Signed-off-by: Thomas Liske <li...@ibh.de> --- This patch sets the PR_SET_DUMPABLE capability before switching to a unprivileged user to allow core dumps (see also the paragraph about set-user-ID in `man 5 core`)
Background: While debugging bird on Alpine we wonder why it was not possible to get a core dump when bird runs under a unprivileged user. Original Alpine Issue: https://gitlab.alpinelinux.org/alpine/aports/-/issues/14408 sysdep/linux/syspriv.h | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/sysdep/linux/syspriv.h b/sysdep/linux/syspriv.h index 8b210f06..efb1fff0 100644 --- a/sysdep/linux/syspriv.h +++ b/sysdep/linux/syspriv.h @@ -73,6 +73,10 @@ drop_uid(uid_t uid) if (prctl(PR_SET_KEEPCAPS, 1) < 0) die("prctl: %m"); + /* allow core dumps after dropping root ID */ + if (prctl(PR_SET_DUMPABLE, 1) < 0) + die("prctl: %m"); + /* completely switch to the unprivileged user ID */ if (setresuid(uid, uid, uid) < 0) die("setresuid: %m"); -- 2.30.2
