threads / patch / 58899

patchline-range: Fix infinite loop bug with degenerate regex

Subject: [PATCH 1/1] line-range: Fix infinite loop bug with degenerate regex

## tl;dr

One message between Dec 5, 2022 and Dec 5, 2022. Diffs are folded; open one to read it.

replies: 0people: 1as markdown or json

Lars Kellogg-Stedman· Dec 5, 2022, 19:23 UTC · lore

When the -L argument to "git log" is passed the degenerate regular expression "$" (as in "-L :$:line-range.c"), this results in an infinite loop in find_funcname_matching_regexp() (the function iterates through the file correctly, but when it reaches the end of the file it matches $ against the empty string, "", and at that points loops forever).

Modify the loop condition from while (1) to while (*start) so that the loop exits when start is the empty string. In this case, "git log" exits with the error:

    fatal: -L parameter '$' starting at line 1: no match
Originally reported in <https://stackoverflow.com/q/74690545/147356>.
Signed-off-by: Lars Kellogg-Stedman <lars@oddbit.com>
---
 line-range.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
Show changes to line-range.c +1 −1
diff --git a/line-range.c b/line-range.c
index 955a8a9535..9482d93d62 100644
--- a/line-range.c
+++ b/line-range.c
@@ -135,7 +135,7 @@ static const char *find_funcname_matching_regexp(xdemitconf_t *xecfg, const char
 {
 	int reg_error;
 	regmatch_t match[1];
-	while (1) {
+	while (*start) {
 		const char *bol, *eol;
 		reg_error = regexec(regexp, start, 1, match, 0);
 		if (reg_error == REG_NOMATCH)
-- 
2.38.1

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