Message ID | b8a0669e-36e4-a0e8-fd35-3dbd890d2170@linux.intel.com (mailing list archive) |
---|---|
State | Not Applicable |
Headers | show |
Series | [v1] perf tool: make Perf tool aware of SELinux access control | expand |
Hi, Is there any thougts, comments or questions so far? Please share you mind. Thanks, Alexey On 13.03.2020 20:27, Alexey Budankov wrote: > > Extend Perf tool with the check of /sys/fs/selinux/enforce value and notify > in case access to perf_event_open() syscall is restricted by the enforced > SELinux policy settings. > > Testing and evaluation (Fedora 31 x86_64 with enforced Targeted policy extended > by perf_event class (see refpolicy [1] master branch)): > > [root@host ~]# ps -Z > LABEL PID TTY TIME CMD > unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 3960 pts/1 00:00:00 bash > unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 4167 pts/1 00:00:00 ps > > [root@host ~]# ls -alhZ /usr/local/bin/ > total 56M > drwxr-xr-x. 2 root root system_u:object_r:bin_t:s0 4.0K Mar 4 12:27 . > drwxr-xr-x. 12 root root system_u:object_r:usr_t:s0 4.0K Jul 25 2019 .. > -rwxr-xr-x. 1 root root system_u:object_r:bin_t:s0 4.1M Jan 23 2017 bash > -rwxr-xr-x. 1 root root system_u:object_r:bin_t:s0 4.1M Jan 23 2017 bash.before_shellshock_patch > ... > -rwxr-xr-x. 1 root root system_u:object_r:bin_t:s0 372 May 14 2019 flask > -rwxr-xr-x. 1 root root unconfined_u:object_r:bin_t:s0 24M Mar 4 12:15 perf <== unprivileged users (perf_event_paranoid) > -rwxr-x---. 1 root perf_users unconfined_u:object_r:bin_t:s0 24M Mar 4 12:19 perf.cap <== perf_users (CAP_SYS_ADMIN) > -rwxr-xr-x. 1 root root system_u:object_r:bin_t:s0 44K Dec 8 2016 spiff > ... > lrwxrwxrwx. 1 root root system_u:object_r:bin_t:s0 4 Aug 21 2018 zstdmt -> zstd > > [root@host ~]# getenforce > Enforcing > > === Access by unprivileged user === > > [user@host ~]$ ps -Z > LABEL PID TTY TIME CMD > unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 4043 pts/2 00:00:00 bash > unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 4168 pts/2 00:00:00 ps > > [user@host ~]$ /usr/local/bin/perf stat -- ls > Error: > Access to performance monitoring and observability operations is limited. > SELinux Enforcing mode is enabled and can limit access to performance > monitoring and observability operations. Inspect system audit records > for more perf_event access control information and adjusting the policy. > Consider adjusting /proc/sys/kernel/perf_event_paranoid setting to open > access to performance monitoring and observability operations for users > without CAP_SYS_ADMIN capability. perf_event_paranoid setting is -1: > -1: Allow use of (almost) all events by all users > Ignore mlock limit after perf_event_mlock_kb without CAP_IPC_LOCK >> = 0: Disallow raw and ftrace function tracepoint access >> = 1: Disallow CPU event access >> = 2: Disallow kernel profiling > To make the adjusted perf_event_paranoid setting permanent preserve it > in /etc/sysctl.conf (e.g. kernel.perf_event_paranoid = <setting>) > > [root@host ~]# journalctl --follow > ... audit[4186]: AVC avc: denied { open } for pid=4186 comm="perf" scontext=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 tcontext=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 tclass=perf_event permissive=0 > ... audit[4186]: AVC avc: denied { open } for pid=4186 comm="perf" scontext=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 tcontext=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 tclass=perf_event permissive=0 > ... setroubleshoot[4194]: SELinux is preventing perf from open access on the perf_event labeled unconfined_t. For complete SELinux messages run: sealert -l 9a6f3db2-3d8f-461e-afad-0b5c3a9c3b9d > ... python3[4194]: SELinux is preventing perf from open access on the perf_event labeled unconfined_t. > > ***** Plugin catchall (100. confidence) suggests ************************** > > If you believe that perf should be allowed open access on perf_event labeled unconfined_t by default. > Then you should report this as a bug. > You can generate a local policy module to allow this access. > Do > allow this access for now by executing: > # ausearch -c 'perf' --raw | audit2allow -M my-perf > # semodule -X 300 -i my-perf.pp > > === Access by perf privileged user === > > [user@host ~]$ ps -Z > LABEL PID TTY TIME CMD > unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 4043 pts/2 00:00:00 bash > unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 4168 pts/2 00:00:00 ps > > [user@host ~]$ libcap/progs/getcap /usr/local/bin/perf.cap > /usr/local/bin/perf.cap = cap_sys_ptrace,cap_syslog,cap_sys_admin+ep > > [user@host ~]$ /usr/local/bin/perf.cap stat -- ls > Error: > Access to performance monitoring and observability operations is limited. > SELinux Enforcing mode is enabled and can limit access to performance > monitoring and observability operations. Inspect system audit records > for more perf_event access control information and adjusting the policy. > Consider adjusting /proc/sys/kernel/perf_event_paranoid setting to open > access to performance monitoring and observability operations for users > without CAP_SYS_ADMIN capability. perf_event_paranoid setting is -1: > -1: Allow use of (almost) all events by all users > Ignore mlock limit after perf_event_mlock_kb without CAP_IPC_LOCK >> = 0: Disallow raw and ftrace function tracepoint access >> = 1: Disallow CPU event access >> = 2: Disallow kernel profiling > To make the adjusted perf_event_paranoid setting permanent preserve it > in /etc/sysctl.conf (e.g. kernel.perf_event_paranoid = <setting>) > > [root@host ~]# journalctl --follow > > ... audit[3926]: AVC avc: denied { open } for pid=3926 comm="perf.cap" scontext=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 tcontext=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 tclass=perf_event permissive=0 > ... audit[3926]: AVC avc: denied { open } for pid=3926 comm="perf.cap" scontext=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 tcontext=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 tclass=perf_event permissive=0 > > ... setroubleshoot[3934]: SELinux is preventing perf from open access on the perf_event labeled unconfined_t. For complete SELinux messages run: sealert -l 9a6f3db2-3d8f-461e-afad-0b5c3a9c3b9d > ... python3[3934]: SELinux is preventing perf from open access on the perf_event labeled unconfined_t. > > ***** Plugin catchall (100. confidence) suggests ************************** > > If you believe that perf should be allowed open access on perf_event labeled unconfined_t by default. > Then you should report this as a bug. > You can generate a local policy module to allow this access. > Do > allow this access for now by executing: > # ausearch -c 'perf' --raw | audit2allow -M my-perf > # semodule -X 300 -i my-perf.pp > > === Open access to performance monitoring and observability operations in unconfined_t domain === > > [root@host ~]# ausearch -c 'perf' --raw | audit2allow -M my-perf && cat my-perf.te > > module my-perf 1.0; > > require { > type unconfined_t; > class perf_event { cpu kernel open read tracepoint write }; > } > > #============= unconfined_t ============== > allow unconfined_t self:perf_event { cpu kernel open read tracepoint write }; > > [root@host ~]# semodule -X 300 -i my-perf.pp > > [user@host ~]$ ps -Z > LABEL PID TTY TIME CMD > unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 4043 pts/2 00:00:00 bash > unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 4168 pts/2 00:00:00 ps > > [user@host ~]$ /usr/local/bin/perf stat -- ls > Desktop Documents Downloads intel Music perf.data perf.data.old Pictures Public Templates Videos > > Performance counter stats for 'ls': > > 0.72 msec task-clock:u # 0.655 CPUs utilized > 0 context-switches:u # 0.000 K/sec > 0 cpu-migrations:u # 0.000 K/sec > 98 page-faults:u # 0.137 M/sec > 908,356 cycles:u # 1.266 GHz > 729,984 instructions:u # 0.80 insn per cycle > 142,774 branches:u # 198.968 M/sec > 8,238 branch-misses:u # 5.77% of all branches > > 0.001095239 seconds time elapsed > > 0.001147000 seconds user > 0.000000000 seconds sys > > [user@host ~]$ /usr/local/bin/perf stat -a > Error: > Access to performance monitoring and observability operations is limited. > SELinux Enforcing mode is enabled and can limit access to performance > monitoring and observability operations. Inspect system audit records > for more perf_event access control information and adjusting the policy. > Consider adjusting /proc/sys/kernel/perf_event_paranoid setting to open > access to performance monitoring and observability operations for users > without CAP_SYS_ADMIN capability. perf_event_paranoid setting is -1: > -1: Allow use of (almost) all events by all users > Ignore mlock limit after perf_event_mlock_kb without CAP_IPC_LOCK >> = 0: Disallow raw and ftrace function tracepoint access >> = 1: Disallow CPU event access >> = 2: Disallow kernel profiling > To make the adjusted perf_event_paranoid setting permanent preserve it > in /etc/sysctl.conf (e.g. kernel.perf_event_paranoid = <setting>) > > [user@host ~]$ /usr/local/bin/perf.cap stat -a > ^C > Performance counter stats for 'system wide': > > 13,427.05 msec cpu-clock # 7.997 CPUs utilized > 783 context-switches # 0.058 K/sec > 29 cpu-migrations # 0.002 K/sec > 6 page-faults # 0.000 K/sec > 161,084,874 cycles # 0.012 GHz > 146,823,131 instructions # 0.91 insn per cycle > 12,164,802 branches # 0.906 M/sec > 380,350 branch-misses # 3.13% of all branches > > 1.678938906 seconds time elapsed > > [1] https://github.com/SELinuxProject/refpolicy > > Signed-off-by: Alexey Budankov <alexey.budankov@linux.intel.com> > --- > tools/perf/util/cloexec.c | 4 ++-- > tools/perf/util/evsel.c | 40 +++++++++++++++++++++++---------------- > 2 files changed, 26 insertions(+), 18 deletions(-) > > diff --git a/tools/perf/util/cloexec.c b/tools/perf/util/cloexec.c > index a12872f2856a..9c8ec816261b 100644 > --- a/tools/perf/util/cloexec.c > +++ b/tools/perf/util/cloexec.c > @@ -65,7 +65,7 @@ static int perf_flag_probe(void) > return 1; > } > > - WARN_ONCE(err != EINVAL && err != EBUSY, > + WARN_ONCE(err != EINVAL && err != EBUSY && err != EACCES, > "perf_event_open(..., PERF_FLAG_FD_CLOEXEC) failed with unexpected error %d (%s)\n", > err, str_error_r(err, sbuf, sizeof(sbuf))); > > @@ -83,7 +83,7 @@ static int perf_flag_probe(void) > if (fd >= 0) > close(fd); > > - if (WARN_ONCE(fd < 0 && err != EBUSY, > + if (WARN_ONCE(fd < 0 && err != EBUSY && err != EACCES, > "perf_event_open(..., 0) failed unexpectedly with error %d (%s)\n", > err, str_error_r(err, sbuf, sizeof(sbuf)))) > return -1; > diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c > index 816d930d774e..f03ce1d362d3 100644 > --- a/tools/perf/util/evsel.c > +++ b/tools/perf/util/evsel.c > @@ -2493,32 +2493,40 @@ int perf_evsel__open_strerror(struct evsel *evsel, struct target *target, > int err, char *msg, size_t size) > { > char sbuf[STRERR_BUFSIZE]; > - int printed = 0; > + int printed = 0, enforced = 0; > > switch (err) { > case EPERM: > case EACCES: > + printed += scnprintf(msg + printed, size - printed, > + "Access to performance monitoring and observability operations is limited.\n"); > + > + if (!sysfs__read_int("fs/selinux/enforce", &enforced)) { > + if (enforced) { > + printed += scnprintf(msg + printed, size - printed, > + "SELinux Enforcing mode is enabled and can limit access to performance\n" > + "monitoring and observability operations. Inspect system audit records\n" > + "for more perf_event access control information and adjusting the policy.\n"); > + } > + } > + > if (err == EPERM) > - printed = scnprintf(msg, size, > - "No permission to enable %s event.\n\n", > + printed += scnprintf(msg, size, > + "No permission to enable %s event.\n", > perf_evsel__name(evsel)); > > return scnprintf(msg + printed, size - printed, > - "You may not have permission to collect %sstats.\n\n" > - "Consider tweaking /proc/sys/kernel/perf_event_paranoid,\n" > - "which controls use of the performance events system by\n" > - "unprivileged users (without CAP_SYS_ADMIN).\n\n" > - "The current value is %d:\n\n" > + "Consider adjusting /proc/sys/kernel/perf_event_paranoid setting to open\n" > + "access to performance monitoring and observability operations for users\n" > + "without CAP_SYS_ADMIN capability. perf_event_paranoid setting is %d:\n" > " -1: Allow use of (almost) all events by all users\n" > " Ignore mlock limit after perf_event_mlock_kb without CAP_IPC_LOCK\n" > - ">= 0: Disallow ftrace function tracepoint by users without CAP_SYS_ADMIN\n" > - " Disallow raw tracepoint access by users without CAP_SYS_ADMIN\n" > - ">= 1: Disallow CPU event access by users without CAP_SYS_ADMIN\n" > - ">= 2: Disallow kernel profiling by users without CAP_SYS_ADMIN\n\n" > - "To make this setting permanent, edit /etc/sysctl.conf too, e.g.:\n\n" > - " kernel.perf_event_paranoid = -1\n" , > - target->system_wide ? "system-wide " : "", > - perf_event_paranoid()); > + ">= 0: Disallow raw and ftrace function tracepoint access\n" > + ">= 1: Disallow CPU event access\n" > + ">= 2: Disallow kernel profiling\n" > + "To make the adjusted perf_event_paranoid setting permanent preserve it\n" > + "in /etc/sysctl.conf (e.g. kernel.perf_event_paranoid = <setting>)", > + perf_event_paranoid()); > case ENOENT: > return scnprintf(msg, size, "The %s event is not supported.", > perf_evsel__name(evsel)); >
