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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.
This commit is contained in:
Zbigniew Jędrzejewski-Szmek 2020-08-21 17:21:04 +02:00
parent 752fedbea7
commit 000c05207d
3 changed files with 46 additions and 10 deletions
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9
src/nspawn/nspawn-seccomp.c
View File

@ -146,13 +146,18 @@ static int seccomp_add_default_syscall_filter(
if (allow_list[i].capability != 0 && (cap_list_retain & (1ULL << allow_list[i].capability)) == 0)
continue;
r = seccomp_add_syscall_filter_item(ctx, allow_list[i].name, SCMP_ACT_ALLOW, syscall_deny_list, false);
r = seccomp_add_syscall_filter_item(ctx,
allow_list[i].name,
SCMP_ACT_ALLOW,
syscall_deny_list,
false,
NULL);
if (r < 0)
return log_error_errno(r, "Failed to add syscall filter item %s: %m", allow_list[i].name);
}
STRV_FOREACH(p, syscall_allow_list) {
r = seccomp_add_syscall_filter_item(ctx, *p, SCMP_ACT_ALLOW, syscall_deny_list, true);
r = seccomp_add_syscall_filter_item(ctx, *p, SCMP_ACT_ALLOW, syscall_deny_list, true, 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));

39
src/shared/seccomp-util.c
View File

@ -902,15 +902,31 @@ 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;
@ -920,7 +936,7 @@ int seccomp_add_syscall_filter_item(scmp_filter_ctx *seccomp, const char *name,
"Filter set %s is not known!",
name);
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;
@ -944,25 +960,34 @@ 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;
}
@ -988,7 +1013,7 @@ 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");

8
src/shared/seccomp-util.h
View File

@ -60,7 +60,13 @@ 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);