The __NR_newfstat and __NR_newfstatat macros accidentally got renamed
in the conversion to the syscall.tbl format, dropping the 'new' portion
of the name.
In an unrelated change, the two syscalls are no longer architecture
specific but are once more defined on all 64-bit architectures, so the
'newstat' ABI keyword can be dropped from the table as a simplification.
Fixes: Fixes: 4fe53bf2ba ("syscalls: add generic scripts/syscall.tbl")
Closes: https://lore.kernel.org/lkml/838053e0-b186-4e9f-9668-9a3384a71f23@app.fastmail.com/T/#t
Reported-by: Florian Weimer <fweimer@redhat.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Chromium sandbox apparently wants to deny statx [1] so it could properly
inspect arguments after the sandboxed process later falls back to fstat.
Because there's currently not a "fd-only" version of statx, so that the
sandbox has no way to ensure the path argument is empty without being
able to peek into the sandboxed process's memory. For architectures able
to do newfstatat though, glibc falls back to newfstatat after getting
-ENOSYS for statx, then the respective SIGSYS handler [2] takes care of
inspecting the path argument, transforming allowed newfstatat's into
fstat instead which is allowed and has the same type of return value.
But, as LoongArch is the first architecture to not have fstat nor
newfstatat, the LoongArch glibc does not attempt falling back at all
when it gets -ENOSYS for statx -- and you see the problem there!
Actually, back when the LoongArch port was under review, people were
aware of the same problem with sandboxing clone3 [3], so clone was
eventually kept. Unfortunately it seemed at that time no one had noticed
statx, so besides restoring fstat/newfstatat to LoongArch uapi (and
postponing the problem further), it seems inevitable that we would need
to tackle seccomp deep argument inspection.
However, this is obviously a decision that shouldn't be taken lightly,
so we just restore fstat/newfstatat by defining __ARCH_WANT_NEW_STAT
in unistd.h. This is the simplest solution for now, and so we hope the
community will tackle the long-standing problem of seccomp deep argument
inspection in the future [4][5].
Also add "newstat" to syscall_abis_64 in Makefile.syscalls due to
upstream asm-generic changes.
More infomation please reading this thread [6].
[1] https://chromium-review.googlesource.com/c/chromium/src/+/2823150
[2] https://chromium.googlesource.com/chromium/src/sandbox/+/c085b51940bd/linux/seccomp-bpf-helpers/sigsys_handlers.cc#355
[3] https://lore.kernel.org/linux-arch/20220511211231.GG7074@brightrain.aerifal.cx/
[4] https://lwn.net/Articles/799557/
[5] https://lpc.events/event/4/contributions/560/attachments/397/640/deep-arg-inspection.pdf
[6] https://lore.kernel.org/loongarch/20240226-granit-seilschaft-eccc2433014d@brauner/T/#t
Cc: stable@vger.kernel.org
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
The uapi/asm/unistd_64.h and asm/syscall_table_64.h headers can now be
generated from scripts/syscall.tbl, which makes this consistent with
the other architectures that have their own syscall.tbl.
Unlike the other architectures using the asm-generic header, loongarch
uses none of the deprecated system calls at the moment.
Both the user visible side of asm/unistd.h and the internal syscall
table in the kernel should have the same effective contents after this.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
