From: Mark Wooding <mdw@distorted.org.uk>
Date: Sun, 21 Oct 2012 14:05:20 +0000 (+0100)
Subject: policy.h, yaid.h: Allow policy rules to match on the user.
X-Git-Tag: 1.0.0~7
X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~mdw/git/yaid/commitdiff_plain/c039c9363c583e347cd269f6c741d302d416d1a6?hp=c74afd8acf88d097561546c9cc5a88b1522cb341

policy.h, yaid.h: Allow policy rules to match on the user.

So we have a user pattern, and all the associated bits and pieces.
This breaks old policy files, but nobody has deployed yet.
---

diff --git a/policy.c b/policy.c
index 630e1dc..32a4550 100644
--- a/policy.c
+++ b/policy.c
@@ -80,6 +80,12 @@ static void print_portpat(const struct portpat *pp)
 static void print_sockpat(const struct addrops *ao, const struct sockpat *sp)
   { print_addrpat(ao, &sp->addr); putchar(' '); print_portpat(&sp->port); }
 
+static void print_userpat(const struct userpat *up)
+{
+  if (up->lo == up->hi) printf("%d", up->lo);
+  else printf("%u-%u", up->lo, up->hi);
+}
+
 static const char *const acttab[] = {
 #define DEFACT(tag, name) name,
   ACTIONS(DEFACT)
@@ -109,6 +115,7 @@ void print_policy(const struct policy *p)
 {
   print_sockpat(p->ao, &p->sp[L]); putchar(' ');
   print_sockpat(p->ao, &p->sp[R]); putchar(' ');
+  print_userpat(&p->up); putchar(' ');
   print_action(&p->act); putchar('\n');
 }
 
@@ -126,12 +133,17 @@ static int match_sockpat(const struct addrops *ao,
 	  match_portpat(&sp->port, s->port));
 }
 
+/* Return true if the uid matches the pattern. */
+static int match_userpat(const struct userpat *up, uid_t u)
+  { unsigned uu = u; return (up->lo <= uu && uu <= up->hi); }
+
 /* Return true if the query matches the patterns in the policy rule. */
 int match_policy(const struct policy *p, const struct query *q)
 {
   return ((!p->ao || p->ao == q->ao) &&
 	  match_sockpat(q->ao, &p->sp[L], &q->s[L]) &&
-	  match_sockpat(q->ao, &p->sp[R], &q->s[R]));
+	  match_sockpat(q->ao, &p->sp[R], &q->s[R]) &&
+	  match_userpat(&p->up, q->u.uid));
 }
 
 /*----- Parsing -----------------------------------------------------------*/
@@ -385,6 +397,27 @@ static int parse_sockpat(FILE *fp, const struct addrops **aop,
   return (T_OK);
 }
 
+/* Parse a user pattern, writing it to UP. */
+static int parse_userpat(FILE *fp, struct userpat *up)
+{
+  struct passwd *pw;
+  char buf[32];
+  int t;
+  char *delim;
+
+  if ((t = scan(fp, buf, sizeof(buf))) != 0) return (t);
+  if (!strcmp(buf, "*")) { up->lo = 0; up->hi = UINT_MAX; }
+  else if ((pw = getpwnam(buf)) != 0) up->lo = up->hi = pw->pw_uid;
+  else {
+    if ((delim = strchr(buf, '-')) != 0) *delim++ = 0;
+    up->lo = strtoul(buf, 0, 0);
+    if (!delim) up->hi = up->lo;
+    else if (!*delim) up->hi = UINT_MAX;
+    else up->hi = strtoul(delim, 0, 0);
+  }
+  return (0);
+}
+
 /* Parse a policy rule line, writing it to P. */
 static int parse_policy(FILE *fp, struct policy *p)
 {
@@ -395,6 +428,7 @@ static int parse_policy(FILE *fp, struct policy *p)
 
   if ((t = parse_sockpat(fp, &p->ao, &p->sp[L])) != 0) goto fail;
   if ((t = parse_sockpat(fp, &p->ao, &p->sp[R])) != 0) goto err;
+  if ((t = parse_userpat(fp, &p->up)) != 0) goto err;
   if ((t = parse_action(fp, &p->act)) != 0) goto err;
   return (0);
 
diff --git a/yaid.h b/yaid.h
index 126c201..387f76e 100644
--- a/yaid.h
+++ b/yaid.h
@@ -282,12 +282,18 @@ struct action {
   } u;
 };
 
+/* A user pattern matches a user if the uid is within the given bounds. */
+struct userpat {
+  unsigned lo, hi;
+};
+
 /* A policy rule: if the query matches the pattern, then perform the
  * action.
  */
 struct policy {
   const struct addrops *ao;
   struct sockpat sp[NDIR];
+  struct userpat up;
   struct action act;
 };
 #define POLICY_INIT(a) { .act.act = a }