From: Waiman Long <longman@redhat.com>
To: David Howells <dhowells@redhat.com>,
Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>,
James Morris <jmorris@namei.org>,
"Serge E. Hallyn" <serge@hallyn.com>,
Mimi Zohar <zohar@linux.ibm.com>
Cc: keyrings@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-security-module@vger.kernel.org,
linux-integrity@vger.kernel.org,
Sumit Garg <sumit.garg@linaro.org>,
Jerry Snitselaar <jsnitsel@redhat.com>,
Roberto Sassu <roberto.sassu@huawei.com>,
Eric Biggers <ebiggers@google.com>,
Chris von Recklinghausen <crecklin@redhat.com>,
Waiman Long <longman@redhat.com>
Subject: [PATCH v3 3/3] KEYS: Use kvmalloc() to better handle large buffer allocation
Date: Fri, 13 Mar 2020 11:21:02 -0400 [thread overview]
Message-ID: <20200313152102.1707-4-longman@redhat.com> (raw)
In-Reply-To: <20200313152102.1707-1-longman@redhat.com>
For large multi-page temporary buffer allocation, the security/keys
subsystem don't need contiguous physical pages. It will work perfectly
fine with virtually mapped pages.
Replace the kmalloc() call by kvmalloc() and provide a __kvzfree()
helper function to clear and free the kvmalloc'ed buffer. This will
reduce the chance of memory allocation failure just because of highly
fragmented pages.
Suggested-by: David Howells <dhowells@redhat.com>
Signed-off-by: Waiman Long <longman@redhat.com>
---
security/keys/internal.h | 14 ++++++++++++++
security/keys/keyctl.c | 10 +++++-----
2 files changed, 19 insertions(+), 5 deletions(-)
diff --git a/security/keys/internal.h b/security/keys/internal.h
index ba3e2da14cef..855b11eb73ee 100644
--- a/security/keys/internal.h
+++ b/security/keys/internal.h
@@ -16,6 +16,8 @@
#include <linux/keyctl.h>
#include <linux/refcount.h>
#include <linux/compat.h>
+#include <linux/mm.h>
+#include <linux/vmalloc.h>
struct iovec;
@@ -349,4 +351,16 @@ static inline void key_check(const struct key *key)
#endif
+/*
+ * Helper function to clear and free a kvmalloc'ed memory object.
+ */
+static inline void __kvzfree(const void *addr, size_t len)
+{
+ if (is_vmalloc_addr(addr)) {
+ memset((void *)addr, 0, len);
+ vfree(addr);
+ } else {
+ kzfree(addr);
+ }
+}
#endif /* _INTERNAL_H */
diff --git a/security/keys/keyctl.c b/security/keys/keyctl.c
index a05a4dd2f9ce..878259cf35d5 100644
--- a/security/keys/keyctl.c
+++ b/security/keys/keyctl.c
@@ -339,7 +339,7 @@ long keyctl_update_key(key_serial_t id,
payload = NULL;
if (plen) {
ret = -ENOMEM;
- payload = kmalloc(plen, GFP_KERNEL);
+ payload = kvmalloc(plen, GFP_KERNEL);
if (!payload)
goto error;
@@ -360,7 +360,7 @@ long keyctl_update_key(key_serial_t id,
key_ref_put(key_ref);
error2:
- kzfree(payload);
+ __kvzfree(payload, plen);
error:
return ret;
}
@@ -893,7 +893,7 @@ long keyctl_read_key(key_serial_t keyid, char __user *buffer, size_t buflen)
*/
if (buflen <= 0x400) {
allocbuf:
- tmpbuf = kmalloc(tmpbuflen, GFP_KERNEL);
+ tmpbuf = kvmalloc(tmpbuflen, GFP_KERNEL);
if (!tmpbuf) {
ret = -ENOMEM;
goto error2;
@@ -911,7 +911,7 @@ long keyctl_read_key(key_serial_t keyid, char __user *buffer, size_t buflen)
*/
if (!tmpbuf || unlikely(ret > tmpbuflen)) {
if (unlikely(tmpbuf))
- kzfree(tmpbuf);
+ __kvzfree(tmpbuf, tmpbuflen);
tmpbuflen = ret;
goto allocbuf;
}
@@ -920,7 +920,7 @@ long keyctl_read_key(key_serial_t keyid, char __user *buffer, size_t buflen)
ret = -EFAULT;
}
if (tmpbuf)
- kzfree(tmpbuf);
+ __kvzfree(tmpbuf, tmpbuflen);
}
error2:
--
2.18.1
next prev parent reply other threads:[~2020-03-13 15:21 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-13 15:20 [PATCH v3 0/3] KEYS: Read keys to internal buffer & then copy to userspace Waiman Long
2020-03-13 15:21 ` [PATCH v3 1/3] KEYS: Don't write out to userspace while holding key semaphore Waiman Long
2020-03-15 19:21 ` Jarkko Sakkinen
2020-03-15 21:27 ` Jarkko Sakkinen
2020-03-16 11:22 ` David Howells
2020-03-16 13:53 ` Jarkko Sakkinen
2020-03-16 16:33 ` Waiman Long
2020-03-17 18:10 ` Waiman Long
2020-03-16 11:34 ` David Howells
2020-03-13 15:21 ` [PATCH v3 2/3] KEYS: Avoid false positive ENOMEM error on key read Waiman Long
2020-03-15 21:32 ` Jarkko Sakkinen
2020-03-17 18:36 ` Waiman Long
2020-03-13 15:21 ` Waiman Long [this message]
2020-03-13 16:43 ` [PATCH v3 3/3] KEYS: Use kvmalloc() to better handle large buffer allocation Eric Biggers
2020-03-13 17:49 ` Waiman Long
2020-03-15 21:52 ` Jarkko Sakkinen
2020-03-15 22:01 ` Waiman Long
2020-03-16 11:50 ` [PATCH v3 1/3] KEYS: Don't write out to userspace while holding key semaphore David Howells
2020-03-17 18:09 ` Waiman Long
2020-03-16 14:24 ` [PATCH v3 3/3] KEYS: Use kvmalloc() to better handle large buffer allocation David Howells
2020-03-16 15:21 ` Waiman Long
2020-03-16 22:19 ` Jarkko Sakkinen
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