Em Thu, Mar 19, 2020 at 09:23:30AM +0300, Alexey Budankov escreveu: > Hi, > > Is there any thougts, comments or questions so far? > Please share you mind. From a quick look, seems ok, I'll do some testing now, - Arnaldo > Thanks, > Alexey > > On 13.03.2020 20:27, Alexey Budankov wrote: > > > > Extend Perf tool with the check of /sys/fs/selinux/enforce value and notify > > in case access to perf_event_open() syscall is restricted by the enforced > > SELinux policy settings. > > > > Testing and evaluation (Fedora 31 x86_64 with enforced Targeted policy extended > > by perf_event class (see refpolicy [1] master branch)): > > > > [root@host ~]# ps -Z > > LABEL PID TTY TIME CMD > > unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 3960 pts/1 00:00:00 bash > > unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 4167 pts/1 00:00:00 ps > > > > [root@host ~]# ls -alhZ /usr/local/bin/ > > total 56M > > drwxr-xr-x. 2 root root system_u:object_r:bin_t:s0 4.0K Mar 4 12:27 . > > drwxr-xr-x. 12 root root system_u:object_r:usr_t:s0 4.0K Jul 25 2019 .. > > -rwxr-xr-x. 1 root root system_u:object_r:bin_t:s0 4.1M Jan 23 2017 bash > > -rwxr-xr-x. 1 root root system_u:object_r:bin_t:s0 4.1M Jan 23 2017 bash.before_shellshock_patch > > ... > > -rwxr-xr-x. 1 root root system_u:object_r:bin_t:s0 372 May 14 2019 flask > > -rwxr-xr-x. 1 root root unconfined_u:object_r:bin_t:s0 24M Mar 4 12:15 perf <== unprivileged users (perf_event_paranoid) > > -rwxr-x---. 1 root perf_users unconfined_u:object_r:bin_t:s0 24M Mar 4 12:19 perf.cap <== perf_users (CAP_SYS_ADMIN) > > -rwxr-xr-x. 1 root root system_u:object_r:bin_t:s0 44K Dec 8 2016 spiff > > ... > > lrwxrwxrwx. 1 root root system_u:object_r:bin_t:s0 4 Aug 21 2018 zstdmt -> zstd > > > > [root@host ~]# getenforce > > Enforcing > > > > === Access by unprivileged user === > > > > [user@host ~]$ ps -Z > > LABEL PID TTY TIME CMD > > unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 4043 pts/2 00:00:00 bash > > unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 4168 pts/2 00:00:00 ps > > > > [user@host ~]$ /usr/local/bin/perf stat -- ls > > Error: > > Access to performance monitoring and observability operations is limited. > > SELinux Enforcing mode is enabled and can limit access to performance > > monitoring and observability operations. Inspect system audit records > > for more perf_event access control information and adjusting the policy. > > Consider adjusting /proc/sys/kernel/perf_event_paranoid setting to open > > access to performance monitoring and observability operations for users > > without CAP_SYS_ADMIN capability. perf_event_paranoid setting is -1: > > -1: Allow use of (almost) all events by all users > > Ignore mlock limit after perf_event_mlock_kb without CAP_IPC_LOCK > >> = 0: Disallow raw and ftrace function tracepoint access > >> = 1: Disallow CPU event access > >> = 2: Disallow kernel profiling > > To make the adjusted perf_event_paranoid setting permanent preserve it > > in /etc/sysctl.conf (e.g. kernel.perf_event_paranoid = <setting>) > > > > [root@host ~]# journalctl --follow > > ... audit[4186]: AVC avc: denied { open } for pid=4186 comm="perf" scontext=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 tcontext=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 tclass=perf_event permissive=0 > > ... audit[4186]: AVC avc: denied { open } for pid=4186 comm="perf" scontext=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 tcontext=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 tclass=perf_event permissive=0 > > ... setroubleshoot[4194]: SELinux is preventing perf from open access on the perf_event labeled unconfined_t. For complete SELinux messages run: sealert -l 9a6f3db2-3d8f-461e-afad-0b5c3a9c3b9d > > ... python3[4194]: SELinux is preventing perf from open access on the perf_event labeled unconfined_t. > > > > ***** Plugin catchall (100. confidence) suggests ************************** > > > > If you believe that perf should be allowed open access on perf_event labeled unconfined_t by default. > > Then you should report this as a bug. > > You can generate a local policy module to allow this access. > > Do > > allow this access for now by executing: > > # ausearch -c 'perf' --raw | audit2allow -M my-perf > > # semodule -X 300 -i my-perf.pp > > > > === Access by perf privileged user === > > > > [user@host ~]$ ps -Z > > LABEL PID TTY TIME CMD > > unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 4043 pts/2 00:00:00 bash > > unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 4168 pts/2 00:00:00 ps > > > > [user@host ~]$ libcap/progs/getcap /usr/local/bin/perf.cap > > /usr/local/bin/perf.cap = cap_sys_ptrace,cap_syslog,cap_sys_admin+ep > > > > [user@host ~]$ /usr/local/bin/perf.cap stat -- ls > > Error: > > Access to performance monitoring and observability operations is limited. > > SELinux Enforcing mode is enabled and can limit access to performance > > monitoring and observability operations. Inspect system audit records > > for more perf_event access control information and adjusting the policy. > > Consider adjusting /proc/sys/kernel/perf_event_paranoid setting to open > > access to performance monitoring and observability operations for users > > without CAP_SYS_ADMIN capability. perf_event_paranoid setting is -1: > > -1: Allow use of (almost) all events by all users > > Ignore mlock limit after perf_event_mlock_kb without CAP_IPC_LOCK > >> = 0: Disallow raw and ftrace function tracepoint access > >> = 1: Disallow CPU event access > >> = 2: Disallow kernel profiling > > To make the adjusted perf_event_paranoid setting permanent preserve it > > in /etc/sysctl.conf (e.g. kernel.perf_event_paranoid = <setting>) > > > > [root@host ~]# journalctl --follow > > > > ... audit[3926]: AVC avc: denied { open } for pid=3926 comm="perf.cap" scontext=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 tcontext=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 tclass=perf_event permissive=0 > > ... audit[3926]: AVC avc: denied { open } for pid=3926 comm="perf.cap" scontext=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 tcontext=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 tclass=perf_event permissive=0 > > > > ... setroubleshoot[3934]: SELinux is preventing perf from open access on the perf_event labeled unconfined_t. For complete SELinux messages run: sealert -l 9a6f3db2-3d8f-461e-afad-0b5c3a9c3b9d > > ... python3[3934]: SELinux is preventing perf from open access on the perf_event labeled unconfined_t. > > > > ***** Plugin catchall (100. confidence) suggests ************************** > > > > If you believe that perf should be allowed open access on perf_event labeled unconfined_t by default. > > Then you should report this as a bug. > > You can generate a local policy module to allow this access. > > Do > > allow this access for now by executing: > > # ausearch -c 'perf' --raw | audit2allow -M my-perf > > # semodule -X 300 -i my-perf.pp > > > > === Open access to performance monitoring and observability operations in unconfined_t domain === > > > > [root@host ~]# ausearch -c 'perf' --raw | audit2allow -M my-perf && cat my-perf.te > > > > module my-perf 1.0; > > > > require { > > type unconfined_t; > > class perf_event { cpu kernel open read tracepoint write }; > > } > > > > #============= unconfined_t ============== > > allow unconfined_t self:perf_event { cpu kernel open read tracepoint write }; > > > > [root@host ~]# semodule -X 300 -i my-perf.pp > > > > [user@host ~]$ ps -Z > > LABEL PID TTY TIME CMD > > unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 4043 pts/2 00:00:00 bash > > unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 4168 pts/2 00:00:00 ps > > > > [user@host ~]$ /usr/local/bin/perf stat -- ls > > Desktop Documents Downloads intel Music perf.data perf.data.old Pictures Public Templates Videos > > > > Performance counter stats for 'ls': > > > > 0.72 msec task-clock:u # 0.655 CPUs utilized > > 0 context-switches:u # 0.000 K/sec > > 0 cpu-migrations:u # 0.000 K/sec > > 98 page-faults:u # 0.137 M/sec > > 908,356 cycles:u # 1.266 GHz > > 729,984 instructions:u # 0.80 insn per cycle > > 142,774 branches:u # 198.968 M/sec > > 8,238 branch-misses:u # 5.77% of all branches > > > > 0.001095239 seconds time elapsed > > > > 0.001147000 seconds user > > 0.000000000 seconds sys > > > > [user@host ~]$ /usr/local/bin/perf stat -a > > Error: > > Access to performance monitoring and observability operations is limited. > > SELinux Enforcing mode is enabled and can limit access to performance > > monitoring and observability operations. Inspect system audit records > > for more perf_event access control information and adjusting the policy. > > Consider adjusting /proc/sys/kernel/perf_event_paranoid setting to open > > access to performance monitoring and observability operations for users > > without CAP_SYS_ADMIN capability. perf_event_paranoid setting is -1: > > -1: Allow use of (almost) all events by all users > > Ignore mlock limit after perf_event_mlock_kb without CAP_IPC_LOCK > >> = 0: Disallow raw and ftrace function tracepoint access > >> = 1: Disallow CPU event access > >> = 2: Disallow kernel profiling > > To make the adjusted perf_event_paranoid setting permanent preserve it > > in /etc/sysctl.conf (e.g. kernel.perf_event_paranoid = <setting>) > > > > [user@host ~]$ /usr/local/bin/perf.cap stat -a > > ^C > > Performance counter stats for 'system wide': > > > > 13,427.05 msec cpu-clock # 7.997 CPUs utilized > > 783 context-switches # 0.058 K/sec > > 29 cpu-migrations # 0.002 K/sec > > 6 page-faults # 0.000 K/sec > > 161,084,874 cycles # 0.012 GHz > > 146,823,131 instructions # 0.91 insn per cycle > > 12,164,802 branches # 0.906 M/sec > > 380,350 branch-misses # 3.13% of all branches > > > > 1.678938906 seconds time elapsed > > > > [1] https://github.com/SELinuxProject/refpolicy > > > > Signed-off-by: Alexey Budankov <alexey.budankov@linux.intel.com> > > --- > > tools/perf/util/cloexec.c | 4 ++-- > > tools/perf/util/evsel.c | 40 +++++++++++++++++++++++---------------- > > 2 files changed, 26 insertions(+), 18 deletions(-) > > > > diff --git a/tools/perf/util/cloexec.c b/tools/perf/util/cloexec.c > > index a12872f2856a..9c8ec816261b 100644 > > --- a/tools/perf/util/cloexec.c > > +++ b/tools/perf/util/cloexec.c > > @@ -65,7 +65,7 @@ static int perf_flag_probe(void) > > return 1; > > } > > > > - WARN_ONCE(err != EINVAL && err != EBUSY, > > + WARN_ONCE(err != EINVAL && err != EBUSY && err != EACCES, > > "perf_event_open(..., PERF_FLAG_FD_CLOEXEC) failed with unexpected error %d (%s)\n", > > err, str_error_r(err, sbuf, sizeof(sbuf))); > > > > @@ -83,7 +83,7 @@ static int perf_flag_probe(void) > > if (fd >= 0) > > close(fd); > > > > - if (WARN_ONCE(fd < 0 && err != EBUSY, > > + if (WARN_ONCE(fd < 0 && err != EBUSY && err != EACCES, > > "perf_event_open(..., 0) failed unexpectedly with error %d (%s)\n", > > err, str_error_r(err, sbuf, sizeof(sbuf)))) > > return -1; > > diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c > > index 816d930d774e..f03ce1d362d3 100644 > > --- a/tools/perf/util/evsel.c > > +++ b/tools/perf/util/evsel.c > > @@ -2493,32 +2493,40 @@ int perf_evsel__open_strerror(struct evsel *evsel, struct target *target, > > int err, char *msg, size_t size) > > { > > char sbuf[STRERR_BUFSIZE]; > > - int printed = 0; > > + int printed = 0, enforced = 0; > > > > switch (err) { > > case EPERM: > > case EACCES: > > + printed += scnprintf(msg + printed, size - printed, > > + "Access to performance monitoring and observability operations is limited.\n"); > > + > > + if (!sysfs__read_int("fs/selinux/enforce", &enforced)) { > > + if (enforced) { > > + printed += scnprintf(msg + printed, size - printed, > > + "SELinux Enforcing mode is enabled and can limit access to performance\n" > > + "monitoring and observability operations. Inspect system audit records\n" > > + "for more perf_event access control information and adjusting the policy.\n"); > > + } > > + } > > + > > if (err == EPERM) > > - printed = scnprintf(msg, size, > > - "No permission to enable %s event.\n\n", > > + printed += scnprintf(msg, size, > > + "No permission to enable %s event.\n", > > perf_evsel__name(evsel)); > > > > return scnprintf(msg + printed, size - printed, > > - "You may not have permission to collect %sstats.\n\n" > > - "Consider tweaking /proc/sys/kernel/perf_event_paranoid,\n" > > - "which controls use of the performance events system by\n" > > - "unprivileged users (without CAP_SYS_ADMIN).\n\n" > > - "The current value is %d:\n\n" > > + "Consider adjusting /proc/sys/kernel/perf_event_paranoid setting to open\n" > > + "access to performance monitoring and observability operations for users\n" > > + "without CAP_SYS_ADMIN capability. perf_event_paranoid setting is %d:\n" > > " -1: Allow use of (almost) all events by all users\n" > > " Ignore mlock limit after perf_event_mlock_kb without CAP_IPC_LOCK\n" > > - ">= 0: Disallow ftrace function tracepoint by users without CAP_SYS_ADMIN\n" > > - " Disallow raw tracepoint access by users without CAP_SYS_ADMIN\n" > > - ">= 1: Disallow CPU event access by users without CAP_SYS_ADMIN\n" > > - ">= 2: Disallow kernel profiling by users without CAP_SYS_ADMIN\n\n" > > - "To make this setting permanent, edit /etc/sysctl.conf too, e.g.:\n\n" > > - " kernel.perf_event_paranoid = -1\n" , > > - target->system_wide ? "system-wide " : "", > > - perf_event_paranoid()); > > + ">= 0: Disallow raw and ftrace function tracepoint access\n" > > + ">= 1: Disallow CPU event access\n" > > + ">= 2: Disallow kernel profiling\n" > > + "To make the adjusted perf_event_paranoid setting permanent preserve it\n" > > + "in /etc/sysctl.conf (e.g. kernel.perf_event_paranoid = <setting>)", > > + perf_event_paranoid()); > > case ENOENT: > > return scnprintf(msg, size, "The %s event is not supported.", > > perf_evsel__name(evsel)); > >
