Message-ID: <ae83bc62a798180281b2bcf6a469e97586d2af7c.camel@huaweicloud.com>
Subject: Re: [PATCH ima-evm-utils v4] Add tests for MMAP_CHECK and
 MMAP_CHECK_REQPROT hooks
From:   Roberto Sassu <roberto.sassu@huaweicloud.com>
To:     Mimi Zohar <zohar@linux.ibm.com>, dmitry.kasatkin@gmail.com,
        jmorris@namei.org, serge@hallyn.com
Cc:     linux-integrity@vger.kernel.org,
        linux-security-module@vger.kernel.org,
        linux-kernel@vger.kernel.org, stefanb@linux.ibm.com,
        viro@zeniv.linux.org.uk, pvorel@suse.cz,
        Roberto Sassu <roberto.sassu@huawei.com>
Date:   Thu, 02 Feb 2023 17:23:28 +0100
In-Reply-To: <fbac5d34fee2c3d4bbf036c06252fd0671577558.camel@linux.ibm.com>
References: <20230202135131.2445816-1-roberto.sassu@huaweicloud.com>
         <fbac5d34fee2c3d4bbf036c06252fd0671577558.camel@linux.ibm.com>
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On Thu, 2023-02-02 at 11:15 -0500, Mimi Zohar wrote:
> On Thu, 2023-02-02 at 14:51 +0100, Roberto Sassu wrote:
> > From: Roberto Sassu <roberto.sassu@huawei.com>
> > 
> > Add tests to ensure that, after applying the kernel patch 'ima: Align
> > ima_file_mmap() parameters with mmap_file LSM hook', the MMAP_CHECK hook
> > checks the protections applied by the kernel and not those requested by the
> > application.
> > 
> > Also ensure that after applying 'ima: Introduce MMAP_CHECK_REQPROT hook',
> > the MMAP_CHECK_REQPROT hook checks the protections requested by the
> > application.
> > 
> > Test both with the test_mmap application that by default requests the
> > PROT_READ protection flag. Its syntax is:
> > 
> > test_mmap <file> <mode>
> > 
> > where mode can be:
> > - exec: adds the PROT_EXEC protection flag to mmap()
> > - read_implies_exec: calls the personality() system call with
> >                      READ_IMPLIES_EXEC as the first argument before mmap()
> > - mprotect: adds the PROT_EXEC protection flag to a memory area in addition
> >             to PROT_READ
> > - exec_on_writable: calls mmap() with PROT_EXEC on a file which has a
> >                     writable mapping
> > 
> > Check the different combinations of hooks/modes and ensure that a
> > measurement entry is found in the IMA measurement list only when it is
> > expected. No measurement entry should be found when only the PROT_READ
> > protection flag is requested or the matching policy rule has the
> > MMAP_CHECK_REQPROT hook and the personality() system call was called with
> > READ_IMPLIES_EXEC.
> > 
> > mprotect() with PROT_EXEC on an existing memory area protected with
> > PROT_READ should be denied (with an appraisal rule), regardless of the MMAP
> > hook specified in the policy. The same applies for mmap() with PROT_EXEC on
> > a file with a writable mapping.
> > 
> > Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
> > ---
> > Changelog
> > 
> > v3:
> > - Check if there are IMA policy rules without fowner= and fsuuid=, and
> >   if yes, skip the tests due to possible interference (suggested by Mimi)
> > - Fix style issues in tests/mmap_check.test
> > 
> > v2:
> > - Distinguish setup-related errors from test-related errors in test_mmap
> > - Rename key_path and key_path_der variables to g_key_path and
> >   g_key_path_der (suggested by Stefan)
> > - Write data to the test file in check_mmap()
> > - Ensure that there are no setup-related errors from test_mmap in
> >   tests/mmap_check.test
> > - Print the found entry in the IMA measurement list (suggested by Mimi)
> > - Check for errors when writing the test file in check_deny()
> > - Pass TST_KEY_PATH to the new environment
> > - Add description to each test (suggested by Mimi)
> > 
> > v1:
> > - Declare PATCHES and uses new expect_pass_if() and expect_fail_if()
> >   (suggested by Stefan)
> > - Replace $FAIL with $HARDFAIL when the error occurs in the setup phase of
> >   the test (to not make an expect_fail test successful for other reasons
> >   than the focus of the test)
> > - Declare local variables in one line (suggested by Stefan)
> > - Print the test being executed at the beginning, so that the message
> >   always appears also if an error occurs
> > - Print the result of the tests in a separate line and separate the output
> >   of each test
> > 
> >  tests/Makefile.am     |   4 +-
> >  tests/mmap_check.test | 357 ++++++++++++++++++++++++++++++++++++++++++
> >  tests/test_mmap.c     | 121 ++++++++++++++
> >  3 files changed, 481 insertions(+), 1 deletion(-)
> >  create mode 100755 tests/mmap_check.test
> >  create mode 100644 tests/test_mmap.c
> > 
> > diff --git a/tests/Makefile.am b/tests/Makefile.am
> > index a0463b7b5b5d..ca9c4ca18380 100644
> > --- a/tests/Makefile.am
> > +++ b/tests/Makefile.am
> > @@ -2,7 +2,9 @@ check_SCRIPTS =
> >  TESTS = $(check_SCRIPTS)
> >  
> >  check_SCRIPTS += ima_hash.test sign_verify.test boot_aggregate.test \
> > -		 fsverity.test portable_signatures.test
> > +		 fsverity.test portable_signatures.test mmap_check.test
> > +
> > +check_PROGRAMS := test_mmap
> >  
> >  .PHONY: check_logs
> >  check_logs:
> > diff --git a/tests/mmap_check.test b/tests/mmap_check.test
> > new file mode 100755
> > index 000000000000..228c417a7f46
> > --- /dev/null
> > +++ b/tests/mmap_check.test
> > @@ -0,0 +1,357 @@
> > +#!/bin/bash
> > +# SPDX-License-Identifier: GPL-2.0
> > +#
> > +# Copyright (C) 2022-2023 Roberto Sassu <roberto.sassu@huawei.com>
> > +#
> > +# Check the behavior of MMAP_CHECK and MMAP_CHECK_REQPROT
> > +
> > +trap '_report_exit_and_cleanup _cleanup_env cleanup' SIGINT SIGTERM SIGSEGV EXIT
> > +
> > +PATCHES=(
> > +'ima: Align ima_file_mmap() parameters with mmap_file LSM hook'
> > +'ima: Introduce MMAP_CHECK_REQPROT hook'
> > +)
> > +
> > +# Base VERBOSE on the environment variable, if set.
> > +VERBOSE="${VERBOSE:-0}"
> > +
> > +# Errors defined in test_mmap
> > +ERR_SETUP=1
> > +ERR_TEST=2
> > +
> > +cd "$(dirname "$0")" || exit "$FAIL"
> > +export PATH=$PWD/../src:$PWD:$PATH
> > +export LD_LIBRARY_PATH=$LD_LIBRARY_PATH
> > +. ./functions.sh
> > +_require evmctl
> > +
> > +cleanup() {
> > +	if [ "$g_loop_mounted" = "1" ]; then
> > +		popd > /dev/null || exit "$FAIL"
> > +		umount "$g_mountpoint"
> > +	fi
> > +
> > +	if [ -n "$g_dev" ]; then
> > +		losetup -d "$g_dev"
> > +	fi
> > +
> > +	if [ -n "$g_image" ]; then
> > +		rm -f "$g_image"
> > +	fi
> > +
> > +	if [ -n "$g_mountpoint" ]; then
> > +		rm -Rf "$g_mountpoint"
> > +	fi
> > +
> > +	if [ -n "$g_key_path_der" ]; then
> > +		rm -f "$g_key_path_der"
> > +	fi
> > +}
> > +
> > +# Use the fsuuid= IMA policy keyword to select only files created/used by the
> > +# tests below. Also use fowner= to differentiate between files created/used by
> > +# individual tests.
