svn commit: r362231 - head/sys/kern
Simon J. Gerraty
sjg at FreeBSD.org
Tue Jun 16 17:02:57 UTC 2020
Author: sjg
Date: Tue Jun 16 17:02:56 2020
New Revision: 362231
URL: https://svnweb.freebsd.org/changeset/base/362231
Log:
Make KENV_MVALLEN tunable
When doing secure boot, loader wants to export loader.ve.hashed
the value of which typically exceeds KENV_MVALLEN.
Replace use of KENV_MVALLEN with tunable kenv_mvallen.
Add getenv_string_buffer() for the case where a stack buffer cannot be
created and use uma_zone_t kenv_zone for suitably sized buffers.
Reviewed by: stevek, kevans
Obtained from: Abhishek Kulkarni <abkulkarni at juniper.net>
MFC after: 1 week
Sponsored by: Juniper Networks
Differential Revision: https://reviews.freebsd.org//D25259
Modified:
head/sys/kern/kern_environment.c
Modified: head/sys/kern/kern_environment.c
==============================================================================
--- head/sys/kern/kern_environment.c Tue Jun 16 16:48:52 2020 (r362230)
+++ head/sys/kern/kern_environment.c Tue Jun 16 17:02:56 2020 (r362231)
@@ -63,6 +63,9 @@ static MALLOC_DEFINE(M_KENV, "kenv", "kernel environme
#define KENV_SIZE 512 /* Maximum number of environment strings */
+static uma_zone_t kenv_zone;
+static int kenv_mvallen = KENV_MVALLEN;
+
/* pointer to the config-generated static environment */
char *kern_envp;
@@ -85,6 +88,8 @@ bool dynamic_kenv;
#define KENV_CHECK if (!dynamic_kenv) \
panic("%s: called before SI_SUB_KMEM", __func__)
+static char *getenv_string_buffer(const char *);
+
int
sys_kenv(td, uap)
struct thread *td;
@@ -110,9 +115,9 @@ sys_kenv(td, uap)
#endif
done = needed = 0;
buflen = uap->len;
- if (buflen > KENV_SIZE * (KENV_MNAMELEN + KENV_MVALLEN + 2))
+ if (buflen > KENV_SIZE * (KENV_MNAMELEN + kenv_mvallen + 2))
buflen = KENV_SIZE * (KENV_MNAMELEN +
- KENV_MVALLEN + 2);
+ kenv_mvallen + 2);
if (uap->len > 0 && uap->value != NULL)
buffer = malloc(buflen, M_TEMP, M_WAITOK|M_ZERO);
mtx_lock(&kenv_lock);
@@ -185,8 +190,8 @@ sys_kenv(td, uap)
error = EINVAL;
goto done;
}
- if (len > KENV_MVALLEN + 1)
- len = KENV_MVALLEN + 1;
+ if (len > kenv_mvallen + 1)
+ len = kenv_mvallen + 1;
value = malloc(len, M_TEMP, M_WAITOK);
error = copyinstr(uap->value, value, len, NULL);
if (error) {
@@ -327,7 +332,7 @@ init_dynamic_kenv_from(char *init_env, int *curpos)
for (cp = init_env; cp != NULL; cp = cpnext) {
cpnext = kernenv_next(cp);
len = strlen(cp) + 1;
- if (len > KENV_MNAMELEN + 1 + KENV_MVALLEN + 1) {
+ if (len > KENV_MNAMELEN + 1 + kenv_mvallen + 1) {
printf(
"WARNING: too long kenv string, ignoring %s\n",
cp);
@@ -375,7 +380,14 @@ static void
init_dynamic_kenv(void *data __unused)
{
int dynamic_envpos;
+ int size;
+ TUNABLE_INT_FETCH("kenv_mvallen", &kenv_mvallen);
+ size = KENV_MNAMELEN + 1 + kenv_mvallen + 1;
+
+ kenv_zone = uma_zcreate("kenv", size, NULL, NULL, NULL, NULL,
+ UMA_ALIGN_PTR, 0);
+
kenvp = malloc((KENV_SIZE + 1) * sizeof(char *), M_KENV,
M_WAITOK | M_ZERO);
@@ -395,7 +407,7 @@ freeenv(char *env)
if (dynamic_kenv && env != NULL) {
