summaryrefslogtreecommitdiff
path: root/src/core/execute.c
diff options
context:
space:
mode:
Diffstat (limited to 'src/core/execute.c')
-rw-r--r--src/core/execute.c467
1 files changed, 123 insertions, 344 deletions
diff --git a/src/core/execute.c b/src/core/execute.c
index 4ff6f4ebd0..a77edbb162 100644
--- a/src/core/execute.c
+++ b/src/core/execute.c
@@ -1259,6 +1259,41 @@ static void rename_process_from_path(const char *path) {
rename_process(process_name);
}
+static bool context_has_address_families(const ExecContext *c) {
+ assert(c);
+
+ return c->address_families_whitelist ||
+ !set_isempty(c->address_families);
+}
+
+static bool context_has_syscall_filters(const ExecContext *c) {
+ assert(c);
+
+ return c->syscall_whitelist ||
+ !set_isempty(c->syscall_filter);
+}
+
+static bool context_has_no_new_privileges(const ExecContext *c) {
+ assert(c);
+
+ if (c->no_new_privileges)
+ return true;
+
+ if (have_effective_cap(CAP_SYS_ADMIN)) /* if we are privileged, we don't need NNP */
+ return false;
+
+ /* We need NNP if we have any form of seccomp and are unprivileged */
+ return context_has_address_families(c) ||
+ c->memory_deny_write_execute ||
+ c->restrict_realtime ||
+ exec_context_restrict_namespaces_set(c) ||
+ c->protect_kernel_tunables ||
+ c->protect_kernel_modules ||
+ c->private_devices ||
+ context_has_syscall_filters(c) ||
+ !set_isempty(c->syscall_archs);
+}
+
#ifdef HAVE_SECCOMP
static bool skip_seccomp_unavailable(const Unit* u, const char* msg) {
@@ -1272,344 +1307,131 @@ static bool skip_seccomp_unavailable(const Unit* u, const char* msg) {
return true;
}
-static int apply_seccomp(const Unit* u, const ExecContext *c) {
- uint32_t negative_action, action;
- scmp_filter_ctx seccomp;
- Iterator i;
- void *id;
- int r;
+static int apply_syscall_filter(const Unit* u, const ExecContext *c) {
+ uint32_t negative_action, default_action, action;
+ assert(u);
assert(c);
- if (skip_seccomp_unavailable(u, "syscall filtering"))
+ if (!context_has_syscall_filters(c))
return 0;
- negative_action = c->syscall_errno == 0 ? SCMP_ACT_KILL : SCMP_ACT_ERRNO(c->syscall_errno);
-
- seccomp = seccomp_init(c->syscall_whitelist ? negative_action : SCMP_ACT_ALLOW);
- if (!seccomp)
- return -ENOMEM;
-
- if (c->syscall_archs) {
+ if (skip_seccomp_unavailable(u, "SystemCallFilter="))
+ return 0;
- SET_FOREACH(id, c->syscall_archs, i) {
- r = seccomp_arch_add(seccomp, PTR_TO_UINT32(id) - 1);
- if (r == -EEXIST)
- continue;
- if (r < 0)
- goto finish;
- }
+ negative_action = c->syscall_errno == 0 ? SCMP_ACT_KILL : SCMP_ACT_ERRNO(c->syscall_errno);
+ if (c->syscall_whitelist) {
+ default_action = negative_action;
+ action = SCMP_ACT_ALLOW;
} else {
- r = seccomp_add_secondary_archs(seccomp);
- if (r < 0)
- goto finish;
+ default_action = SCMP_ACT_ALLOW;
+ action = negative_action;
}
- action = c->syscall_whitelist ? SCMP_ACT_ALLOW : negative_action;
- SET_FOREACH(id, c->syscall_filter, i) {
- r = seccomp_rule_add(seccomp, action, PTR_TO_INT(id) - 1, 0);
- if (r < 0)
- goto finish;
- }
-
- r = seccomp_attr_set(seccomp, SCMP_FLTATR_CTL_NNP, 0);
- if (r < 0)
- goto finish;
-
- r = seccomp_load(seccomp);
-
-finish:
- seccomp_release(seccomp);
- return r;
+ return seccomp_load_syscall_filter_set_raw(default_action, c->syscall_filter, action);
}
-static int apply_address_families(const Unit* u, const ExecContext *c) {
- scmp_filter_ctx seccomp;
- Iterator i;
- int r;
-
+static int apply_syscall_archs(const Unit *u, const ExecContext *c) {
+ assert(u);
assert(c);
- if (skip_seccomp_unavailable(u, "RestrictAddressFamilies="))
