Fix CVE-2016-7947 and CVE-2016-7948. https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2016-7947 https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2016-7948 Patch copied from upstream source repository: https://cgit.freedesktop.org/xorg/lib/libXrandr/commit/?id=a0df3e1c7728205e5c7650b2e6dce684139254a6 From a0df3e1c7728205e5c7650b2e6dce684139254a6 Mon Sep 17 00:00:00 2001 From: Tobias Stoeckmann Date: Sun, 25 Sep 2016 22:21:40 +0200 Subject: [PATCH] Avoid out of boundary accesses on illegal responses The responses of the connected X server have to be properly checked to avoid out of boundary accesses that could otherwise be triggered by a malicious server. Signed-off-by: Tobias Stoeckmann Reviewed-by: Matthieu Herrb --- src/XrrConfig.c | 32 +++++++++++++-------- src/XrrCrtc.c | 83 ++++++++++++++++++++++++++++++++++++++++++------------- src/XrrMonitor.c | 18 ++++++++++++ src/XrrOutput.c | 11 ++++++++ src/XrrProvider.c | 28 ++++++++++++++++--- src/XrrScreen.c | 52 ++++++++++++++++++++++------------ 6 files changed, 172 insertions(+), 52 deletions(-) diff --git a/src/XrrConfig.c b/src/XrrConfig.c index 2f0282b..e68c45a 100644 --- a/src/XrrConfig.c +++ b/src/XrrConfig.c @@ -29,6 +29,7 @@ #include #endif +#include #include #include /* we need to be able to manipulate the Display structure on events */ @@ -272,23 +273,30 @@ static XRRScreenConfiguration *_XRRGetScreenInfo (Display *dpy, rep.rate = 0; rep.nrateEnts = 0; } + if (rep.length < INT_MAX >> 2) { + nbytes = (long) rep.length << 2; - nbytes = (long) rep.length << 2; + nbytesRead = (long) (rep.nSizes * SIZEOF (xScreenSizes) + + ((rep.nrateEnts + 1)& ~1) * 2 /* SIZEOF(CARD16) */); - nbytesRead = (long) (rep.nSizes * SIZEOF (xScreenSizes) + - ((rep.nrateEnts + 1)& ~1) * 2 /* SIZEOF (CARD16) */); + /* + * first we must compute how much space to allocate for + * randr library's use; we'll allocate the structures in a single + * allocation, on cleanlyness grounds. + */ - /* - * first we must compute how much space to allocate for - * randr library's use; we'll allocate the structures in a single - * allocation, on cleanlyness grounds. - */ + rbytes = sizeof (XRRScreenConfiguration) + + (rep.nSizes * sizeof (XRRScreenSize) + + rep.nrateEnts * sizeof (int)); - rbytes = sizeof (XRRScreenConfiguration) + - (rep.nSizes * sizeof (XRRScreenSize) + - rep.nrateEnts * sizeof (int)); + scp = (struct _XRRScreenConfiguration *) Xmalloc(rbytes); + } else { + nbytes = 0; + nbytesRead = 0; + rbytes = 0; + scp = NULL; + } - scp = (struct _XRRScreenConfiguration *) Xmalloc(rbytes); if (scp == NULL) { _XEatData (dpy, (unsigned long) nbytes); return NULL; diff --git a/src/XrrCrtc.c b/src/XrrCrtc.c index 5ae35c5..6665092 100644 --- a/src/XrrCrtc.c +++ b/src/XrrCrtc.c @@ -24,6 +24,7 @@ #include #endif +#include #include #include /* we need to be able to manipulate the Display structure on events */ @@ -57,22 +58,33 @@ XRRGetCrtcInfo (Display *dpy, XRRScreenResources *resources, RRCrtc crtc) return NULL; } - nbytes = (long) rep.length << 2; + if (rep.length < INT_MAX >> 2) + { + nbytes = (long) rep.length << 2; - nbytesRead = (long) (rep.nOutput * 4 + - rep.nPossibleOutput * 4); + nbytesRead = (long) (rep.nOutput * 4 + + rep.nPossibleOutput * 4); - /* - * first we must compute how much space to allocate for - * randr library's use; we'll allocate the structures in a single - * allocation, on cleanlyness grounds. - */ + /* + * first we must compute how much space to allocate for + * randr library's use; we'll allocate the structures in a single + * allocation, on cleanlyness grounds. + */ - rbytes = (sizeof (XRRCrtcInfo) + - rep.nOutput * sizeof (RROutput) + - rep.nPossibleOutput * sizeof (RROutput)); + rbytes = (sizeof (XRRCrtcInfo) + + rep.nOutput * sizeof (RROutput) + + rep.nPossibleOutput * sizeof (RROutput)); + + xci = (XRRCrtcInfo *) Xmalloc(rbytes); + } + else + { + nbytes = 0; + nbytesRead = 0; + rbytes = 0; + xci = NULL; + } - xci = (XRRCrtcInfo *) Xmalloc(rbytes); if (xci == NULL) { _XEatDataWords (dpy, rep.length); UnlockDisplay (dpy); @@ -194,12 +206,21 @@ XRRGetCrtcGamma (Display *dpy, RRCrtc crtc) if (!_XReply (dpy, (xReply *) &rep, 0, xFalse)) goto out; - nbytes = (long) rep.length << 2; + if (rep.length < INT_MAX >> 2) + { + nbytes = (long) rep.length << 2; - /* three channels of CARD16 data */ - nbytesRead = (rep.size * 2 * 3); + /* three channels of CARD16 data */ + nbytesRead = (rep.size * 2 * 3); - crtc_gamma = XRRAllocGamma (rep.size); + crtc_gamma = XRRAllocGamma (rep.size); + } + else + { + nbytes = 0; + nbytesRead = 0; + crtc_gamma = NULL; + } if (!crtc_gamma) { @@ -357,7 +378,7 @@ XRRGetCrtcTransform (Display *dpy, xRRGetCrtcTransformReq *req; int major_version, minor_version; XRRCrtcTransformAttributes *attr; - char *extra = NULL, *e; + char *extra = NULL, *end = NULL, *e; int p; *attributes = NULL; @@ -395,9 +416,17 @@ XRRGetCrtcTransform (Display *dpy, else { int extraBytes = rep.length * 4 - CrtcTransformExtra; - extra = Xmalloc (extraBytes); + if (rep.length < INT_MAX / 4 && + rep.length * 4 >= CrtcTransformExtra) { + extra = Xmalloc (extraBytes); + end = extra + extraBytes; + } else + extra = NULL; if (!extra) { - _XEatDataWords (dpy, rep.length - (CrtcTransformExtra >> 2)); + if (rep.length > (CrtcTransformExtra >> 2)) + _XEatDataWords (dpy, rep.length - (CrtcTransformExtra >> 2)); + else + _XEatDataWords (dpy, rep.length); UnlockDisplay (dpy); SyncHandle (); return False; @@ -429,22 +458,38 @@ XRRGetCrtcTransform (Display *dpy, e = extra; + if (e + rep.pendingNbytesFilter > end) { + XFree (extra); + return False; + } memcpy (attr->pendingFilter, e, rep.pendingNbytesFilter); attr->pendingFilter[rep.pendingNbytesFilter] = '\0'; e += (rep.pendingNbytesFilter + 3) & ~3; for (p = 0; p < rep.pendingNparamsFilter; p++) { INT32 f; + if (e + 4 > end) { + XFree (extra); + return False; + } memcpy (&f, e, 4); e += 4; attr->pendingParams[p] = (XFixed) f; } attr->pendingNparams = rep.pendingNparamsFilter; + if (e + rep.currentNbytesFilter > end) { + XFree (extra); + return False; + } memcpy (attr->currentFilter, e, rep.currentNbytesFilter); attr->currentFilter[rep.currentNbytesFilter] = '\0'; e += (rep.currentNbytesFilter + 3) & ~3; for (p = 0; p < rep.currentNparamsFilter; p++) { INT32 f; + if (e + 4 > end) { + XFree (extra); + return False; + } memcpy (&f, e, 4); e += 4; attr->currentParams[p] = (XFixed) f; diff --git a/src/XrrMonitor.c b/src/XrrMonitor.c index a9eaa7b..adc5330 100644 --- a/src/XrrMonitor.c +++ b/src/XrrMonitor.c @@ -24,6 +24,7 @@ #include #endif +#include #include #include /* we need to be able to manipulate the Display structure on events */ @@ -65,6 +66,15 @@ XRRGetMonitors(Display *dpy, Window window, Bool get_active, int *nmonitors) return NULL; } + if (rep.length > INT_MAX >> 2 || + rep.nmonitors > INT_MAX / SIZEOF(xRRMonitorInfo) || + rep.noutputs > INT_MAX / 4 || + rep.nmonitors * SIZEOF(xRRMonitorInfo) > INT_MAX - rep.noutputs * 4) { + _XEatData (dpy, rep.length); + UnlockDisplay (dpy); + SyncHandle (); + return NULL; + } nbytes = (long) rep.length << 2; nmon = rep.nmonitors; noutput = rep.noutputs; @@ -111,6 +121,14 @@ XRRGetMonitors(Display *dpy, Window window, Bool get_active, int *nmonitors) mon[m].outputs = output; buf += SIZEOF (xRRMonitorInfo); xoutput = (CARD32 *) buf; + if (xmon->noutput > rep.noutputs) { + Xfree(buf); + Xfree(mon); + UnlockDisplay (dpy); + SyncHandle (); + return NULL; + } + rep.noutputs -= xmon->noutput; for (o = 0; o < xmon->noutput; o++) output[o] = xoutput[o]; output += xmon->noutput; diff --git a/src/XrrOutput.c b/src/XrrOutput.c index 85f0b6e..30f3d40 100644 --- a/src/XrrOutput.c +++ b/src/XrrOutput.c @@ -25,6 +25,7 @@ #include #endif +#include #include #include /* we need to be able to manipulate the Display structure on events */ @@ -60,6 +61,16 @@ XRRGetOutputInfo (Display *dpy, XRRScreenResources *resources, RROutput output) return NULL; } + if (rep.length > INT_MAX >> 2 || rep.length < (OutputInfoExtra >> 2)) + { + if (rep.length > (OutputInfoExtra >> 2)) + _XEatDataWords (dpy, rep.length - (OutputInfoExtra >> 2)); + else + _XEatDataWords (dpy, rep.length); + UnlockDisplay (dpy); + SyncHandle (); + return NULL; + } nbytes = ((long) (rep.length) << 2) - OutputInfoExtra; nbytesRead = (long) (rep.nCrtcs * 4 + diff --git a/src/XrrProvider.c b/src/XrrProvider.c index 9e620c7..d796cd0 100644 --- a/src/XrrProvider.c +++ b/src/XrrProvider.c @@ -25,6 +25,7 @@ #include #endif +#include #include #include /* we need to be able to manipulate the Display structure on events */ @@ -59,12 +60,20 @@ XRRGetProviderResources(Display *dpy, Window window) return NULL; } - nbytes = (long) rep.length << 2; + if (rep.length < INT_MAX >> 2) { + nbytes = (long) rep.length << 2; - nbytesRead = (long) (rep.nProviders * 4); + nbytesRead = (long) (rep.nProviders * 4); - rbytes = (sizeof(XRRProviderResources) + rep.nProviders * sizeof(RRProvider)); - xrpr = (XRRProviderResources *) Xmalloc(rbytes); + rbytes = (sizeof(XRRProviderResources) + rep.nProviders * + sizeof(RRProvider)); + xrpr = (XRRProviderResources *) Xmalloc(rbytes); + } else { + nbytes = 