From: Christian Göttsche <cgzones@xxxxxxxxxxxxxx> Since the status page is currently only allocated on first use, the sequence number of the initial policyload (i.e. 1) is not stored, leading to the observable sequence of 0, 2, 3, 4, ... Pre-allocate the status page during the initialization of the selinuxfs, so selinux_status_update_policyload() will set the sequence number. This brings the status page to return the actual sequence number for the initial policy load, which is also observable via the netlink socket. I could not find any occurrence where userspace depends on the actual value returned by selinux_status_policyload(3), thus the breakage should be unnoticed. Reported-by: Milos Malik Closes: https://lore.kernel.org/selinux/87o7fmua12.fsf@xxxxxxxxxx/ Signed-off-by: Christian Göttsche <cgzones@xxxxxxxxxxxxxx> --- security/selinux/selinuxfs.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/security/selinux/selinuxfs.c b/security/selinux/selinuxfs.c index 7e9aa5d151b4..ad57b5ad5829 100644 --- a/security/selinux/selinuxfs.c +++ b/security/selinux/selinuxfs.c @@ -2131,6 +2131,7 @@ static int __init init_sel_fs(void) { struct qstr null_name = QSTR_INIT(NULL_FILE_NAME, sizeof(NULL_FILE_NAME)-1); + struct page *status; int err; if (!selinux_enabled_boot) @@ -2163,6 +2164,14 @@ static int __init init_sel_fs(void) return err; } + /* + * Pre-allocate the status page, so the sequence number of the initial + * policy load can be stored. + */ + status = selinux_kernel_status_page(); + if (!status) + return -ENOMEM; + return err; } -- 2.43.0