+ if (set_isempty(c->syscall_archs))
return 0;
- r = seccomp_init_conservative(&seccomp, SCMP_ACT_ALLOW);
- if (r < 0)
- return r;
-
- if (c->address_families_whitelist) {
- int af, first = 0, last = 0;
- void *afp;
-
- /* If this is a whitelist, we first block the address
- * families that are out of range and then everything
- * that is not in the set. First, we find the lowest
- * and highest address family in the set. */
-
- SET_FOREACH(afp, c->address_families, i) {
- af = PTR_TO_INT(afp);
-
- if (af <= 0 || af >= af_max())
- continue;
-
- if (first == 0 || af < first)
- first = af;
-
- if (last == 0 || af > last)
- last = af;
- }
-
- assert((first == 0) == (last == 0));
-
- if (first == 0) {
-
- /* No entries in the valid range, block everything */
- r = seccomp_rule_add(
- seccomp,
- SCMP_ACT_ERRNO(EPROTONOSUPPORT),
- SCMP_SYS(socket),
- 0);
- if (r < 0)
- goto finish;
-
- } else {
+ if (skip_seccomp_unavailable(u, "SystemCallArchitectures="))
+ return 0;
- /* Block everything below the first entry */
- r = seccomp_rule_add(
- seccomp,
- SCMP_ACT_ERRNO(EPROTONOSUPPORT),
- SCMP_SYS(socket),
- 1,
- SCMP_A0(SCMP_CMP_LT, first));
- if (r < 0)
- goto finish;
-
- /* Block everything above the last entry */
- r = seccomp_rule_add(
- seccomp,
- SCMP_ACT_ERRNO(EPROTONOSUPPORT),
- SCMP_SYS(socket),
- 1,
- SCMP_A0(SCMP_CMP_GT, last));
- if (r < 0)
- goto finish;
-
- /* Block everything between the first and last
- * entry */
- for (af = 1; af < af_max(); af++) {
-
- if (set_contains(c->address_families, INT_TO_PTR(af)))
- continue;
+ return seccomp_restrict_archs(c->syscall_archs);
+}
- r = seccomp_rule_add(
- seccomp,
- SCMP_ACT_ERRNO(EPROTONOSUPPORT),
- SCMP_SYS(socket),
- 1,
- SCMP_A0(SCMP_CMP_EQ, af));
- if (r < 0)
- goto finish;
- }
- }
+static int apply_address_families(const Unit* u, const ExecContext *c) {
+ assert(u);
+ assert(c);
- } else {
- void *af;
-
- /* If this is a blacklist, then generate one rule for
- * each address family that are then combined in OR
- * checks. */
-
- SET_FOREACH(af, c->address_families, i) {
-
- r = seccomp_rule_add(
- seccomp,
- SCMP_ACT_ERRNO(EPROTONOSUPPORT),
- SCMP_SYS(socket),
- 1,
- SCMP_A0(SCMP_CMP_EQ, PTR_TO_INT(af)));
- if (r < 0)
- goto finish;
- }
- }
+ if (!context_has_address_families(c))
+ return 0;
- r = seccomp_load(seccomp);
+ if (skip_seccomp_unavailable(u, "RestrictAddressFamilies="))
+ return 0;
-finish:
- seccomp_release(seccomp);
- return r;
+ return seccomp_restrict_address_families(c->address_families, c->address_families_whitelist);
}
static int apply_memory_deny_write_execute(const Unit* u, const ExecContext *c) {
- scmp_filter_ctx seccomp;
- int r;
-
+ assert(u);
assert(c);
- if (skip_seccomp_unavailable(u, "MemoryDenyWriteExecute="))
+ if (!c->memory_deny_write_execute)
return 0;
- r = seccomp_init_conservative(&seccomp, SCMP_ACT_ALLOW);
- if (r < 0)
- return r;
-
- r = seccomp_rule_add(
- seccomp,
- SCMP_ACT_ERRNO(EPERM),
- SCMP_SYS(mmap),
- 1,
- SCMP_A2(SCMP_CMP_MASKED_EQ, PROT_EXEC|PROT_WRITE, PROT_EXEC|PROT_WRITE));
- if (r < 0)
- goto finish;
-
- r = seccomp_rule_add(
- seccomp,
- SCMP_ACT_ERRNO(EPERM),
- SCMP_SYS(mprotect),
- 1,
- SCMP_A2(SCMP_CMP_MASKED_EQ, PROT_EXEC, PROT_EXEC));
- if (r < 0)
- goto finish;
-
- r = seccomp_rule_add(
- seccomp,
- SCMP_ACT_ERRNO(EPERM),
- SCMP_SYS(shmat),
- 1,
- SCMP_A2(SCMP_CMP_MASKED_EQ, SHM_EXEC, SHM_EXEC));
- if (r < 0)
- goto finish;
-
- r = seccomp_load(seccomp);
+ if (skip_seccomp_unavailable(u, "MemoryDenyWriteExecute="))
+ return 0;
-finish:
- seccomp_release(seccomp);
- return r;
+ return seccomp_memory_deny_write_execute();
