posix-timers: Get rid of [COMPAT_]SYS_NI() uses

[ Upstream commit a4aebe936554dac6a91e5d091179c934f8325708 ]

Only the posix timer system calls use this (when the posix timer support
is disabled, wh

posix-timers: Get rid of [COMPAT_]SYS_NI() uses

[ Upstream commit a4aebe936554dac6a91e5d091179c934f8325708 ]

Only the posix timer system calls use this (when the posix timer support
is disabled, which does not actually happen in any normal case), because
they had debug code to print out a warning about missing system calls.

Get rid of that special case, and just use the standard COND_SYSCALL
interface that creates weak system call stubs that return -ENOSYS for
when the system call does not exist.

This fixes a kCFI issue with the SYS_NI() hackery:

CFI failure at int80_emulation+0x67/0xb0 (target: sys_ni_posix_timers+0x0/0x70; expected type: 0xb02b34d9)
WARNING: CPU: 0 PID: 48 at int80_emulation+0x67/0xb0

Reported-by: kernel test robot <oliver.sang@intel.com>
Reviewed-by: Sami Tolvanen <samitolvanen@google.com>
Tested-by: Sami Tolvanen <samitolvanen@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

show more ...

arm64: avoid prototype warnings for syscalls

With W=1 warnings enabled, there are lots of complaints about
missing prototypes for system calls, plus a few other related
ones:

arch/arm64/kernel/sys_

arm64: avoid prototype warnings for syscalls

With W=1 warnings enabled, there are lots of complaints about
missing prototypes for system calls, plus a few other related
ones:

arch/arm64/kernel/sys_compat.c:68:6: error: no previous prototype for 'compat_arm_syscall' [-Werror=missing-prototypes]
arch/arm64/include/asm/syscall_wrapper.h:76:32: error: no previous prototype for '__arm64_sys_io_setup' [-Werror=missing-prototypes]
arch/arm64/include/asm/syscall_wrapper.h:41:32: error: no previous prototype for '__arm64_compat_sys_io_setup' [-Werror=missing-prototypes]
arch/arm64/include/asm/syscall_wrapper.h:76:32: error: no previous prototype for '__arm64_sys_io_destroy' [-Werror=missing-prototypes]
arch/arm64/include/asm/syscall_wrapper.h:76:32: error: no previous prototype for '__arm64_sys_io_submit' [-Werror=missing-prototypes]

Add declarations to the syscall macros to avoid all of these, plus
one for the compat syscall entry.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20230516160642.523862-4-arnd@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

show more ...

arm64/syscall: Include asm/ptrace.h in syscall_wrapper header.

Add the same change for ARM64 as done in the commit 9440c4294160
("x86/syscall: Include asm/ptrace.h in syscall_wrapper header") to
mak

arm64/syscall: Include asm/ptrace.h in syscall_wrapper header.

Add the same change for ARM64 as done in the commit 9440c4294160
("x86/syscall: Include asm/ptrace.h in syscall_wrapper header") to
make sure all syscalls see 'struct pt_regs' definition and resulted
BTF for '__arm64_sys_*(struct pt_regs *regs)' functions point to
actual struct.

Without this patch, the BPF verifier refuses to load a tracing prog
which accesses pt_regs.

bpf(BPF_PROG_LOAD, {prog_type=0x1a, ...}, 128) = -1 EACCES

With this patch, we can see the correct error, which saves us time
in debugging the prog.

bpf(BPF_PROG_LOAD, {prog_type=0x1a, ...}, 128) = 4
bpf(BPF_RAW_TRACEPOINT_OPEN, {raw_tracepoint={name=NULL, prog_fd=4}}, 128) = -1 ENOTSUPP

Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20221031215728.50389-1-kuniyu@amazon.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

show more ...

arm64: simplify syscall wrapper ifdeffery

Back in commit:

4378a7d4be30ec69 ("arm64: implement syscall wrappers")

... I implemented the arm64 syscall wrapper glue following the approach
taken on

arm64: simplify syscall wrapper ifdeffery

Back in commit:

4378a7d4be30ec69 ("arm64: implement syscall wrappers")

... I implemented the arm64 syscall wrapper glue following the approach
taken on x86. While doing so, I also copied across some ifdeffery that
isn't necessary on arm64.

