x86/syscall: Include asm/ptrace.h in syscall_wrapper header
authorJiri Olsa <olsajiri@gmail.com>
Tue, 18 Oct 2022 12:27:08 +0000 (14:27 +0200)
committerBorislav Petkov <bp@suse.de>
Mon, 24 Oct 2022 15:57:28 +0000 (17:57 +0200)
commit9440c42941606af4c379afa3cf8624f0dc43a629
tree34cc85ed376aa6adbff3d4b56d6f0cd528340b2a
parent247f34f7b80357943234f93f247a1ae6b6c3a740
x86/syscall: Include asm/ptrace.h in syscall_wrapper header

With just the forward declaration of the 'struct pt_regs' in
syscall_wrapper.h, the syscall stub functions:

  __[x64|ia32]_sys_*(struct pt_regs *regs)

will have different definition of 'regs' argument in BTF data
based on which object file they are defined in.

If the syscall's object includes 'struct pt_regs' definition,
the BTF argument data will point to a 'struct pt_regs' record,
like:

  [226] STRUCT 'pt_regs' size=168 vlen=21
         'r15' type_id=1 bits_offset=0
         'r14' type_id=1 bits_offset=64
         'r13' type_id=1 bits_offset=128
  ...

If not, it will point to a fwd declaration record:

  [15439] FWD 'pt_regs' fwd_kind=struct

and make bpf tracing program hooking on those functions unable
to access fields from 'struct pt_regs'.

Include asm/ptrace.h directly in syscall_wrapper.h to make sure all
syscalls see 'struct pt_regs' definition. This then results in BTF for
'__*_sys_*(struct pt_regs *regs)' functions to point to the actual
struct, not just the forward declaration.

  [ bp: No Fixes tag as this is not really a bug fix but "adjustment" so
    that BTF is happy. ]

Reported-by: Akihiro HARAI <jharai0815@gmail.com>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Cc: <stable@vger.kernel.org> # this is needed only for BTF so kernels >= 5.15
Link: https://lore.kernel.org/r/20221018122708.823792-1-jolsa@kernel.org
arch/x86/include/asm/syscall_wrapper.h