}
static int apply_restrict_realtime(const Unit* u, const ExecContext *c) {
- static const int permitted_policies[] = {
- SCHED_OTHER,
- SCHED_BATCH,
- SCHED_IDLE,
- };
-
- scmp_filter_ctx seccomp;
- unsigned i;
- int r, p, max_policy = 0;
-
+ assert(u);
assert(c);
- if (skip_seccomp_unavailable(u, "RestrictRealtime="))
+ if (!c->restrict_realtime)
return 0;
- r = seccomp_init_conservative(&seccomp, SCMP_ACT_ALLOW);
- if (r < 0)
- return r;
-
- /* Determine the highest policy constant we want to allow */
- for (i = 0; i < ELEMENTSOF(permitted_policies); i++)
- if (permitted_policies[i] > max_policy)
- max_policy = permitted_policies[i];
-
- /* Go through all policies with lower values than that, and block them -- unless they appear in the
- * whitelist. */
- for (p = 0; p < max_policy; p++) {
- bool good = false;
-
- /* Check if this is in the whitelist. */
- for (i = 0; i < ELEMENTSOF(permitted_policies); i++)
- if (permitted_policies[i] == p) {
- good = true;
- break;
- }
-
- if (good)
- continue;
-
- /* Deny this policy */
- r = seccomp_rule_add(
- seccomp,
- SCMP_ACT_ERRNO(EPERM),
- SCMP_SYS(sched_setscheduler),
- 1,
- SCMP_A1(SCMP_CMP_EQ, p));
- if (r < 0)
- goto finish;
- }
-
- /* Blacklist all other policies, i.e. the ones with higher values. Note that all comparisons are unsigned here,
- * hence no need no check for < 0 values. */
- r = seccomp_rule_add(
- seccomp,
- SCMP_ACT_ERRNO(EPERM),
- SCMP_SYS(sched_setscheduler),
- 1,
- SCMP_A1(SCMP_CMP_GT, max_policy));
- if (r < 0)
- goto finish;
-
- r = seccomp_load(seccomp);
+ if (skip_seccomp_unavailable(u, "RestrictRealtime="))
+ return 0;
-finish:
- seccomp_release(seccomp);
- return r;
+ return seccomp_restrict_realtime();
}
static int apply_protect_sysctl(const Unit *u, const ExecContext *c) {
- scmp_filter_ctx seccomp;
- int r;
-
+ assert(u);
assert(c);
/* Turn off the legacy sysctl() system call. Many distributions turn this off while building the kernel, but
* let's protect even those systems where this is left on in the kernel. */
- if (skip_seccomp_unavailable(u, "ProtectKernelTunables="))
+ if (!c->protect_kernel_tunables)
return 0;
- r = seccomp_init_conservative(&seccomp, SCMP_ACT_ALLOW);
- if (r < 0)
- return r;
-
- r = seccomp_rule_add(
- seccomp,
- SCMP_ACT_ERRNO(EPERM),
- SCMP_SYS(_sysctl),
- 0);
- if (r < 0)
- goto finish;
-
- r = seccomp_load(seccomp);
+ if (skip_seccomp_unavailable(u, "ProtectKernelTunables="))
+ return 0;
-finish:
- seccomp_release(seccomp);
- return r;
+ return seccomp_protect_sysctl();
}
static int apply_protect_kernel_modules(const Unit *u, const ExecContext *c) {
+ assert(u);
assert(c);
/* Turn off module syscalls on ProtectKernelModules=yes */
+ if (!c->protect_kernel_modules)
+ return 0;
+
if (skip_seccomp_unavailable(u, "ProtectKernelModules="))
return 0;
- return seccomp_load_filter_set(SCMP_ACT_ALLOW, syscall_filter_sets + SYSCALL_FILTER_SET_MODULE, SCMP_ACT_ERRNO(EPERM));
+ return seccomp_load_syscall_filter_set(SCMP_ACT_ALLOW, syscall_filter_sets + SYSCALL_FILTER_SET_MODULE, SCMP_ACT_ERRNO(EPERM));
}
static int apply_private_devices(const Unit *u, const ExecContext *c) {
+ assert(u);
assert(c);
/* If PrivateDevices= is set, also turn off iopl and all @raw-io syscalls. */
+ if (!c->private_devices)
+ return 0;
+
if (skip_seccomp_unavailable(u, "PrivateDevices="))
return 0;
- return seccomp_load_filter_set(SCMP_ACT_ALLOW, syscall_filter_sets + SYSCALL_FILTER_SET_RAW_IO, SCMP_ACT_ERRNO(EPERM));
+ return seccomp_load_syscall_filter_set(SCMP_ACT_ALLOW, syscall_filter_sets + SYSCALL_FILTER_SET_RAW_IO, SCMP_ACT_ERRNO(EPERM));
