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From 201006fa521199ebf109016c9dd22812c435dfe9 Mon Sep 17 00:00:00 2001
From: Ismo Puustinen <ismo.puustinen@intel.com>
Date: Fri, 8 Jan 2016 00:00:04 +0200
Subject: [PATCH] capabilities: keep bounding set in non-inverted format.
Change the capability bounding set parser and logic so that the bounding
set is kept as a positive set internally. This means that the set
reflects those capabilities that we want to keep instead of drop.
Resolves: #1387398
---
src/core/dbus-execute.c | 4 +-
src/core/execute.c | 9 +--
src/core/execute.h | 2 +-
src/core/load-fragment-gperf.gperf.m4 | 2 +-
src/core/load-fragment.c | 25 ++++----
src/core/load-fragment.h | 2 +-
src/core/main.c | 10 +--
src/core/unit.c | 2 +-
src/import/import-common.c | 2 +-
src/nspawn/nspawn.c | 2 +-
src/shared/capability.c | 16 ++---
src/shared/capability.h | 12 +++-
src/test/test-unit-file.c | 89 +++++++++++++++------------
13 files changed, 96 insertions(+), 81 deletions(-)
diff --git a/src/core/dbus-execute.c b/src/core/dbus-execute.c
index da8b10d2b3..a564c53fae 100644
--- a/src/core/dbus-execute.c
+++ b/src/core/dbus-execute.c
@@ -324,9 +324,7 @@ static int property_get_capability_bounding_set(
assert(reply);
assert(c);
- /* We store this negated internally, to match the kernel, but
- * we expose it normalized. */
- return sd_bus_message_append(reply, "t", ~c->capability_bounding_set_drop);
+ return sd_bus_message_append(reply, "t", c->capability_bounding_set);
}
static int property_get_capabilities(
diff --git a/src/core/execute.c b/src/core/execute.c
index f72b20966f..40db11e284 100644
--- a/src/core/execute.c
+++ b/src/core/execute.c
@@ -1733,8 +1733,8 @@ static int exec_child(
}
}
- if (context->capability_bounding_set_drop) {
- r = capability_bounding_set_drop(context->capability_bounding_set_drop, false);
+ if (!cap_test_all(context->capability_bounding_set)) {
+ r = capability_bounding_set_drop(context->capability_bounding_set, false);
if (r < 0) {
*exit_status = EXIT_CAPABILITIES;
return r;
@@ -1988,6 +1988,7 @@ void exec_context_init(ExecContext *c) {
c->timer_slack_nsec = NSEC_INFINITY;
c->personality = 0xffffffffUL;
c->runtime_directory_mode = 0755;
+ c->capability_bounding_set = CAP_ALL;
}
void exec_context_done(ExecContext *c) {
@@ -2419,12 +2420,12 @@ void exec_context_dump(ExecContext *c, FILE* f, const char *prefix) {
(c->secure_bits & 1<<SECURE_NOROOT) ? " noroot" : "",
(c->secure_bits & 1<<SECURE_NOROOT_LOCKED) ? "noroot-locked" : "");
- if (c->capability_bounding_set_drop) {
+ if (c->capability_bounding_set != CAP_ALL) {
unsigned long l;
fprintf(f, "%sCapabilityBoundingSet:", prefix);
for (l = 0; l <= cap_last_cap(); l++)
- if (!(c->capability_bounding_set_drop & ((uint64_t) 1ULL << (uint64_t) l)))
+ if (c->capability_bounding_set & (UINT64_C(1) << l))
fprintf(f, " %s", strna(capability_to_name(l)));
fputs("\n", f);
diff --git a/src/core/execute.h b/src/core/execute.h
index cadd0e6b47..40f7b794c5 100644
--- a/src/core/execute.h
+++ b/src/core/execute.h
@@ -150,7 +150,7 @@ struct ExecContext {
char **read_write_dirs, **read_only_dirs, **inaccessible_dirs;
unsigned long mount_flags;
- uint64_t capability_bounding_set_drop;
+ uint64_t capability_bounding_set;
cap_t capabilities;
int secure_bits;
diff --git a/src/core/load-fragment-gperf.gperf.m4 b/src/core/load-fragment-gperf.gperf.m4
index b50fe45b47..e4ce292100 100644
--- a/src/core/load-fragment-gperf.gperf.m4
+++ b/src/core/load-fragment-gperf.gperf.m4
@@ -47,7 +47,7 @@ $1.SyslogLevel, config_parse_log_level, 0,
$1.SyslogLevelPrefix, config_parse_bool, 0, offsetof($1, exec_context.syslog_level_prefix)
$1.Capabilities, config_parse_exec_capabilities, 0, offsetof($1, exec_context)
