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analyze-security: include an actual syscall name in the message 

This information was already available in the debug output, but I think it
is good to include it in the message in the table. This makes it easier to wrap
one's head around the allowlist/denylist filtering.
This commit is contained in:
Zbigniew Jędrzejewski-Szmek 2020-08-01 11:41:57 +02:00
parent 01ecb3674a
commit a9134af2e3
1 changed files with 21 additions and 12 deletions
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33
src/analyze/analyze-security.c
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@ -493,7 +493,7 @@ static int assess_system_call_architectures(
#if HAVE_SECCOMP
static bool syscall_names_in_filter(Set *s, bool allow_list, const SyscallFilterSet *f) {
static bool syscall_names_in_filter(Set *s, bool allow_list, const SyscallFilterSet *f, const char **ret_offending_syscall) {
const char *syscall;
NULSTR_FOREACH(syscall, f->value) {
@ -503,7 +503,7 @@ static bool syscall_names_in_filter(Set *s, bool allow_list, const SyscallFilter
const SyscallFilterSet *g;
assert_se(g = syscall_filter_set_find(syscall));
if (syscall_names_in_filter(s, allow_list, g))
if (syscall_names_in_filter(s, allow_list, g, ret_offending_syscall))
return true; /* bad! */
continue;
@ -516,10 +516,13 @@ static bool syscall_names_in_filter(Set *s, bool allow_list, const SyscallFilter
if (set_contains(s, syscall) == allow_list) {
log_debug("Offending syscall filter item: %s", syscall);
if (ret_offending_syscall)
*ret_offending_syscall = syscall;
return true; /* bad! */
}
}
*ret_offending_syscall = NULL;
return false;
}
@ -530,42 +533,48 @@ static int assess_system_call_filter(
uint64_t *ret_badness,
char **ret_description) {
const SyscallFilterSet *f;
char *d = NULL;
uint64_t b;
assert(a);
assert(info);
assert(ret_badness);
assert(ret_description);
assert(a->parameter < _SYSCALL_FILTER_SET_MAX);
f = syscall_filter_sets + a->parameter;
const SyscallFilterSet *f = syscall_filter_sets + a->parameter;
char *d = NULL;
uint64_t b;
if (!info->system_call_filter_allow_list && set_isempty(info->system_call_filter)) {
d = strdup("Service does not filter system calls");
b = 10;
} else {
bool bad;
const char *offender = NULL;
log_debug("Analyzing system call filter, checking against: %s", f->name);
bad = syscall_names_in_filter(info->system_call_filter, info->system_call_filter_allow_list, f);
bad = syscall_names_in_filter(info->system_call_filter, info->system_call_filter_allow_list, f, &offender);
log_debug("Result: %s", bad ? "bad" : "good");
if (info->system_call_filter_allow_list) {
if (bad) {
(void) asprintf(&d, "System call allow list defined for service, and %s is included", f->name);
(void) asprintf(&d, "System call allow list defined for service, and %s is included "
"(e.g. %s is allowed)",
f->name, offender);
b = 9;
} else {
(void) asprintf(&d, "System call allow list defined for service, and %s is not included", f->name);
(void) asprintf(&d, "System call allow list defined for service, and %s is not included",
f->name);
b = 0;
}
} else {
if (bad) {
(void) asprintf(&d, "System call deny list defined for service, and %s is not included", f->name);
(void) asprintf(&d, "System call deny list defined for service, and %s is not included "
"(e.g. %s is allowed)",
f->name, offender);
b = 10;
} else {
(void) asprintf(&d, "System call deny list defined for service, and %s is included", f->name);
(void) asprintf(&d, "System call deny list defined for service, and %s is included",
f->name);
b = 0;
}
}