rerere: avoid buffer overrun

check_one_conflict() compares `i` to `active_nr` in two places to avoid
buffer overruns, but left out an important third location.

The code did used to have a check here comparing i to active_nr, back
before commit fb70a06da2f1 ("rerere: fix an off-by-one non-bug",
2015-06-28), however the code at the time used an 'if' rather than a
'while' meaning back then that this loop could not have read past the
end of the array, making the check unnecessary and it was removed.
Unfortunately, in commit 5eda906b2873 ("rerere: handle conflicts with
multiple stage #1 entries", 2015-07-24), the 'if' was changed to a
'while' and the check comparing i and active_nr was not re-instated,
leading to this problem.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/rerere.c b/rerere.c
index ea24d4c2f47ab6495d97f38245dd420a1ad38391..ee02dd32446eacfd3bf93dc68ad7e35416e63098 100644 (file)
--- a/rerere.c
+++ b/rerere.c
@@ -532,7 +532,7 @@ static int check_one_conflict(int i, int *type)
        }
 
        *type = PUNTED;
-       while (ce_stage(active_cache[i]) == 1)
+       while (i < active_nr && ce_stage(active_cache[i]) == 1)
                i++;
 
        /* Only handle regular files with both stages #2 and #3 */

diff --git a/t/t4200-rerere.sh b/t/t4200-rerere.sh
index ed9e495fa75c0f7b650e9065fed70c4330d7886c..8da998f661e55c849599c6a0dcb02e43a327f413 100755 (executable)
--- a/t/t4200-rerere.sh
+++ b/t/t4200-rerere.sh
@@ -599,7 +599,7 @@ test_expect_success 'setup simple stage 1 handling' '
        )
 '
 
-test_expect_failure 'test simple stage 1 handling' '
+test_expect_success 'test simple stage 1 handling' '
        (
                cd stage_1_handling &&