> > +IMA_UUID="28b23254-9467-44c0-b6ba-34b12e85a26e"
> > +MMAP_CHECK_FOWNER=2000
> > +MMAP_CHECK_REQPROT_FOWNER=2001
> > +MEASURE_MMAP_CHECK_RULE="measure func=MMAP_CHECK fsuuid=$IMA_UUID fowner=$MMAP_CHECK_FOWNER"
> > +MEASURE_MMAP_CHECK_REQPROT_RULE="measure func=MMAP_CHECK_REQPROT fsuuid=$IMA_UUID fowner=$MMAP_CHECK_REQPROT_FOWNER"
> > +APPRAISE_MMAP_CHECK_RULE="appraise func=MMAP_CHECK fsuuid=$IMA_UUID fowner=$MMAP_CHECK_FOWNER"
> > +APPRAISE_MMAP_CHECK_REQPROT_RULE="appraise func=MMAP_CHECK_REQPROT fsuuid=$IMA_UUID fowner=$MMAP_CHECK_REQPROT_FOWNER"
> > +
> > +check_load_ima_rule() {
> > +	local rule_loaded result new_policy
> > +
> > +	rule_loaded=$(grep "$1" /sys/kernel/security/ima/policy)
> > +	if [ -z "$rule_loaded" ]; then
> > +		new_policy=$(mktemp -p "$g_mountpoint")
> > +		echo "$1" > "$new_policy"
> > +		echo "$new_policy" > /sys/kernel/security/ima/policy
> > +		result=$?
> > +		rm -f "$new_policy"
> > +
> > +		if [ "$result" -ne 0 ]; then
> > +			echo "${RED}Failed to set IMA policy${NORM}"
> > +			return "$HARDFAIL"
> > +		fi
> > +	fi
> > +
> > +	return "$OK"
> > +}
> > +
> > +check_mmap() {
> > +	local hook="$1"
> > +	local arg="$2"
> > +	local test_file fowner rule result test_file_entry
> > +
> > +	echo -e "\nTest: ${FUNCNAME[0]} (hook=\"$hook\", test_mmap arg: \"$arg\")"
> > +
> > +	if ! test_file=$(mktemp -p "$PWD"); then
> > +		echo "${RED}Cannot create $test_file${NORM}"
> > +		return "$HARDFAIL"
> > +	fi
> > +
> > +	if ! echo "test" > "$test_file"; then
> > +		echo "${RED}Cannot write $test_file${NORM}"
> > +		return "$FAIL"
> > +	fi
> > +
> > +	fowner="$MMAP_CHECK_FOWNER"
> > +	rule="$MEASURE_MMAP_CHECK_RULE"
> > +
> > +	if [ "$hook" = "MMAP_CHECK_REQPROT" ]; then
> > +		fowner="$MMAP_CHECK_REQPROT_FOWNER"
> > +		rule="$MEASURE_MMAP_CHECK_REQPROT_RULE"
> > +	fi
> > +
> > +	if ! chown "$fowner" "$test_file"; then
> > +		echo "${RED}Cannot change owner of $test_file${NORM}"
> > +		return "$HARDFAIL"
> > +	fi
> > +
> > +	check_load_ima_rule "$rule"
> > +	result=$?
> > +	if [ $result -ne "$OK" ]; then
> > +		return $result
> > +	fi
> > +
> > +	test_mmap "$test_file" "$arg"
> > +	result=$?
