    u.server.access_mode = va_arg(ap, Mask);
> ++	    u.server.status = Success; /* default allow */
> ++	    prv = &u.server.status;
> + 	    break;
> +-	}
> + 	case XACE_SCREEN_ACCESS:
> +-	case XACE_SCREENSAVER_ACCESS: {
> +-	    XaceScreenAccessRec rec;
> +-	    rec.client = va_arg(ap, ClientPtr);
> +-	    rec.screen = va_arg(ap, ScreenPtr);
> +-	    rec.access_mode = va_arg(ap, Mask);
> +-	    rec.status = Success; /* default allow */
> +-	    calldata = &rec;
> +-	    prv = &rec.status;
> ++	case XACE_SCREENSAVER_ACCESS:
> ++	    u.screen.client = va_arg(ap, ClientPtr);
> ++	    u.screen.screen = va_arg(ap, ScreenPtr);
> ++	    u.screen.access_mode = va_arg(ap, Mask);
> ++	    u.screen.status = Success; /* default allow */
> ++	    prv = &u.screen.status;
> + 	    break;
> +-	}
> +-	case XACE_AUTH_AVAIL: {
> +-	    XaceAuthAvailRec rec;
> +-	    rec.client = va_arg(ap, ClientPtr);
> +-	    rec.authId = va_arg(ap, XID);
> +-	    calldata = &rec;
> ++	case XACE_AUTH_AVAIL:
> ++	    u.auth.client = va_arg(ap, ClientPtr);
> ++	    u.auth.authId = va_arg(ap, XID);
> + 	    break;
> +-	}
> +-	case XACE_KEY_AVAIL: {
> +-	    XaceKeyAvailRec rec;
> +-	    rec.event = va_arg(ap, xEventPtr);
> +-	    rec.keybd = va_arg(ap, DeviceIntPtr);
> +-	    rec.count = va_arg(ap, int);
> +-	    calldata = &rec;
> ++	case XACE_KEY_AVAIL:
> ++	    u.key.event = va_arg(ap, xEventPtr);
> ++	    u.key.keybd = va_arg(ap, DeviceIntPtr);
> ++	    u.key.count = va_arg(ap, int);
> + 	    break;
> +-	}
> +-	default: {
> ++	default:
> + 	    va_end(ap);
> + 	    return 0;	/* unimplemented hook number */
> +-	}
> +     }
> +     va_end(ap);
> +  
> +     /* call callbacks and return result, if any. */
> +-    CallCallbacks(&XaceHooks[hook], calldata);
> ++    CallCallbacks(&XaceHooks[hook], &u);
> +     return prv ? *prv : Success;
> + }
> + 
> +--
> +cgit v0.9.0.2-2-gbebe
> diff --git a/meta/recipes-graphics/xorg-xserver/xserver-kdrive_1.7.99.2.bb b/meta/recipes-graphics/xorg-xserver/xserver-kdrive_1.7.99.2.bb
> index 360a0f3..d90dc25 100644
> --- a/meta/recipes-graphics/xorg-xserver/xserver-kdrive_1.7.99.2.bb
> +++ b/meta/recipes-graphics/xorg-xserver/xserver-kdrive_1.7.99.2.bb
> @@ -7,7 +7,7 @@ RDEPENDS_${PN} += "xkeyboard-config"
>  EXTRA_OECONF += "--disable-glx"
>  
>  PE = "1"
> -PR = "r29"
> +PR = "r30"
>  
>  SRC_URI = "${XORG_MIRROR}/individual/xserver/xorg-server-${PV}.tar.bz2 \
>  	file://extra-kmodes.patch \
> @@ -20,6 +20,7 @@ SRC_URI = "${XORG_MIRROR}/individual/xserver/xorg-server-${PV}.tar.bz2 \
>  	file://fix-newer-xorg-headers.patch \
>  	file://crosscompile.patch \
>  	file://error-address-work-around.patch \
> +        file://fix-bogus-stack-variables.patch \
>  	file://nodolt.patch"
>  #	file://kdrive-evdev.patch
>  #	file://kdrive-use-evdev.patch
> -- 
> 1.7.7.6
> 
> 
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-- 
Martin 'JaMa' Jansa     jabber: Martin.Jansa@gmail.com

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