From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001

From: Benjamin Marzinski <bmarzins@redhat.com>

Date: Wed, 14 Dec 2022 15:38:20 -0600

Subject: [PATCH] libmutipath: validate the argument count of config strings

The features, path_selector, and hardware_handler config options pass

their strings directly into the kernel.  If users omit the argument

counts from these strings, or use the wrong value, the kernel's table

parsing gets completely messed up, and the error messages it prints

don't reflect what actully went wrong. To avoid messing up the

kernel table parsing, verify that these strings correctly set the

argument count to the number of arguments they have.

Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com>

Reviewed-by: Martin Wilck <mwilck@suse.com>

---

 libmultipath/dict.c | 110 ++++++++++++++++++++++++++++++++++++++++----

 1 file changed, 101 insertions(+), 9 deletions(-)

diff --git a/libmultipath/dict.c b/libmultipath/dict.c

index 861d1d17..eb2f33a2 100644

--- a/libmultipath/dict.c

+++ b/libmultipath/dict.c

@@ -142,6 +142,58 @@ set_dir(vector strvec, void *ptr, const char *file, int line_nr)

 	return 0;

 }

+static int

+set_arg_str(vector strvec, void *ptr, int count_idx, const char *file,

+	    int line_nr)

+{

+	char **str_ptr = (char **)ptr;

+	char *old_str = *str_ptr;

+	const char * const spaces = " \f\r\t\v";

+	char *p, *end;

+	int idx = -1;

+	long int count = -1;

+

+	*str_ptr = set_value(strvec);

+	if (!*str_ptr) {

+		free(old_str);

+		return 1;

+	}

+	p = *str_ptr;

+	while (*p != '\0') {

+		p += strspn(p, spaces);

+		if (*p == '\0')

+			break;

+		idx += 1;

+		if (idx == count_idx) {

+			errno = 0;

+			count = strtol(p, &end, 10);

+			if (errno == ERANGE || end == p ||

+			    !(isspace(*end) || *end == '\0')) {

+				count = -1;

+				break;

+			}

+		}

+		p += strcspn(p, spaces);

+	}

+	if (count < 0) {

+		condlog(1, "%s line %d, missing argument count for %s",

+			file, line_nr, (char*)VECTOR_SLOT(strvec, 0));

+		goto fail;

+	}

+	if (count != idx - count_idx) {

+		condlog(1, "%s line %d, invalid argument count for %s:, got '%ld' expected '%d'",

+			file, line_nr, (char*)VECTOR_SLOT(strvec, 0), count,

+			idx - count_idx);

+		goto fail;

+	}

+	free(old_str);

+	return 0;

+fail:

+	free(*str_ptr);

+	*str_ptr = old_str;

+	return 0;

+}

+

 static int

 set_path(vector strvec, void *ptr, const char *file, int line_nr)

 {

@@ -294,6 +346,14 @@ def_ ## option ## _handler (struct config *conf, vector strvec,         \

 	return set_int(strvec, &conf->option, minval, maxval, file, line_nr); \

 }

+#define declare_def_arg_str_handler(option, count_idx)			\

+static int								\

+def_ ## option ## _handler (struct config *conf, vector strvec,		\

+			    const char *file, int line_nr)		\

+{									\

+	return set_arg_str(strvec, &conf->option, count_idx, file, line_nr); \

+}

+

 #define declare_def_snprint(option, function)				\

 static int								\

 snprint_def_ ## option (struct config *conf, struct strbuf *buff,	\

@@ -346,6 +406,17 @@ hw_ ## option ## _handler (struct config *conf, vector strvec,		\

