From: Richard Henderson <richard.hender...@linaro.org>
Verify that addr + size - 1 does not wrap around.
Reviewed-by: Peter Maydell <peter.mayd...@linaro.org>
Signed-off-by: Richard Henderson <richard.hender...@linaro.org>
Message-id: 20210212184902.1251044-7-richard.hender...@linaro.org
Signed-off-by: Peter Maydell <peter.mayd...@linaro.org>
---
linux-user/qemu.h | 17 ++++++++++++-----
1 file changed, 12 insertions(+), 5 deletions(-)
diff --git a/linux-user/qemu.h b/linux-user/qemu.h
index 17aa9921657..441ba6a78bb 100644
--- a/linux-user/qemu.h
+++ b/linux-user/qemu.h
@@ -491,12 +491,19 @@ extern unsigned long guest_stack_size;
#define VERIFY_READ 0
#define VERIFY_WRITE 1 /* implies read access */
-static inline int access_ok(int type, abi_ulong addr, abi_ulong size)
+static inline bool access_ok(int type, abi_ulong addr, abi_ulong size)
{
- return guest_addr_valid(addr) &&
- (size == 0 || guest_addr_valid(addr + size - 1)) &&
- page_check_range((target_ulong)addr, size,
- (type == VERIFY_READ) ? PAGE_READ : (PAGE_READ |
PAGE_WRITE)) == 0;
+ if (!guest_addr_valid(addr)) {
+ return false;
+ }
+ if (size != 0 &&
+ (addr + size - 1 < addr ||
+ !guest_addr_valid(addr + size - 1))) {
+ return false;
+ }
+ return page_check_range((target_ulong)addr, size,
+ (type == VERIFY_READ) ? PAGE_READ :
+ (PAGE_READ | PAGE_WRITE)) == 0;
}
/* NOTE __get_user and __put_user use host pointers and don't check access.
--
2.20.1
