Re: [PATCH v15 05/17] arms64: untag user pointers passed to memory syscalls

Andrew Murray
2019-05-24T15:41:50Z

On Mon, May 06, 2019 at 06:30:51PM +0200, Andrey Konovalov wrote:
> This patch is a part of a series that extends arm64 kernel ABI to allow to
> pass tagged user pointers (with the top byte set to something else other
> than 0x00) as syscall arguments.
>
> This patch allows tagged pointers to be passed to the following memory
> syscalls: brk, get_mempolicy, madvise, mbind, mincore, mlock, mlock2,
> mmap, mmap_pgoff, mprotect, mremap, msync, munlock, munmap,
> remap_file_pages, shmat and shmdt.
>
> This is done by untagging pointers passed to these syscalls in the
> prologues of their handlers.
>
> Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
> ---

> +SYSCALL_DEFINE2(arm64_mlock, unsigned long, start, size_t, len)
> +{
> + start = untagged_addr(start);
> + return ksys_mlock(start, len, VM_LOCKED);
> +}
> +
> +SYSCALL_DEFINE2(arm64_mlock2, unsigned long, start, size_t, len)
> +{
> + start = untagged_addr(start);
> + return ksys_mlock(start, len, VM_LOCKED);
> +}

I think this may be a copy/paste error...

Shouldn't mlock2 have a third 'flags' argument to distinguish is from mlock?

Thanks,

Andrew Murray

> +
> +SYSCALL_DEFINE2(arm64_munlock, unsigned long, start, size_t, len)
> +{
> + start = untagged_addr(start);
> + return ksys_munlock(start, len);
> +}
> +
> +SYSCALL_DEFINE3(arm64_mprotect, unsigned long, start, size_t, len,
> + unsigned long, prot)
> +{
> + start = untagged_addr(start);
> + return ksys_mprotect_pkey(start, len, prot, -1);
> +}
> +
> +SYSCALL_DEFINE3(arm64_msync, unsigned long, start, size_t, len, int, flags)
> +{
> + start = untagged_addr(start);
> + return ksys_msync(start, len, flags);
> +}
> +
> +SYSCALL_DEFINE3(arm64_mincore, unsigned long, start, size_t, len,
> + unsigned char __user *, vec)
> +{
> + start = untagged_addr(start);
> + return ksys_mincore(start, len, vec);
> +}
> +
> +SYSCALL_DEFINE5(arm64_remap_file_pages, unsigned long, start,
> + unsigned long, size, unsigned long, prot,
> + unsigned long, pgoff, unsigned long, flags)
> +{
> + start = untagged_addr(start);
> + return ksys_remap_file_pages(start, size, prot, pgoff, flags);
> +}
> +
> +SYSCALL_DEFINE3(arm64_shmat, int, shmid, char __user *, shmaddr, int, shmflg)
> +{
> + shmaddr = untagged_addr(shmaddr);
> + return ksys_shmat(shmid, shmaddr, shmflg);
> +}
> +
> +SYSCALL_DEFINE1(arm64_shmdt, char __user *, shmaddr)
> +{
> + shmaddr = untagged_addr(shmaddr);
> + return ksys_shmdt(shmaddr);
> +}
> +
> /*
> * Wrappers to pass the pt_regs argument.
> */
> #define sys_personality sys_arm64_personality
> +#define sys_mmap_pgoff sys_arm64_mmap_pgoff
> +#define sys_mremap sys_arm64_mremap
> +#define sys_munmap sys_arm64_munmap
> +#define sys_brk sys_arm64_brk
> +#define sys_get_mempolicy sys_arm64_get_mempolicy
> +#define sys_madvise sys_arm64_madvise
> +#define sys_mbind sys_arm64_mbind
> +#define sys_mlock sys_arm64_mlock
> +#define sys_mlock2 sys_arm64_mlock2
> +#define sys_munlock sys_arm64_munlock
> +#define sys_mprotect sys_arm64_mprotect
> +#define sys_msync sys_arm64_msync
> +#define sys_mincore sys_arm64_mincore
> +#define sys_remap_file_pages sys_arm64_remap_file_pages
> +#define sys_shmat sys_arm64_shmat
> +#define sys_shmdt sys_arm64_shmdt
>
> asmlinkage long sys_ni_syscall(const struct pt_regs *);
> #define __arm64_sys_ni_syscall sys_ni_syscall
> --
> 2.21.0.1020.gf2820cf01a-goog
>
>
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel