From: Ira Weiny ira.weiny@intel.com
mainline inclusion from mainline-v5.13-rc1 commit 633b0616cfe085679471a4c0fae02e8c3a1a9866 category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/I4SIGI CVE: NA
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kmap() is inefficient and is being replaced by kmap_local_page(), if possible. There is no readily apparent reason why initp_page needs to be allocated and kmap'ed() except that 'sigstruct' needs to be page-aligned and 'token' 512 byte-aligned.
Rather than change it to kmap_local_page(), use kmalloc() instead because kmalloc() can give this alignment when allocating PAGE_SIZE bytes.
Remove the alloc_page()/kmap() and replace with kmalloc(PAGE_SIZE, ...) to get a page aligned kernel address.
In addition, add a comment to document the alignment requirements so that others don't attempt to 'fix' this again.
[ bp: Massage commit message. ]
Intel-SIG: commit 633b0616cfe0 x86/sgx: Remove unnecessary kmap() from sgx_ioc_enclave_init() Backport for SGX Foundations support
Signed-off-by: Ira Weiny ira.weiny@intel.com Signed-off-by: Borislav Petkov bp@suse.de Link: https://lkml.kernel.org/r/20210324182246.2484875-1-ira.weiny@intel.com Signed-off-by: Fan Du fan.du@intel.com #openEuler_contributor Signed-off-by: Laibin Qiu qiulaibin@huawei.com Reviewed-by: Bamvor Zhang bamvor.zhang@suse.com Signed-off-by: Zheng Zengkai zhengzengkai@huawei.com --- arch/x86/kernel/cpu/sgx/ioctl.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-)
diff --git a/arch/x86/kernel/cpu/sgx/ioctl.c b/arch/x86/kernel/cpu/sgx/ioctl.c index 90a5caf76939..2e10367ea66c 100644 --- a/arch/x86/kernel/cpu/sgx/ioctl.c +++ b/arch/x86/kernel/cpu/sgx/ioctl.c @@ -604,7 +604,6 @@ static long sgx_ioc_enclave_init(struct sgx_encl *encl, void __user *arg) { struct sgx_sigstruct *sigstruct; struct sgx_enclave_init init_arg; - struct page *initp_page; void *token; int ret;
@@ -615,11 +614,15 @@ static long sgx_ioc_enclave_init(struct sgx_encl *encl, void __user *arg) if (copy_from_user(&init_arg, arg, sizeof(init_arg))) return -EFAULT;
- initp_page = alloc_page(GFP_KERNEL); - if (!initp_page) + /* + * 'sigstruct' must be on a page boundary and 'token' on a 512 byte + * boundary. kmalloc() will give this alignment when allocating + * PAGE_SIZE bytes. + */ + sigstruct = kmalloc(PAGE_SIZE, GFP_KERNEL); + if (!sigstruct) return -ENOMEM;
- sigstruct = kmap(initp_page); token = (void *)((unsigned long)sigstruct + PAGE_SIZE / 2); memset(token, 0, SGX_LAUNCH_TOKEN_SIZE);
@@ -645,8 +648,7 @@ static long sgx_ioc_enclave_init(struct sgx_encl *encl, void __user *arg) ret = sgx_encl_init(encl, sigstruct, token);
out: - kunmap(initp_page); - __free_page(initp_page); + kfree(sigstruct); return ret; }