svn commit: r356507 - head/sys/opencrypto
John Baldwin
jhb at FreeBSD.org
Wed Jan 8 18:59:24 UTC 2020
Author: jhb
Date: Wed Jan 8 18:59:23 2020
New Revision: 356507
URL: https://svnweb.freebsd.org/changeset/base/356507
Log:
Add a reference count to cryptodev sessions.
This prevents use-after-free races with crypto requests (which may
sleep) and CIOCFSESSION as well as races from current CIOCFSESSION
requests.
admbugs: 949
Reported by: Yuval Kanarenstein <yuvalk at ssd-disclosure.com>
Reviewed by: cem
MFC after: 1 week
Sponsored by: Chelsio Communications
Differential Revision: https://reviews.freebsd.org/D23077
Modified:
head/sys/opencrypto/cryptodev.c
Modified: head/sys/opencrypto/cryptodev.c
==============================================================================
--- head/sys/opencrypto/cryptodev.c Wed Jan 8 18:26:23 2020 (r356506)
+++ head/sys/opencrypto/cryptodev.c Wed Jan 8 18:59:23 2020 (r356507)
@@ -266,6 +266,7 @@ crypt_kop_to_32(const struct crypt_kop *from, struct c
struct csession {
TAILQ_ENTRY(csession) next;
crypto_session_t cses;
+ volatile u_int refs;
u_int32_t ses;
struct mtx lock; /* for op submission */
@@ -292,6 +293,7 @@ struct cryptop_data {
struct fcrypt {
TAILQ_HEAD(csessionlist, csession) csessions;
int sesn;
+ struct mtx lock;
};
static struct timeval warninterval = { .tv_sec = 60, .tv_usec = 0 };
@@ -323,8 +325,8 @@ static struct fileops cryptofops = {
};
static struct csession *csefind(struct fcrypt *, u_int);
-static int csedelete(struct fcrypt *, struct csession *);
-static struct csession *cseadd(struct fcrypt *, struct csession *);
+static bool csedelete(struct fcrypt *, u_int);
+static void cseadd(struct fcrypt *, struct csession *);
static struct csession *csecreate(struct fcrypt *, crypto_session_t, caddr_t,
u_int64_t, caddr_t, u_int64_t, u_int32_t, u_int32_t, struct enc_xform *,
struct auth_hash *);
@@ -668,13 +670,10 @@ bail:
break;
case CIOCFSESSION:
ses = *(u_int32_t *)data;
- cse = csefind(fcr, ses);
- if (cse == NULL) {
+ if (!csedelete(fcr, ses)) {
SDT_PROBE1(opencrypto, dev, ioctl, error, __LINE__);
return (EINVAL);
}
- csedelete(fcr, cse);
- csefree(cse);
break;
case CIOCCRYPT:
#ifdef COMPAT_FREEBSD32
@@ -691,6 +690,7 @@ bail:
return (EINVAL);
}
error = cryptodev_op(cse, cop, active_cred, td);
+ csefree(cse);
#ifdef COMPAT_FREEBSD32
if (error == 0 && cmd == CIOCCRYPT32)
crypt_op_to_32(cop, data);
@@ -757,6 +757,7 @@ bail:
return (EINVAL);
}
error = cryptodev_aead(cse, caead, active_cred, td);
+ csefree(cse);
break;
default:
error = EINVAL;
@@ -1375,6 +1376,9 @@ cryptof_close(struct file *fp, struct thread *td)
while ((cse = TAILQ_FIRST(&fcr->csessions))) {
TAILQ_REMOVE(&fcr->csessions, cse, next);
+ KASSERT(cse->refs == 1,
+ ("%s: crypto session %p with %d refs", __func__, cse,
+ cse->refs));
csefree(cse);
}
free(fcr, M_XDATA);
@@ -1395,34 +1399,36 @@ csefind(struct fcrypt *fcr, u_int ses)
{
struct csession *cse;
- TAILQ_FOREACH(cse, &fcr->csessions, next)
- if (cse->ses == ses)
+ mtx_lock(&fcr->lock);
+ TAILQ_FOREACH(cse, &fcr->csessions, next) {
+ if (cse->ses == ses) {
+ refcount_acquire(&cse->refs);
+ mtx_unlock(&fcr->lock);
return (cse);
+ }
+ }
+ mtx_unlock(&fcr->lock);
return (NULL);
}
-static int
-csedelete(struct fcrypt *fcr, struct csession *cse_del)
+static bool
+csedelete(struct fcrypt *fcr, u_int ses)
{
struct csession *cse;
+ mtx_lock(&fcr->lock);
TAILQ_FOREACH(cse, &fcr->csessions, next) {
- if (cse == cse_del) {
+ if (cse->ses == ses) {
TAILQ_REMOVE(&fcr->csessions, cse, next);
- return (1);
+ mtx_unlock(&fcr->lock);
+ csefree(cse);
+ return (true);
}
}
- return (0);
+ mtx_unlock(&fcr->lock);
+ return (false);
}
-static struct csession *
-cseadd(struct fcrypt *fcr, struct csession *cse)
-{
- TAILQ_INSERT_TAIL(&fcr->csessions, cse, next);
- cse->ses = fcr->sesn++;
- return (cse);
-}
-
struct csession *
csecreate(struct fcrypt *fcr, crypto_session_t cses, caddr_t key, u_int64_t keylen,
caddr_t mackey, u_int64_t mackeylen, u_int32_t cipher, u_int32_t mac,
@@ -1434,6 +1440,7 @@ csecreate(struct fcrypt *fcr, crypto_session_t cses, c
if (cse == NULL)
return NULL;
mtx_init(&cse->lock, "cryptodev", "crypto session lock", MTX_DEF);
+ refcount_init(&cse->refs, 1);
cse->key = key;
cse->keylen = keylen/8;
cse->mackey = mackey;
@@ -1443,7 +1450,10 @@ csecreate(struct fcrypt *fcr, crypto_session_t cses, c
cse->mac = mac;
cse->txform = txform;
cse->thash = thash;
- cseadd(fcr, cse);
+ mtx_lock(&fcr->lock);
+ TAILQ_INSERT_TAIL(&fcr->csessions, cse, next);
+ cse->ses = fcr->sesn++;
+ mtx_unlock(&fcr->lock);
return (cse);
}
@@ -1451,6 +1461,8 @@ static void
csefree(struct csession *cse)
{
+ if (!refcount_release(&cse->refs))
+ return;
crypto_freesession(cse->cses);
mtx_destroy(&cse->lock);
if (cse->key)
@@ -1487,13 +1499,14 @@ cryptoioctl(struct cdev *dev, u_long cmd, caddr_t data
switch (cmd) {
case CRIOGET:
- fcr = malloc(sizeof(struct fcrypt), M_XDATA, M_WAITOK);
+ fcr = malloc(sizeof(struct fcrypt), M_XDATA, M_WAITOK | M_ZERO);
TAILQ_INIT(&fcr->csessions);
- fcr->sesn = 0;
+ mtx_init(&fcr->lock, "fcrypt", NULL, MTX_DEF);
error = falloc(td, &f, &fd, 0);
if (error) {
+ mtx_destroy(&fcr->lock);
free(fcr, M_XDATA);
return (error);
}
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