The following commit has been merged into the x86/urgent branch of tip:
Commit-ID: eb786ee1390b8fbba633c01a971709c6906fd8bf
Gitweb: https://git.kernel.org/tip/eb786ee1390b8fbba633c01a971709c6906fd8bf
Author: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
AuthorDate: Mon, 26 Aug 2024 15:53:04 +03:00
Committer: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
CommitterDate: Mon, 26 Aug 2024 07:04:09 -07:00
x86/tdx: Fix data leak in mmio_read()
The mmio_read() function makes a TDVMCALL to retrieve MMIO data for an
address from the VMM.
Sean noticed that mmio_read() unintentionally exposes the value of an
initialized variable on the stack to the VMM.
Do not send the original value of *val to the VMM.
Fixes: 31d58c4e557d ("x86/tdx: Handle in-kernel MMIO")
Reported-by: Sean Christopherson <seanjc@xxxxxxxxxx>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Signed-off-by: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc:stable@xxxxxxxxxxxxxxx
Link: https://lore.kernel.org/all/20240826125304.1566719-1-kirill.shutemov%40linux.intel.com
---
arch/x86/coco/tdx/tdx.c | 1 -
1 file changed, 1 deletion(-)
diff --git a/arch/x86/coco/tdx/tdx.c b/arch/x86/coco/tdx/tdx.c
index 078e2ba..da8b66d 100644
--- a/arch/x86/coco/tdx/tdx.c
+++ b/arch/x86/coco/tdx/tdx.c
@@ -389,7 +389,6 @@ static bool mmio_read(int size, unsigned long addr, unsigned long *val)
.r12 = size,
.r13 = EPT_READ,
.r14 = addr,
- .r15 = *val,
};
if (__tdx_hypercall(&args))
|