$1.SecureBits, config_parse_exec_secure_bits, 0, offsetof($1, exec_context)
-$1.CapabilityBoundingSet, config_parse_bounding_set, 0, offsetof($1, exec_context.capability_bounding_set_drop)
+$1.CapabilityBoundingSet, config_parse_capability_set, 0, offsetof($1, exec_context.capability_bounding_set)
$1.TimerSlackNSec, config_parse_nsec, 0, offsetof($1, exec_context.timer_slack_nsec)
$1.NoNewPrivileges, config_parse_no_new_privileges, 0, offsetof($1, exec_context)
m4_ifdef(`HAVE_SECCOMP',
diff --git a/src/core/load-fragment.c b/src/core/load-fragment.c
index ab3b0c2e92..dbaaf2fee7 100644
--- a/src/core/load-fragment.c
+++ b/src/core/load-fragment.c
@@ -1015,7 +1015,7 @@ int config_parse_exec_secure_bits(const char *unit,
return 0;
}
-int config_parse_bounding_set(
+int config_parse_capability_set(
const char *unit,
const char *filename,
unsigned line,
@@ -1027,8 +1027,8 @@ int config_parse_bounding_set(
void *data,
void *userdata) {
- uint64_t *capability_bounding_set_drop = data;
- uint64_t capability_bounding_set, sum = 0;
+ uint64_t *capability_set = data;
+ uint64_t sum = 0, initial = 0;
bool invert = false;
const char *p;
@@ -1042,10 +1042,8 @@ int config_parse_bounding_set(
rvalue++;
}
- /* Note that we store this inverted internally, since the
- * kernel wants it like this. But we actually expose it
- * non-inverted everywhere to have a fully normalized
- * interface. */
+ if (strcmp(lvalue, "CapabilityBoundingSet") == 0)
+ initial = CAP_ALL; /* initialized to all bits on */
p = rvalue;
for (;;) {
@@ -1071,11 +1069,14 @@ int config_parse_bounding_set(
sum |= ((uint64_t) UINT64_C(1)) << (uint64_t) cap;
}
- capability_bounding_set = invert ? ~sum : sum;
- if (*capability_bounding_set_drop != 0 && capability_bounding_set != 0)
- *capability_bounding_set_drop = ~(~*capability_bounding_set_drop | capability_bounding_set);
+ sum = invert ? ~sum : sum;
+
+ if (sum == 0 || *capability_set == initial)
+ /* "" or uninitialized data -> replace */
+ *capability_set = sum;
else
- *capability_bounding_set_drop = ~capability_bounding_set;
+ /* previous data -> merge */
+ *capability_set |= sum;
return 0;
}
@@ -4050,7 +4051,7 @@ void unit_dump_config_items(FILE *f) {
{ config_parse_log_level, "LEVEL" },
{ config_parse_exec_capabilities, "CAPABILITIES" },
{ config_parse_exec_secure_bits, "SECUREBITS" },
- { config_parse_bounding_set, "BOUNDINGSET" },
+ { config_parse_capability_set, "BOUNDINGSET" },
{ config_parse_limit, "LIMIT" },
{ config_parse_unit_deps, "UNIT [...]" },
{ config_parse_exec, "PATH [ARGUMENT [...]]" },
diff --git a/src/core/load-fragment.h b/src/core/load-fragment.h
index 9dd7d1bda0..2059353d38 100644
--- a/src/core/load-fragment.h
+++ b/src/core/load-fragment.h
@@ -54,7 +54,7 @@ int config_parse_exec_cpu_sched_prio(const char *unit, const char *filename, uns
int config_parse_exec_cpu_affinity(const char *unit, const char *filename, unsigned line, const char *section, unsigned section_line, const char *lvalue, int ltype, const char *rvalue, void *data, void *userdata);
int config_parse_exec_capabilities(const char *unit, const char *filename, unsigned line, const char *section, unsigned section_line, const char *lvalue, int ltype, const char *rvalue, void *data, void *userdata);
int config_parse_exec_secure_bits(const char *unit, const char *filename, unsigned line, const char *section, unsigned section_line, const char *lvalue, int ltype, const char *rvalue, void *data, void *userdata);
-int config_parse_bounding_set(const char *unit, const char *filename, unsigned line, const char *section, unsigned section_line, const char *lvalue, int ltype, const char *rvalue, void *data, void *userdata);
