Commit 2ca408d9 authored by Brian Gerst's avatar Brian Gerst Committed by Borislav Petkov
Browse files

fanotify: Fix sys_fanotify_mark() on native x86-32 



Commit

  121b32a5 ("x86/entry/32: Use IA32-specific wrappers for syscalls taking 64-bit arguments")

converted native x86-32 which take 64-bit arguments to use the
compat handlers to allow conversion to passing args via pt_regs.
sys_fanotify_mark() was however missed, as it has a general compat
handler. Add a config option that will use the syscall wrapper that
takes the split args for native 32-bit.

 [ bp: Fix typo in Kconfig help text. ]

Fixes: 121b32a5 ("x86/entry/32: Use IA32-specific wrappers for syscalls taking 64-bit arguments")
Reported-by: default avatarPaweł Jasiak <pawel@jasiak.xyz>
Signed-off-by: default avatarBrian Gerst <brgerst@gmail.com>
Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
Acked-by: default avatarJan Kara <jack@suse.cz>
Acked-by: default avatarAndy Lutomirski <luto@kernel.org>
Link: https://lkml.kernel.org/r/20201130223059.101286-1-brgerst@gmail.com
parent 5c8fe583

arch/Kconfig

+6 −0
Original line number Diff line number Diff line
@@ -1105,6 +1105,12 @@ config HAVE_ARCH_PFN_VALID 
config ARCH_SUPPORTS_DEBUG_PAGEALLOC

	bool



config ARCH_SPLIT_ARG64

	bool

	help

	   If a 32-bit architecture requires 64-bit arguments to be split into

	   pairs of 32-bit arguments, select this option.



source "kernel/gcov/Kconfig"



source "scripts/gcc-plugins/Kconfig"

arch/x86/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -19,6 +19,7 @@ config X86_32 
	select KMAP_LOCAL

	select MODULES_USE_ELF_REL

	select OLD_SIGACTION

	select ARCH_SPLIT_ARG64



config X86_64

	def_bool y

fs/notify/fanotify/fanotify_user.c

+7 −10
Original line number Diff line number Diff line
@@ -1285,25 +1285,22 @@ static int do_fanotify_mark(int fanotify_fd, unsigned int flags, __u64 mask, 
	return ret;

}



#ifndef CONFIG_ARCH_SPLIT_ARG64

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,

#if defined(CONFIG_ARCH_SPLIT_ARG64) || defined(CONFIG_COMPAT)

SYSCALL32_DEFINE6(fanotify_mark,

				int, fanotify_fd, unsigned int, flags,

				__u32, mask0, __u32, mask1, int, dfd,

				SC_ARG64(mask), 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

	return do_fanotify_mark(fanotify_fd, flags, SC_VAL64(__u64, mask),

				dfd, pathname);

}

#endif

include/linux/syscalls.h

+24 −0
Original line number Diff line number Diff line
@@ -251,6 +251,30 @@ static inline int is_syscall_trace_event(struct trace_event_call *tp_event) 
	static inline long __do_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__))

#endif /* __SYSCALL_DEFINEx */



/* For split 64-bit arguments on 32-bit architectures */

#ifdef __LITTLE_ENDIAN

#define SC_ARG64(name) u32, name##_lo, u32, name##_hi

#else

#define SC_ARG64(name) u32, name##_hi, u32, name##_lo

#endif

#define SC_VAL64(type, name) ((type) name##_hi << 32 | name##_lo)



#ifdef CONFIG_COMPAT

#define SYSCALL32_DEFINE1 COMPAT_SYSCALL_DEFINE1

#define SYSCALL32_DEFINE2 COMPAT_SYSCALL_DEFINE2

#define SYSCALL32_DEFINE3 COMPAT_SYSCALL_DEFINE3

#define SYSCALL32_DEFINE4 COMPAT_SYSCALL_DEFINE4

#define SYSCALL32_DEFINE5 COMPAT_SYSCALL_DEFINE5

#define SYSCALL32_DEFINE6 COMPAT_SYSCALL_DEFINE6

#else

#define SYSCALL32_DEFINE1 SYSCALL_DEFINE1

#define SYSCALL32_DEFINE2 SYSCALL_DEFINE2

#define SYSCALL32_DEFINE3 SYSCALL_DEFINE3

#define SYSCALL32_DEFINE4 SYSCALL_DEFINE4

#define SYSCALL32_DEFINE5 SYSCALL_DEFINE5

#define SYSCALL32_DEFINE6 SYSCALL_DEFINE6

#endif



/*

 * Called before coming back to user-mode. Returning to user-mode with an

 * address limit different than USER_DS can allow to overwrite kernel memory.