From: José Hiram Soltren Date: Mon, 17 Aug 2015 16:01:44 -0500 Subject: Use secure_getenv(3) to improve security This patch is in response to the following security vulnerabilities (CVEs) reported to NVIDIA against libvdpau: CVE-2015-5198 CVE-2015-5199 CVE-2015-5200 To address these CVEs, this patch: - replaces all uses of getenv(3) with secure_getenv(3); - uses secure_getenv(3) when available, with a fallback option; - protects VDPAU_DRIVER against directory traversal by checking for '/' On platforms where secure_getenv(3) is not available, the C preprocessor will print a warning at compile time. Then, a preprocessor macro will replace secure_getenv(3) with our getenv_wrapper(), which utilizes the check: getuid() == geteuid() && getgid() == getegid() See getuid(2) and getgid(2) for further details. Signed-off-by: Aaron Plattner Reviewed-by: Florian Weimer --- configure.ac | 4 ++++ src/Makefile.am | 1 + src/mesa_dri2.c | 6 ++++-- src/util.h | 48 ++++++++++++++++++++++++++++++++++++++++++++++++ src/vdpau_wrapper.c | 28 ++++++++++++++++------------ trace/vdpau_trace.cpp | 8 +++++--- 6 files changed, 78 insertions(+), 17 deletions(-) create mode 100644 src/util.h diff --git a/configure.ac b/configure.ac index 29ad593..0f7d1da 100644 --- a/configure.ac +++ b/configure.ac @@ -6,6 +6,10 @@ AM_MAINTAINER_MODE AC_CONFIG_HEADERS(config.h) +# Check for secure_getenv +AC_USE_SYSTEM_EXTENSIONS +AC_CHECK_FUNCS([__secure_getenv secure_getenv]) + # Disable static libraries by default. Use --enable-static if you really want # them. AC_DISABLE_STATIC diff --git a/src/Makefile.am b/src/Makefile.am index 32daa8e..ef72f43 100644 --- a/src/Makefile.am +++ b/src/Makefile.am @@ -9,6 +9,7 @@ lib_LTLIBRARIES = libvdpau.la libvdpau_la_SOURCES = \ vdpau_wrapper.c \ + util.h \ $(DRI2_SOURCES) if DRI2 diff --git a/src/mesa_dri2.c b/src/mesa_dri2.c index 5f7146a..51e8794 100644 --- a/src/mesa_dri2.c +++ b/src/mesa_dri2.c @@ -1,6 +1,6 @@ /* * Copyright © 2008 Red Hat, Inc. - * Copyright © 2010 NVIDIA Corporation + * Copyright © 2010-2015 NVIDIA Corporation * * Permission is hereby granted, free of charge, to any person obtaining a * copy of this software and associated documentation files (the "Soft- @@ -30,6 +30,7 @@ * Authors: * Kristian Høgsberg (krh@redhat.com) * Modified for VDPAU by Aaron Plattner (aplattner@nvidia.com) + * and José Hiram Soltren (jsoltren@nvidia.com) */ @@ -39,6 +40,7 @@ #include #include #include "mesa_dri2.h" +#include "util.h" static char dri2ExtensionName[] = DRI2_NAME; static XExtensionInfo *dri2Info; @@ -130,7 +132,7 @@ _vdp_DRI2Connect(Display * dpy, XID window, char **driverName, char **deviceName req->driverType = DRI2DriverVDPAU; #ifdef DRI2DriverPrimeShift { - char *prime = getenv("DRI_PRIME"); + char *prime = secure_getenv("DRI_PRIME"); if (prime) { unsigned int primeid; errno = 0; diff --git a/src/util.h b/src/util.h new file mode 100644 index 0000000..1452c06 --- /dev/null +++ b/src/util.h @@ -0,0 +1,48 @@ +/* + * Copyright (c) 2015 NVIDIA Corporation + * + * Permission is hereby granted, free of charge, to any person obtaining a copy + * of this software and associated documentation files (the "Software"), to deal + * in the Software without restriction, including without limitation the rights + * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell + * copies of the Software, and to permit persons to whom the Software is + * furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice (including the next + * paragraph) shall be included in all copies or substantial portions of the + * Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE + * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE + * SOFTWARE. + */ + +#ifdef HAVE_CONFIG_H +#include "config.h" +#endif + +#include +#include + +static char * getenv_wrapper(const char *name) +{ + if (getuid() == geteuid() && getgid() == getegid()) { + return getenv(name); + } + else { + return NULL; + } +} + +#ifndef HAVE_SECURE_GETENV +# ifdef HAVE___SECURE_GETENV +# define secure_getenv __secure_getenv +# else +# warning Neither secure_getenv nor __secure_getenv is available. +# define secure_getenv getenv_wrapper +# endif +#endif diff --git a/src/vdpau_wrapper.c b/src/vdpau_wrapper.c index e273bcf..42f705c 100644 --- a/src/vdpau_wrapper.c +++ b/src/vdpau_wrapper.c @@ -1,5 +1,5 @@ /* - * Copyright (c) 2008-2009 NVIDIA, Corporation + * Copyright (c) 2008-2015 NVIDIA Corporation * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this software and associated documentation files (the "Software"), to deal @@ -36,6 +36,7 @@ #include "mesa_dri2.h" #include #endif +#include "util.h" typedef void SetDllHandle( void * driver_dll_handle @@ -122,7 +123,12 @@ static VdpStatus _vdp_open_driver( char const * func_name; char const ** module_path; - vdpau_driver = getenv("VDPAU_DRIVER"); + vdpau_driver = secure_getenv("VDPAU_DRIVER"); + if (vdpau_driver) { + if (strchr(vdpau_driver, '/')) { + vdpau_driver = NULL; + } + } if (!vdpau_driver) { vdpau_driver = vdpau_driver_dri2 = _vdp_get_driver_name_from_dri2(display, screen); @@ -133,15 +139,13 @@ static VdpStatus _vdp_open_driver( _vdp_driver_dll = NULL; - if (geteuid() == getuid()) { - /* don't allow setuid apps to use VDPAU_DRIVER_PATH */ - vdpau_driver_path = getenv("VDPAU_DRIVER_PATH"); - if (vdpau_driver_path && - snprintf(vdpau_driver_lib, sizeof(vdpau_driver_lib), - DRIVER_LIB_FORMAT, vdpau_driver_path, vdpau_driver) < - sizeof(vdpau_driver_lib)) { - _vdp_driver_dll = dlopen(vdpau_driver_lib, RTLD_NOW | RTLD_GLOBAL); - } + /* Don't allow setuid apps to use VDPAU_DRIVER_PATH */ + vdpau_driver_path = secure_getenv("VDPAU_DRIVER_PATH"); + if (vdpau_driver_path && + snprintf(vdpau_driver_lib, sizeof(vdpau_driver_lib), + DRIVER_LIB_FORMAT, vdpau_driver_path, vdpau_driver) < + sizeof(vdpau_driver_lib)) { + _vdp_driver_dll = dlopen(vdpau_driver_lib, RTLD_NOW | RTLD_GLOBAL); } /* Fallback to VDPAU_MODULEDIR when VDPAU_DRIVER_PATH is not set, @@ -181,7 +185,7 @@ static VdpStatus _vdp_open_driver( _vdp_backend_dll = _vdp_driver_dll; - vdpau_trace = getenv("VDPAU_TRACE"); + vdpau_trace = secure_getenv("VDPAU_TRACE"); if (vdpau_trace && atoi(vdpau_trace)) { SetDllHandle * set_dll_handle; diff --git a/trace/vdpau_trace.cpp b/trace/vdpau_trace.cpp index 31c988a..05a0530 100644 --- a/trace/vdpau_trace.cpp +++ b/trace/vdpau_trace.cpp @@ -1,5 +1,5 @@ /* - * Copyright (c) 2008-2009 NVIDIA, Corporation + * Copyright (c) 2008-2015 NVIDIA Corporation * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this software and associated documentation files (the "Software"), to deal @@ -31,6 +31,8 @@ #include #include +#include "../src/util.h" + #define _VDP_TRACE_ARSIZE(_x_) ((sizeof (_x_)) / (sizeof ((_x_)[0]))) #if DEBUG @@ -4558,13 +4560,13 @@ VdpStatus vdp_trace_device_create_x11( } else { _vdp_cap_data.level = 0; - char const * vdpau_trace = getenv("VDPAU_TRACE"); + char const * vdpau_trace = secure_getenv("VDPAU_TRACE"); if (vdpau_trace) { _vdp_cap_data.level = atoi(vdpau_trace); } _vdp_cap_data.fp = 0; - char const * vdpau_trace_file = getenv("VDPAU_TRACE_FILE"); + char const * vdpau_trace_file = secure_getenv("VDPAU_TRACE_FILE"); if (vdpau_trace_file && strlen(vdpau_trace_file)) { if (vdpau_trace_file[0] == '&') { int fd = atoi(&vdpau_trace_file[1]);