+int config_parse_capability_set(const char *unit, const char *filename, unsigned line, const char *section, unsigned section_line, const char *lvalue, int ltype, const char *rvalue, void *data, void *userdata);
int config_parse_limit(const char *unit, const char *filename, unsigned line, const char *section, unsigned section_line, const char *lvalue, int ltype, const char *rvalue, void *data, void *userdata);
int config_parse_bytes_limit(const char *unit, const char *filename, unsigned line, const char *section, unsigned section_line, const char *lvalue, int ltype, const char *rvalue, void *data, void *userdata);
int config_parse_sec_limit(const char *unit, const char *filename, unsigned line, const char *section, unsigned section_line, const char *lvalue, int ltype, const char *rvalue, void *data, void *userdata);
diff --git a/src/core/main.c b/src/core/main.c
index a0df1e5cec..cba992cea2 100644
--- a/src/core/main.c
+++ b/src/core/main.c
@@ -108,7 +108,7 @@ static usec_t arg_runtime_watchdog = 0;
static usec_t arg_shutdown_watchdog = 10 * USEC_PER_MINUTE;
static char **arg_default_environment = NULL;
static struct rlimit *arg_default_rlimit[_RLIMIT_MAX] = {};
-static uint64_t arg_capability_bounding_set_drop = 0;
+static uint64_t arg_capability_bounding_set = CAP_ALL;
static nsec_t arg_timer_slack_nsec = NSEC_INFINITY;
static usec_t arg_default_timer_accuracy_usec = 1 * USEC_PER_MINUTE;
static Set* arg_syscall_archs = NULL;
@@ -642,7 +642,7 @@ static int parse_config_file(void) {
{ "Manager", "JoinControllers", config_parse_join_controllers, 0, &arg_join_controllers },
{ "Manager", "RuntimeWatchdogSec", config_parse_sec, 0, &arg_runtime_watchdog },
{ "Manager", "ShutdownWatchdogSec", config_parse_sec, 0, &arg_shutdown_watchdog },
- { "Manager", "CapabilityBoundingSet", config_parse_bounding_set, 0, &arg_capability_bounding_set_drop },
+ { "Manager", "CapabilityBoundingSet", config_parse_capability_set, 0, &arg_capability_bounding_set },
#ifdef HAVE_SECCOMP
{ "Manager", "SystemCallArchitectures", config_parse_syscall_archs, 0, &arg_syscall_archs },
#endif
@@ -1622,14 +1622,14 @@ int main(int argc, char *argv[]) {
if (prctl(PR_SET_TIMERSLACK, arg_timer_slack_nsec) < 0)
log_error_errno(errno, "Failed to adjust timer slack: %m");
- if (arg_capability_bounding_set_drop) {
- r = capability_bounding_set_drop_usermode(arg_capability_bounding_set_drop);
+ if (!cap_test_all(arg_capability_bounding_set)) {
+ r = capability_bounding_set_drop_usermode(arg_capability_bounding_set);
if (r < 0) {
log_emergency_errno(r, "Failed to drop capability bounding set of usermode helpers: %m");
error_message = "Failed to drop capability bounding set of usermode helpers";
goto finish;
}
- r = capability_bounding_set_drop(arg_capability_bounding_set_drop, true);
+ r = capability_bounding_set_drop(arg_capability_bounding_set, true);
if (r < 0) {
log_emergency_errno(r, "Failed to drop capability bounding set: %m");
error_message = "Failed to drop capability bounding set";
diff --git a/src/core/unit.c b/src/core/unit.c
index 4eb0d78f44..103f92084c 100644
--- a/src/core/unit.c
+++ b/src/core/unit.c
@@ -3213,7 +3213,7 @@ int unit_patch_contexts(Unit *u) {
ec->no_new_privileges = true;
if (ec->private_devices)
- ec->capability_bounding_set_drop |= (uint64_t) 1ULL << (uint64_t) CAP_MKNOD;
+ ec->capability_bounding_set &= ~(UINT64_C(1) << CAP_MKNOD);
}
cc = unit_get_cgroup_context(u);
diff --git a/src/import/import-common.c b/src/import/import-common.c
index f10a453eed..243e657c56 100644
--- a/src/import/import-common.c
+++ b/src/import/import-common.c
@@ -526,7 +526,7 @@ int import_fork_tar(const char *path, pid_t *ret) {
if (unshare(CLONE_NEWNET) < 0)
