From c2e4cf5b21e8c775c669f3933d25a0946774ec0d Mon Sep 17 00:00:00 2001 From: Ondrej Mosnacek Date: Tue, 26 Oct 2021 13:52:35 +0200 Subject: [PATCH] libselinux: make selinux_log() thread-safe Ensure that selinux_log() is thread-safe by guarding the call to the underlying callback with a mutex. Signed-off-by: Ondrej Mosnacek --- libselinux/src/callbacks.c | 8 +++++--- libselinux/src/callbacks.h | 13 ++++++++++++- 2 files changed, 17 insertions(+), 4 deletions(-) diff --git a/libselinux/src/callbacks.c b/libselinux/src/callbacks.c index c18ccc54754a..469c4055f4d7 100644 --- a/libselinux/src/callbacks.c +++ b/libselinux/src/callbacks.c @@ -10,6 +10,8 @@ #include #include "callbacks.h" +pthread_mutex_t log_mutex = PTHREAD_MUTEX_INITIALIZER; + /* default implementations */ static int __attribute__ ((format(printf, 2, 3))) default_selinux_log(int type __attribute__((unused)), const char *fmt, ...) @@ -56,7 +58,7 @@ default_selinux_policyload(int seqno __attribute__((unused))) /* callback pointers */ int __attribute__ ((format(printf, 2, 3))) -(*selinux_log)(int, const char *, ...) = +(*selinux_log_direct)(int, const char *, ...) = default_selinux_log; int @@ -81,7 +83,7 @@ selinux_set_callback(int type, union selinux_callback cb) { switch (type) { case SELINUX_CB_LOG: - selinux_log = cb.func_log; + selinux_log_direct = cb.func_log; break; case SELINUX_CB_AUDIT: selinux_audit = cb.func_audit; @@ -106,7 +108,7 @@ selinux_get_callback(int type) switch (type) { case SELINUX_CB_LOG: - cb.func_log = selinux_log; + cb.func_log = selinux_log_direct; break; case SELINUX_CB_AUDIT: cb.func_audit = selinux_audit; diff --git a/libselinux/src/callbacks.h b/libselinux/src/callbacks.h index 03d87f0cbdfe..f4dab15789f9 100644 --- a/libselinux/src/callbacks.h +++ b/libselinux/src/callbacks.h @@ -10,9 +10,11 @@ #include #include +#include "selinux_internal.h" + /* callback pointers */ extern int __attribute__ ((format(printf, 2, 3))) -(*selinux_log) (int type, const char *, ...) ; +(*selinux_log_direct) (int type, const char *, ...) ; extern int (*selinux_audit) (void *, security_class_t, char *, size_t) ; @@ -26,4 +28,13 @@ extern int extern int (*selinux_netlink_policyload) (int seqno) ; +/* Thread-safe selinux_log() function */ +extern pthread_mutex_t log_mutex; + +#define selinux_log(type, ...) do { \ + __pthread_mutex_lock(&log_mutex); \ + selinux_log_direct(type, __VA_ARGS__); \ + __pthread_mutex_unlock(&log_mutex); \ +} while(0) + #endif /* _SELINUX_CALLBACKS_H_ */ -- 2.33.1