From: Joel Granados <j.granados@xxxxxxxxxxx> When registering tables to the sysctl subsystem there is a check to see if header is a permanently empty directory (used for mounts). This check evaluates the first element of the ctl_table. This results in an out of bounds evaluation when registering empty directories. The function register_sysctl_mount_point now passes a ctl_table of size 1 instead of size 0. It now relies solely on the type to identify a permanently empty register. Make sure that the ctl_table has at least one element before testing for permanent emptiness. Signed-off-by: Joel Granados <j.granados@xxxxxxxxxxx> Reported-by: kernel test robot <oliver.sang@xxxxxxxxx> Closes: https://lore.kernel.org/oe-lkp/202311201431.57aae8f3-oliver.sang@xxxxxxxxx --- fs/proc/proc_sysctl.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c index de484195f49f..5b5cdc747cef 100644 --- a/fs/proc/proc_sysctl.c +++ b/fs/proc/proc_sysctl.c @@ -44,7 +44,7 @@ static struct ctl_table sysctl_mount_point[] = { */ struct ctl_table_header *register_sysctl_mount_point(const char *path) { - return register_sysctl_sz(path, sysctl_mount_point, 0); + return register_sysctl(path, sysctl_mount_point); } EXPORT_SYMBOL(register_sysctl_mount_point); @@ -233,7 +233,8 @@ static int insert_header(struct ctl_dir *dir, struct ctl_table_header *header) return -EROFS; /* Am I creating a permanently empty directory? */ - if (sysctl_is_perm_empty_ctl_table(header->ctl_table)) { + if (header->ctl_table_size > 0 && + sysctl_is_perm_empty_ctl_table(header->ctl_table)) { if (!RB_EMPTY_ROOT(&dir->root)) return -EINVAL; sysctl_set_perm_empty_ctl_header(dir_h); @@ -1213,6 +1214,10 @@ static bool get_links(struct ctl_dir *dir, struct ctl_table_header *tmp_head; struct ctl_table *entry, *link; + if (header->ctl_table_size == 0 || + sysctl_is_perm_empty_ctl_table(header->ctl_table)) + return true; + /* Are there links available for every entry in table? */ list_for_each_table_entry(entry, header) { const char *procname = entry->procname; -- 2.30.2