log_error_errno(errno, "Failed to lock tar into network namespace, ignoring: %m");
- r = capability_bounding_set_drop(~retain, true);
+ r = capability_bounding_set_drop(retain, true);
if (r < 0)
log_error_errno(r, "Failed to drop capabilities, ignoring: %m");
diff --git a/src/nspawn/nspawn.c b/src/nspawn/nspawn.c
index a37b64094b..d0003d3790 100644
--- a/src/nspawn/nspawn.c
+++ b/src/nspawn/nspawn.c
@@ -1863,7 +1863,7 @@ static int setup_journal(const char *directory) {
}
static int drop_capabilities(void) {
- return capability_bounding_set_drop(~arg_retain, false);
+ return capability_bounding_set_drop(arg_retain, false);
}
static int register_machine(pid_t pid, int local_ifindex) {
diff --git a/src/shared/capability.c b/src/shared/capability.c
index 2b963fde3f..3ed31df5ab 100644
--- a/src/shared/capability.c
+++ b/src/shared/capability.c
@@ -98,7 +98,7 @@ unsigned long cap_last_cap(void) {
return p;
}
-int capability_bounding_set_drop(uint64_t drop, bool right_now) {
+int capability_bounding_set_drop(uint64_t keep, bool right_now) {
_cleanup_cap_free_ cap_t after_cap = NULL;
cap_flag_value_t fv;
unsigned long i;
@@ -139,7 +139,7 @@ int capability_bounding_set_drop(uint64_t drop, bool right_now) {
for (i = 0; i <= cap_last_cap(); i++) {
- if (drop & ((uint64_t) 1ULL << (uint64_t) i)) {
+ if (!(keep & (UINT64_C(1) << i))) {
cap_value_t v;
/* Drop it from the bounding set */
@@ -178,7 +178,7 @@ finish:
return r;
}
-static int drop_from_file(const char *fn, uint64_t drop) {
+static int drop_from_file(const char *fn, uint64_t keep) {
int r, k;
uint32_t hi, lo;
uint64_t current, after;
@@ -198,7 +198,7 @@ static int drop_from_file(const char *fn, uint64_t drop) {
return -EIO;
current = (uint64_t) lo | ((uint64_t) hi << 32ULL);
- after = current & ~drop;
+ after = current & keep;
if (current == after)
return 0;
@@ -215,14 +215,14 @@ static int drop_from_file(const char *fn, uint64_t drop) {
return r;
}
-int capability_bounding_set_drop_usermode(uint64_t drop) {
+int capability_bounding_set_drop_usermode(uint64_t keep) {
int r;
- r = drop_from_file("/proc/sys/kernel/usermodehelper/inheritable", drop);
+ r = drop_from_file("/proc/sys/kernel/usermodehelper/inheritable", keep);
if (r < 0)
return r;
- r = drop_from_file("/proc/sys/kernel/usermodehelper/bset", drop);
+ r = drop_from_file("/proc/sys/kernel/usermodehelper/bset", keep);
if (r < 0)
return r;
@@ -259,7 +259,7 @@ int drop_privileges(uid_t uid, gid_t gid, uint64_t keep_capabilities) {
return log_error_errno(errno, "Failed to disable keep capabilities flag: %m");
/* Drop all caps from the bounding set, except the ones we want */
- r = capability_bounding_set_drop(~keep_capabilities, true);
+ r = capability_bounding_set_drop(keep_capabilities, true);
if (r < 0)
return log_error_errno(r, "Failed to drop capabilities: %m");
diff --git a/src/shared/capability.h b/src/shared/capability.h
index 6f2f6f997d..04cd6e54e2 100644
--- a/src/shared/capability.h
+++ b/src/shared/capability.h
@@ -27,10 +27,12 @@
#include "util.h"
+#define CAP_ALL (uint64_t) -1
+
unsigned long cap_last_cap(void);
int have_effective_cap(int value);
-int capability_bounding_set_drop(uint64_t drop, bool right_now);
-int capability_bounding_set_drop_usermode(uint64_t drop);
+int capability_bounding_set_drop(uint64_t keep, bool right_now);
+int capability_bounding_set_drop_usermode(uint64_t keep);
int drop_privileges(uid_t uid, gid_t gid, uint64_t keep_capabilites);
@@ -44,3 +46,9 @@ static inline void cap_free_charpp(char **p) {
cap_free(*p);
}
#define _cleanup_cap_free_charp_ _cleanup_(cap_free_charpp)
+
+static inline bool cap_test_all(uint64_t caps) {
+ uint64_t m;
+ m = (UINT64_C(1) << (cap_last_cap() + 1)) - 1;
