From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dmitry Vyukov Subject: Re: [PATCH] drm/vkms: fix use-after-free when drm_gem_handle_create() fails Date: Tue, 5 Mar 2019 15:25:57 +0100 Message-ID: References: <20190226213053.GC218103@gmail.com> <20190226220858.214438-1-ebiggers@kernel.org> <20190227231202.tycdbcqtk5ylwp4k@smtp.gmail.com> <20190304232312.qy6x2xmtueq22m3j@smtp.gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Return-path: In-Reply-To: <20190304232312.qy6x2xmtueq22m3j@smtp.gmail.com> Sender: linux-kernel-owner@vger.kernel.org To: Rodrigo Siqueira Cc: Eric Biggers , DRI , syzkaller-bugs , LKML , Haneen Mohammed , Daniel Vetter , Chris Wilson , stable List-Id: dri-devel@lists.freedesktop.org On Tue, Mar 5, 2019 at 12:23 AM Rodrigo Siqueira wrote: > > On 02/28, Dmitry Vyukov wrote: > > On Thu, Feb 28, 2019 at 12:12 AM Rodrigo Siqueira > > wrote: > > > > > > On 02/26, Eric Biggers wrote: > > > > From: Eric Biggers > > > > > > > > If drm_gem_handle_create() fails in vkms_gem_create(), then the > > > > vkms_gem_object is freed twice: once when the reference is dropped by > > > > drm_gem_object_put_unlocked(), and again by the extra calls to > > > > drm_gem_object_release() and kfree(). > > > > > > > > Fix it by skipping the second release and free. > > > > > > > > This bug was originally found in the vgem driver by syzkaller using > > > > fault injection, but I noticed it's also present in the vkms driver. > > > > > > > > Fixes: 559e50fd34d1 ("drm/vkms: Add dumb operations") > > > > Cc: Rodrigo Siqueira > > > > Cc: Haneen Mohammed > > > > Cc: Daniel Vetter > > > > Cc: Chris Wilson > > > > Cc: stable@vger.kernel.org > > > > Signed-off-by: Eric Biggers > > > > --- > > > > drivers/gpu/drm/vkms/vkms_gem.c | 5 +---- > > > > 1 file changed, 1 insertion(+), 4 deletions(-) > > > > > > > > diff --git a/drivers/gpu/drm/vkms/vkms_gem.c b/drivers/gpu/drm/vkms/vkms_gem.c > > > > index 138b0bb325cf9..69048e73377dc 100644 > > > > --- a/drivers/gpu/drm/vkms/vkms_gem.c > > > > +++ b/drivers/gpu/drm/vkms/vkms_gem.c > > > > @@ -111,11 +111,8 @@ struct drm_gem_object *vkms_gem_create(struct drm_device *dev, > > > > > > > > ret = drm_gem_handle_create(file, &obj->gem, handle); > > > > drm_gem_object_put_unlocked(&obj->gem); > > > > - if (ret) { > > > > - drm_gem_object_release(&obj->gem); > > > > - kfree(obj); > > > > + if (ret) > > > > return ERR_PTR(ret); > > > > - } > > > > > > > > return &obj->gem; > > > > } > > > > -- > > > > 2.21.0.rc2.261.ga7da99ff1b-goog > > > > > > > > > > Hi, > > > > > > Thanks for your patch! :) > > > > > > The patch looks good for me. I also tested it under the IGT tests on my > > > local VM and everything was fine. > > Hi, > > Patch applied to drm-misc-fixes. > > > Hi Rodrigo, > > > > What are IGT tests? How can I run them? > > Hi Dmitry, > > IGT is a test suite focused on DRM drivers. > > You can clone the project using the link below: > > https://gitlab.freedesktop.org/drm/igt-gpu-tools.git > > In the README, you will find the software dependencies. After you > install all the required package, just use: > > mkdir build && meson build && cd build && ninja Hi Rodrigo, Thanks for the info, but this did not work for me. I installed all recommended packages (including libdw-dev), but then got: igt-gpu-tools$ mkdir -p build && meson build && cd build && ninja The Meson build system Version: 0.46.1 Source dir: /src/igt-gpu-tools Build dir: /src/igt-gpu-tools/build Build type: native build Project name: igt-gpu-tools Native C compiler: ccache cc (gcc 7.3.0 "cc (Debian 7.3.0-5) 7.3.0") Build machine cpu family: x86_64 Build machine cpu: x86_64 Compiler for C supports arguments -Wbad-function-cast: YES Compiler for C supports arguments -Wdeclaration-after-statement: YES Compiler for C supports arguments -Wformat=2: YES Compiler for C supports arguments -Wimplicit-fallthrough=0: YES Compiler for C supports arguments -Wlogical-op: YES Compiler for