}
static int apply_restrict_namespaces(Unit *u, const ExecContext *c) {
+ assert(u);
assert(c);
if (!exec_context_restrict_namespaces_set(c))
@@ -2310,41 +2132,6 @@ static int close_remaining_fds(
return close_all_fds(dont_close, n_dont_close);
}
-static bool context_has_address_families(const ExecContext *c) {
- assert(c);
-
- return c->address_families_whitelist ||
- !set_isempty(c->address_families);
-}
-
-static bool context_has_syscall_filters(const ExecContext *c) {
- assert(c);
-
- return c->syscall_whitelist ||
- !set_isempty(c->syscall_filter) ||
- !set_isempty(c->syscall_archs);
-}
-
-static bool context_has_no_new_privileges(const ExecContext *c) {
- assert(c);
-
- if (c->no_new_privileges)
- return true;
-
- if (have_effective_cap(CAP_SYS_ADMIN)) /* if we are privileged, we don't need NNP */
- return false;
-
- /* We need NNP if we have any form of seccomp and are unprivileged */
- return context_has_address_families(c) ||
- c->memory_deny_write_execute ||
- c->restrict_realtime ||
- exec_context_restrict_namespaces_set(c) ||
- c->protect_kernel_tunables ||
- c->protect_kernel_modules ||
- c->private_devices ||
- context_has_syscall_filters(c);
-}
-
static int send_user_lookup(
Unit *unit,
int user_lookup_fd,
@@ -2904,28 +2691,22 @@ static int exec_child(
}
#ifdef HAVE_SECCOMP
- if (context_has_address_families(context)) {
- r = apply_address_families(unit, context);
- if (r < 0) {
- *exit_status = EXIT_ADDRESS_FAMILIES;
- return r;
- }
+ r = apply_address_families(unit, context);
+ if (r < 0) {
+ *exit_status = EXIT_ADDRESS_FAMILIES;
+ return r;
}
- if (context->memory_deny_write_execute) {
- r = apply_memory_deny_write_execute(unit, context);
- if (r < 0) {
- *exit_status = EXIT_SECCOMP;
- return r;
- }
+ r = apply_memory_deny_write_execute(unit, context);
+ if (r < 0) {
+ *exit_status = EXIT_SECCOMP;
+ return r;
}
- if (context->restrict_realtime) {
- r = apply_restrict_realtime(unit, context);
- if (r < 0) {
- *exit_status = EXIT_SECCOMP;
- return r;
- }
+ r = apply_restrict_realtime(unit, context);
+ if (r < 0) {
+ *exit_status = EXIT_SECCOMP;
+ return r;
}
r = apply_restrict_namespaces(unit, context);
@@ -2934,38 +2715,36 @@ static int exec_child(
return r;
}
- if (context->protect_kernel_tunables) {
- r = apply_protect_sysctl(unit, context);
- if (r < 0) {
- *exit_status = EXIT_SECCOMP;
- return r;
- }
+ r = apply_protect_sysctl(unit, context);
+ if (r < 0) {
+ *exit_status = EXIT_SECCOMP;
+ return r;
}
- if (context->protect_kernel_modules) {
- r = apply_protect_kernel_modules(unit, context);
- if (r < 0) {
- *exit_status = EXIT_SECCOMP;
- return r;
- }
+ r = apply_protect_kernel_modules(unit, context);
+ if (r < 0) {
+ *exit_status = EXIT_SECCOMP;
+ return r;
}
- if (context->private_devices) {
- r = apply_private_devices(unit, context);
- if (r < 0) {
- *exit_status = EXIT_SECCOMP;
- return r;
- }
+ r = apply_private_devices(unit, context);
+ if (r < 0) {
+ *exit_status = EXIT_SECCOMP;
+ return r;
+ }
+
+ r = apply_syscall_archs(unit, context);
+ if (r < 0) {
+ *exit_status = EXIT_SECCOMP;
+ return r;
}
/* This really should remain the last step before the execve(), to make sure our own code is unaffected
* by the filter as little as possible. */
- if (context_has_syscall_filters(context)) {
- r = apply_seccomp(unit, context);
- if (r < 0) {
- *exit_status = EXIT_SECCOMP;
- return r;
- }
+ r = apply_syscall_filter(unit, context);
+ if (r < 0) {
+ *exit_status = EXIT_SECCOMP;
+ return r;
}
#endif
}
generated by cgit v1.2.3-54-g00ecf (git 2.45.2) at 2024-11-25 21:31:17 +0000