From ace9e3edbca62d978b1e8f392d8a5d78500272d9 Mon Sep 17 00:00:00 2001 From: Sam James Date: Sun, 5 Jun 2022 04:57:10 +0100 Subject: [PATCH] nss: handle stat failure in check_reload_and_get (BZ #28752) Skip the chroot test if the database isn't loaded correctly (because the chroot test uses some existing DB state). The __stat64_time64 -> fstatat call can fail if running under an (aggressive) seccomp filter, like Firefox seems to use. This manifested in a crash when using glib built with FAM support with such a Firefox build. Suggested-by: DJ Delorie Signed-off-by: Sam James Reviewed-by: DJ Delorie --- nss/nss_database.c | 39 ++++++++++++++++++++++++--------------- 1 file changed, 24 insertions(+), 15 deletions(-) diff --git a/nss/nss_database.c b/nss/nss_database.c index d56c5b798d..f2ed2f2c25 100644 --- a/nss/nss_database.c +++ b/nss/nss_database.c @@ -420,23 +420,32 @@ nss_database_check_reload_and_get (struct nss_database_state *local, return true; } - /* Before we reload, verify that "/" hasn't changed. We assume that - errors here are very unlikely, but the chance that we're entering - a container is also very unlikely, so we err on the side of both - very unlikely things not happening at the same time. */ - if (__stat64_time64 ("/", &str) != 0 - || (local->root_ino != 0 - && (str.st_ino != local->root_ino - || str.st_dev != local->root_dev))) + int stat_rv = __stat64_time64 ("/", &str); + + if (local->data.services[database_index] != NULL) { - /* Change detected; disable reloading and return current state. */ - atomic_store_release (&local->data.reload_disabled, 1); - *result = local->data.services[database_index]; - __libc_lock_unlock (local->lock); - return true; + /* Before we reload, verify that "/" hasn't changed. We assume that + errors here are very unlikely, but the chance that we're entering + a container is also very unlikely, so we err on the side of both + very unlikely things not happening at the same time. */ + if (stat_rv != 0 + || (local->root_ino != 0 + && (str.st_ino != local->root_ino + || str.st_dev != local->root_dev))) + { + /* Change detected; disable reloading and return current state. */ + atomic_store_release (&local->data.reload_disabled, 1); + *result = local->data.services[database_index]; + __libc_lock_unlock (local->lock); + return true; + } } - local->root_ino = str.st_ino; - local->root_dev = str.st_dev; + if (stat_rv == 0) + { + local->root_ino = str.st_ino; + local->root_dev = str.st_dev; + } + __libc_lock_unlock (local->lock); /* Avoid overwriting the global configuration until we have loaded