From 1f9d2a8199c261593aa6a11df9cce5d31e23c714 Mon Sep 17 00:00:00 2001 From: Daan De Meyer Date: Fri, 15 Jul 2022 01:49:25 +0200 Subject: coredump: Connect stdout/stderr to /dev/null before doing anything When invoked as the coredump handler by the kernel, systemd-coredump's stdout and stderr streams are closed. This is dangerous as this means the fd's can get reallocated, leading to hard to debug errors such as log messages ending up being appended to a compressed coredump file. To avoid such issues in the future, let's bind stdout/stderr to /dev/null so the file descriptors can't get used for anything else. --- src/coredump/coredump.c | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'src/coredump') diff --git a/src/coredump/coredump.c b/src/coredump/coredump.c index 994d968d87..10a96ab568 100644 --- a/src/coredump/coredump.c +++ b/src/coredump/coredump.c @@ -1271,6 +1271,13 @@ static int process_kernel(int argc, char* argv[]) { struct iovec_wrapper *iovw; int r; + /* When we're invoked by the kernel, stdout/stderr are closed which is dangerous because the fds + * could get reallocated. To avoid hard to debug issues, let's instead bind stdout/stderr to + * /dev/null. */ + r = rearrange_stdio(STDIN_FILENO, -1, -1); + if (r < 0) + return log_error_errno(r, "Failed to connect stdout/stderr to /dev/null: %m"); + log_debug("Processing coredump received from the kernel..."); iovw = iovw_new(); -- cgit v1.2.1