libopenarc: respect body length in the AMS l tag

flowerysong · Nov 22, 2024 · a75a7c8 · a75a7c8
1 parent 3ff4b07
commit a75a7c8
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Showing 3 changed files with 29 additions and 2 deletions.
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -17,6 +17,8 @@ All notable changes to this project will be documented in this file.
 - Build issues on FreeBSD.
 - libopenarc - `arc_free()` accepts NULL.
 - libopenarc - `c` is not a required tag in `ARC-Message-Signature`.
+- libopenarc = `ARC-Message-Signature` headers covering a limited body length
+  are processed correctly.
 
 ## [1.1.0](https://github.com/flowerysong/OpenARC/releases/tag/v1.1.0) - 2024-11-05
 

diff --git a/libopenarc/arc-canon.c b/libopenarc/arc-canon.c
@@ -1868,6 +1868,12 @@ arc_canon_closebody(ARC_MESSAGE *msg)
 
         arc_canon_buffer(cur, NULL, 0);
 
+        if (cur->canon_remain > 0)
+        {
+            arc_error(msg, "body length in signature longer than actual body");
+            return ARC_STAT_SYNTAX;
+        }
+
         /* finalize */
         arc_canon_finalize(cur);
 

diff --git a/libopenarc/arc.c b/libopenarc/arc.c
@@ -1750,7 +1750,15 @@ arc_process_set(ARC_MESSAGE    *msg,
         }
         ARC_FREE(hcopy);
 
-        /* test validity of "t", "x", and "i" */
+        /* test validity of "l", "t", "x", and "i" */
+        p = arc_param_get(set, "l");
+        if (p != NULL && !arc_check_uint(p, NULL))
+        {
+            arc_error(msg, "invalid \"l\" value in %s data", settype);
+            set->set_bad = true;
+            return ARC_STAT_SYNTAX;
+        }
+
         p = arc_param_get(set, "t");
         if (p != NULL)
         {
@@ -2732,6 +2740,7 @@ arc_eoh_verify(ARC_MESSAGE *msg)
 {
     unsigned int         n;
     unsigned int         hashtype;
+    uint64_t             len;
     char                *c;
     ARC_STAT             status;
     struct arc_hdrfield *h = NULL;
@@ -2819,6 +2828,16 @@ arc_eoh_verify(ARC_MESSAGE *msg)
             body_canon = ARC_CANON_SIMPLE;
         }
 
+        c = arc_param_get(h->hdr_data, "l");
+        if (c != NULL)
+        {
+            arc_check_uint(c, &len);
+        }
+        else
+        {
+            len = -1;
+        }
+
         status = arc_add_canon(msg, ARC_CANONTYPE_HEADER, hdr_canon, hashtype,
                                htag, h, (ssize_t) -1, &msg->arc_hdrcanons[n]);
 
@@ -2831,7 +2850,7 @@ arc_eoh_verify(ARC_MESSAGE *msg)
 
         /* body, validation */
         status = arc_add_canon(msg, ARC_CANONTYPE_BODY, body_canon, hashtype,
-                               NULL, NULL, (ssize_t) -1,
+                               NULL, NULL, (ssize_t) len,
                                &msg->arc_bodycanons[n]);
 
         if (status != ARC_STAT_OK)