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tests: Add ktrace capability violation test cases

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Introduce regression tests for ktrace(2) that target capability
violations.

These test cases ensure that ktrace(2) records these violations:
- CAPFAIL_NOTCAPABLE
- CAPFAIL_INCREASE
- CAPFAIL_SYSCALL
- CAPFAIL_SIGNAL
- CAPFAIL_PROTO
- CAPFAIL_SOCKADDR
- CAPFAIL_NAMEI
- CAPFAIL_CPUSET

A portion of these test cases create processes that do NOT enter
capability mode, but raise violations. This is intended behavior.
Users may run `ktrace -t p` on non-Capsicumized programs to detect
violations that would occur if the process were in capability mode.

Reviewed by:	markj
Approved by:	markj (mentor)
MFC after:	1 month
Differential Revision:	https://reviews.freebsd.org/D40682
This commit is contained in:
Jake Freeland 2024-04-06 13:31:30 -05:00
parent aa32d7cbc9
commit 2f39a98664
2 changed files with 490 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
tests/sys/kern/Makefile
View File

@ -21,6 +21,7 @@ ATF_TESTS_C+= kill_zombie
.if ${MK_OPENSSL} != "no" .if ${MK_OPENSSL} != "no"
ATF_TESTS_C+= ktls_test ATF_TESTS_C+= ktls_test
.endif .endif
ATF_TESTS_C+= ktrace_test
ATF_TESTS_C+= listener_wakeup ATF_TESTS_C+= listener_wakeup
ATF_TESTS_C+= module_test ATF_TESTS_C+= module_test
ATF_TESTS_C+= ptrace_test ATF_TESTS_C+= ptrace_test
@ -86,6 +87,7 @@ LIBADD.socket_msg_waitall+= pthread
LIBADD.sendfile_helper+= pthread LIBADD.sendfile_helper+= pthread
LIBADD.fdgrowtable_test+= util pthread kvm procstat LIBADD.fdgrowtable_test+= util pthread kvm procstat
LIBADD.sigwait+= rt LIBADD.sigwait+= rt
LIBADD.ktrace_test+= sysdecode
NETBSD_ATF_TESTS_C+= lockf_test NETBSD_ATF_TESTS_C+= lockf_test
NETBSD_ATF_TESTS_C+= mqueue_test NETBSD_ATF_TESTS_C+= mqueue_test

488
tests/sys/kern/ktrace_test.c Normal file
View File

@ -0,0 +1,488 @@
/*-
* Copyright (c) 2015 John Baldwin <jhb@FreeBSD.org>
* Copyright (c) 2023 The FreeBSD Foundation
*
* This software was developed by Jake Freeland <jfree@FreeBSD.org>
* under sponsorship from the FreeBSD Foundation.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/param.h>
#include <sys/capsicum.h>
#include <sys/cpuset.h>
#include <sys/ktrace.h>
#include <sys/socket.h>
#include <sys/sysent.h>
#include <sys/time.h>
#include <sys/uio.h>
#include <sys/user.h>
#include <sys/wait.h>
#include <machine/sysarch.h>
#include <netinet/in.h>
#include <atf-c.h>
#include <capsicum_helpers.h>
#include <errno.h>
#include <fcntl.h>
#include <netdb.h>
#include <signal.h>
#include <sysdecode.h>
/*
* A variant of ATF_REQUIRE that is suitable for use in child
* processes. This only works if the parent process is tripped up by
* the early exit and fails some requirement itself.
*/
#define CHILD_REQUIRE(exp) do { \
if (!(exp)) \
child_fail_require(__FILE__, __LINE__, \
#exp " not met\n"); \
} while (0)
#define CHILD_REQUIRE_EQ(actual, expected) do { \
__typeof__(expected) _e = expected; \
__typeof__(actual) _a = actual; \
if (_e != _a) \
child_fail_require(__FILE__, __LINE__, #actual \
" (%jd) == " #expected " (%jd) not met\n", \
(intmax_t)_a, (intmax_t)_e); \
} while (0)
static __dead2 void
child_fail_require(const char *file, int line, const char *fmt, ...)