Em Thu, Mar 19, 2020 at 04:01:26PM -0300, Arnaldo Carvalho de Melo escreveu: > Em Thu, Mar 19, 2020 at 09:23:30AM +0300, Alexey Budankov escreveu: > > Is there any thougts, comments or questions so far? > > Please share you mind. > From a quick look, seems ok, I'll do some testing now, > > On 13.03.2020 20:27, Alexey Budankov wrote: > > > Extend Perf tool with the check of /sys/fs/selinux/enforce value and notify > > > in case access to perf_event_open() syscall is restricted by the enforced > > > SELinux policy settings. > > > > > > Testing and evaluation (Fedora 31 x86_64 with enforced Targeted policy extended > > > by perf_event class (see refpolicy [1] master branch)): So I'll try the steps below with/without your patch, and then... what are the steps that a tester needs to go thru to have that refpolicy in? Install some new SELinux package or library, spelling out in detail the steps one needs to go thru helps reviewing/testing, - Arnaldo > > > [root@host ~]# ps -Z > > > LABEL PID TTY TIME CMD > > > unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 3960 pts/1 00:00:00 bash > > > unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 4167 pts/1 00:00:00 ps > > > > > > [root@host ~]# ls -alhZ /usr/local/bin/ > > > total 56M > > > drwxr-xr-x. 2 root root system_u:object_r:bin_t:s0 4.0K Mar 4 12:27 . > > > drwxr-xr-x. 12 root root system_u:object_r:usr_t:s0 4.0K Jul 25 2019 .. > > > -rwxr-xr-x. 1 root root system_u:object_r:bin_t:s0 4.1M Jan 23 2017 bash > > > -rwxr-xr-x. 1 root root system_u:object_r:bin_t:s0 4.1M Jan 23 2017 bash.before_shellshock_patch > > > ... > > > -rwxr-xr-x. 1 root root system_u:object_r:bin_t:s0 372 May 14 2019 flask > > > -rwxr-xr-x. 1 root root unconfined_u:object_r:bin_t:s0 24M Mar 4 12:15 perf <== unprivileged users (perf_event_paranoid) > > > -rwxr-x---. 1 root perf_users unconfined_u:object_r:bin_t:s0 24M Mar 4 12:19 perf.cap <== perf_users (CAP_SYS_ADMIN) > > > -rwxr-xr-x. 1 root root system_u:object_r:bin_t:s0 44K Dec 8 2016 spiff > > > ... > > > lrwxrwxrwx. 1 root root system_u:object_r:bin_t:s0 4 Aug 21 2018 zstdmt -> zstd > > > > > > [root@host ~]# getenforce > > > Enforcing > > > > > > === Access by unprivileged user === > > > > > > [user@host ~]$ ps -Z > > > LABEL PID TTY TIME CMD > > > unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 4043 pts/2 00:00:00 bash > > > unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 4168 pts/2 00:00:00 ps > > > > > > [user@host ~]$ /usr/local/bin/perf stat -- ls > > > Error: > > > Access to performance monitoring and observability operations is limited. > > > SELinux Enforcing mode is enabled and can limit access to performance > > > monitoring and observability operations. Inspect system audit records > > > for more perf_event access control information and adjusting the policy. > > > Consider adjusting /proc/sys/kernel/perf_event_paranoid setting to open > > > access to performance monitoring and observability operations for users > > > without CAP_SYS_ADMIN capability. perf_event_paranoid setting is -1: > > > -1: Allow use of (almost) all events by all users > > > Ignore mlock limit after perf_event_mlock_kb without CAP_IPC_LOCK > > >> = 0: Disallow raw and ftrace function tracepoint access > > >> = 1: Disallow CPU event access > > >> = 2: Disallow kernel profiling > > > To make the adjusted perf_event_paranoid setting permanent preserve it > > > in /etc/sysctl.conf (e.g. kernel.perf_event_paranoid = <setting>) > > > > > > [root@host ~]# journalctl --follow > > > ... audit[4186]: AVC avc: denied { open } for pid=4186 comm="perf" scontext=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 tcontext=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 tclass=perf_event permissive=0 > > > ... audit[4186]: AVC avc: denied { open } for pid=4186 comm="perf" scontext=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 tcontext=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 tclass=perf_event permissive=0 > > > ... setroubleshoot[4194]: SELinux is preventing perf from open access on the perf_event labeled unconfined_t. For complete SELinux messages run: sealert -l 9a6f3db2-3d8f-461e-afad-0b5c3a9c3b9d > > > ... python3[4194]: SELinux is preventing perf from open access on the perf_event labeled unconfined_t. > > > > > > ***** Plugin catchall (100. confidence) suggests ************************** > > > > > > If you believe that perf should be allowed open access on perf_event labeled unconfined_t by default. > > > Then you should report this as a bug. > > > You can generate a local policy module to allow this access. > > > Do > > > allow this access for now by executing: > > > # ausearch -c 'perf' --raw | audit2allow -M my-perf > > > # semodule -X 300 -i my-perf.pp > > > > > > === Access by perf privileged user === > > > > > > [user@host ~]$ ps -Z > > > LABEL PID TTY TIME CMD > > > unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 4043 pts/2 00:00:00 bash > > > unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 4168 pts/2 00:00:00 ps > > > > > > [user@host ~]$ libcap/progs/getcap /usr/local/bin/perf.cap > > > /usr/local/bin/perf.cap = cap_sys_ptrace,cap_syslog,cap_sys_admin+ep > > > > > > [user@host ~]$ /usr/local/bin/perf.cap stat -- ls > > > Error: > > > Access to performance monitoring and observability operations is limited. > > > SELinux Enforcing mode is enabled and can limit access to performance > > > monitoring and observability operations. Inspect system audit records > > > for more perf_event access control information and adjusting the policy. > > > Consider adjusting /proc/sys/kernel/perf_event_paranoid setting to open > > > access to performance monitoring and observability operations for users > > > without CAP_SYS_ADMIN capability. perf_event_paranoid setting is -1: > > > -1: Allow use of (almost) all events by all users > > > Ignore mlock limit after perf_event_mlock_kb without CAP_IPC_LOCK > > >> = 0: Disallow raw and ftrace function tracepoint access > > >> = 1: Disallow CPU event access > > >> = 2: Disallow kernel profiling > > > To make the adjusted perf_event_paranoid setting permanent preserve it > > > in /etc/sysctl.conf (e.g. kernel.perf_event_paranoid = <setting>) > > > > > > [root@host ~]# journalctl --follow > > > > > > ... audit[3926]: AVC avc: denied { open } for pid=3926 comm="perf.cap" scontext=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 tcontext=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 tclass=perf_event permissive=0 > > > ... audit[3926]: AVC avc: denied { open } for pid=3926 comm="perf.cap" scontext=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 tcontext=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 tclass=perf_event permissive=0 > > > > > > ... setroubleshoot[3934]: SELinux is preventing perf from open access on the perf_event labeled unconfined_t. For complete SELinux messages run: sealert -l 9a6f3db2-3d8f-461e-afad-0b5c3a9c3b9d > > > ... python3[3934]: SELinux is preventing perf from open access on the perf_event labeled unconfined_t. > > > > > > ***** Plugin catchall (100. confidence) suggests ************************** > > > > > > If you believe that perf should be allowed open access on perf_event labeled unconfined_t by default. > > > Then you should report this as a bug. > > > You can generate a local policy module to allow this access. > > > Do > > > allow this access for now by executing: > > > # ausearch -c 'perf' --raw | audit2allow -M my-perf > > > # semodule -X 300 -i my-perf.pp > > > > > > === Open access to performance monitoring and observability operations in unconfined_t domain === > > > > > > [root@host ~]# ausearch -c 'perf' --raw | audit2allow -M my-perf && cat my-perf.te > > > > > > module my-perf 1.0; > > > > > > require { > > > type unconfined_t; > > > class perf_event { cpu kernel open read tracepoint write }; > > > } > > > > > > #============= unconfined_t ============== > > > allow unconfined_t self:perf_event { cpu kernel open read tracepoint write }; > > > > > > [root@host ~]# semodule -X 300 -i my-perf.pp > > > > > > [user@host ~]$ ps -Z > > > LABEL PID TTY TIME CMD > > > unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 4043 pts/2 00:00:00 bash > > > unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 4168 pts/2 00:00:00 ps > > > > > > [user@host ~]$ /usr/local/bin/perf stat -- ls > > > Desktop Documents Downloads intel Music perf.data perf.data.old Pictures Public Templates Videos > > > > > > Performance counter stats for 'ls': > > > > > > 0.72 msec task-clock:u # 0.655 CPUs utilized > > > 0 context-switches:u # 0.000 K/sec > > > 0 cpu-migrations:u # 0.000 K/sec > > > 98 page-faults:u # 0.137 M/sec > > > 908,356 cycles:u # 1.266 GHz > > > 729,984 instructions:u # 0.80 insn per cycle > > > 142,774 branches:u # 198.968 M/sec > > > 8,238 branch-misses:u # 5.77% of all branches > > > > > > 0.001095239 seconds time elapsed > > > > > > 0.001147000 seconds user > > > 0.000000000 seconds sys > > > > > > [user@host ~]$ /usr/local/bin/perf stat -a > > > Error: > > > Access to performance monitoring and observability operations is limited. > > > SELinux Enforcing mode is enabled and can limit access to performance > > > monitoring and observability operations. Inspect system audit records > > > for more perf_event access control information and adjusting the policy. > > > Consider adjusting /proc/sys/kernel/perf_event_paranoid setting to open > > > access to performance monitoring and observability operations for users > > > without CAP_SYS_ADMIN capability. perf_event_paranoid setting is -1: > > > -1: Allow use of (almost) all events by all users > > > Ignore mlock limit after perf_event_mlock_kb without CAP_IPC_LOCK > > >> = 0: Disallow raw and ftrace function tracepoint access > > >> = 1: Disallow CPU event access > > >> = 2: Disallow kernel profiling > > > To make the adjusted perf_event_paranoid setting permanent preserve it > > > in /etc/sysctl.conf (e.g. kernel.perf_event_paranoid = <setting>) > > > > > > [user@host ~]$ /usr/local/bin/perf.cap stat -a > > > ^C > > > Performance counter stats for 'system wide': > > > > > > 13,427.05 msec cpu-clock # 7.997 CPUs utilized > > > 783 context-switches # 0.058 K/sec > > > 29 cpu-migrations # 0.002 K/sec > > > 6 page-faults # 0.000 K/sec > > > 161,084,874 cycles # 0.012 GHz > > > 146,823,131 instructions # 0.91 insn per cycle > > > 12,164,802 branches # 0.906 M/sec > > > 380,350 branch-misses # 3.13% of all branches > > > > > > 1.678938906 seconds time elapsed > > > > > > [1] https://github.com/SELinuxProject/refpolicy > > > > > > Signed-off-by: Alexey Budankov <alexey.budankov@linux.intel.com> > > > --- > > > tools/perf/util/cloexec.c | 4 ++-- > > > tools/perf/util/evsel.c | 40 +++++++++++++++++++++++---------------- > > > 2 files changed, 26 insertions(+), 18 deletions(-) > > > > > > diff --git a/tools/perf/util/cloexec.c b/tools/perf/util/cloexec.c > > > index a12872f2856a..9c8ec816261b 100644 > > > --- a/tools/perf/util/cloexec.c > > > +++ b/tools/perf/util/cloexec.c > > > @@ -65,7 +65,7 @@ static int perf_flag_probe(void) > > > return 1; > > > } > > > > > > - WARN_ONCE(err != EINVAL && err != EBUSY, > > > + WARN_ONCE(err != EINVAL && err != EBUSY && err != EACCES, > > > "perf_event_open(..., PERF_FLAG_FD_CLOEXEC) failed with unexpected error %d (%s)\n", > > > err, str_error_r(err, sbuf, sizeof(sbuf))); > > > > > > @@ -83,7 +83,7 @@ static int perf_flag_probe(void) > > > if (fd >= 0) > > > close(fd); > > > > > > - if (WARN_ONCE(fd < 0 && err != EBUSY, > > > + if (WARN_ONCE(fd < 0 && err != EBUSY && err != EACCES, > > > "perf_event_open(..., 0) failed unexpectedly with error %d (%s)\n", > > > err, str_error_r(err, sbuf, sizeof(sbuf)))) > > > return -1; > > > diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c > > > index 816d930d774e..f03ce1d362d3 100644 > > > --- a/tools/perf/util/evsel.c > > > +++ b/tools/perf/util/evsel.c > > > @@ -2493,32 +2493,40 @@ int perf_evsel__open_strerror(struct evsel *evsel, struct target *target, > > > int err, char *msg, size_t size) > > > { > > > char sbuf[STRERR_BUFSIZE]; > > > - int printed = 0; > > > + int printed = 0, enforced = 0; > > > > > > switch (err) { > > > case EPERM: > > > case EACCES: > > > + printed += scnprintf(msg + printed, size - printed, > > > + "Access to performance monitoring and observability operations is limited.\n"); > > > + > > > + if (!sysfs__read_int("fs/selinux/enforce", &enforced)) { > > > + if (enforced) { > > > + printed += scnprintf(msg + printed, size - printed, > > > + "SELinux Enforcing mode is enabled and can limit access to performance\n" > > > + "monitoring and observability operations. Inspect system audit records\n" > > > + "for more perf_event access control information and adjusting the policy.\n"); > > > + } > > > + } > > > + > > > if (err == EPERM) > > > - printed = scnprintf(msg, size, > > > - "No permission to enable %s event.\n\n", > > > + printed += scnprintf(msg, size, > > > + "No permission to enable %s event.\n", > > > perf_evsel__name(evsel)); > > > > > > return scnprintf(msg + printed, size - printed, > > > - "You may not have permission to collect %sstats.\n\n" > > > - "Consider tweaking /proc/sys/kernel/perf_event_paranoid,\n" > > > - "which controls use of the performance events system by\n" > > > - "unprivileged users (without CAP_SYS_ADMIN).\n\n" > > > - "The current value is %d:\n\n" > > > + "Consider adjusting /proc/sys/kernel/perf_event_paranoid setting to open\n" > > > + "access to performance monitoring and observability operations for users\n" > > > + "without CAP_SYS_ADMIN capability. perf_event_paranoid setting is %d:\n" > > > " -1: Allow use of (almost) all events by all users\n" > > > " Ignore mlock limit after perf_event_mlock_kb without CAP_IPC_LOCK\n" > > > - ">= 0: Disallow ftrace function tracepoint by users without CAP_SYS_ADMIN\n" > > > - " Disallow raw tracepoint access by users without CAP_SYS_ADMIN\n" > > > - ">= 1: Disallow CPU event access by users without CAP_SYS_ADMIN\n" > > > - ">= 2: Disallow kernel profiling by users without CAP_SYS_ADMIN\n\n" > > > - "To make this setting permanent, edit /etc/sysctl.conf too, e.g.:\n\n" > > > - " kernel.perf_event_paranoid = -1\n" , > > > - target->system_wide ? "system-wide " : "", > > > - perf_event_paranoid()); > > > + ">= 0: Disallow raw and ftrace function tracepoint access\n" > > > + ">= 1: Disallow CPU event access\n" > > > + ">= 2: Disallow kernel profiling\n" > > > + "To make the adjusted perf_event_paranoid setting permanent preserve it\n" > > > + "in /etc/sysctl.conf (e.g. kernel.perf_event_paranoid = <setting>)", > > > + perf_event_paranoid()); > > > case ENOENT: > > > return scnprintf(msg, size, "The %s event is not supported.", > > > perf_evsel__name(evsel)); > > > > > -- > > - Arnaldo
