Re: [PATCH v2 13/18] uaccess: generalize access_ok()
From: Arnd Bergmann <arnd@arndb.de>
Date: 2022-02-17 07:52:52
Also in:
linux-alpha, linux-api, linux-arch, linux-m68k, linux-mips, linux-mm, linux-riscv, linux-s390, linux-sh, linuxppc-dev, lkml, sparclinux
On Wed, Feb 16, 2022 at 2:13 PM Arnd Bergmann [off-list ref] wrote:
+ * limit and catch all possible overflows. + * On architectures with separate user address space (m68k, s390, parisc, + * sparc64) or those without an MMU, this should always return true.
...
+static inline int __access_ok(const void __user *ptr, unsigned long size)
+{
+ unsigned long limit = user_addr_max();
+ unsigned long addr = (unsigned long)ptr;
+
+ if (IS_ENABLED(CONFIG_ALTERNATE_USER_ADDRESS_SPACE))
+ return true;
I noticed that I'm missing the check for !CONFIG_MMU here, despite
mentioning that in the comment above it. I've added it now.
Arnd