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authorJohn Baldwin <jhb@FreeBSD.org>2021-06-14 14:28:26 -0700
committerJohn Baldwin <jhb@FreeBSD.org>2021-06-14 14:55:48 -0700
commit09db4332c6017ab57cd136788c48e5a81e3b9399 (patch)
treed0c6e194cab1c0161bd3c4b94f8980a6b5eb5614 /gdb/fbsd-nat.c
parentc9923e71ff57ce6e824833560aae59057c6f5783 (diff)
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fbsd nat: Disable address space randomization when requested.
Use procctl(2) with PROC_ASLR_CTL to disable address space randomization in the current gdb process before forking a child process for a new inferior when address space randomization is disabled. gdb/ChangeLog: * configure.ac: Check for <sys/procctl.h>. * config.in, configure: Regenerate. * fbsd-nat.c: Include <sys/procctl.h> if present. [PROC_ASLR_CTL] (maybe_disable_address_space_randomization): New. (fbsd_nat_target::create_inferior) (fbsd_nat_target::supports_disable_randomization): New. * fbsd-nat.h (fbsd_nat_target::create_inferior) (fbsd_nat_target::supports_disable_randomization): New.
Diffstat (limited to 'gdb/fbsd-nat.c')
-rw-r--r--gdb/fbsd-nat.c75
1 files changed, 75 insertions, 0 deletions
diff --git a/gdb/fbsd-nat.c b/gdb/fbsd-nat.c
index 581c04d..234e74f 100644
--- a/gdb/fbsd-nat.c
+++ b/gdb/fbsd-nat.c
@@ -29,6 +29,9 @@
#include "gdbsupport/gdb_wait.h"
#include "inf-ptrace.h"
#include <sys/types.h>
+#ifdef HAVE_SYS_PROCCTL_H
+#include <sys/procctl.h>
+#endif
#include <sys/procfs.h>
#include <sys/ptrace.h>
#include <sys/signal.h>
@@ -1401,6 +1404,68 @@ fbsd_nat_target::supports_stopped_by_sw_breakpoint ()
}
#endif
+#ifdef PROC_ASLR_CTL
+class maybe_disable_address_space_randomization
+{
+public:
+ explicit maybe_disable_address_space_randomization (bool disable_randomization)
+ {
+ if (disable_randomization)
+ {
+ if (procctl (P_PID, getpid (), PROC_ASLR_STATUS, &m_aslr_ctl) == -1)
+ {
+ warning (_("Failed to fetch current address space randomization "
+ "status: %s"), safe_strerror (errno));
+ return;
+ }
+
+ m_aslr_ctl &= ~PROC_ASLR_ACTIVE;
+ if (m_aslr_ctl == PROC_ASLR_FORCE_DISABLE)
+ return;
+
+ int ctl = PROC_ASLR_FORCE_DISABLE;
+ if (procctl (P_PID, getpid (), PROC_ASLR_CTL, &ctl) == -1)
+ {
+ warning (_("Error disabling address space randomization: %s"),
+ safe_strerror (errno));
+ return;
+ }
+
+ m_aslr_ctl_set = true;
+ }
+ }
+
+ ~maybe_disable_address_space_randomization ()
+ {
+ if (m_aslr_ctl_set)
+ {
+ if (procctl (P_PID, getpid (), PROC_ASLR_CTL, &m_aslr_ctl) == -1)
+ warning (_("Error restoring address space randomization: %s"),
+ safe_strerror (errno));
+ }
+ }
+
+ DISABLE_COPY_AND_ASSIGN (maybe_disable_address_space_randomization);
+
+private:
+ bool m_aslr_ctl_set = false;
+ int m_aslr_ctl = 0;
+};
+#endif
+
+void
+fbsd_nat_target::create_inferior (const char *exec_file,
+ const std::string &allargs,
+ char **env, int from_tty)
+{
+#ifdef PROC_ASLR_CTL
+ maybe_disable_address_space_randomization restore_aslr_ctl
+ (disable_randomization);
+#endif
+
+ inf_ptrace_target::create_inferior (exec_file, allargs, env, from_tty);
+}
+
#ifdef TDP_RFPPWAIT
/* Target hook for follow_fork. On entry and at return inferior_ptid is
the ptid of the followed inferior. */
@@ -1526,6 +1591,16 @@ fbsd_nat_target::supports_multi_process ()
return true;
}
+bool
+fbsd_nat_target::supports_disable_randomization ()
+{
+#ifdef PROC_ASLR_CTL
+ return true;
+#else
+ return false;
+#endif
+}
+
void _initialize_fbsd_nat ();
void
_initialize_fbsd_nat ()