74 lines
2.1 KiB
Diff
74 lines
2.1 KiB
Diff
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Fix CVE-2016-7950:
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https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2016-7950
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Patch copied from upstream source repository:
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https://cgit.freedesktop.org/xorg/lib/libXrender/commit/?id=8fad00b0b647ee662ce4737ca15be033b7a21714
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From 8fad00b0b647ee662ce4737ca15be033b7a21714 Mon Sep 17 00:00:00 2001
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From: Tobias Stoeckmann <tobias@stoeckmann.org>
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Date: Sun, 25 Sep 2016 21:42:09 +0200
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Subject: [PATCH] Avoid OOB write in XRenderQueryFilters
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The memory for filter names is reserved right after receiving the reply.
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After that, filters are iterated and each individual filter name is
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stored in that reserved memory.
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The individual name lengths are not checked for validity, which means
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that a malicious server can reserve less memory than it will write to
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during each iteration.
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v2: consume remaining bytes in reply buffer on error.
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Signed-off-by: Tobias Stoeckmann <tobias@stoeckmann.org>
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Reviewed-by: Matthieu Herrb <matthieu@herrb.eu>
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---
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src/Filter.c | 13 ++++++++++++-
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1 file changed, 12 insertions(+), 1 deletion(-)
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diff --git a/src/Filter.c b/src/Filter.c
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index edfa572..8d701eb 100644
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--- a/src/Filter.c
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+++ b/src/Filter.c
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@@ -38,7 +38,7 @@ XRenderQueryFilters (Display *dpy, Drawable drawable)
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char *name;
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char len;
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int i;
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- unsigned long nbytes, nbytesAlias, nbytesName;
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+ unsigned long nbytes, nbytesAlias, nbytesName, reply_left;
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if (!RenderHasExtension (info))
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return NULL;
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@@ -114,6 +114,7 @@ XRenderQueryFilters (Display *dpy, Drawable drawable)
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* Read the filter aliases
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*/
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_XRead16Pad (dpy, filters->alias, 2 * rep.numAliases);
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+ reply_left = 8 + rep.length - 2 * rep.numAliases;;
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/*
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* Read the filter names
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@@ -122,9 +123,19 @@ XRenderQueryFilters (Display *dpy, Drawable drawable)
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{
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int l;
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_XRead (dpy, &len, 1);
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+ reply_left--;
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l = len & 0xff;
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+ if ((unsigned long)l + 1 > nbytesName) {
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+ _XEatDataWords(dpy, reply_left);
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+ Xfree(filters);
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+ UnlockDisplay (dpy);
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+ SyncHandle ();
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+ return NULL;
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+ }
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+ nbytesName -= l + 1;
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filters->filter[i] = name;
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_XRead (dpy, name, l);
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+ reply_left -= l;
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name[l] = '\0';
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name += l + 1;
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}
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--
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2.10.1
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