fix rejection of dns responses with pointers past 512 byte offset

[musl] / src / exit / abort.c

diff --git a/src/exit/abort.c b/src/exit/abort.c
index 9a1c3d4..f21f458 100644 (file)
--- a/src/exit/abort.c
+++ b/src/exit/abort.c
@@ -1,8 +1,30 @@
 #include <stdlib.h>
 #include <signal.h>
+#include "syscall.h"
+#include "pthread_impl.h"
+#include "atomic.h"
+#include "lock.h"
+#include "ksigaction.h"
 
-void abort(void)
+_Noreturn void abort(void)
 {
        raise(SIGABRT);
-       for (;;);
+
+       /* If there was a SIGABRT handler installed and it returned, or if
+        * SIGABRT was blocked or ignored, take an AS-safe lock to prevent
+        * sigaction from installing a new SIGABRT handler, uninstall any
+        * handler that may be present, and re-raise the signal to generate
+        * the default action of abnormal termination. */
+       __block_all_sigs(0);
+       LOCK(__abort_lock);
+       __syscall(SYS_rt_sigaction, SIGABRT,
+               &(struct k_sigaction){.handler = SIG_DFL}, 0, _NSIG/8);
+       __syscall(SYS_tkill, __pthread_self()->tid, SIGABRT);
+       __syscall(SYS_rt_sigprocmask, SIG_UNBLOCK,
+               &(long[_NSIG/(8*sizeof(long))]){1UL<<(SIGABRT-1)}, 0, _NSIG/8);
+
+       /* Beyond this point should be unreachable. */
+       a_crash();
+       raise(SIGKILL);
+       _Exit(127);
 }