> > +
> > +	if [ $result -ne 0 ] && [ $result -ne "$ERR_TEST" ]; then
> > +		echo "${RED}Unexpected exit status $result from test_mmap${NORM}"
> > +		return "$HARDFAIL"
> > +	fi
> > +
> > +	if [ "$TFAIL" != "yes" ]; then
> > +		echo -n "Result (expect found): "
> > +	else
> > +		echo -n "Result (expect not found): "
> > +	fi
> > +
> > +	test_file_entry=$(awk '$5 == "'"$test_file"'"' < /sys/kernel/security/ima/ascii_runtime_measurements)
> > +	if [ -z "$test_file_entry" ]; then
> > +		echo "not found"
> > +		return "$FAIL"
> > +	fi
> > +
> > +	echo "found"
> > +
> > +	if [ "$VERBOSE" -gt 0 ]; then
> > +		echo "$test_file_entry"
> > +	fi
> > +
> > +	return "$OK"
> > +}
> > +
> > +check_deny() {
> > +	local hook="$1"
> > +	local arg="$2"
> > +	local test_file fowner rule result
> > +
> > +	echo -e "\nTest: ${FUNCNAME[0]} (hook=\"$hook\", test_mmap arg: \"$arg\")"
> > +
> > +	if ! test_file=$(mktemp -p "$PWD"); then
> > +		echo "${RED}Cannot create $test_file${NORM}"
> > +		return "$HARDFAIL"
> > +	fi
> > +
> > +	if ! echo "test" > "$test_file"; then
> > +		echo "${RED}Cannot write $test_file${NORM}"
> > +		return "$FAIL"
> > +	fi
> > +
> > +	if ! evmctl ima_sign -a sha256 --key "$g_key_path" "$test_file" &> /dev/null; then
> > +		echo "${RED}Cannot sign $test_file${NORM}"
> > +		return "$HARDFAIL"
> > +	fi
> > +
> > +	fowner="$MMAP_CHECK_FOWNER"
> > +	rule="$APPRAISE_MMAP_CHECK_RULE"
> > +
> > +	if [ "$hook" = "MMAP_CHECK_REQPROT" ]; then
> > +		fowner="$MMAP_CHECK_REQPROT_FOWNER"
> > +		rule="$APPRAISE_MMAP_CHECK_REQPROT_RULE"
> > +	fi
> > +
> > +	if ! chown "$fowner" "$test_file"; then
> > +		echo "${RED}Cannot change owner of $test_file${NORM}"
> > +		return "$HARDFAIL"
> > +	fi
> > +
> > +	check_load_ima_rule "$rule"
> > +	result=$?
> > +	if [ $result -ne "$OK" ]; then
> > +		return $result
> > +	fi
> > +
> > +	test_mmap "$test_file" exec
> > +	result=$?
> > +
> > +	if [ $result -ne 0 ] && [ $result -ne "$ERR_TEST" ]; then
> > +		echo "${RED}Unexpected exit status $result from test_mmap${NORM}"
> > +		return "$HARDFAIL"
> > +	fi
> > +
> > +	test_mmap "$test_file" "$arg"
> > +	result=$?
> > +
> > +	if [ $result -ne 0 ] && [ $result -ne "$ERR_TEST" ]; then
> > +		echo "${RED}Unexpected exit status $result from test_mmap${NORM}"
> > +		return "$HARDFAIL"
> > +	fi
> > +
> > +	if [ "$TFAIL" != "yes" ]; then
> > +		echo -n "Result (expect denied): "
> > +	else
> > +		echo -n "Result (expect allowed): "
> > +	fi
> > +
> > +	if [ $result -eq 0 ]; then
> > +		echo "allowed"
> > +		return "$FAIL"
> > +	fi
> > +
> > +	echo "denied"
> > +	return "$OK"
> > +}
> > +
> > +# Run in the new environment if TST_ENV is set.
> > +_run_env "$TST_KERNEL" "$PWD/$(basename "$0")" "TST_ENV=$TST_ENV TST_KERNEL=$TST_KERNEL PATH=$PATH LD_LIBRARY_PATH=$LD_LIBRARY_PATH VERBOSE=$VERBOSE TST_KEY_PATH=$TST_KEY_PATH"
> > +
> > +# Exit from the creator of the new environment.
> > +_exit_env "$TST_KERNEL"
> > +
> > +# Mount filesystems in the new environment.
> > +_init_env
> > +
> > +if [ "$(whoami)" != "root" ]; then
> > +	echo "${CYAN}This script must be executed as root${NORM}"
> > +	exit "$SKIP"
> > +fi
> > +
> > +if [ ! -f /sys/kernel/security/ima/policy ]; then
> > +	echo "${CYAN}IMA policy file not found${NORM}"
> > +	exit "$SKIP"
> > +fi
> > +
> > +if ! cat /sys/kernel/security/ima/policy &> /dev/null; then
> > +	echo "${CYAN}IMA policy file is not readable${NORM}"
> > +	exit "$SKIP"
> > +fi
> > +
> > +if ! awk '$0 ~ /^(measure|appraise)/ && $0 !~ /fsuuid=/ && $0 !~ /fowner=/ { exit 1 }' < /sys/kernel/security/ima/policy; then
> > +	echo "${CYAN}IMA policy rules without fsuuid= and fowner=, cannot continue due to possible interference with the tests${NORM}"
> > +	exit "$SKIP
> 
> Since you're only adding mmap tests, I'd prefer the above test was
> limited to "func=MMAP_CHECK".
