sid: fix off by one parsing bug

In the string representation, hyphen is always succeeded by a number
so we need to terminate at input length minus one.

2 files changed, 6 insertions, 1 deletions

diff --git a/sid.ml b/sid.ml
index a2590fd..c6c7d3d 100644
--- a/sid.ml
+++ b/sid.ml
@@ -94,7 +94,7 @@ module StringFmt = struct
         let p = 4 in
         let p, ia = read_decimal_u64 s p in
         let sa = ref [] and p' = ref p in
-        while !p' < n && List.length !sa < max_subauth_count do
+        while !p' < n - 1 && List.length !sa < max_subauth_count do
           expect_char s '-' !p';
           let np, d = read_decimal_u32 s (!p' + 1) in
           sa := d :: !sa;
diff --git a/sid_test.ml b/sid_test.ml
index f34e4b0..61e5366 100644
--- a/sid_test.ml
+++ b/sid_test.ml
@@ -72,6 +72,10 @@ let sf_parse_ia_junk_fail () =
       assert_equal
         e "Invalid SID [S-I-3-3-7]: expected ‘1’ at position 2, found ‘I’"
 
+let sf_parse_trailing_ok () =
+  let s = unwrap_of_string "S-1-0-0-" in
+  assert_equal (Sid.to_string s) "S-1-0-0"
+
 let sf_parse_long_ok () =
   let s = unwrap_of_string "S-1-1-0-1-2-3-4-5-6-7-8-9-10-11-12-13-14"
   and l = max_sid in
@@ -274,6 +278,7 @@ let string_format_test = "string-format-syntax" >:::
   ; "parse-empty-fail"      >:: sf_parse_empty_fail
   ; "parse-junk-fail"       >:: sf_parse_junk_fail
   ; "parse-ia-junk-fail"    >:: sf_parse_ia_junk_fail
+  ; "parse-trailing-ok"     >:: sf_parse_trailing_ok
   ; "parse-long-ok"         >:: sf_parse_long_ok
   ; "parse-too-long-ok"     >:: sf_parse_too_long_ok
   ]