From 9a8db9356c07d16a9337df416a3261c0527afeb7 Mon Sep 17 00:00:00 2001 From: Ondrej Mosnacek Date: Tue, 26 Oct 2021 13:52:36 +0200 Subject: [PATCH] libselinux: make is_context_customizable() thread-safe MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Use the __selinux_once() macro to ensure that threads don't race to initialize the list of customizable types. Reported-by: Christian Göttsche Signed-off-by: Ondrej Mosnacek Tested-by: Christian Göttsche --- libselinux/src/is_customizable_type.c | 23 +++++++++++------------ 1 file changed, 11 insertions(+), 12 deletions(-) diff --git a/libselinux/src/is_customizable_type.c b/libselinux/src/is_customizable_type.c index 1b17860c3622..f83e1e83e944 100644 --- a/libselinux/src/is_customizable_type.c +++ b/libselinux/src/is_customizable_type.c @@ -9,7 +9,10 @@ #include "selinux_internal.h" #include "context_internal.h" -static int get_customizable_type_list(char *** retlist) +static char **customizable_list = NULL; +static pthread_once_t customizable_once = PTHREAD_ONCE_INIT; + +static void customizable_init(void) { FILE *fp; char *buf; @@ -18,12 +21,12 @@ static int get_customizable_type_list(char *** retlist) fp = fopen(selinux_customizable_types_path(), "re"); if (!fp) - return -1; + return; buf = malloc(selinux_page_size); if (!buf) { fclose(fp); - return -1; + return; } while (fgets_unlocked(buf, selinux_page_size, fp) && ctr < UINT_MAX) { ctr++; @@ -54,23 +57,19 @@ static int get_customizable_type_list(char *** retlist) fclose(fp); free(buf); if (!list) - return -1; - *retlist = list; - return 0; + return; + customizable_list = list; } -static char **customizable_list = NULL; - int is_context_customizable(const char * scontext) { int i; const char *type; context_t c; - if (!customizable_list) { - if (get_customizable_type_list(&customizable_list) != 0) - return -1; - } + __selinux_once(customizable_once, customizable_init); + if (!customizable_list) + return -1; c = context_new(scontext); if (!c) -- 2.33.1