From: Karel Zak <kzak@redhat.com>
Date: Tue, 27 Aug 2024 11:07:56 +0000 (+0200)
Subject: env: save parsed variables into ul_env_list
X-Git-Tag: v2.42-start~214^2~6
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=aa789c1efcd28223308d010c830bc7f22c52927b;p=thirdparty%2Futil-linux.git

env: save parsed variables into ul_env_list

The struct ul_env_list is currently only used to store the value of
env when sanitizing environ[]. It would be beneficial to also use the
functions related to ul_env_list for other purposes. In order to do
this, it is important to keep the NAME and VALUE components separate.

* Accept non-terminated name and value for env_list_add().

* Add env_list_add_from_string() to add item to the list from a
  "name=value" string.

* Add env_list_add_variable() to add item to the list using separate
  "name" and "value" strings.

* Update __sanitize_env() to use env_list_add_from_string().

* Modify the test to use "abc" as the value instead of copying the
  variable name (with '=') to the value.

Signed-off-by: Karel Zak <kzak@redhat.com>
---

diff --git a/include/env.h b/include/env.h
index 9b2991950..5e9198c88 100644
--- a/include/env.h
+++ b/include/env.h
@@ -13,6 +13,10 @@ struct ul_env_list;
 extern void sanitize_env(void);
 extern void __sanitize_env(struct ul_env_list **org);
 
+extern struct ul_env_list *env_list_add_variable(struct ul_env_list *ls,
+				const char *name, const char *value);
+
+
 extern int env_list_setenv(struct ul_env_list *ls);
 extern void env_list_free(struct ul_env_list *ls);
 extern struct ul_env_list *env_from_fd(int pid);
diff --git a/lib/env.c b/lib/env.c
index 2bdfe5697..bab8822b0 100644
--- a/lib/env.c
+++ b/lib/env.c
@@ -52,36 +52,74 @@ static char * const noslash[] = {
 
 
 struct ul_env_list {
-	char *env;
+	char	*name;
+	char	*value;
+
 	struct ul_env_list *next;
 };
 
 /*
- * Saves @name env.variable to @ls, returns pointer to the new head of the list.
+ * Saves to the list and returns a pointer to the new head of the list.
  */
-static struct ul_env_list *env_list_add(struct ul_env_list *ls0, const char *str)
+static struct ul_env_list *env_list_add( struct ul_env_list *ls0,
+					 const char *name, size_t namesz,
+					 const char *value, size_t valsz)
 {
 	struct ul_env_list *ls;
-	char *p;
-	size_t sz = 0;
 
-	if (!str || !*str)
+	ls = calloc(1, sizeof(struct ul_env_list) + namesz + valsz + 2);
+	if (!ls)
 		return ls0;
 
-	sz = strlen(str) + 1;
-	p = malloc(sizeof(struct ul_env_list) + sz);
-	if (!p)
-		return ls0;
+	ls->name = ((char *) ls) + sizeof(struct ul_env_list);
+	ls->value = ls->name + namesz + 1;
 
-	ls = (struct ul_env_list *) p;
-	p += sizeof(struct ul_env_list);
-	memcpy(p, str, sz);
-	ls->env = p;
+	memcpy(ls->name, name, namesz);
+	memcpy(ls->value, value, valsz);
 
 	ls->next = ls0;
 	return ls;
 }
 
+
+/*
+ * Saves the @str (with the name=value string) to the @ls and returns a pointer
+ * to the new head of the list.
+ */
+static struct ul_env_list *env_list_add_from_string(struct ul_env_list *ls,
+						    const char *str)
+{
+	size_t namesz = 0, valsz = 0;
+	const char *val;
+
+	if (!str || !*str)
+		return ls;
+
+	val = strchr(str, '=');
+	if (!val)
+		return NULL;
+	namesz = val - str;
+
+	val++;
+	valsz = strlen(val);
+
+	return env_list_add(ls, str, namesz, val, valsz);
+}
+
+/*
+ * Saves the @name and @value to @ls0 and returns a pointer to the new head of
+ * the list.
+ */
+struct ul_env_list *env_list_add_variable(
+				struct ul_env_list *ls,
+				const char *name, const char *value)
+{
+	if (!name || !*name)
+		return ls;
+
+	return env_list_add(ls, name, strlen(name), value, value ? strlen(value) : 0);
+}
+
 /*
  * Use env_from_fd() to read environment from @fd.
  *
@@ -99,7 +137,7 @@ struct ul_env_list *env_from_fd(int fd)
 	p = buf;
 
 	while (rc > 0) {
-		ls = env_list_add(ls, p);
+		ls = env_list_add_from_string(ls, p);
 		p += strlen(p) + 1;
 		rc -= strlen(p) + 1;
 	}
@@ -110,22 +148,14 @@ struct ul_env_list *env_from_fd(int fd)
 
 /*
  * Use setenv() for all stuff in @ls.
- *
- * It would be possible to use putenv(), but we want to keep @ls free()-able.
  */
 int env_list_setenv(struct ul_env_list *ls)
 {
 	int rc = 0;
 
 	while (ls && rc == 0) {
-		if (ls->env) {
-			char *val = strchr(ls->env, '=');
-			if (!val)
-				continue;
-			*val = '\0';
-			rc = setenv(ls->env, val + 1, 0);
-			*val = '=';
-		}
+		if (ls->name && ls->value)
+			rc = setenv(ls->name, ls->value, 0);
 		ls = ls->next;
 	}
 	return rc;
@@ -158,7 +188,7 @@ void __sanitize_env(struct ul_env_list **org)
                 for (bad = forbid; *bad; bad++) {
                         if (strncmp(*cur, *bad, strlen(*bad)) == 0) {
 				if (org)
-					*org = env_list_add(*org, *cur);
+					*org = env_list_add_from_string(*org, *cur);
                                 last = remove_entry(envp, cur - envp, last);
                                 cur--;
                                 break;
@@ -173,7 +203,7 @@ void __sanitize_env(struct ul_env_list **org)
                         if (!strchr(*cur, '/'))
                                 continue;  /* OK */
 			if (org)
-				*org = env_list_add(*org, *cur);
+				*org = env_list_add_from_string(*org, *cur);
                         last = remove_entry(envp, cur - envp, last);
                         cur--;
                         break;
@@ -217,12 +247,13 @@ int main(void)
 	int retval = EXIT_SUCCESS;
 	struct ul_env_list *removed = NULL;
 
+	/* define env. */
 	for (bad = forbid; *bad; bad++) {
 		strcpy(copy, *bad);
 		p = strchr(copy, '=');
 		if (p)
 			*p = '\0';
-		setenv(copy, copy, 1);
+		setenv(copy, "abc", 1);
 	}
 
 	/* removed */