[PATCH 07/16] transport-helper: avoid reading past end-of-string
From: Jeff King <hidden>
Date: 2016-06-15 23:01:41
Subsystem:
the rest · Maintainer:
Linus Torvalds
We detect the "import-marks" capability by looking for that
string, but _without_ a trailing space. Then we skip past it
using strlen("import-marks "), with a space. So if a remote
helper gives us exactly "import-marks", we will read past
the end-of-string by one character.
This is unlikely to be a problem in practice, because such
input is malformed in the first place, and because there is
a good chance that the string has an extra NUL terminator
one character after the original (because it formerly had a
newline in it that we parsed off).
We can fix it by using skip_prefix with "import-marks ",
with the space. The other form appears to be a typo from
a515ebe (transport-helper: implement marks location as
capability, 2011-07-16); "import-marks" has never existed
without an argument, and it should match the "export-marks"
definition above.
Speaking of which, we can also use skip_prefix in a few
other places while we are in the function.
Signed-off-by: Jeff King <redacted>
---
transport-helper.c | 14 +++++++-------
1 file changed, 7 insertions(+), 7 deletions(-)
diff --git a/transport-helper.c b/transport-helper.c
index 84c616f..3d8fe7d 100644
--- a/transport-helper.c
+++ b/transport-helper.c@@ -153,7 +153,7 @@ static struct child_process *get_helper(struct transport *transport) write_constant(helper->in, "capabilities\n"); while (1) { - const char *capname; + const char *capname, *arg; int mandatory = 0; if (recvline(data, &buf)) exit(128);
@@ -183,19 +183,19 @@ static struct child_process *get_helper(struct transport *transport) data->export = 1; else if (!strcmp(capname, "check-connectivity")) data->check_connectivity = 1; - else if (!data->refspecs && starts_with(capname, "refspec ")) { + else if (!data->refspecs && skip_prefix(capname, "refspec ", &arg)) { ALLOC_GROW(refspecs, refspec_nr + 1, refspec_alloc); - refspecs[refspec_nr++] = xstrdup(capname + strlen("refspec ")); + refspecs[refspec_nr++] = xstrdup(arg); } else if (!strcmp(capname, "connect")) { data->connect = 1; } else if (!strcmp(capname, "signed-tags")) { data->signed_tags = 1; - } else if (starts_with(capname, "export-marks ")) { - data->export_marks = xstrdup(capname + strlen("export-marks ")); - } else if (starts_with(capname, "import-marks")) { - data->import_marks = xstrdup(capname + strlen("import-marks ")); + } else if (skip_prefix(capname, "export-marks ", &arg)) { + data->export_marks = xstrdup(arg); + } else if (skip_prefix(capname, "import-marks ", &arg)) { + data->import_marks = xstrdup(arg); } else if (starts_with(capname, "no-private-update")) { data->no_private_update = 1; } else if (mandatory) {
--
2.0.0.566.gfe3e6b2