x86: asm: make sure __put_user_size() evaluates pointer once
authorAlexander Potapenko <glider@google.com>
Mon, 24 Oct 2022 21:21:43 +0000 (23:21 +0200)
committerAndrew Morton <akpm@linux-foundation.org>
Fri, 28 Oct 2022 20:37:23 +0000 (13:37 -0700)
commit59c8a02e24894e75639bcecc3cb1e768a2792220
tree0a1d7eb39339b0bf5f92d857d252a226435eb7da
parent921757bc9b611efc483a548b86769934384e9c79
x86: asm: make sure __put_user_size() evaluates pointer once

User access macros must ensure their arguments are evaluated only once if
they are used more than once in the macro body.  Adding
instrument_put_user() to __put_user_size() resulted in double evaluation
of the `ptr` argument, which led to correctness issues when performing
e.g.  unsafe_put_user(..., p++, ...).

To fix those issues, evaluate the `ptr` argument of __put_user_size() at
the beginning of the macro.

Link: https://lkml.kernel.org/r/20221024212144.2852069-4-glider@google.com
Fixes: 888f84a6da4d ("x86: asm: instrument usercopy in get_user() and put_user()")
Signed-off-by: Alexander Potapenko <glider@google.com>
Reported-by: youling257 <youling257@gmail.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
arch/x86/include/asm/uaccess.h