Merge branch 'js/regexec-buf' into maint

Some codepaths in "git diff" used regexec(3) on a buffer that was
mmap(2)ed, which may not have a terminating NUL, leading to a read
beyond the end of the mapped region.  This was fixed by introducing
a regexec_buf() helper that takes a <ptr,len> pair with REG_STARTEND
extension.

* js/regexec-buf:
  regex: use regexec_buf()
  regex: add regexec_buf() that can work on a non NUL-terminated string
  regex: -G<pattern> feeds a non NUL-terminated string to regexec() and fails

1 files changed, 4 insertions, 9 deletions

diff --git a/xdiff-interface.c b/xdiff-interface.c
index f34ea762e4..50702a215d 100644
--- a/xdiff-interface.c
+++ b/xdiff-interface.c
@@ -214,11 +214,10 @@ struct ff_regs {
 static long ff_regexp(const char *line, long len,
 		char *buffer, long buffer_size, void *priv)
 {
-	char *line_buffer;
 	struct ff_regs *regs = priv;
 	regmatch_t pmatch[2];
 	int i;
-	int result = -1;
+	int result;
 
 	/* Exclude terminating newline (and cr) from matching */
 	if (len > 0 && line[len-1] == '\n') {
@@ -228,18 +227,16 @@ static long ff_regexp(const char *line, long len,
 			len--;
 	}
 
-	line_buffer = xstrndup(line, len); /* make NUL terminated */
-
 	for (i = 0; i < regs->nr; i++) {
 		struct ff_reg *reg = regs->array + i;
-		if (!regexec(&reg->re, line_buffer, 2, pmatch, 0)) {
+		if (!regexec_buf(&reg->re, line, len, 2, pmatch, 0)) {
 			if (reg->negate)
-				goto fail;
+				return -1;
 			break;
 		}
 	}
 	if (regs->nr <= i)
-		goto fail;
+		return -1;
 	i = pmatch[1].rm_so >= 0 ? 1 : 0;
 	line += pmatch[i].rm_so;
 	result = pmatch[i].rm_eo - pmatch[i].rm_so;
@@ -248,8 +245,6 @@ static long ff_regexp(const char *line, long len,
 	while (result > 0 && (isspace(line[result - 1])))
 		result--;
 	memcpy(buffer, line, result);
- fail:
-	free(line_buffer);
 	return result;
 }