Re: PROBLEM: fanotify_mark EFAULT on x86

["Paweł Jasiak" <pawel@jasiak.xyz>]

On 23/11/20, Jan Kara wrote:
> OK, with a help of Boris Petkov I think I have a fix that looks correct
> (attach). Can you please try whether it works for you? Thanks!

Unfortunately I am getting a linker error.

ld: arch/x86/entry/syscall_32.o:(.rodata+0x54c): undefined reference to `__ia32_sys_ia32_fanotify_mark'

> -- 
> Jan Kara <jack@suse.com>
> SUSE Labs, CR

> From fc9104a50a774ec198c1e3a145372cde77df7967 Mon Sep 17 00:00:00 2001
> From: Jan Kara <jack@suse.cz>
> Date: Mon, 23 Nov 2020 17:37:00 +0100
> Subject: [PATCH] fanotify: Fix fanotify_mark() on 32-bit archs
> MIME-Version: 1.0
> Content-Type: text/plain; charset=UTF-8
> Content-Transfer-Encoding: 8bit
> 
> Commit converting syscalls taking 64-bit arguments to new scheme of compat
> handlers omitted converting fanotify_mark(2) which then broke the
> syscall for 32-bit ABI. Add missed conversion.
> 
> CC: Brian Gerst <brgerst@gmail.com>
> Suggested-by: Borislav Petkov <bp@suse.de>
> Reported-by: Paweł Jasiak <pawel@jasiak.xyz>
> Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org>
> Fixes: 121b32a58a3a ("x86/entry/32: Use IA32-specific wrappers for syscalls taking 64-bit arguments")
> CC: stable@vger.kernel.org
> Signed-off-by: Jan Kara <jack@suse.cz>
> ---
>  arch/x86/entry/syscalls/syscall_32.tbl | 2 +-
>  fs/notify/fanotify/fanotify_user.c     | 2 +-
>  2 files changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/x86/entry/syscalls/syscall_32.tbl b/arch/x86/entry/syscalls/syscall_32.tbl
> index 0d0667a9fbd7..b2ec6ff88307 100644
> --- a/arch/x86/entry/syscalls/syscall_32.tbl
> +++ b/arch/x86/entry/syscalls/syscall_32.tbl
> @@ -350,7 +350,7 @@
>  336	i386	perf_event_open		sys_perf_event_open
>  337	i386	recvmmsg		sys_recvmmsg_time32		compat_sys_recvmmsg_time32
>  338	i386	fanotify_init		sys_fanotify_init
> -339	i386	fanotify_mark		sys_fanotify_mark		compat_sys_fanotify_mark
> +339	i386	fanotify_mark		sys_ia32_fanotify_mark
>  340	i386	prlimit64		sys_prlimit64
>  341	i386	name_to_handle_at	sys_name_to_handle_at
>  342	i386	open_by_handle_at	sys_open_by_handle_at		compat_sys_open_by_handle_at
> diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c
> index 3e01d8f2ab90..e20e7b53a87f 100644
> --- a/fs/notify/fanotify/fanotify_user.c
> +++ b/fs/notify/fanotify/fanotify_user.c
> @@ -1293,7 +1293,7 @@ SYSCALL_DEFINE5(fanotify_mark, int, fanotify_fd, unsigned int, flags,
>  }
>  
>  #ifdef CONFIG_COMPAT
> -COMPAT_SYSCALL_DEFINE6(fanotify_mark,
> +SYSCALL_DEFINE6(ia32_fanotify_mark,
>  				int, fanotify_fd, unsigned int, flags,
>  				__u32, mask0, __u32, mask1, int, dfd,
>  				const char  __user *, pathname)
> -- 
> 2.16.4
> 


-- 

Paweł Jasiak