 	return set_int(strvec, &hwe->option, minval, maxval, file, line_nr); \

 }

+#define declare_hw_arg_str_handler(option, count_idx)			\

+static int								\

+hw_ ## option ## _handler (struct config *conf, vector strvec,		\

+			    const char *file, int line_nr)		\

+{									\

+	struct hwentry * hwe = VECTOR_LAST_SLOT(conf->hwtable);		\

+	if (!hwe)							\

+		return 1;						\

+	return set_arg_str(strvec, &hwe->option, count_idx, file, line_nr); \

+}

+

 #define declare_hw_snprint(option, function)				\

 static int								\

@@ -377,6 +448,16 @@ ovr_ ## option ## _handler (struct config *conf, vector strvec,		\

 		       file, line_nr); \

 }

+#define declare_ovr_arg_str_handler(option, count_idx)			\

+static int								\

+ovr_ ## option ## _handler (struct config *conf, vector strvec,		\

+			    const char *file, int line_nr)		\

+{									\

+	if (!conf->overrides)						\

+		return 1;						\

+	return set_arg_str(strvec, &conf->overrides->option, count_idx, file, line_nr); \

+}

+

 #define declare_ovr_snprint(option, function)				\

 static int								\

 snprint_ovr_ ## option (struct config *conf, struct strbuf *buff,	\

@@ -407,6 +488,17 @@ mp_ ## option ## _handler (struct config *conf, vector strvec,		\

 	return set_int(strvec, &mpe->option, minval, maxval, file, line_nr); \

 }

+#define declare_mp_arg_str_handler(option, count_idx)			\

+static int								\

+mp_ ## option ## _handler (struct config *conf, vector strvec,		\

+			    const char *file, int line_nr)		\

+{									\

+	struct mpentry * mpe = VECTOR_LAST_SLOT(conf->mptable);		\

+	if (!mpe)							\

+		return 1;						\

+	return set_arg_str(strvec, &mpe->option, count_idx, file, line_nr); \

+}

+

 #define declare_mp_snprint(option, function)				\

 static int								\

 snprint_mp_ ## option (struct config *conf, struct strbuf *buff,	\

@@ -591,13 +683,13 @@ snprint_def_marginal_pathgroups(struct config *conf, struct strbuf *buff,

 }

-declare_def_handler(selector, set_str)

+declare_def_arg_str_handler(selector, 1)

 declare_def_snprint_defstr(selector, print_str, DEFAULT_SELECTOR)

-declare_hw_handler(selector, set_str)

+declare_hw_arg_str_handler(selector, 1)

 declare_hw_snprint(selector, print_str)

-declare_ovr_handler(selector, set_str)

+declare_ovr_arg_str_handler(selector, 1)

 declare_ovr_snprint(selector, print_str)

-declare_mp_handler(selector, set_str)

+declare_mp_arg_str_handler(selector, 1)

 declare_mp_snprint(selector, print_str)

 static int snprint_uid_attrs(struct config *conf, struct strbuf *buff,

@@ -672,13 +764,13 @@ declare_hw_snprint(prio_args, print_str)

 declare_mp_handler(prio_args, set_str)

 declare_mp_snprint(prio_args, print_str)

-declare_def_handler(features, set_str)

+declare_def_arg_str_handler(features, 0)

 declare_def_snprint_defstr(features, print_str, DEFAULT_FEATURES)

-declare_ovr_handler(features, set_str)

+declare_ovr_arg_str_handler(features, 0)

 declare_ovr_snprint(features, print_str)

-declare_hw_handler(features, set_str)

+declare_hw_arg_str_handler(features, 0)

 declare_hw_snprint(features, print_str)

-declare_mp_handler(features, set_str)

+declare_mp_arg_str_handler(features, 0)

 declare_mp_snprint(features, print_str)

 declare_def_handler(checker_name, set_str)

@@ -1857,7 +1949,7 @@ declare_hw_snprint(revision, print_str)

 declare_hw_handler(bl_product, set_str)

 declare_hw_snprint(bl_product, print_str)

-declare_hw_handler(hwhandler, set_str)

+declare_hw_arg_str_handler(hwhandler, 0)

 declare_hw_snprint(hwhandler, print_str)

 /*