From mboxrd@z Thu Jan 1 00:00:00 1970 From: Waiman Long Date: Fri, 13 Mar 2020 15:21:02 +0000 Subject: [PATCH v3 3/3] KEYS: Use kvmalloc() to better handle large buffer allocation Message-Id: <20200313152102.1707-4-longman@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit List-Id: References: <20200313152102.1707-1-longman@redhat.com> In-Reply-To: <20200313152102.1707-1-longman@redhat.com> To: David Howells , Jarkko Sakkinen , James Morris , "Serge E. Hallyn" , Mimi Zohar Cc: keyrings@vger.kernel.org, linux-kernel@vger.kernel.org, linux-security-module@vger.kernel.org, linux-integrity@vger.kernel.org, Sumit Garg , Jerry Snitselaar , Roberto Sassu , Eric Biggers , Chris von Recklinghausen , Waiman Long 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 Signed-off-by: Waiman Long --- 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 #include #include +#include +#include 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