+ return (caps & m) == m;
+}
diff --git a/src/test/test-unit-file.c b/src/test/test-unit-file.c
index 0f00a8fff1..38ecfe972e 100644
--- a/src/test/test-unit-file.c
+++ b/src/test/test-unit-file.c
@@ -550,6 +550,53 @@ static uint64_t make_cap(int cap) {
return ((uint64_t) 1ULL << (uint64_t) cap);
}
+static void test_config_parse_capability_set(void) {
+ /* int config_parse_capability_set(
+ const char *unit,
+ const char *filename,
+ unsigned line,
+ const char *section,
+ unsigned section_line,
+ const char *lvalue,
+ int ltype,
+ const char *rvalue,
+ void *data,
+ void *userdata) */
+ int r;
+ uint64_t capability_bounding_set = 0;
+
+ r = config_parse_capability_set(NULL, "fake", 1, "section", 1,
+ "CapabilityBoundingSet", 0, "CAP_NET_RAW",
+ &capability_bounding_set, NULL);
+ assert_se(r >= 0);
+ assert_se(capability_bounding_set == make_cap(CAP_NET_RAW));
+
+ r = config_parse_capability_set(NULL, "fake", 1, "section", 1,
+ "CapabilityBoundingSet", 0, "CAP_NET_ADMIN",
+ &capability_bounding_set, NULL);
+ assert_se(r >= 0);
+ assert_se(capability_bounding_set == (make_cap(CAP_NET_RAW) | make_cap(CAP_NET_ADMIN)));
+
+ r = config_parse_capability_set(NULL, "fake", 1, "section", 1,
+ "CapabilityBoundingSet", 0, "",
+ &capability_bounding_set, NULL);
+ assert_se(r >= 0);
+ assert_se(capability_bounding_set == UINT64_C(0));
+
+ r = config_parse_capability_set(NULL, "fake", 1, "section", 1,
+ "CapabilityBoundingSet", 0, "~",
+ &capability_bounding_set, NULL);
+ assert_se(r >= 0);
+ assert_se(cap_test_all(capability_bounding_set));
+
+ capability_bounding_set = 0;
+ r = config_parse_capability_set(NULL, "fake", 1, "section", 1,
+ "CapabilityBoundingSet", 0, " 'CAP_NET_RAW' WAT_CAP??? CAP_NET_ADMIN CAP'_trailing_garbage",
+ &capability_bounding_set, NULL);
+ assert_se(r >= 0);
+ assert_se(capability_bounding_set == (make_cap(CAP_NET_RAW) | make_cap(CAP_NET_ADMIN)));
+}
+
static void test_config_parse_rlimit(void) {
struct rlimit * rl[_RLIMIT_MAX] = {};
@@ -665,46 +712,6 @@ static void test_config_parse_rlimit(void) {
free(rl[RLIMIT_RTTIME]);
}
-static void test_config_parse_bounding_set(void) {
- /* int config_parse_bounding_set(
- const char *unit,
- const char *filename,
- unsigned line,
- const char *section,
- unsigned section_line,
- const char *lvalue,
- int ltype,
- const char *rvalue,
- void *data,
- void *userdata) */
- int r;
- uint64_t capability_bounding_set_drop = 0;
-
- r = config_parse_bounding_set(NULL, "fake", 1, "section", 1,
- "CapabilityBoundingSet", 0, "CAP_NET_RAW",
- &capability_bounding_set_drop, NULL);
- assert_se(r >= 0);
- assert_se(capability_bounding_set_drop == ~make_cap(CAP_NET_RAW));
-
- r = config_parse_bounding_set(NULL, "fake", 1, "section", 1,
- "CapabilityBoundingSet", 0, "CAP_NET_ADMIN",
- &capability_bounding_set_drop, NULL);
- assert_se(r >= 0);
- assert_se(capability_bounding_set_drop == ~(make_cap(CAP_NET_RAW) | make_cap(CAP_NET_ADMIN)));
-
- r = config_parse_bounding_set(NULL, "fake", 1, "section", 1,
- "CapabilityBoundingSet", 0, "",
- &capability_bounding_set_drop, NULL);
- assert_se(r >= 0);
- assert_se(capability_bounding_set_drop == ~((uint64_t) 0ULL));
-
- r = config_parse_bounding_set(NULL, "fake", 1, "section", 1,
- "CapabilityBoundingSet", 0, "~",
- &capability_bounding_set_drop, NULL);
- assert_se(r >= 0);
- assert_se(capability_bounding_set_drop == (uint64_t) 0ULL);
-}
-
int main(int argc, char *argv[]) {
int r;
@@ -713,8 +720,8 @@ int main(int argc, char *argv[]) {
r = test_unit_file_get_set();
test_config_parse_exec();
+ test_config_parse_capability_set();
test_config_parse_rlimit();
- test_config_parse_bounding_set();
test_load_env_file_1();
test_load_env_file_2();
test_load_env_file_3();