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[73.214.169.22]) by smtp.gmail.com with ESMTPSA id o9-20020a6b5a09000000b006c0cb1e1ea8sm12192765iob.12.2023.01.19.09.44.08 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 19 Jan 2023 09:44:09 -0800 (PST) Date: Thu, 19 Jan 2023 12:44:07 -0500 From: Brian Masney To: Giuseppe Scrivano Cc: linux-kernel@vger.kernel.org, keescook@chromium.org, bristot@redhat.com, ebiederm@xmission.com, brauner@kernel.org, cyphar@cyphar.com, viro@zeniv.linux.org.uk, alexl@redhat.com, peterz@infradead.org Subject: Re: [PATCH v2 2/2] selftests: add tests for prctl(SET_HIDE_SELF_EXE) Message-ID: References: <20230119170718.3129938-1-gscrivan@redhat.com> <20230119170718.3129938-2-gscrivan@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230119170718.3129938-2-gscrivan@redhat.com> User-Agent: Mutt/2.2.7 (2022-08-07) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jan 19, 2023 at 06:07:18PM +0100, Giuseppe Scrivano wrote: > Signed-off-by: Giuseppe Scrivano > --- > tools/testing/selftests/prctl/Makefile | 2 +- > tools/testing/selftests/prctl/hide-self-exe.c | 101 ++++++++++++++++++ > 2 files changed, 102 insertions(+), 1 deletion(-) > create mode 100644 tools/testing/selftests/prctl/hide-self-exe.c > > diff --git a/tools/testing/selftests/prctl/Makefile b/tools/testing/selftests/prctl/Makefile > index c7923b205222..024e107b26ec 100644 > --- a/tools/testing/selftests/prctl/Makefile > +++ b/tools/testing/selftests/prctl/Makefile > @@ -5,7 +5,7 @@ ARCH ?= $(shell echo $(uname_M) | sed -e s/i.86/x86/ -e s/x86_64/x86/) > > ifeq ($(ARCH),x86) > TEST_PROGS := disable-tsc-ctxt-sw-stress-test disable-tsc-on-off-stress-test \ > - disable-tsc-test > + disable-tsc-test hide-self-exe > all: $(TEST_PROGS) > > include ../lib.mk > diff --git a/tools/testing/selftests/prctl/hide-self-exe.c b/tools/testing/selftests/prctl/hide-self-exe.c > new file mode 100644 > index 000000000000..f86cef8e061c > --- /dev/null > +++ b/tools/testing/selftests/prctl/hide-self-exe.c > @@ -0,0 +1,101 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * Tests for prctl(PR_GET_HIDE_SELF_EXE, ...) / prctl(PR_SET_HIDE_SELF_EXE, ...) > + * > + */ > + > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > + > +#include > +#include > + > +#ifndef PR_SET_HIDE_SELF_EXE > +# define PR_SET_HIDE_SELF_EXE 65 > +# define PR_GET_HIDE_SELF_EXE 66 > +#endif > + > +int main(void) > +{ > + int status; > + pid_t pid; > + int ret; > + > + ret = open("/proc/self/exe", O_RDONLY); > + if (ret < 0) { > + perror("open /proc/self/exe"); > + exit(EXIT_FAILURE); > + } > + close(ret); > + > + ret = prctl(PR_GET_HIDE_SELF_EXE, 0, 0, 0, 0); > + if (ret != 0) { > + perror("prctl(PR_GET_HIDE_SELF_EXE)"); > + exit(EXIT_FAILURE); > + } > + > + ret = prctl(PR_SET_HIDE_SELF_EXE, 1, 0, 0, 0); > + if (ret != 0) { > + perror("prctl(PR_SET_HIDE_SELF_EXE)"); > + exit(EXIT_FAILURE); > + } > + > + /* check it doesn't fail a second time. */ > + ret = prctl(PR_SET_HIDE_SELF_EXE, 1, 0, 0, 0); > + if (ret != 0) { > + perror("prctl(PR_SET_HIDE_SELF_EXE)"); > + exit(EXIT_FAILURE); > + } > + > + ret = prctl(PR_GET_HIDE_SELF_EXE, 0, 0, 0, 0); > + if (ret != 1) { > + perror("prctl(PR_GET_HIDE_SELF_EXE)"); > + exit(EXIT_FAILURE); > + } > + > + ret = open("/proc/self/exe", O_RDONLY); > + if (ret >= 0 || errno != ENOENT) { > + perror("open /proc/self/exe succeeded"); > + exit(EXIT_FAILURE); > + } > + > + pid = fork(); > + if (pid < 0) { > + perror("fork"); > + exit(EXIT_FAILURE); > + } > + if (pid == 0) { > + /* Verify that it is still unreachable after fork(). */ > + ret = open("/proc/self/exe", O_RDONLY); > + if (ret >= 0 || errno != ENOENT) > + exit(EXIT_FAILURE); > + close(ret); > + > + /* And that it cannot be unset. */ > + ret = prctl(PR_GET_HIDE_SELF_EXE, 0, 0, 0, 0); Should this be PR_SET_HIDE_SELF_EXE? Brian