From 1ce53e2c2ac069e7b3c400a427002a70deb4a916 Mon Sep 17 00:00:00 2001 From: Alejandro Colomar Date: Sat, 28 Nov 2020 13:39:46 +0100 Subject: futex: Change utime parameter to be 'const ... *' futex(2) says that 'utime' is a pointer to 'const'. The implementation doesn't use 'const'; however, it _never_ modifies the contents of utime. - futex() either uses 'utime' as a pointer to struct or as a 'u32'. - In case it's used as a 'u32', it makes a copy of it, and of course it is not dereferenced. - In case it's used as a 'struct __kernel_timespec __user *', the pointer is not dereferenced inside the futex() definition, and it is only passed to a function: get_timespec64(), which accepts a 'const struct __kernel_timespec __user *'. [ tglx: Make the same change to the compat syscall and fixup the prototypes. ] Signed-off-by: Alejandro Colomar Signed-off-by: Thomas Gleixner Link: https://lore.kernel.org/r/20201128123945.4592-1-alx.manpages@gmail.com --- kernel/futex.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'kernel/futex.c') diff --git a/kernel/futex.c b/kernel/futex.c index c47d1015d759..d0775aab8da9 100644 --- a/kernel/futex.c +++ b/kernel/futex.c @@ -3790,8 +3790,8 @@ long do_futex(u32 __user *uaddr, int op, u32 val, ktime_t *timeout, SYSCALL_DEFINE6(futex, u32 __user *, uaddr, int, op, u32, val, - struct __kernel_timespec __user *, utime, u32 __user *, uaddr2, - u32, val3) + const struct __kernel_timespec __user *, utime, + u32 __user *, uaddr2, u32, val3) { struct timespec64 ts; ktime_t t, *tp = NULL; @@ -3986,7 +3986,7 @@ err_unlock: #ifdef CONFIG_COMPAT_32BIT_TIME SYSCALL_DEFINE6(futex_time32, u32 __user *, uaddr, int, op, u32, val, - struct old_timespec32 __user *, utime, u32 __user *, uaddr2, + const struct old_timespec32 __user *, utime, u32 __user *, uaddr2, u32, val3) { struct timespec64 ts; -- cgit v1.2.3