> 
> 
> > +fi
> > +
> > +if [ -n "$TST_KEY_PATH" ]; then
> > +	if [ "${TST_KEY_PATH:0:1}" != "/" ]; then
> > +		echo "${RED}Absolute path required for the signing key${NORM}"
> > +		exit "$FAIL"
> > +	fi
> > +
> > +	if [ ! -f "$TST_KEY_PATH" ]; then
> > +		echo "${RED}Kernel signing key not found in $TST_KEY_PATH${NORM}"
> > +		exit "$FAIL"
> > +	fi
> > +
> > +	g_key_path="$TST_KEY_PATH"
> > +elif [ -f "$PWD/../signing_key.pem" ]; then
> > +	g_key_path="$PWD/../signing_key.pem"
> > +elif [ -f "/lib/modules/$(uname -r)/source/certs/signing_key.pem" ]; then
> > +	g_key_path="/lib/modules/$(uname -r)/source/certs/signing_key.pem"
> > +elif [ -f "/lib/modules/$(uname -r)/build/certs/signing_key.pem" ]; then
> > +	g_key_path="/lib/modules/$(uname -r)/build/certs/signing_key.pem"
> > +else
> > +	echo "${CYAN}Kernel signing key not found${NORM}"
> > +	exit "$SKIP"
> > +fi
> > +
> > +g_key_path_der=$(mktemp)
> > +
> > +openssl x509 -in "$g_key_path" -out "$g_key_path_der" -outform der
> > +if ! keyctl padd asymmetric pubkey %keyring:.ima < "$g_key_path_der" &> /dev/null; then
> > +	echo "${RED}Public key cannot be added to the IMA keyring${NORM}"
> > +	exit "$FAIL"
> > +fi
> > +
> > +g_mountpoint=$(mktemp -d)
> > +g_image=$(mktemp)
> > +
> > +if [ -z "$g_mountpoint" ]; then
> > +	echo "${RED}Mountpoint directory not created${NORM}"
> > +	exit "$FAIL"
> > +fi
> > +
> > +if ! dd if=/dev/zero of="$g_image" bs=1M count=20 &> /dev/null; then
> > +	echo "${RED}Cannot create test image${NORM}"
> > +	exit "$FAIL"
> > +fi
> > +
> > +g_dev=$(losetup -f "$g_image" --show)
> > +if [ -z "$g_dev" ]; then
> > +	echo "${RED}Cannot create loop device${NORM}"
> > +	exit "$FAIL"
> > +fi
> > +
> > +if ! mkfs.ext4 -U "$IMA_UUID" -b 4096 "$g_dev" &> /dev/null; then
> > +	echo "${RED}Cannot format $g_dev${NORM}"
> > +	exit "$FAIL"
> > +fi
> > +
> > +if ! mount -o i_version "$g_dev" "$g_mountpoint"; then
> > +	echo "${RED}Cannot mount loop device${NORM}"
> > +	exit "$FAIL"
> > +fi
> > +
> > +g_loop_mounted=1
> > +pushd "$g_mountpoint" > /dev/null || exit "$FAIL"
> > +
> > +# Ensure that IMA does not add a new measurement entry if an application calls
> > +# mmap() with PROT_READ, and a policy rule contains the MMAP_CHECK hook.
> > +# In this case, both the protections requested by the application and the final
> > +# protections applied by the kernel contain only PROT_READ, so there is no
> > +# match with the IMA rule, which expects PROT_EXEC to be set.
