PTRACE_GET_SYSCALL_INFO is a generic ptrace API that lets ptracer obtain
details of the syscall the tracee is blocked in.
There are two reasons for a special syscall-related ptrace request.
Firstly, with the current ptrace API there are cases when ptracer cannot
retrieve necessary information about syscalls. Some examples include:
* The notorious int-0x80-from-64-bit-task issue. See [1] for details.
In short, if a 64-bit task performs a syscall through int 0x80, its
tracer has no reliable means to find out that the syscall was, in
fact, a compat syscall, and misidentifies it.
* Syscall-enter-stop and syscall-exit-stop look the same for the
tracer. Common practice is to keep track of the sequence of
ptrace-stops in order not to mix the two syscall-stops up. But it is
not as simple as it looks; for example, strace had a (just recently
fixed) long-standing bug where attaching strace to a tracee that is
performing the execve system call led to the tracer identifying the
following syscall-exit-stop as syscall-enter-stop, which messed up
all the state tracking.
* Since the introduction of commit 84d77d3f06 ("ptrace: Don't allow
accessing an undumpable mm"), both PTRACE_PEEKDATA and
process_vm_readv become unavailable when the process dumpable flag is
cleared. On such architectures as ia64 this results in all syscall
arguments being unavailable for the tracer.
Secondly, ptracers also have to support a lot of arch-specific code for
obtaining information about the tracee. For some architectures, this
requires a ptrace(PTRACE_PEEKUSER, ...) invocation for every syscall
argument and return value.
PTRACE_GET_SYSCALL_INFO returns the following structure:
struct ptrace_syscall_info {
__u8 op; /* PTRACE_SYSCALL_INFO_* */
__u32 arch __attribute__((__aligned__(sizeof(__u32))));
__u64 instruction_pointer;
__u64 stack_pointer;
union {
struct {
__u64 nr;
__u64 args[6];
} entry;
struct {
__s64 rval;
__u8 is_error;
} exit;
struct {
__u64 nr;
__u64 args[6];
__u32 ret_data;
} seccomp;
};
};
The structure was chosen according to [2], except for the following
changes:
* seccomp substructure was added as a superset of entry substructure
* the type of nr field was changed from int to __u64 because syscall
numbers are, as a practical matter, 64 bits
* stack_pointer field was added along with instruction_pointer field
since it is readily available and can save the tracer from extra
PTRACE_GETREGS/PTRACE_GETREGSET calls
* arch is always initialized to aid with tracing system calls such as
execve()
* instruction_pointer and stack_pointer are always initialized so they
could be easily obtained for non-syscall stops
* a boolean is_error field was added along with rval field, this way
the tracer can more reliably distinguish a return value from an error
value
strace has been ported to PTRACE_GET_SYSCALL_INFO. Starting with
release 4.26, strace uses PTRACE_GET_SYSCALL_INFO API as the preferred
mechanism of obtaining syscall information.
[1] https://lore.kernel.org/lkml/CA+55aFzcSVmdDj9Lh_gdbz1OzHyEm6ZrGPBDAJnywm2LF_eVyg@mail.gmail.com/
[2] https://lore.kernel.org/lkml/CAObL_7GM0n80N7J_DFw_eQyfLyzq+sf4y2AvsCCV88Tb3AwEHA@mail.gmail.com/
This patch (of 7):
All syscall_get_*() and syscall_set_*() functions must be defined as
static inline as on all other architectures, otherwise asm/syscall.h
cannot be included in more than one compilation unit.
This bug has to be fixed in order to extend the generic
ptrace API with PTRACE_GET_SYSCALL_INFO request.
Link: http://lkml.kernel.org/r/20190510152749.GA28558@altlinux.org
Fixes: 1932fbe36e ("nds32: System calls handling")
Signed-off-by: Dmitry V. Levin <ldv@altlinux.org>
Reported-by: kbuild test robot <lkp@intel.com>
Acked-by: Greentime Hu <greentime@andestech.com>
Cc: Vincent Chen <deanbo422@gmail.com>
Cc: Elvira Khabirova <lineprinter@altlinux.org>
Cc: Eugene Syromyatnikov <esyr@redhat.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Helge Deller <deller@gmx.de> [parisc]
Cc: James E.J. Bottomley <jejb@parisc-linux.org>
Cc: James Hogan <jhogan@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Burton <paul.burton@mips.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Richard Kuo <rkuo@codeaurora.org>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-----BEGIN PGP SIGNATURE-----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=p8Fp
-----END PGP SIGNATURE-----
Merge tag 'audit-pr-20190507' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/audit
Pull audit updates from Paul Moore:
"We've got a reasonably broad set of audit patches for the v5.2 merge
window, the highlights are below:
- The biggest change, and the source of all the arch/* changes, is
the patchset from Dmitry to help enable some of the work he is
doing around PTRACE_GET_SYSCALL_INFO.
To be honest, including this in the audit tree is a bit of a
stretch, but it does help move audit a little further along towards
proper syscall auditing for all arches, and everyone else seemed to
agree that audit was a "good" spot for this to land (or maybe they
just didn't want to merge it? dunno.).
- We can now audit time/NTP adjustments.
- We continue the work to connect associated audit records into a
single event"
* tag 'audit-pr-20190507' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/audit: (21 commits)
audit: fix a memory leak bug
ntp: Audit NTP parameters adjustment
timekeeping: Audit clock adjustments
audit: purge unnecessary list_empty calls
audit: link integrity evm_write_xattrs record to syscall event
syscall_get_arch: add "struct task_struct *" argument
unicore32: define syscall_get_arch()
Move EM_UNICORE to uapi/linux/elf-em.h
nios2: define syscall_get_arch()
nds32: define syscall_get_arch()
Move EM_NDS32 to uapi/linux/elf-em.h
m68k: define syscall_get_arch()
hexagon: define syscall_get_arch()
Move EM_HEXAGON to uapi/linux/elf-em.h
h8300: define syscall_get_arch()
c6x: define syscall_get_arch()
arc: define syscall_get_arch()
Move EM_ARCOMPACT and EM_ARCV2 to uapi/linux/elf-em.h
audit: Make audit_log_cap and audit_copy_inode static
audit: connect LOGIN record to its syscall record
...
This patch corrects the SPDX License Identifier style
in the nds32 Hardware Architecture related files.
Suggested-by: Joe Perches <joe@perches.com>
Signed-off-by: Nishad Kamdar <nishadkamdar@gmail.com>
Acked-by: Greentime Hu <greentime@andestech.com>
Signed-off-by: Greentime Hu <greentime@andestech.com>
syscall_get_arch() is required to be implemented on all architectures
in addition to already implemented syscall_get_nr(),
syscall_get_arguments(), syscall_get_error(), and
syscall_get_return_value() functions in order to extend the generic
ptrace API with PTRACE_GET_SYSCALL_INFO request.
Acked-by: Paul Moore <paul@paul-moore.com>
Acked-by: Vincent Chen <vincentc@andestech.com>
Acked-by: Greentime Hu <greentime@andestech.com>
Cc: Elvira Khabirova <lineprinter@altlinux.org>
Cc: Eugene Syromyatnikov <esyr@redhat.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: linux-audit@redhat.com
Signed-off-by: Dmitry V. Levin <ldv@altlinux.org>
Signed-off-by: Paul Moore <paul@paul-moore.com>
This patch adds support for system calls.
Signed-off-by: Vincent Chen <vincentc@andestech.com>
Signed-off-by: Greentime Hu <greentime@andestech.com>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
