[PATCH ghak57 V1] selinux: format all invalid context as untrusted
All instances of one field type should be encoded in the same way.
Since some invalid_context fields can contain untrusted strings, encode
all instances of this field the same way.
Please see github issue
https://github.com/linux-audit/audit-kernel/issues/57
Signed-off-by: Richard Guy Briggs <rgb(a)redhat.com>
---
Passes audit-testsuite.
security/selinux/ss/services.c | 48 +++++++++++++++++++++++++++++++++---------
1 file changed, 38 insertions(+), 10 deletions(-)
diff --git a/security/selinux/ss/services.c b/security/selinux/ss/services.c
index cc043bc8fd4c..817576802f7d 100644
--- a/security/selinux/ss/services.c
+++ b/security/selinux/ss/services.c
@@ -1588,6 +1588,8 @@ static int compute_sid_handle_invalid_context(
struct policydb *policydb = &state->ss->policydb;
char *s = NULL, *t = NULL, *n = NULL;
u32 slen, tlen, nlen;
+ struct audit_buffer *ab;
+ size_t audit_size;
if (context_struct_to_string(policydb, scontext, &s, &slen))
goto out;
@@ -1595,12 +1597,22 @@ static int compute_sid_handle_invalid_context(
goto out;
if (context_struct_to_string(policydb, newcontext, &n, &nlen))
goto out;
- audit_log(audit_context(), GFP_ATOMIC, AUDIT_SELINUX_ERR,
- "op=security_compute_sid invalid_context=%s"
- " scontext=%s"
- " tcontext=%s"
- " tclass=%s",
- n, s, t, sym_name(policydb, SYM_CLASSES, tclass-1));
+ /* We strip a nul only if it is at the end, otherwise the
+ * context contains a nul and we should audit that */
+ if (n) {
+ if (n[nlen - 1] == '\0')
+ audit_size = nlen - 1;
+ else
+ audit_size = nlen;
+ } else {
+ audit_size = 0;
+ }
+ ab = audit_log_start(audit_context(), GFP_ATOMIC, AUDIT_SELINUX_ERR);
+ audit_log_format(ab, "op=security_compute_sid invalid_context=");
+ audit_log_n_untrustedstring(ab, n, audit_size);
+ audit_log_format(ab, " scontext=%s tcontext=%s tclass=%s",
+ s, t, sym_name(policydb, SYM_CLASSES, tclass-1));
+ audit_log_end(ab);
out:
kfree(s);
kfree(t);
@@ -3007,10 +3019,26 @@ int security_sid_mls_copy(struct selinux_state *state,
if (rc) {
if (!context_struct_to_string(policydb, &newcon, &s,
&len)) {
- audit_log(audit_context(),
- GFP_ATOMIC, AUDIT_SELINUX_ERR,
- "op=security_sid_mls_copy "
- "invalid_context=%s", s);
+ struct audit_buffer *ab;
+ size_t audit_size;
+
+ /* We strip a nul only if it is at the
+ * end, otherwise the context contains a
+ * nul and we should audit that */
+ if (s) {
+ if (s[len - 1] == '\0')
+ audit_size = len - 1;
+ else
+ audit_size = len;
+ } else {
+ audit_size = 0;
+ }
+ ab = audit_log_start(audit_context(),
+ GFP_ATOMIC,
+ AUDIT_SELINUX_ERR);
+ audit_log_format(ab, "op=security_sid_mls_copy invalid_context=");
+ audit_log_n_untrustedstring(ab, s, audit_size);
+ audit_log_end(ab);
kfree(s);
}
goto out_unlock;
--
1.8.3.1