sgx_validate_offset_length() function verifies "offset" and "length"
arguments provided by userspace, but was missing an overflow check on
their addition.
This code was originally introduced in commit c6d26d370767 ("x86/sgx:
Add SGX_IOC_ENCLAVE_ADD_PAGES") and later refactored in commit
dda03e2c331b ("x86/sgx: Create utility to validate user provided offset
and length").
Fixes: c6d26d370767 ("x86/sgx: Add SGX_IOC_ENCLAVE_ADD_PAGES")
Signed-off-by: Borys Popławski <borysp@xxxxxxxxxxxxxxxxxxxxxx>
---
Applies on top of tip/x86/sgx ee56a283988d739c25d2d00ffb22707cb487ab47
arch/x86/kernel/cpu/sgx/ioctl.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/arch/x86/kernel/cpu/sgx/ioctl.c b/arch/x86/kernel/cpu/sgx/ioctl.c
index ebe79d60619f..da8b8ea6b063 100644
--- a/arch/x86/kernel/cpu/sgx/ioctl.c
+++ b/arch/x86/kernel/cpu/sgx/ioctl.c
@@ -356,6 +356,9 @@ static int sgx_validate_offset_length(struct sgx_encl *encl,
if (!length || !IS_ALIGNED(length, PAGE_SIZE))
return -EINVAL;
+ if (offset + length < offset)
+ return -EINVAL;
+
if (offset + length - PAGE_SIZE >= encl->size)
return -EINVAL;
--
2.37.3
