x86/entry: Fix entry/exit mismatch on failed fast 32-bit syscalls
authorAndy Lutomirski <luto@kernel.org>
Thu, 4 Mar 2021 19:05:54 +0000 (11:05 -0800)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Wed, 17 Mar 2021 16:06:36 +0000 (17:06 +0100)
commite40384fcd6005bf887c5e31c6e8c408c0e55aad2
treee80b4441d0fb8afc23bbc0273bb7eae39a051ee5
parenta2bab396cb97f5a6468f54caca0d25b23b75539c
x86/entry: Fix entry/exit mismatch on failed fast 32-bit syscalls

commit 5d5675df792ff67e74a500c4c94db0f99e6a10ef upstream.

On a 32-bit fast syscall that fails to read its arguments from user
memory, the kernel currently does syscall exit work but not
syscall entry work.  This confuses audit and ptrace.  For example:

    $ ./tools/testing/selftests/x86/syscall_arg_fault_32
    ...
    strace: pid 264258: entering, ptrace_syscall_info.op == 2
    ...

This is a minimal fix intended for ease of backporting.  A more
complete cleanup is coming.

Fixes: 0b085e68f407 ("x86/entry: Consolidate 32/64 bit syscall entry")
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/8c82296ddf803b91f8d1e5eac89e5803ba54ab0e.1614884673.git.luto@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
arch/x86/entry/common.c