From mboxrd@z Thu Jan 1 00:00:00 1970 From: Rodrigo Siqueira Subject: Re: [PATCH] drm/vkms: fix use-after-free when drm_gem_handle_create() fails Date: Sun, 10 Mar 2019 12:36:18 -0300 Message-ID: <20190310153618.pvi2ysb3snajqmoe@smtp.gmail.com> 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: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="g5fo5fu5zxtmglip" Return-path: Content-Disposition: inline In-Reply-To: Sender: stable-owner@vger.kernel.org To: Dmitry Vyukov Cc: Eric Biggers , DRI , syzkaller-bugs , LKML , Haneen Mohammed , Daniel Vetter , Chris Wilson , stable List-Id: dri-devel@lists.freedesktop.org --g5fo5fu5zxtmglip Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On 03/05, Dmitry Vyukov wrote: > 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 droppe= d 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 usi= ng > > > > > fault injection, but I noticed it's also present in the vkms driv= er. > > > > > > > > > > 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/vk= ms/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(struc= t drm_device *dev, > > > > > > > > > > ret =3D 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 o= n 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 >=20 > Hi Rodrigo, >=20 > Thanks for the info, but this did not work for me. > I installed all recommended packages (including libdw-dev), but then got: Hi Dmitry, I would like to recommend you to join the dri-devel channel (Freenode). There you can quickly get help from me and others ;) My nick in the dri-devel is 'siqueira'. Best Regards =20 > 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=3D2: YES > Compiler for C supports arguments -Wimplicit-fallthrough=3D0: 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-paramete= r: YES > Compiler for C supports arguments -Wno-unused-result -Wunused-result: YES > Compiler for C supports arguments -Werror=3Daddress: YES > Compiler for C supports arguments -Werror=3Darray-bounds: YES > Compiler for C supports arguments -Werror=3Dimplicit: YES > Compiler for C supports arguments -Werror=3Dinit-self: YES > Compiler for C supports arguments -Werror=3Dint-to-pointer-cast: YES > Compiler for C supports arguments -Werror=3Dmain: YES > Compiler for C supports arguments -Werror=3Dmissing-braces: YES > Compiler for C supports arguments -Werror=3Dnonnull: YES > Compiler for C supports arguments -Werror=3Dpointer-to-int-cast: YES > Compiler for C supports arguments -Werror=3Dreturn-type: YES > Compiler for C supports arguments -Werror=3Dsequence-point: YES > Compiler for C supports arguments -Werror=3Dtrigraphs: YES > Compiler for C supports arguments -Werror=3Dwrite-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 >=20 > meson.build:151:0: ERROR: Could not generate cargs for libdw: >=20 > A full log can be found at /src/igt-gpu-tools/build/meson-logs/meson-log.= txt >=20 >=20 > and meson-log.txt ends with: >=20 > Compiler for C supports arguments -Werror=3Dwrite-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-c= onfig' >=20 > meson.build:151:0: ERROR: Could not generate cargs for libdw: --=20 Rodrigo Siqueira https://siqueira.tech Graduate Student Department of Computer Science University of S=E3o Paulo 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