On 19.03.2020 22:05, Arnaldo Carvalho de Melo wrote: > Em Thu, Mar 19, 2020 at 04:01:26PM -0300, Arnaldo Carvalho de Melo escreveu: <SNIP> > > So I'll try the steps below with/without your patch, and then... what > are the steps that a tester needs to go thru to have that refpolicy in? > Install some new SELinux package or library, spelling out in detail the > steps one needs to go thru helps reviewing/testing, Yes, sure. Steps to extend FC31 Targeted policy for testing perf_events access control: * download selinux-policy srpm [1]: selinux-policy-3.14.4-48.fc31.src.rpm on my FC31 * install srpm - it creates rpmbuild dir: [root@host ~]# rpm -Uhv selinux-policy-3.14.4-48.fc31.src.rpm * get into rpmbuild/SPECS dir and unpack sources: [root@host ~]# rpmbuild -bp selinux-policy.spec * Place patch below at rpmbuild/BUILD/selinux-policy-b86eaaf4dbcf2d51dd4432df7185c0eaf3cbcc02 dir and apply it: [root@host ~]# patch -p1 < selinux-policy-perf-events-perfmon.patch patching file policy/flask/access_vectors patching file policy/flask/security_classes [root@host ~]# cat selinux-policy-perf-events-perfmon.patch diff -Nura a/policy/flask/access_vectors b/policy/flask/access_vectors --- a/policy/flask/access_vectors 2020-02-04 18:19:53.000000000 +0300 +++ b/policy/flask/access_vectors 2020-02-28 23:37:25.000000000 +0300 @@ -174,6 +174,7 @@ wake_alarm block_suspend audit_read + perfmon } # @@ -1099,3 +1100,15 @@ class xdp_socket inherits socket + +class perf_event +{ + open + cpu + kernel + tracepoint + read + write +} + + diff -Nura a/policy/flask/security_classes b/policy/flask/security_classes --- a/policy/flask/security_classes 2020-02-04 18:19:53.000000000 +0300 +++ b/policy/flask/security_classes 2020-02-28 21:35:17.000000000 +0300 @@ -200,4 +200,6 @@ class xdp_socket +class perf_event + # FLASK [root@host ~]# * get into rpmbuild/SPECS dir and build policy packages from patched sources: [root@host ~]# rpmbuild --noclean --noprep -ba selinux-policy.spec so you have this: [root@host ~]# ls -alh rpmbuild/RPMS/noarch/ total 33M drwxr-xr-x. 2 root root 4.0K Mar 20 12:16 . drwxr-xr-x. 3 root root 4.0K Mar 20 12:16 .. -rw-r--r--. 1 root root 112K Mar 20 12:16 selinux-policy-3.14.4-48.fc31.noarch.rpm -rw-r--r--. 1 root root 1.2M Mar 20 12:17 selinux-policy-devel-3.14.4-48.fc31.noarch.rpm -rw-r--r--. 1 root root 2.3M Mar 20 12:17 selinux-policy-doc-3.14.4-48.fc31.noarch.rpm -rw-r--r--. 1 root root 12M Mar 20 12:17 selinux-policy-minimum-3.14.4-48.fc31.noarch.rpm -rw-r--r--. 1 root root 4.5M Mar 20 12:16 selinux-policy-mls-3.14.4-48.fc31.noarch.rpm -rw-r--r--. 1 root root 111K Mar 20 12:16 selinux-policy-sandbox-3.14.4-48.fc31.noarch.rpm -rw-r--r--. 1 root root 14M Mar 20 12:17 selinux-policy-targeted-3.14.4-48.fc31.noarch.rpm * install SELinux packages from FC repo [2], if not already done so, and update with the patched rpms above: [root@host ~]# rpm -Uhv rpmbuild/RPMS/noarch/selinux-policy-* * there are also packages providing GUI interface and visualizing SELinux management [root@host ~]# dnf install policycoreutils-gui * enable SELinux Permissive mode for Targeted policy, if not already done so: [root@host ~]# cat /etc/selinux/config # This file controls the state of SELinux on the system. # SELINUX= can take one of these three values: # enforcing - SELinux security policy is enforced. # permissive - SELinux prints warnings instead of enforcing. # disabled - No SELinux policy is loaded. SELINUX=permissive # SELINUXTYPE= can take one of these three values: # targeted - Targeted processes are protected, # minimum - Modification of targeted policy. Only selected processes are protected. # mls - Multi Level Security protection. SELINUXTYPE=targeted * enable filesystem SELinux labeling at the next reboot [root@host ~]# touch /.autorelabel * reboot machine and it will label filesystems and load Targeted policy into the kernel * login and check that dmesg output doesn't mention that perf_event class is unknown to SELinux subsystem * check that SELinux is enabled and in Permissive mode [root@host ~]# getenforce Permissive * turn SELinux into Enforcing mode: [root@host ~]# setenforce 1 [root@host ~]# getenforce Enforcing * Now the machine is enabled to test the patch --- If something went wrong --- * To turn SELinux into Permissive mode: setenforce 0 * To fully disable SELinux during kernel boot [3] set kernel command line parameter: selinux=0 * To remove SELinux labeling from local filesystems: find / -mount -print0 | xargs -0 setfattr -h -x security.selinux * To fully turn SELinux off a machine set SELINUX=disabled at /etc/selinux/config file and reboot ~Alexey [1] https://download-ib01.fedoraproject.org/pub/fedora/linux/updates/31/Everything/SRPMS/Packages/s/selinux-policy-3.14.4-49.fc31.src.rpm [2] https://docs.fedoraproject.org/en-US/Fedora/11/html/Security-Enhanced_Linux/sect-Security-Enhanced_Linux-Working_with_SELinux-Enabling_and_Disabling_SELinux.html [3] https://danwalsh.livejournal.com/10972.html
Em Fri, Mar 20, 2020 at 03:24:47PM +0300, Alexey Budankov escreveu: > > On 19.03.2020 22:05, Arnaldo Carvalho de Melo wrote: > > Em Thu, Mar 19, 2020 at 04:01:26PM -0300, Arnaldo Carvalho de Melo escreveu: > <SNIP> > > > > So I'll try the steps below with/without your patch, and then... what > > are the steps that a tester needs to go thru to have that refpolicy in? > > Install some new SELinux package or library, spelling out in detail the > > steps one needs to go thru helps reviewing/testing, > > Yes, sure. Steps to extend FC31 Targeted policy for testing perf_events access control: Thanks a lot! This is the level of detail I was talking about, good job! - Arnaldo > * download selinux-policy srpm [1]: selinux-policy-3.14.4-48.fc31.src.rpm on my FC31 > > * install srpm - it creates rpmbuild dir: > [root@host ~]# rpm -Uhv selinux-policy-3.14.4-48.fc31.src.rpm > > * get into rpmbuild/SPECS dir and unpack sources: > [root@host ~]# rpmbuild -bp selinux-policy.spec > > * Place patch below at rpmbuild/BUILD/selinux-policy-b86eaaf4dbcf2d51dd4432df7185c0eaf3cbcc02 > dir and apply it: > [root@host ~]# patch -p1 < selinux-policy-perf-events-perfmon.patch > patching file policy/flask/access_vectors > patching file policy/flask/security_classes > [root@host ~]# cat selinux-policy-perf-events-perfmon.patch > diff -Nura a/policy/flask/access_vectors b/policy/flask/access_vectors > --- a/policy/flask/access_vectors 2020-02-04 18:19:53.000000000 +0300 > +++ b/policy/flask/access_vectors 2020-02-28 23:37:25.000000000 +0300 > @@ -174,6 +174,7 @@ > wake_alarm > block_suspend > audit_read > + perfmon > } > > # > @@ -1099,3 +1100,15 @@ > > class xdp_socket > inherits socket > + > +class perf_event > +{ > + open > + cpu > + kernel > + tracepoint > + read > + write > +} > + > + > diff -Nura a/policy/flask/security_classes b/policy/flask/security_classes > --- a/policy/flask/security_classes 2020-02-04 18:19:53.000000000 +0300 > +++ b/policy/flask/security_classes 2020-02-28 21:35:17.000000000 +0300 > @@ -200,4 +200,6 @@ > > class xdp_socket > > +class perf_event > + > # FLASK > > [root@host ~]# > > * get into rpmbuild/SPECS dir and build policy packages from patched sources: > [root@host ~]# rpmbuild --noclean --noprep -ba selinux-policy.spec > so you have this: > [root@host ~]# ls -alh rpmbuild/RPMS/noarch/ > total 33M > drwxr-xr-x. 2 root root 4.0K Mar 20 12:16 . > drwxr-xr-x. 3 root root 4.0K Mar 20 12:16 .. > -rw-r--r--. 