On arm64 we don't share any of the native wrappers with compat tasks,
and unlike x86 we don't have alternative implementations of
SYSCALL_DEFINE0(), COND_SYSCALL(), or SYS_NI() defined when AArch32
compat support is enabled.

Thus we don't need to prevent multiple definitions of these macros, and
can remove the #ifndef ... #endif guards protecting them. If any of
these had been previously defined elsewhere, syscalls are unlikely to
work correctly, and we'd want the compiler to warn about the multiple
definitions.

Acked-by: Will Deacon <will@kernel.org>
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

show more ...

arm64: fix function types in COND_SYSCALL

Define a weak function in COND_SYSCALL instead of a weak alias to
sys_ni_syscall, which has an incompatible type. This fixes indirect
call mismatches with C

arm64: fix function types in COND_SYSCALL

Define a weak function in COND_SYSCALL instead of a weak alias to
sys_ni_syscall, which has an incompatible type. This fixes indirect
call mismatches with Control-Flow Integrity (CFI) checking.

Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Will Deacon <will@kernel.org>

show more ...

arm64: use the correct function type in SYSCALL_DEFINE0

Although a syscall defined using SYSCALL_DEFINE0 doesn't accept
parameters, use the correct function type to avoid indirect call
type mismatch

arm64: use the correct function type in SYSCALL_DEFINE0

Although a syscall defined using SYSCALL_DEFINE0 doesn't accept
parameters, use the correct function type to avoid indirect call
type mismatches with Control-Flow Integrity checking.

Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

show more ...

arm64: implement syscall wrappers

To minimize the risk of userspace-controlled values being used under
speculation, this patch adds pt_regs based syscall wrappers for arm64,
which pass the minimum s

arm64: implement syscall wrappers

To minimize the risk of userspace-controlled values being used under
speculation, this patch adds pt_regs based syscall wrappers for arm64,
which pass the minimum set of required userspace values to syscall
implementations. For each syscall, a wrapper which takes a pt_regs
argument is automatically generated, and this extracts the arguments
before calling the "real" syscall implementation.

Each syscall has three functions generated:

* __do_<compat_>sys_<name> is the "real" syscall implementation, with
the expected prototype.

* __se_<compat_>sys_<name> is the sign-extension/narrowing wrapper,
inherited from common code. This takes a series of long parameters,
casting each to the requisite types required by the "real" syscall
implementation in __do_<compat_>sys_<name>.

This wrapper *may* not be necessary on arm64 given the AAPCS rules on
unused register bits, but it seemed safer to keep the wrapper for now.

* __arm64_<compat_>_sys_<name> takes a struct pt_regs pointer, and
extracts *only* the relevant register values, passing these on to the
__se_<compat_>sys_<name> wrapper.

The syscall invocation code is updated to handle the calling convention
required by __arm64_<compat_>_sys_<name>, and passes a single struct
pt_regs pointer.

The compiler can fold the syscall implementation and its wrappers, such
that the overhead of this approach is minimized.

Note that we play games with sys_ni_syscall(). It can't be defined with
SYSCALL_DEFINE0() because we must avoid the possibility of error
injection. Additionally, there are a couple of locations where we need
to call it from C code, and we don't (currently) have a
ksys_ni_syscall(). While it has no wrapper, passing in a redundant
pt_regs pointer is benign per the AAPCS.

When ARCH_HAS_SYSCALL_WRAPPER is selected, no prototype is defines for
sys_ni_syscall(). Since we need to treat it differently for in-kernel
calls and the syscall tables, the prototype is defined as-required.

The wrappers are largely the same as their x86 counterparts, but
simplified as we don't have a variety of compat calling conventions that
require separate stubs. Unlike x86, we have some zero-argument compat
syscalls, and must define COMPAT_SYSCALL_DEFINE0() to ensure that these
are also given an __arm64_compat_sys_ prefix.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

show more ...

arm64: simplify syscall wrapper ifdeffery

Back in commit:

4378a7d4be30ec69 ("arm64: implement syscall wrappers")

... I implemented the arm64 syscall wrapper glue followin

arm64: simplify syscall wrapper ifdeffery

Back in commit:

4378a7d4be30ec69 ("arm64: implement syscall wrappers")

... I implemented the arm64 syscall wrapper glue following the approach
taken on x86. While doing so, I also copied across some ifdeffery that
isn't necessary on arm64.