explicit_bzero(env, strlen(env));
- free(env, M_KENV);
+ uma_zfree(kenv_zone, env);
}
}
@@ -470,14 +482,11 @@ _getenv_static(const char *name)
char *
kern_getenv(const char *name)
{
- char buf[KENV_MNAMELEN + 1 + KENV_MVALLEN + 1];
char *ret;
if (dynamic_kenv) {
- if (getenv_string(name, buf, sizeof(buf))) {
- ret = strdup(buf, M_KENV);
- } else {
- ret = NULL;
+ ret = getenv_string_buffer(name);
+ if (ret == NULL) {
WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL,
"getenv");
}
@@ -548,7 +557,7 @@ kern_setenv(const char *name, const char *value)
if (namelen > KENV_MNAMELEN + 1)
return (-1);
vallen = strlen(value) + 1;
- if (vallen > KENV_MVALLEN + 1)
+ if (vallen > kenv_mvallen + 1)
return (-1);
buf = malloc(namelen + vallen, M_KENV, M_WAITOK);
sprintf(buf, "%s=%s", name, value);
@@ -607,6 +616,33 @@ kern_unsetenv(const char *name)
}
/*
+ * Return a buffer containing the string value from an environment variable
+ */
+static char *
+getenv_string_buffer(const char *name)
+{
+ char *cp, *ret;
+ int len;
+
+ if (dynamic_kenv) {
+ len = KENV_MNAMELEN + 1 + kenv_mvallen + 1;
+ ret = uma_zalloc(kenv_zone, M_WAITOK | M_ZERO);
+ mtx_lock(&kenv_lock);
+ cp = _getenv_dynamic(name, NULL);
+ if (cp != NULL)
+ strlcpy(ret, cp, len);
+ mtx_unlock(&kenv_lock);
+ if (cp == NULL) {
+ uma_zfree(kenv_zone, ret);
+ ret = NULL;
+ }
+ } else
+ ret = _getenv_static(name);
+
+ return (ret);
+}
+
+/*
* Return a string value from an environment variable.
*/
int
@@ -635,17 +671,19 @@ int
getenv_array(const char *name, void *pdata, int size, int *psize,
int type_size, bool allow_signed)
{
- char buf[KENV_MNAMELEN + 1 + KENV_MVALLEN + 1];
uint8_t shift;
int64_t value;
int64_t old;
+ char *buf;
char *end;
char *ptr;
int n;
+ int rc;
- if (getenv_string(name, buf, sizeof(buf)) == 0)
+ if ((buf = getenv_string_buffer(name)) == NULL)
return (0);
+ rc = 0; /* assume failure */
/* get maximum number of elements */
size /= type_size;
@@ -758,9 +796,11 @@ getenv_array(const char *name, void *pdata, int size,
*psize = n * type_size;
if (n != 0)
- return (1); /* success */
+ rc = 1; /* success */
error:
- return (0); /* failure */
+ if (dynamic_kenv)
+ uma_zfree(kenv_zone, buf);
+ return (rc);
}
/*
@@ -859,15 +899,17 @@ getenv_ulong(const char *name, unsigned long *data)
int
getenv_quad(const char *name, quad_t *data)
{
- char value[KENV_MNAMELEN + 1 + KENV_MVALLEN + 1];
- char *vtp;
+ char *value, *vtp;
quad_t iv;
- if (!getenv_string(name, value, sizeof(value)))
+ value = getenv_string_buffer(name);
+ if (value == NULL)
return (0);
iv = strtoq(value, &vtp, 0);
- if (vtp == value || (vtp[0] != '\0' && vtp[1] != '\0'))
+ if (vtp == value || (vtp[0] != '\0' && vtp[1] != '\0')) {
+ freeenv(value);
return (0);
+ }
switch (vtp[0]) {
case 't': case 'T':
iv *= 1024;
@@ -883,8 +925,10 @@ getenv_quad(const char *name, quad_t *data)
case '\0':
break;
default:
+ freeenv(value);
return (0);
}
+ freeenv(value);
*data = iv;
return (1);
}
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