{
va_list ap;
char buf[1024];
/* Use write() not fprintf() to avoid possible duplicate output. */
snprintf(buf, sizeof(buf), "%s:%d: ", file, line);
write(STDERR_FILENO, buf, strlen(buf));
va_start(ap, fmt);
vsnprintf(buf, sizeof(buf), fmt, ap);
write(STDERR_FILENO, buf, strlen(buf));
va_end(ap);
_exit(32);
}
/*
* Determine sysdecode ABI based on proc's ABI in sv_flags.
*/
static enum sysdecode_abi
syscallabi(u_int sv_flags)
{
switch (sv_flags & SV_ABI_MASK) {
case SV_ABI_FREEBSD:
return (SYSDECODE_ABI_FREEBSD);
case SV_ABI_LINUX:
#ifdef __LP64__
if ((sv_flags & SV_ILP32) != 0)
return (SYSDECODE_ABI_LINUX32);
#endif
return (SYSDECODE_ABI_LINUX);
}
return (SYSDECODE_ABI_UNKNOWN);
}
/*
* Start tracing capability violations and notify child that it can execute.
* Return @numv capability violations from child in @v.
*/
static void
cap_trace_child(int cpid, struct ktr_cap_fail *v, int numv)
{
struct ktr_header header;
int error, fd, i;
ATF_REQUIRE((fd = open("ktrace.out",
O_RDONLY | O_CREAT | O_TRUNC)) != -1);
ATF_REQUIRE(ktrace("ktrace.out", KTROP_SET,
KTRFAC_CAPFAIL, cpid) != -1);
/* Notify child that we've starting tracing. */
ATF_REQUIRE(kill(cpid, SIGUSR1) != -1);
/* Wait for child to raise violation and exit. */
ATF_REQUIRE(waitpid(cpid, &error, 0) != -1);
ATF_REQUIRE(WIFEXITED(error));
ATF_REQUIRE_EQ(WEXITSTATUS(error), 0);
/* Read ktrace header and ensure violation occurred. */
for (i = 0; i < numv; ++i) {
ATF_REQUIRE((error = read(fd, &header, sizeof(header))) != -1);
ATF_REQUIRE_EQ(error, sizeof(header));
ATF_REQUIRE_EQ(header.ktr_len, sizeof(*v));
ATF_REQUIRE_EQ(header.ktr_pid, cpid);
/* Read the capability violation. */
ATF_REQUIRE((error = read(fd, v + i,
sizeof(*v))) != -1);
ATF_REQUIRE_EQ(error, sizeof(*v));
}
ATF_REQUIRE(close(fd) != -1);
}
/*
* Test if ktrace will record an operation that is done with
* insufficient rights.
*/
ATF_TC_WITHOUT_HEAD(ktrace__cap_not_capable);
ATF_TC_BODY(ktrace__cap_not_capable, tc)
{
struct ktr_cap_fail violation;
cap_rights_t rights;
sigset_t set = { };
pid_t pid;
int error;
/* Block SIGUSR1 so child does not terminate. */
ATF_REQUIRE(sigaddset(&set, SIGUSR1) != -1);
ATF_REQUIRE(sigprocmask(SIG_BLOCK, &set, NULL) != -1);
ATF_REQUIRE((pid = fork()) != -1);
if (pid == 0) {
/* Limit fd rights to CAP_READ. */
cap_rights_init(&rights, CAP_READ);
CHILD_REQUIRE(caph_rights_limit(STDIN_FILENO, &rights) != -1);
CHILD_REQUIRE(caph_enter() != -1);
/* Wait until ktrace has started. */
CHILD_REQUIRE(sigwait(&set, &error) != -1);
CHILD_REQUIRE_EQ(error, SIGUSR1);
/* Write without CAP_WRITE. */
CHILD_REQUIRE(write(STDIN_FILENO, &pid, sizeof(pid)) == -1);
CHILD_REQUIRE_EQ(errno, ENOTCAPABLE);
exit(0);
}
cap_trace_child(pid, &violation, 1);
ATF_REQUIRE_EQ(violation.cap_type, CAPFAIL_NOTCAPABLE);
ATF_REQUIRE(cap_rights_is_set(&violation.cap_data.cap_needed,
CAP_WRITE));
}
/*
* Test if ktrace will record an attempt to increase rights.