On arm64 we don't share any of the native wrappers with compat tasks,
and unlike x86 we don't have alternative implementations of
SYSCALL_DEFINE0(), COND_SYSCALL(), or SYS_NI() defined when AArch32
compat support is enabled.

Thus we don't need to prevent multiple definitions of these macros, and
can remove the #ifndef ... #endif guards protecting them. If any of
these had been previously defined elsewhere, syscalls are unlikely to
work correctly, and we'd want the compiler to warn about the multiple
definitions.

Acked-by: Will Deacon <will@kernel.org>
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

show more ...

arm64: fix function types in COND_SYSCALL

Define a weak function in COND_SYSCALL instead of a weak alias to
sys_ni_syscall, which has an incompatible type. This fixes indirect
call m

arm64: fix function types in COND_SYSCALL

Define a weak function in COND_SYSCALL instead of a weak alias to
sys_ni_syscall, which has an incompatible type. This fixes indirect
call mismatches with Control-Flow Integrity (CFI) checking.

Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Will Deacon <will@kernel.org>

show more ...

arm64: use the correct function type in SYSCALL_DEFINE0

Although a syscall defined using SYSCALL_DEFINE0 doesn't accept
parameters, use the correct function type to avoid indirect call

arm64: use the correct function type in SYSCALL_DEFINE0

Although a syscall defined using SYSCALL_DEFINE0 doesn't accept
parameters, use the correct function type to avoid indirect call
type mismatches with Control-Flow Integrity checking.

Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

show more ...

arm64: implement syscall wrappers

To minimize the risk of userspace-controlled values being used under
speculation, this patch adds pt_regs based syscall wrappers for arm64,
which pa

arm64: implement syscall wrappers

To minimize the risk of userspace-controlled values being used under
speculation, this patch adds pt_regs based syscall wrappers for arm64,
which pass the minimum set of required userspace values to syscall
implementations. For each syscall, a wrapper which takes a pt_regs
argument is automatically generated, and this extracts the arguments
before calling the "real" syscall implementation.

Each syscall has three functions generated:

* __do_<compat_>sys_<name> is the "real" syscall implementation, with
the expected prototype.

* __se_<compat_>sys_<name> is the sign-extension/narrowing wrapper,
inherited from common code. This takes a series of long parameters,
casting each to the requisite types required by the "real" syscall
implementation in __do_<compat_>sys_<name>.

This wrapper *may* not be necessary on arm64 given the AAPCS rules on
unused register bits, but it seemed safer to keep the wrapper for now.

* __arm64_<compat_>_sys_<name> takes a struct pt_regs pointer, and
extracts *only* the relevant register values, passing these on to the
__se_<compat_>sys_<name> wrapper.

The syscall invocation code is updated to handle the calling convention
required by __arm64_<compat_>_sys_<name>, and passes a single struct
pt_regs pointer.

The compiler can fold the syscall implementation and its wrappers, such
that the overhead of this approach is minimized.

Note that we play games with sys_ni_syscall(). It can't be defined with
SYSCALL_DEFINE0() because we must avoid the possibility of error
injection. Additionally, there are a couple of locations where we need
to call it from C code, and we don't (currently) have a
ksys_ni_syscall(). While it has no wrapper, passing in a redundant
pt_regs pointer is benign per the AAPCS.

When ARCH_HAS_SYSCALL_WRAPPER is selected, no prototype is defines for
sys_ni_syscall(). Since we need to treat it differently for in-kernel
calls and the syscall tables, the prototype is defined as-required.

The wrappers are largely the same as their x86 counterparts, but
simplified as we don't have a variety of compat calling conventions that
require separate stubs. Unlike x86, we have some zero-argument compat
syscalls, and must define COMPAT_SYSCALL_DEFINE0() to ensure that these
are also given an __arm64_compat_sys_ prefix.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

show more ...