From eaad892c513806801e3d2055788fa202372b3f15 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Zbigniew=20J=C4=99drzejewski-Szmek?= <zbyszek@in.waw.pl>
Date: Fri, 21 Aug 2020 17:21:04 +0200
Subject: [PATCH] shared/seccomp-util: added functionality to make list of
filtred syscalls
While at it, start removing the "seccomp_" prefix from our
own functions. It is used by libseccomp.
(cherry picked from commit 000c05207d68658b76af9e1caf9aa3a4e3fa697b)
Related: #2040247
---
src/nspawn/nspawn-seccomp.c | 9 +++++++--
src/shared/seccomp-util.c | 39 ++++++++++++++++++++++++++++++-------
src/shared/seccomp-util.h | 8 +++++++-
3 files changed, 46 insertions(+), 10 deletions(-)
diff --git a/src/nspawn/nspawn-seccomp.c b/src/nspawn/nspawn-seccomp.c
index 17abfcec26..2b4a65e875 100644
--- a/src/nspawn/nspawn-seccomp.c
+++ b/src/nspawn/nspawn-seccomp.c
@@ -148,13 +148,18 @@ static int seccomp_add_default_syscall_filter(
if (whitelist[i].capability != 0 && (cap_list_retain & (1ULL << whitelist[i].capability)) == 0)
continue;
- r = seccomp_add_syscall_filter_item(ctx, whitelist[i].name, SCMP_ACT_ALLOW, syscall_blacklist, false);
+ r = seccomp_add_syscall_filter_item(ctx,
+ whitelist[i].name,
+ SCMP_ACT_ALLOW,
+ syscall_blacklist,
+ false,
+ NULL);
if (r < 0)
return log_error_errno(r, "Failed to add syscall filter item %s: %m", whitelist[i].name);
}
STRV_FOREACH(p, syscall_whitelist) {
- r = seccomp_add_syscall_filter_item(ctx, *p, SCMP_ACT_ALLOW, syscall_blacklist, false);
+ r = seccomp_add_syscall_filter_item(ctx, *p, SCMP_ACT_ALLOW, syscall_blacklist, false, NULL);
if (r < 0)
log_warning_errno(r, "Failed to add rule for system call %s on %s, ignoring: %m",
*p, seccomp_arch_to_string(arch));
diff --git a/src/shared/seccomp-util.c b/src/shared/seccomp-util.c
index 710a734715..56075d92e0 100644
--- a/src/shared/seccomp-util.c
+++ b/src/shared/seccomp-util.c
@@ -874,15 +874,31 @@ const SyscallFilterSet *syscall_filter_set_find(const char *name) {
return NULL;
}
-static int seccomp_add_syscall_filter_set(scmp_filter_ctx seccomp, const SyscallFilterSet *set, uint32_t action, char **exclude, bool log_missing);
+static int add_syscall_filter_set(
+ scmp_filter_ctx seccomp,
+ const SyscallFilterSet *set,
+ uint32_t action,
+ char **exclude,
+ bool log_missing,
+ char ***added);
+
+int seccomp_add_syscall_filter_item(
+ scmp_filter_ctx *seccomp,
+ const char *name,
+ uint32_t action,
+ char **exclude,
+ bool log_missing,
+ char ***added) {
-int seccomp_add_syscall_filter_item(scmp_filter_ctx *seccomp, const char *name, uint32_t action, char **exclude, bool log_missing) {
assert(seccomp);
assert(name);
if (strv_contains(exclude, name))
return 0;
+ /* Any syscalls that are handled are added to the *added strv. The pointer
+ * must be either NULL or point to a valid pre-initialized possibly-empty strv. */
+
if (name[0] == '@') {
const SyscallFilterSet *other;
@@ -892,7 +908,7 @@ int seccomp_add_syscall_filter_item(scmp_filter_ctx *seccomp, const char *name,
return -EINVAL;
}
- return seccomp_add_syscall_filter_set(seccomp, other, action, exclude, log_missing);
+ return add_syscall_filter_set(seccomp, other, action, exclude, log_missing, added);
} else {
int id, r;
@@ -916,25 +932,34 @@ int seccomp_add_syscall_filter_item(scmp_filter_ctx *seccomp, const char *name,
return r;
}
+ if (added) {
+ r = strv_extend(added, name);
+ if (r < 0)
+ return r;
+ }
+
return 0;
}
}
-static int seccomp_add_syscall_filter_set(
+static int add_syscall_filter_set(
scmp_filter_ctx seccomp,
const SyscallFilterSet *set,
uint32_t action,
char **exclude,
- bool log_missing) {
+ bool log_missing,
+ char ***added) {
const char *sys;
int r;
+ /* Any syscalls that are handled are added to the *added strv. It needs to be initialized. */
+
assert(seccomp);
assert(set);
NULSTR_FOREACH(sys, set->value) {
- r = seccomp_add_syscall_filter_item(seccomp, sys, action, exclude, log_missing);
+ r = seccomp_add_syscall_filter_item(seccomp, sys, action, exclude, log_missing, added);
if (r < 0)
return r;
}
@@ -960,7 +985,7 @@ int seccomp_load_syscall_filter_set(uint32_t default_action, const SyscallFilter
if (r < 0)
return r;
- r = seccomp_add_syscall_filter_set(seccomp, set, action, NULL, log_missing);
+ r = add_syscall_filter_set(seccomp, set, action, NULL, log_missing, NULL);
if (r < 0)
return log_debug_errno(r, "Failed to add filter set: %m");
diff --git a/src/shared/seccomp-util.h b/src/shared/seccomp-util.h
index 541ba1e067..291b2bffe0 100644
--- a/src/shared/seccomp-util.h
+++ b/src/shared/seccomp-util.h
@@ -59,7 +59,13 @@ const SyscallFilterSet *syscall_filter_set_find(const char *name);
int seccomp_filter_set_add(Hashmap *s, bool b, const SyscallFilterSet *set);
-int seccomp_add_syscall_filter_item(scmp_filter_ctx *ctx, const char *name, uint32_t action, char **exclude, bool log_missing);
+int seccomp_add_syscall_filter_item(
+ scmp_filter_ctx *ctx,
+ const char *name,
+ uint32_t action,
+ char **exclude,
+ bool log_missing,
+ char ***added);
int seccomp_load_syscall_filter_set(uint32_t default_action, const SyscallFilterSet *set, uint32_t action, bool log_missing);
int seccomp_load_syscall_filter_set_raw(uint32_t default_action, Hashmap* set, uint32_t action, bool log_missing);