C supports arguments -Wmissing-declarations: YES Compiler for C supports arguments -Wmissing-format-attribute: YES Compiler for C supports arguments -Wmissing-noreturn: YES Compiler for C supports arguments -Wmissing-prototypes: YES Compiler for C supports arguments -Wnested-externs: YES Compiler for C supports arguments -Wold-style-definition: YES Compiler for C supports arguments -Wpointer-arith: YES Compiler for C supports arguments -Wredundant-decls: YES Compiler for C supports arguments -Wshadow: YES Compiler for C supports arguments -Wstrict-prototypes: YES Compiler for C supports arguments -Wuninitialized: YES Compiler for C supports arguments -Wunused: YES Compiler for C supports arguments -Wno-clobbered -Wclobbered: YES Compiler for C supports arguments -Wno-maybe-uninitialized -Wmaybe-uninitialized: YES Compiler for C supports arguments -Wno-missing-field-initializers -Wmissing-field-initializers: YES Compiler for C supports arguments -Wno-pointer-arith -Wpointer-arith: YES Compiler for C supports arguments -Wno-sign-compare -Wsign-compare: YES Compiler for C supports arguments -Wno-type-limits -Wtype-limits: YES Compiler for C supports arguments -Wno-unused-parameter -Wunused-parameter: YES Compiler for C supports arguments -Wno-unused-result -Wunused-result: YES Compiler for C supports arguments -Werror=address: YES Compiler for C supports arguments -Werror=array-bounds: YES Compiler for C supports arguments -Werror=implicit: YES Compiler for C supports arguments -Werror=init-self: YES Compiler for C supports arguments -Werror=int-to-pointer-cast: YES Compiler for C supports arguments -Werror=main: YES Compiler for C supports arguments -Werror=missing-braces: YES Compiler for C supports arguments -Werror=nonnull: YES Compiler for C supports arguments -Werror=pointer-to-int-cast: YES Compiler for C supports arguments -Werror=return-type: YES Compiler for C supports arguments -Werror=sequence-point: YES Compiler for C supports arguments -Werror=trigraphs: YES Compiler for C supports arguments -Werror=write-strings: YES Found pkg-config: /usr/bin/pkg-config (0.29) Native dependency libdrm found: YES 2.4.91 Native dependency libdrm_intel found: YES 2.4.91 Native dependency libdrm_nouveau found: YES 2.4.91 Native dependency libdrm_amdgpu found: YES 2.4.91 Native dependency pciaccess found: YES 0.13.4 Native dependency libkmod found: YES 24 Native dependency libprocps found: YES 3.3.15 Native dependency libunwind found: YES 1.21 meson.build:151:0: ERROR: Could not generate cargs for libdw: A full log can be found at /src/igt-gpu-tools/build/meson-logs/meson-log.txt and meson-log.txt ends with: Compiler for C supports arguments -Werror=write-strings: YES Found pkg-config: /usr/bin/pkg-config (0.29) Determining dependency 'libdrm' with pkg-config executable '/usr/bin/pkg-config' Native dependency libdrm found: YES 2.4.91 Determining dependency 'libdrm_intel' with pkg-config executable '/usr/bin/pkg-config' Native dependency libdrm_intel found: YES 2.4.91 Determining dependency 'libdrm_nouveau' with pkg-config executable '/usr/bin/pkg-config' Native dependency libdrm_nouveau found: YES 2.4.91 Determining dependency 'libdrm_amdgpu' with pkg-config executable '/usr/bin/pkg-config' Native dependency libdrm_amdgpu found: YES 2.4.91 Determining dependency 'pciaccess' with pkg-config executable '/usr/bin/pkg-config' Native dependency pciaccess found: YES 0.13.4 Determining dependency 'libkmod' with pkg-config executable '/usr/bin/pkg-config' Native dependency libkmod found: YES 24 Determining dependency 'libprocps' with pkg-config executable '/usr/bin/pkg-config' Native dependency libprocps found: YES 3.3.15 Determining dependency 'libunwind' with pkg-config executable '/usr/bin/pkg-config' Native dependency libunwind found: YES 1.21 Determining dependency 'libdw' with pkg-config executable '/usr/bin/pkg-config' meson.build:151:0: ERROR: Could not generate cargs for libdw: