convert: Safer handling of $Id$ contraction.

The code to contract $Id:xxxxx$ strings could eat an arbitrary amount
of source text if the terminating $ was lost. It now refuses to
contract $Id:xxxxx$ strings spanning multiple lines.

Signed-off-by: Henrik Grubbström <grubba@grubba.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 12 insertions, 0 deletions

diff --git a/convert.c b/convert.c
index 4f8fcb7bb..239fa0ab9 100644
--- a/convert.c
+++ b/convert.c
@@ -425,6 +425,8 @@ static int count_ident(const char *cp, unsigned long size)
 				cnt++;
 				break;
 			}
+			if (ch == '\n')
+				break;
 		}
 	}
 	return cnt;
@@ -455,6 +457,11 @@ static int ident_to_git(const char *path, const char *src, size_t len,
 			dollar = memchr(src + 3, '$', len - 3);
 			if (!dollar)
 				break;
+			if (memchr(src + 3, '\n', dollar - src - 3)) {
+				/* Line break before the next dollar. */
+				continue;
+			}
+
 			memcpy(dst, "Id$", 3);
 			dst += 3;
 			len -= dollar + 1 - src;
@@ -514,6 +521,11 @@ static int ident_to_worktree(const char *path, const char *src, size_t len,
 				break;
 			}
 
+			if (memchr(src + 3, '\n', dollar - src - 3)) {
+				/* Line break before the next dollar. */
+				continue;
+			}
+
 			len -= dollar + 1 - src;
 			src  = dollar + 1;
 		} else {