0; + nbytesRead = 0; + rbytes = 0; + xrpr = NULL; + } if (xrpr == NULL) { _XEatDataWords (dpy, rep.length); @@ -121,6 +130,17 @@ XRRGetProviderInfo(Display *dpy, XRRScreenResources *resources, RRProvider provi return NULL; } + if (rep.length > INT_MAX >> 2 || rep.length < ProviderInfoExtra >> 2) + { + if (rep.length < ProviderInfoExtra >> 2) + _XEatDataWords (dpy, rep.length); + else + _XEatDataWords (dpy, rep.length - (ProviderInfoExtra >> 2)); + UnlockDisplay (dpy); + SyncHandle (); + return NULL; + } + nbytes = ((long) rep.length << 2) - ProviderInfoExtra; nbytesRead = (long)(rep.nCrtcs * 4 + diff --git a/src/XrrScreen.c b/src/XrrScreen.c index b8ce7e5..1f7ffe6 100644 --- a/src/XrrScreen.c +++ b/src/XrrScreen.c @@ -24,6 +24,7 @@ #include #endif +#include #include #include /* we need to be able to manipulate the Display structure on events */ @@ -105,27 +106,36 @@ doGetScreenResources (Display *dpy, Window window, int poll) xrri->has_rates = _XRRHasRates (xrri->minor_version, xrri->major_version); } - nbytes = (long) rep.length << 2; + if (rep.length < INT_MAX >> 2) { + nbytes = (long) rep.length << 2; - nbytesRead = (long) (rep.nCrtcs * 4 + - rep.nOutputs * 4 + - rep.nModes * SIZEOF (xRRModeInfo) + - ((rep.nbytesNames + 3) & ~3)); + nbytesRead = (long) (rep.nCrtcs * 4 + + rep.nOutputs * 4 + + rep.nModes * SIZEOF (xRRModeInfo) + + ((rep.nbytesNames + 3) & ~3)); - /* - * first we must compute how much space to allocate for - * randr library's use; we'll allocate the structures in a single - * allocation, on cleanlyness grounds. - */ + /* + * first we must compute how much space to allocate for + * randr library's use; we'll allocate the structures in a single + * allocation, on cleanlyness grounds. + */ + + rbytes = (sizeof (XRRScreenResources) + + rep.nCrtcs * sizeof (RRCrtc) + + rep.nOutputs * sizeof (RROutput) + + rep.nModes * sizeof (XRRModeInfo) + + rep.nbytesNames + rep.nModes); /* '\0' terminate names */ - rbytes = (sizeof (XRRScreenResources) + - rep.nCrtcs * sizeof (RRCrtc) + - rep.nOutputs * sizeof (RROutput) + - rep.nModes * sizeof (XRRModeInfo) + - rep.nbytesNames + rep.nModes); /* '\0' terminate names */ + xrsr = (XRRScreenResources *) Xmalloc(rbytes); + wire_names = (char *) Xmalloc (rep.nbytesNames); + } else { + nbytes = 0; + nbytesRead = 0; + rbytes = 0; + xrsr = NULL; + wire_names = NULL; + } - xrsr = (XRRScreenResources *) Xmalloc(rbytes); - wire_names = (char *) Xmalloc (rep.nbytesNames); if (xrsr == NULL || wire_names == NULL) { Xfree (xrsr); Xfree (wire_names); @@ -174,6 +184,14 @@ doGetScreenResources (Display *dpy, Window window, int poll) wire_name = wire_names; for (i = 0; i < rep.nModes; i++) { xrsr->modes[i].name = names; + if (xrsr->modes[i].nameLength > rep.nbytesNames) { + Xfree (xrsr); + Xfree (wire_names); + UnlockDisplay (dpy); + SyncHandle (); + return NULL; + } + rep.nbytesNames -= xrsr->modes[i].nameLength; memcpy (names, wire_name, xrsr->modes[i].nameLength); names[xrsr->modes[i].nameLength] = '\0'; names += xrsr->modes[i].nameLength + 1; -- 2.10.1