Fixes cap_is_valid, which checks that the capability has a valid form

kth-step · Nov 12, 2023 · c2e8f37 · c2e8f37
1 parent a831dc3
commit c2e8f37
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Showing 3 changed files with 23 additions and 18 deletions.
diff --git a/kernel/inc/cap_util.h b/kernel/inc/cap_util.h
@@ -29,6 +29,5 @@ static inline uint64_t pmp_napot_encode(uint64_t base, uint64_t size)
 	return (base | (size / 2 - 1)) >> 2;
 }
 
-bool cap_is_valid(cap_t cap);
-bool cap_is_derivable(cap_t parent, cap_t child);
+bool cap_is_valid(const cap_t cap);
 void cap_snprint(char *restrict buf, size_t size, cap_t cap);
diff --git a/kernel/src/cap_ops.c b/kernel/src/cap_ops.c
@@ -188,10 +188,6 @@ err_t cap_derive_time(cte_t src, cap_t cap, cte_t dst, cap_t new_cap)
 {
 	if (new_cap.type != CAPTY_TIME)
 		return ERR_INVALID_DERIVATION;
-	if (new_cap.time.bgn != new_cap.time.mrk)
-		return ERR_INVALID_DERIVATION;
-	if (new_cap.time.bgn >= new_cap.time.end)
-		return ERR_INVALID_DERIVATION;
 	if (new_cap.time.hart != cap.time.hart)
 		return ERR_INVALID_DERIVATION;
 	if (new_cap.time.bgn != cap.time.mrk)
@@ -264,10 +260,6 @@ err_t cap_derive_memory(cte_t src, cap_t cap, cte_t dst, cap_t new_cap)
 	if (new_cap.type == CAPTY_MEMORY) {
 		if (cap.mem.tag != new_cap.mem.tag)
 			return ERR_INVALID_DERIVATION;
-		if (new_cap.mem.bgn != new_cap.mem.mrk)
-			return ERR_INVALID_DERIVATION;
-		if (new_cap.mem.bgn >= new_cap.mem.end)
-			return ERR_INVALID_DERIVATION;
 		if (cap.mem.tag != new_cap.mem.tag)
 			return ERR_INVALID_DERIVATION;
 		if (new_cap.mem.bgn < cap.mem.mrk)
@@ -375,10 +367,6 @@ err_t cap_derive_monitor(cte_t src, cap_t cap, cte_t dst, cap_t new_cap)
 {
 	if (new_cap.type != CAPTY_MONITOR)
 		return ERR_INVALID_DERIVATION;
-	if (new_cap.mon.bgn != new_cap.mon.mrk)
-		return ERR_INVALID_DERIVATION;
-	if (new_cap.mon.bgn >= new_cap.mon.end)
-		return ERR_INVALID_DERIVATION;
 	if (new_cap.mon.bgn < cap.mon.mrk)
 		return ERR_INVALID_DERIVATION;
 	if (new_cap.mon.end >= cap.mon.end)
@@ -435,10 +423,6 @@ err_t cap_revoke_channel(cte_t parent, cap_t pcap)
 err_t cap_derive_channel(cte_t src, cap_t cap, cte_t dst, cap_t new_cap)
 {
 	if (new_cap.type == CAPTY_CHANNEL) {
-		if (new_cap.chan.bgn != new_cap.chan.mrk)
-			return ERR_INVALID_DERIVATION;
-		if (new_cap.chan.bgn >= new_cap.chan.end)
-			return ERR_INVALID_DERIVATION;
 		if (new_cap.chan.bgn < cap.chan.mrk)
 			return ERR_INVALID_DERIVATION;
 		if (new_cap.chan.end >= cap.chan.end)

diff --git a/kernel/src/cap_util.c b/kernel/src/cap_util.c
@@ -127,3 +127,25 @@ void cap_snprint(char *restrict buf, size_t size, cap_t cap)
 		alt_snprintf(buf, size, "UNKNOWN{raw=0x%X}", cap.raw);
 	}
 }
+
+bool cap_is_valid(const cap_t cap)
+{
+	switch (cap.type)
+	{
+	case CAPTY_TIME:
+		return cap.time.bgn < cap.time.end && cap.time.bgn == cap.time.mrk;
+	case CAPTY_MEMORY:
+		return cap.mem.lck == 0 && cap.mem.bgn < cap.mem.end &&
+		cap.mem.mrk == cap.mem.bgn;
+	case CAPTY_PMP:
+		return cap.pmp.used == 0 && cap.pmp.slot == 0;
+	case CAPTY_MONITOR:
+		return cap.mon.bgn < cap.mon.end && cap.mon.bgn == cap.mon.mrk;
+	case CAPTY_CHANNEL:
+		return cap.mem.bgn < cap.mem.end && cap.mem.bgn == cap.mem.mrk;
+	case CAPTY_SOCKET:
+		return (cap.sock.mode == IPC_YIELD) || (cap.sock.mode == IPC_NOYIELD);
+	default:
+		return false;
+	}
+}