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[209.85.208.43]) by smtp.gmail.com with ESMTPSA id 4fb4d7f45d1cf-5b83a153f34sm3934392a12.56.2024.08.04.12.18.22 for (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sun, 04 Aug 2024 12:18:22 -0700 (PDT) Received: by mail-ed1-f43.google.com with SMTP id 4fb4d7f45d1cf-5b7b6a30454so4495009a12.2 for ; Sun, 04 Aug 2024 12:18:22 -0700 (PDT) X-Forwarded-Encrypted: i=1; AJvYcCWVoPOARRM0X0DpK7GRTY2zfX5ZmFiTBjIvqY7tAOwbJmYsJ3kpNWzDWwOcwvoF7fIEsRYb+pAcOy2jWDj6MZDA0ow= X-Received: by 2002:a17:907:1c92:b0:a7a:acae:340e with SMTP id a640c23a62f3a-a7dc4fa3fb7mr733558966b.26.1722799102160; Sun, 04 Aug 2024 12:18:22 -0700 (PDT) MIME-Version: 1.0 References: <20240804152327.GA27866@redhat.com> <20240804185338.GB27866@redhat.com> In-Reply-To: <20240804185338.GB27866@redhat.com> From: Linus Torvalds Date: Sun, 4 Aug 2024 12:18:05 -0700 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [RFC PATCH] piped/ptraced coredump (was: Dump smaller VMAs first in ELF cores) To: Oleg Nesterov Cc: Brian Mak , "Eric W. Biederman" , Kees Cook , Alexander Viro , Christian Brauner , Jan Kara , "linux-fsdevel@vger.kernel.org" , "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" Content-Type: text/plain; charset="UTF-8" X-Rspamd-Queue-Id: 2AF3380007 X-Stat-Signature: fgf88fx6ekaj3g8pwkqoe9o8pmwsmpc4 X-Rspamd-Server: rspam09 X-Rspam-User: X-HE-Tag: 1722799104-943267 X-HE-Meta: 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 8/wj6Tbd MnQtLzxaGMVK3iKmCd512qUaaLYNU6f1kB64xJ9AuFxJGr4ml+Z9Lo6GtkBlM1aaf3cnHqCfnHOwMEip/a8w+w95jPwGU4X56zB+m4aM6a1le063frenJjBekPRuTyuTc7txvDhJ56UKpVIUGUtfGgMb0kXWLUSdNqdhkP0BKbAycVf/e+7/XLo/s8WtE75A77XndXKDiKx4PB5tS+S4UuIMRLoEdRd8TITrT3xdZXrXq9s3ncfZ48XVdcNjL0BDJQodLrLrFdaIg0j6LXf1UVXHvLz1xev2BA+J/mjX4nFGrMBer0WPSHR8tvZIpuh+Z7iUmPawmGyC6emhPU2TdX6GVZKhGhwZ2R6HYrjkfdTosZdT8quu/NdYnDDE+abfG/1/WxdpUE3E/Mgw52uD5Xu0m+Or1jy8VOH4X2smj3H8z746DsgocxES5jv87A3whSNgqGPx+YqCpBB8ngQNkuco9kMj/q0ZS/Qp61ByvopISoFExAIvtj7Lscz5vZ8TK0HUFubhTE0LZsIEkM/u7A8l4izPhhPl3gk98JJvWKBC9CZI= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000001, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Sun, 4 Aug 2024 at 11:53, Oleg Nesterov wrote: > > Apart from SIGKILL, the dumper already has the full control. What do you mean? It's a regular usermodehelper. It gets the dump data as input. That's all the control it has. > And note that the dumper can already use ptrace. .. with the normal ptrace() rules, yes. You realize that some setups literally disable ptrace() system calls, right? Which your patch now effectively sidesteps. THAT is why I don't like it. ptrace() is *dangerous*. It is very typically one of the things that people limit for various reasons. Just adding some implicit tracing willy-nilly needs to be something people really worry about. Linus