The following commit has been merged into the locking/core branch of tip: Commit-ID: 1ce53e2c2ac069e7b3c400a427002a70deb4a916 Gitweb: https://git.kernel.org/tip/1ce53e2c2ac069e7b3c400a427002a70deb4a916 Author: Alejandro Colomar <alx.manpa...@gmail.com> AuthorDate: Sat, 28 Nov 2020 13:39:46 +01:00 Committer: Thomas Gleixner <t...@linutronix.de> CommitterDate: Thu, 28 Jan 2021 13:20:18 +01:00
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 <alx.manpa...@gmail.com> Signed-off-by: Thomas Gleixner <t...@linutronix.de> Link: https://lore.kernel.org/r/20201128123945.4592-1-alx.manpa...@gmail.com --- include/linux/syscalls.h | 8 ++++---- kernel/futex.c | 6 +++--- 2 files changed, 7 insertions(+), 7 deletions(-) diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h index f3929af..5cb74ed 100644 --- a/include/linux/syscalls.h +++ b/include/linux/syscalls.h @@ -583,11 +583,11 @@ asmlinkage long sys_unshare(unsigned long unshare_flags); /* kernel/futex.c */ asmlinkage long sys_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); asmlinkage long sys_futex_time32(u32 __user *uaddr, int op, u32 val, - struct old_timespec32 __user *utime, u32 __user *uaddr2, - u32 val3); + const struct old_timespec32 __user *utime, + u32 __user *uaddr2, u32 val3); asmlinkage long sys_get_robust_list(int pid, struct robust_list_head __user * __user *head_ptr, size_t __user *len_ptr); diff --git a/kernel/futex.c b/kernel/futex.c index c47d101..d0775aa 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;