1 root root 112K Mar 20 12:16 selinux-policy-3.14.4-48.fc31.noarch.rpm > -rw-r--r--. 1 root root 1.2M Mar 20 12:17 selinux-policy-devel-3.14.4-48.fc31.noarch.rpm > -rw-r--r--. 1 root root 2.3M Mar 20 12:17 selinux-policy-doc-3.14.4-48.fc31.noarch.rpm > -rw-r--r--. 1 root root 12M Mar 20 12:17 selinux-policy-minimum-3.14.4-48.fc31.noarch.rpm > -rw-r--r--. 1 root root 4.5M Mar 20 12:16 selinux-policy-mls-3.14.4-48.fc31.noarch.rpm > -rw-r--r--. 1 root root 111K Mar 20 12:16 selinux-policy-sandbox-3.14.4-48.fc31.noarch.rpm > -rw-r--r--. 1 root root 14M Mar 20 12:17 selinux-policy-targeted-3.14.4-48.fc31.noarch.rpm > > * install SELinux packages from FC repo [2], if not already done so, and > update with the patched rpms above: > [root@host ~]# rpm -Uhv rpmbuild/RPMS/noarch/selinux-policy-* > > * there are also packages providing GUI interface and visualizing SELinux management > [root@host ~]# dnf install policycoreutils-gui > > * enable SELinux Permissive mode for Targeted policy, if not already done so: > [root@host ~]# cat /etc/selinux/config > # This file controls the state of SELinux on the system. > # SELINUX= can take one of these three values: > # enforcing - SELinux security policy is enforced. > # permissive - SELinux prints warnings instead of enforcing. > # disabled - No SELinux policy is loaded. > SELINUX=permissive > # SELINUXTYPE= can take one of these three values: > # targeted - Targeted processes are protected, > # minimum - Modification of targeted policy. Only selected processes are protected. > # mls - Multi Level Security protection. > SELINUXTYPE=targeted > > * enable filesystem SELinux labeling at the next reboot > [root@host ~]# touch /.autorelabel > > * reboot machine and it will label filesystems and load Targeted policy into the kernel > > * login and check that dmesg output doesn't mention that perf_event class is unknown to SELinux subsystem > > * check that SELinux is enabled and in Permissive mode > [root@host ~]# getenforce > Permissive > > * turn SELinux into Enforcing mode: > [root@host ~]# setenforce 1 > [root@host ~]# getenforce > Enforcing > > * Now the machine is enabled to test the patch > > --- If something went wrong --- > > * To turn SELinux into Permissive mode: setenforce 0 > * To fully disable SELinux during kernel boot [3] set kernel command line parameter: selinux=0 > * To remove SELinux labeling from local filesystems: find / -mount -print0 | xargs -0 setfattr -h -x security.selinux > * To fully turn SELinux off a machine set SELINUX=disabled at /etc/selinux/config file and reboot > > ~Alexey > > [1] https://download-ib01.fedoraproject.org/pub/fedora/linux/updates/31/Everything/SRPMS/Packages/s/selinux-policy-3.14.4-49.fc31.src.rpm > [2] https://docs.fedoraproject.org/en-US/Fedora/11/html/Security-Enhanced_Linux/sect-Security-Enhanced_Linux-Working_with_SELinux-Enabling_and_Disabling_SELinux.html > [3] https://danwalsh.livejournal.com/10972.html >
diff --git a/tools/perf/util/cloexec.c b/tools/perf/util/cloexec.c index a12872f2856a..9c8ec816261b 100644 --- a/tools/perf/util/cloexec.c +++ b/tools/perf/util/cloexec.c @@ -65,7 +65,7 @@ static int perf_flag_probe(void) return 1; } - WARN_ONCE(err != EINVAL && err != EBUSY, + WARN_ONCE(err != EINVAL && err != EBUSY && err != EACCES, "perf_event_open(..., PERF_FLAG_FD_CLOEXEC) failed with unexpected error %d (%s)\n", err, str_error_r(err, sbuf, sizeof(sbuf))); @@ -83,7 +83,7 @@ static int perf_flag_probe(void) if (fd >= 0) close(fd); - if (WARN_ONCE(fd < 0 && err != EBUSY, + if (WARN_ONCE(fd < 0 && err != EBUSY && err != EACCES, "perf_event_open(..., 0) failed unexpectedly with error %d (%s)\n", err, str_error_r(err, sbuf, sizeof(sbuf)))) return -1; diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c index 816d930d774e..f03ce1d362d3 100644 --- a/tools/perf/util/evsel.c +++ b/tools/perf/util/evsel.c @@ -2493,32 +2493,40 @@ int perf_evsel__open_strerror(struct evsel *evsel, struct target *target, int err, char *msg, size_t size) { char sbuf[STRERR_BUFSIZE]; - int printed = 0; + int printed = 0, enforced = 0; switch (err) { case EPERM: case EACCES: + printed += scnprintf(msg + printed, size - printed, + "Access to performance monitoring and observability operations is limited.\n"); + + if (!sysfs__read_int("fs/selinux/enforce", &enforced)) { + if (enforced) { + printed += scnprintf(msg + printed, size - printed, + "SELinux Enforcing mode is enabled and can limit access to performance\n" + "monitoring and observability operations. Inspect system audit records\n" + "for more perf_event access control information and adjusting the policy.\n"); + } + } + if (err == EPERM) - printed = scnprintf(msg, size, - "No permission to enable %s event.\n\n", + printed += scnprintf(msg, size, + "No permission to enable %s event.\n", perf_evsel__name(evsel)); return scnprintf(msg + printed, size - printed, - "You may not have permission to collect %sstats.\n\n" - "Consider tweaking /proc/sys/kernel/perf_event_paranoid,\n" - "which controls use of the performance events system by\n" - "unprivileged users (without CAP_SYS_ADMIN).\n\n" - "The current value is %d:\n\n" + "Consider adjusting /proc/sys/kernel/perf_event_paranoid setting to open\n" + "access to performance monitoring and observability operations for users\n" + "without CAP_SYS_ADMIN capability. perf_event_paranoid setting is %d:\n" " -1: Allow use of (almost) all events by all users\n" " Ignore mlock limit after perf_event_mlock_kb without CAP_IPC_LOCK\n" - ">= 0: Disallow ftrace function tracepoint by users without CAP_SYS_ADMIN\n" - " Disallow raw tracepoint access by users without CAP_SYS_ADMIN\n" - ">= 1: Disallow CPU event access by users without CAP_SYS_ADMIN\n" - ">= 2: Disallow kernel profiling by users without CAP_SYS_ADMIN\n\n" - "To make this setting permanent, edit /etc/sysctl.conf too, e.g.:\n\n" - " kernel.perf_event_paranoid = -1\n" , - target->system_wide ? "system-wide " : "", - perf_event_paranoid()); + ">= 0: Disallow raw and ftrace function tracepoint access\n" + ">= 1: Disallow CPU event access\n" + ">= 2: Disallow kernel profiling\n" + "To make the adjusted perf_event_paranoid setting permanent preserve it\n" + "in /etc/sysctl.conf (e.g. kernel.perf_event_paranoid = <setting>)", + perf_event_paranoid()); case ENOENT: return scnprintf(msg, size, "The %s event is not supported.", perf_evsel__name(evsel));