Re: [PATCH v2 1/2] rev-parse: fix segfault with missing --path-format argument
From: Jeff King <hidden>
Date: 2021-05-17 08:18:48
Subsystem:
the rest · Maintainer:
Linus Torvalds
On Mon, May 17, 2021 at 10:02:42AM +0200, Wolfgang Müller wrote:
quoted hunk ↗ jump to hunk
Calling "git rev-parse --path-format" without an argument segfaults instead of giving an error message. Commit fac60b8925 (rev-parse: add option for absolute or relative path formatting, 2020-12-13) added the argument parsing code but forgot to handle NULL. Returning an error makes sense here because there is no default value we could use. Add a test case to verify. Signed-off-by: Wolfgang Müller <redacted> --- builtin/rev-parse.c | 2 ++ t/t1500-rev-parse.sh | 4 ++++ 2 files changed, 6 insertions(+)diff --git a/builtin/rev-parse.c b/builtin/rev-parse.c index 85bad9052e..7af8dab8bc 100644 --- a/builtin/rev-parse.c +++ b/builtin/rev-parse.c@@ -759,6 +759,8 @@ int cmd_rev_parse(int argc, const char **argv, const char *prefix) continue; } if (opt_with_value(arg, "--path-format", &arg)) { + if (!arg) + die("--path-format requires an argument"); if (!strcmp(arg, "absolute")) { format = FORMAT_CANONICAL; } else if (!strcmp(arg, "relative")) {
This looks like a fine solution, but I do think this code using opt_with_value() is a bit of a curiosity in the first place. I looked at the other callers (because I wanted to see if there were similar problems), and they are all cases where the argument is truly optional (so matching "--foo" or "--foo=bar" is correct, and matching "--foo bar" would be actively wrong). For cases where the argument is not optional, we seem to use skip_prefix(), like:
diff --git a/builtin/rev-parse.c b/builtin/rev-parse.c
index c4263404bd..9553cc7c10 100644
--- a/builtin/rev-parse.c
+++ b/builtin/rev-parse.c@@ -760,7 +760,7 @@ int cmd_rev_parse(int argc, const char **argv, const char *prefix) show(arg); continue; } - if (opt_with_value(arg, "--path-format", &arg)) { + if (skip_prefix(arg, "--path-format=", &arg)) { if (!strcmp(arg, "absolute")) { format = FORMAT_CANONICAL; } else if (!strcmp(arg, "relative")) {
I don't have a strong preference for one or the other. It is maybe helpful to diagnose "--path-format" without an equals as an error, as your patch would, rather than quietly passing it along as an unknown (as the hunk above would). I dunno. That perhaps applies to the rest of the options, too. :) (In an ideal world, we would probably match "--path-format <arg>" here, as our usual parse-options API does. But that is a much bigger change). -Peff