[for_v23,1/4] x86/sgx: Pass EADD the kernel's virtual address for the source page
diff mbox series

Message ID 20191010225530.26400-2-sean.j.christopherson@intel.com
State New
Headers show
Series
  • x86/sgx: Fix add page bugs
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Commit Message

Sean Christopherson Oct. 10, 2019, 10:55 p.m. UTC
Use the kernel's virtual address to reference the source page when
EADDing a page to the enclave.  gup() "does not guarantee that the page
exists in the user mappings", i.e. EADD can still fault and deadlock
due to mmap_sem contention if it consumes the userspace address.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
---
 arch/x86/kernel/cpu/sgx/ioctl.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

Patch
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diff --git a/arch/x86/kernel/cpu/sgx/ioctl.c b/arch/x86/kernel/cpu/sgx/ioctl.c
index eeed919ed3e2..62965d003fda 100644
--- a/arch/x86/kernel/cpu/sgx/ioctl.c
+++ b/arch/x86/kernel/cpu/sgx/ioctl.c
@@ -328,16 +328,14 @@  static int __sgx_encl_add_page(struct sgx_encl *encl,
 	if (ret < 1)
 		return ret;
 
-	__uaccess_begin();
-
 	pginfo.secs = (unsigned long)sgx_epc_addr(encl->secs.epc_page);
 	pginfo.addr = SGX_ENCL_PAGE_ADDR(encl_page);
 	pginfo.metadata = (unsigned long)secinfo;
-	pginfo.contents = (unsigned long)src;
+	pginfo.contents = (unsigned long)kmap_atomic(src_page);
 
 	ret = __eadd(&pginfo, sgx_epc_addr(epc_page));
 
-	__uaccess_end();
+	kunmap_atomic((void *)pginfo.contents);
 	put_page(src_page);
 
 	return ret ? -EFAULT : 0;