*/
ATF_TC_WITHOUT_HEAD(ktrace__cap_increase_rights);
ATF_TC_BODY(ktrace__cap_increase_rights, tc)
{
struct ktr_cap_fail violation;
cap_rights_t rights;
sigset_t set = { };
pid_t pid;
int error;
/* Block SIGUSR1 so child does not terminate. */
ATF_REQUIRE(sigaddset(&set, SIGUSR1) != -1);
ATF_REQUIRE(sigprocmask(SIG_BLOCK, &set, NULL) != -1);
ATF_REQUIRE((pid = fork()) != -1);
if (pid == 0) {
/* Limit fd rights to CAP_READ. */
cap_rights_init(&rights, CAP_READ);
CHILD_REQUIRE(caph_rights_limit(STDIN_FILENO, &rights) != -1);
CHILD_REQUIRE(caph_enter() != -1);
/* Wait until ktrace has started. */
CHILD_REQUIRE(sigwait(&set, &error) != -1);
CHILD_REQUIRE_EQ(error, SIGUSR1);
/* Increase fd rights to include CAP_WRITE. */
cap_rights_set(&rights, CAP_WRITE);
CHILD_REQUIRE(caph_rights_limit(STDIN_FILENO, &rights) == -1);
CHILD_REQUIRE_EQ(errno, ENOTCAPABLE);
exit(0);
}
cap_trace_child(pid, &violation, 1);
ATF_REQUIRE_EQ(violation.cap_type, CAPFAIL_INCREASE);
ATF_REQUIRE(cap_rights_is_set(&violation.cap_data.cap_needed,
CAP_WRITE));
}
/*
* Test if disallowed syscalls are reported as capability violations.
*/
ATF_TC_WITHOUT_HEAD(ktrace__cap_syscall);
ATF_TC_BODY(ktrace__cap_syscall, tc)
{
struct kinfo_file kinf;
struct ktr_cap_fail violation[2];
sigset_t set = { };
pid_t pid;
int error;
/* Block SIGUSR1 so child does not terminate. */
ATF_REQUIRE(sigaddset(&set, SIGUSR1) != -1);
ATF_REQUIRE(sigprocmask(SIG_BLOCK, &set, NULL) != -1);
ATF_REQUIRE((pid = fork()) != -1);
if (pid == 0) {
/* Wait until ktrace has started. */
CHILD_REQUIRE(sigwait(&set, &error) != -1);
CHILD_REQUIRE_EQ(error, SIGUSR1);
/* chdir() is not permitted in capability mode. */
CHILD_REQUIRE(chdir(".") != -1);
kinf.kf_structsize = sizeof(struct kinfo_file);
/*
* fcntl() is permitted in capability mode,
* but the F_KINFO cmd is not.
*/
CHILD_REQUIRE(fcntl(STDIN_FILENO, F_KINFO, &kinf) != -1);
exit(0);
}
cap_trace_child(pid, violation, 2);
ATF_REQUIRE_EQ(violation[0].cap_type, CAPFAIL_SYSCALL);
error = syscallabi(violation[0].cap_svflags);
ATF_REQUIRE_STREQ(sysdecode_syscallname(error, violation[0].cap_code),
"chdir");
ATF_REQUIRE_EQ(violation[1].cap_type, CAPFAIL_SYSCALL);
error = syscallabi(violation[1].cap_svflags);
ATF_REQUIRE_STREQ(sysdecode_syscallname(error, violation[1].cap_code),
"fcntl");
ATF_REQUIRE_EQ(violation[1].cap_data.cap_int, F_KINFO);
}
/*
* Test if sending a signal to another process is reported as
* a signal violation.
*/
ATF_TC_WITHOUT_HEAD(ktrace__cap_signal);
ATF_TC_BODY(ktrace__cap_signal, tc)
{
struct ktr_cap_fail violation;
sigset_t set = { };
pid_t pid;
int error;
/* Block SIGUSR1 so child does not terminate. */
ATF_REQUIRE(sigaddset(&set, SIGUSR1) != -1);
ATF_REQUIRE(sigprocmask(SIG_BLOCK, &set, NULL) != -1);
ATF_REQUIRE((pid = fork()) != -1);
if (pid == 0) {
/* Wait until ktrace has started. */
CHILD_REQUIRE(sigwait(&set, &error) != -1);
CHILD_REQUIRE_EQ(error, SIGUSR1);
/*
* Signals may only be sent to ourself. Sending signals
* to other processes is not allowed in capability mode.
*/
CHILD_REQUIRE(kill(getppid(), SIGCONT) != -1);
exit(0);
}
cap_trace_child(pid, &violation, 1);
ATF_REQUIRE_EQ(violation.cap_type, CAPFAIL_SIGNAL);
error = syscallabi(violation.cap_svflags);
ATF_REQUIRE_STREQ(sysdecode_syscallname(error, violation.cap_code),
"kill");
ATF_REQUIRE_EQ(violation.cap_data.cap_int, SIGCONT);
}
/*
* Test if opening a socket with a restricted protocol is reported
* as a protocol violation.
*/
ATF_TC_WITHOUT_HEAD(ktrace__cap_proto);
ATF_TC_BODY(ktrace__cap_proto, tc)
{
struct ktr_cap_fail violation;
sigset_t set = { };
pid_t pid;
int error;
/* Block SIGUSR1 so child does not terminate. */
ATF_REQUIRE(sigaddset(&set, SIGUSR1) != -1);
ATF_REQUIRE(sigprocmask(SIG_BLOCK, &set, NULL) != -1);
ATF_REQUIRE((pid = fork()) != -1);
if (pid == 0) {
/* Wait until ktrace has started. */
CHILD_REQUIRE(sigwait(&set, &error) != -1);
CHILD_REQUIRE_EQ(error, SIGUSR1);
/*
* Certain protocols may not be used in capability mode.
* ICMP's raw-protocol interface is not allowed.
*/
CHILD_REQUIRE(close(socket(AF_INET, SOCK_RAW,
IPPROTO_ICMP)) != -1);
exit(0);
}
cap_trace_child(pid, &violation, 1);
ATF_REQUIRE_EQ(violation.cap_type, CAPFAIL_PROTO);
error = syscallabi(violation.cap_svflags);
ATF_REQUIRE_STREQ(sysdecode_syscallname(error, violation.cap_code),
"socket");
ATF_REQUIRE_EQ(violation.cap_data.cap_int, IPPROTO_ICMP);
}
/*
* Test if sending data to an address using a socket is
* reported as a sockaddr violation.
*/
ATF_TC_WITHOUT_HEAD(ktrace__cap_sockaddr);
ATF_TC_BODY(ktrace__cap_sockaddr, tc)
{
struct sockaddr_in addr = { }, *saddr;
struct ktr_cap_fail violation;
sigset_t set = { };
pid_t pid;
int error, sfd;
/* Block SIGUSR1 so child does not terminate. */
ATF_REQUIRE(sigaddset(&set, SIGUSR1) != -1);
ATF_REQUIRE(sigprocmask(SIG_BLOCK, &set, NULL) != -1);
CHILD_REQUIRE((sfd = socket(AF_INET, SOCK_DGRAM,
IPPROTO_UDP)) != -1);
addr.sin_family = AF_INET;
addr.sin_port = htons(5000);
addr.sin_addr.s_addr = INADDR_ANY;
CHILD_REQUIRE(bind(sfd, (const struct sockaddr *)&addr,
sizeof(addr)) != -1);
ATF_REQUIRE((pid = fork()) != -1);
if (pid == 0) {
/* Wait until ktrace has started. */
CHILD_REQUIRE(sigwait(&set, &error) != -1);
CHILD_REQUIRE_EQ(error, SIGUSR1);
/*
* Sending data to an address is not permitted.
* In this case, sending data to @addr causes a
* violation.
*/
CHILD_REQUIRE(sendto(sfd, NULL, 0, 0,
(const struct sockaddr *)&addr, sizeof(addr)) != -1);
exit(0);
}
cap_trace_child(pid, &violation, 1);
ATF_REQUIRE_EQ(violation.cap_type, CAPFAIL_SOCKADDR);
error = syscallabi(violation.cap_svflags);
ATF_REQUIRE_STREQ(sysdecode_syscallname(error, violation.cap_code),
"sendto");
saddr = (struct sockaddr_in *)&violation.cap_data.cap_sockaddr;
ATF_REQUIRE_EQ(saddr->sin_family, AF_INET);
ATF_REQUIRE_EQ(saddr->sin_port, htons(5000));
ATF_REQUIRE_EQ(saddr->sin_addr.s_addr, INADDR_ANY);
close(sfd);
}
/*
* Test if openat() with AT_FDCWD and absolute path are reported
* as namei violations.
