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SubjectRe: PROBLEM: fanotify_mark EFAULT on x86
On Tue 03-11-20 22:17:47, Paweł Jasiak wrote:
> I have written small patch that fixes problem for me and doesn't break
> x86_64.

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!

Honza

>
> diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c
> index 3e01d8f2ab90..cf0b97309975 100644
> --- a/fs/notify/fanotify/fanotify_user.c
> +++ b/fs/notify/fanotify/fanotify_user.c
> @@ -1285,12 +1285,27 @@ static int do_fanotify_mark(int fanotify_fd, unsigned int flags, __u64 mask,
> return ret;
> }
>
> +#if defined(CONFIG_X86) && !defined(CONFIG_64BIT)
> +SYSCALL_DEFINE6(fanotify_mark,
> + int, fanotify_fd, unsigned int, flags, __u32, mask0,
> + __u32, mask1, int, dfd, const char __user *, pathname)
> +{
> + return do_fanotify_mark(fanotify_fd, flags,
> +#ifdef __BIG_ENDIAN
> + ((__u64)mask0 << 32) | mask1,
> +#else
> + ((__u64)mask1 << 32) | mask0,
> +#endif
> + dfd, pathname);
> +}
> +#else
> SYSCALL_DEFINE5(fanotify_mark, int, fanotify_fd, unsigned int, flags,
> __u64, mask, int, dfd,
> const char __user *, pathname)
> {
> return do_fanotify_mark(fanotify_fd, flags, mask, dfd, pathname);
> }
> +#endif
>
> #ifdef CONFIG_COMPAT
> COMPAT_SYSCALL_DEFINE6(fanotify_mark,
>
>
> --
>
> Paweł Jasiak
--
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
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