> > +expect_fail check_mmap "MMAP_CHECK" ""
> > +
> > +# Ensure that IMA adds a new measurement entry if an application calls mmap()
> > +# with PROT_READ | PROT_EXEC, and a policy rule contains the MMAP_CHECK hook.
> > +expect_pass check_mmap "MMAP_CHECK" "exec"
> > +
> > +# Same as in the first test, but in this case the application calls the
> > +# personality() system call with READ_IMPLIES_EXEC, which causes the kernel to
> > +# add PROT_EXEC in the final protections passed to the MMAP_CHECK hook.
> > +#
> > +# Ensure that the bug introduced by 98de59bfe4b2 ("take calculation of final
> > +# protections in security_mmap_file() into a helper") is fixed, by passing the
> > +# final protections again to the MMAP_CHECK hook. Due to the bug, the hook
> > +# received the protections requested by the application. Since those protections
> > +# don't have PROT_EXEC, IMA was not creating a measurement entry.
> > +expect_pass_if '0' check_mmap "MMAP_CHECK" "read_implies_exec"
> > +
> > +# Repeat the previous three tests, but with the new MMAP_CHECK_REQPROT hook,
> > +# which behaves like the buggy MMAP_CHECK hook. In the third test, expect that
> > +# no new measurement entry is created, since the MMAP_CHECK_REQPROT hook sees
> > +# the protections requested by the application (PROT_READ).
> > +expect_fail_if '1' check_mmap "MMAP_CHECK_REQPROT" ""
> > +expect_pass_if '1' check_mmap "MMAP_CHECK_REQPROT" "exec"
> > +expect_fail_if '1' check_mmap "MMAP_CHECK_REQPROT" "read_implies_exec"
> > +
> > +# Ensure that IMA refuses an mprotect() with PROT_EXEC on a memory area
> > +# obtained with an mmap() with PROT_READ. This is due to the inability of IMA
> > +# to measure/appraise the file for which mmap() was called (locking issue).
> > +expect_pass check_deny "MMAP_CHECK" "mprotect"
> > +
> > +# Ensure that MMAP_CHECK_REQPROT has the same behavior of MMAP_CHECK for the
> > +# previous test.
> > +expect_pass_if '1' check_deny "MMAP_CHECK_REQPROT" "mprotect"
> > +
> > +# Ensure that there cannot be an mmap() with PROT_EXEC on a file with writable
> > +# mappings, due to the inability of IMA to make a reliable measurement of that
> > +# file.
> > +expect_pass check_deny "MMAP_CHECK" "exec_on_writable"
> > +
> > +# Ensure that MMAP_CHECK_REQPROT has the same behavior of MMAP_CHECK for the
> > +# previous test.
> > +expect_pass_if '1' check_deny "MMAP_CHECK_REQPROT" "exec_on_writable"
> > diff --git a/tests/test_mmap.c b/tests/test_mmap.c
> > new file mode 100644
> > index 000000000000..7106ba70fc53
> > --- /dev/null
> > +++ b/tests/test_mmap.c
> > @@ -0,0 +1,121 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * Copyright (C) 2023 Huawei Technologies Duesseldorf GmbH
> > + *
> > + * Tool to test IMA MMAP_CHECK and MMAP_CHECK_REQPROT hooks.
> > + */
> > +#include <stdio.h>
> > +#include <errno.h>
> > +#include <fcntl.h>
> > +#include <string.h>
> > +#include <unistd.h>
> > +#include <sys/stat.h>
> > +#include <sys/mman.h>
> > +#include <sys/personality.h>
> > +
> > +/*
> > + * Convention: return 1 for errors that should not occur, as they are
> > + * setup-related, return 2 for errors that might occur due to testing
> > + * conditions.
> > + */
> > +#define ERR_SETUP 1
> > +#define ERR_TEST 2
> > +
> > +int main(int argc, char *argv[])
> > +{
> > +	struct stat st;
> > +	void *ptr, *ptr_write = NULL;
> > +	int ret, fd, fd_write, prot = PROT_READ;
> > +
> > +	if (!argv[1]) {
> > +		printf("Missing file parameter\n");
> > +		return ERR_SETUP;
> > +	}
> > +
> > +	if (argv[2] && !strcmp(argv[2], "read_implies_exec")) {
> > +		ret = personality(READ_IMPLIES_EXEC);
> > +		if (ret == -1) {
> > +			printf("Failed to set personality, err: %d (%s)\n",
> > +			       -errno, strerror(errno));
> > +			return ERR_SETUP;
> > +		}
> > +	}
> > +
> > +	if (stat(argv[1], &st) == -1) {
> > +		printf("Failed to access %s, err: %d (%s)\n", argv[1], -errno,
> > +		       strerror(errno));
> > +		return ERR_SETUP;
> > +	}
> > +
> > +	if (argv[2] && !strcmp(argv[2], "exec_on_writable")) {
> > +		fd_write = open(argv[1], O_RDWR);
> > +		if (fd_write == -1) {
> > +			printf("Failed to open %s in r/w, err: %d (%s)\n",
> > +			       argv[1], -errno, strerror(errno));
> > +			return ERR_SETUP;
> > +		}
> > +
> > +		ptr_write = mmap(0, st.st_size, PROT_WRITE, MAP_SHARED,
> > +				 fd_write, 0);
> > +		close(fd_write);
> > +
> > +		if (ptr_write == MAP_FAILED) {
> > +			printf("Failed mmap() with PROT_WRITE on %s, err: %d (%s)\n",
> > +			       argv[1], -errno, strerror(errno));
> > +			return ERR_SETUP;
> > +		}
> > +	}
> > +
> > +	fd = open(argv[1], O_RDONLY);
> > +	if (fd == -1) {
> > +		printf("Failed to open %s in ro, err: %d (%s)\n", argv[1],
> > +		       -errno, strerror(errno));
> > +
> > +		if (ptr_write && munmap(ptr_write, st.st_size) == -1)
> > +			printf("Failed munmap() of writable mapping on %s, err: %d (%s)\n",
> > +			       argv[1], -errno, strerror(errno));
> > +
> > +		return ERR_SETUP;
> > +	}
> > +
> > +	if (argv[2] && !strncmp(argv[2], "exec", 4))
> > +		prot |= PROT_EXEC;
> > +
> > +	ptr = mmap(0, st.st_size, prot, MAP_PRIVATE, fd, 0);
> > +
> > +	close(fd);
> > +
> > +	if (ptr_write && munmap(ptr_write, st.st_size) == -1) {
> > +		printf("Failed munmap() of writable mapping on %s, err: %d (%s)\n",
> > +		       argv[1], -errno, strerror(errno));
> > +		return ERR_SETUP;
> > +	}
> > +
> > +	if (ptr == MAP_FAILED) {
> > +		ret = ERR_SETUP;
> > +		if (argv[2] && !strcmp(argv[2], "exec_on_writable") &&
> > +		    errno == EACCES)
> > +			ret = ERR_TEST;
> > +
> 
> FYI, on an older distro kernel, the mmap fails and results in following
> without any explanation.
> 
> Test: check_mmap (hook="MMAP_CHECK", test_mmap arg: "exec")
> Unexpected exit status 1 from test_mmap
> 
> With some additional debugging, I'm seeing:
> Failed mmap() /tmp/tmp.4gD2UjSvC4/tmp.PlzUEm09hO, err: -13 (Permission
> denied)b

Uhm, ok. Which kernel is failing?

Thanks

Roberto

> Mimi
> 
> > +		return ret;
> > +	}
> > +
> > +	ret = 0;
> > +
> > +	if (argv[2] && !strcmp(argv[2], "mprotect")) {
> > +		ret = mprotect(ptr, st.st_size, PROT_EXEC);
> > +		if (ret == -1) {
> > +			ret = ERR_SETUP;
> > +			if (errno == EPERM)
> > +				ret = ERR_TEST;
> > +		}
> > +	}
> > +
> > +	if (munmap(ptr, st.st_size) == -1) {
> > +		printf("Failed munmap() of mapping on %s, err: %d (%s)\n",
> > +		       argv[1], -errno, strerror(errno));
> > +		return ERR_SETUP;
> > +	}
> > +
> > +	return ret;
> > +}