*/
ATF_TC_WITHOUT_HEAD(ktrace__cap_namei);
ATF_TC_BODY(ktrace__cap_namei, tc)
{
struct ktr_cap_fail violation[2];
sigset_t set = { };
pid_t pid;
int error;
/* Block SIGUSR1 so child does not terminate. */
ATF_REQUIRE(sigaddset(&set, SIGUSR1) != -1);
ATF_REQUIRE(sigprocmask(SIG_BLOCK, &set, NULL) != -1);
ATF_REQUIRE((pid = fork()) != -1);
if (pid == 0) {
/* Wait until ktrace has started. */
CHILD_REQUIRE(sigwait(&set, &error) != -1);
CHILD_REQUIRE_EQ(error, SIGUSR1);
/*
* The AT_FDCWD file descriptor has not been opened
* and will be inaccessible in capability mode.
*/
CHILD_REQUIRE(close(openat(AT_FDCWD, "ktrace.out",
O_RDONLY | O_CREAT)) != -1);
/*
* Absolute paths are inaccessible in capability mode.
*/
CHILD_REQUIRE(close(openat(-1, "/", O_RDONLY)) != -1);
exit(0);
}
cap_trace_child(pid, violation, 2);
ATF_REQUIRE_EQ(violation[0].cap_type, CAPFAIL_NAMEI);
error = syscallabi(violation[0].cap_svflags);
ATF_REQUIRE_STREQ(sysdecode_syscallname(error, violation[0].cap_code),
"openat");
ATF_REQUIRE_STREQ(violation[0].cap_data.cap_path, "AT_FDCWD");
ATF_REQUIRE_EQ(violation[1].cap_type, CAPFAIL_NAMEI);
error = syscallabi(violation[1].cap_svflags);
ATF_REQUIRE_STREQ(sysdecode_syscallname(error, violation[1].cap_code),
"openat");
ATF_REQUIRE_STREQ(violation[1].cap_data.cap_path, "/");
}
/*
* Test if changing another process's cpu set is recorded as
* a cpuset violation.
*/
ATF_TC_WITHOUT_HEAD(ktrace__cap_cpuset);
ATF_TC_BODY(ktrace__cap_cpuset, tc)
{
struct ktr_cap_fail violation;
cpuset_t cpuset_mask = { };
sigset_t set = { };
pid_t pid;
int error;
/* Block SIGUSR1 so child does not terminate. */
ATF_REQUIRE(sigaddset(&set, SIGUSR1) != -1);
ATF_REQUIRE(sigprocmask(SIG_BLOCK, &set, NULL) != -1);
ATF_REQUIRE((pid = fork()) != -1);
if (pid == 0) {
/* Wait until ktrace has started. */
CHILD_REQUIRE(sigwait(&set, &error) != -1);
CHILD_REQUIRE_EQ(error, SIGUSR1);
/*
* Set cpu 0 affinity for parent process.
* Other process's cpu sets are restricted in capability
* mode, so this will raise a violation.
*/
CPU_SET(0, &cpuset_mask);
CHILD_REQUIRE(cpuset_setaffinity(CPU_LEVEL_WHICH, CPU_WHICH_PID,
getppid(), sizeof(cpuset_mask), &cpuset_mask) != -1);
exit(0);
}
cap_trace_child(pid, &violation, 1);
ATF_REQUIRE_EQ(violation.cap_type, CAPFAIL_CPUSET);
error = syscallabi(violation.cap_svflags);
ATF_REQUIRE_STREQ(sysdecode_syscallname(error, violation.cap_code),
"cpuset_setaffinity");
}
ATF_TP_ADD_TCS(tp)
{
ATF_TP_ADD_TC(tp, ktrace__cap_not_capable);
ATF_TP_ADD_TC(tp, ktrace__cap_increase_rights);
ATF_TP_ADD_TC(tp, ktrace__cap_syscall);
ATF_TP_ADD_TC(tp, ktrace__cap_signal);
ATF_TP_ADD_TC(tp, ktrace__cap_proto);
ATF_TP_ADD_TC(tp, ktrace__cap_sockaddr);
ATF_TP_ADD_TC(tp, ktrace__cap_namei);
ATF_TP_ADD_TC(tp, ktrace__cap_cpuset);
return (atf_no_error());
}