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[binutils-gdb] Fix use-after-free in gdbserver
- From: Tom Tromey <tromey at sourceware dot org>
- To: gdb-cvs at sourceware dot org
- Date: 29 Nov 2018 17:48:55 -0000
- Subject: [binutils-gdb] Fix use-after-free in gdbserver
https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=d105de22fc385da878e8db44c9503a7f30419322
commit d105de22fc385da878e8db44c9503a7f30419322
Author: Tom Tromey <tom@tromey.com>
Date: Sun Jul 29 19:21:01 2018 -0600
Fix use-after-free in gdbserver
-fsanitize=address pointed out a use-after-free in gdbserver. In
particular, handle_detach could reference "process" after it was
deleted by detach_inferior. Avoiding this also necessitated changing
target_ops::join to take a pid rather than a process_info*.
Tested by the buildbot using a few of the gdbserver builders.
gdb/gdbserver/ChangeLog
2018-11-29 Tom Tromey <tom@tromey.com>
* win32-low.c (win32_join): Take pid, not process.
* target.h (struct target_ops) <join>: Change argument type.
(join_inferior): Change argument name.
* spu-low.c (spu_join): Take pid, not process.
* server.c (handle_detach): Preserve pid before destroying
process.
* lynx-low.c (lynx_join): Take pid, not process.
* linux-low.c (linux_join): Take pid, not process.
Diff:
---
gdb/gdbserver/ChangeLog | 11 +++++++++++
gdb/gdbserver/linux-low.c | 4 ++--
gdb/gdbserver/lynx-low.c | 2 +-
gdb/gdbserver/server.c | 10 +++++++---
gdb/gdbserver/spu-low.c | 4 ++--
gdb/gdbserver/target.h | 8 ++++----
gdb/gdbserver/win32-low.c | 4 ++--
7 files changed, 29 insertions(+), 14 deletions(-)
diff --git a/gdb/gdbserver/ChangeLog b/gdb/gdbserver/ChangeLog
index 91a62b6..ec4d72f 100644
--- a/gdb/gdbserver/ChangeLog
+++ b/gdb/gdbserver/ChangeLog
@@ -1,3 +1,14 @@
+2018-11-29 Tom Tromey <tom@tromey.com>
+
+ * win32-low.c (win32_join): Take pid, not process.
+ * target.h (struct target_ops) <join>: Change argument type.
+ (join_inferior): Change argument name.
+ * spu-low.c (spu_join): Take pid, not process.
+ * server.c (handle_detach): Preserve pid before destroying
+ process.
+ * lynx-low.c (lynx_join): Take pid, not process.
+ * linux-low.c (linux_join): Take pid, not process.
+
2018-11-23 Alan Hayward <alan.hayward@arm.com>
* linux-aarch64-low.c (aarch64_cannot_store_register): Remove.
diff --git a/gdb/gdbserver/linux-low.c b/gdb/gdbserver/linux-low.c
index 701f3e8..4d84927 100644
--- a/gdb/gdbserver/linux-low.c
+++ b/gdb/gdbserver/linux-low.c
@@ -1670,12 +1670,12 @@ linux_mourn (struct process_info *process)
}
static void
-linux_join (process_info *proc)
+linux_join (int pid)
{
int status, ret;
do {
- ret = my_waitpid (proc->pid, &status, 0);
+ ret = my_waitpid (pid, &status, 0);
if (WIFEXITED (status) || WIFSIGNALED (status))
break;
} while (ret != -1 || errno != ECHILD);
diff --git a/gdb/gdbserver/lynx-low.c b/gdb/gdbserver/lynx-low.c
index 6c5933b..3bf3588 100644
--- a/gdb/gdbserver/lynx-low.c
+++ b/gdb/gdbserver/lynx-low.c
@@ -562,7 +562,7 @@ lynx_mourn (struct process_info *proc)
/* Implement the join target_ops method. */
static void
-lynx_join (process_info *proc)
+lynx_join (int pid)
{
/* The PTRACE_DETACH is sufficient to detach from the process.
So no need to do anything extra. */
diff --git a/gdb/gdbserver/server.c b/gdb/gdbserver/server.c
index 4ec3548..a0be0d4 100644
--- a/gdb/gdbserver/server.c
+++ b/gdb/gdbserver/server.c
@@ -1255,11 +1255,15 @@ handle_detach (char *own_buf)
fprintf (stderr, "Detaching from process %d\n", process->pid);
stop_tracing ();
+
+ /* We'll need this after PROCESS has been destroyed. */
+ int pid = process->pid;
+
if (detach_inferior (process) != 0)
write_enn (own_buf);
else
{
- discard_queued_stop_replies (ptid_t (process->pid));
+ discard_queued_stop_replies (ptid_t (pid));
write_ok (own_buf);
if (extended_protocol || target_running ())
@@ -1269,7 +1273,7 @@ handle_detach (char *own_buf)
and instead treat this like a normal program exit. */
cs.last_status.kind = TARGET_WAITKIND_EXITED;
cs.last_status.value.integer = 0;
- cs.last_ptid = ptid_t (process->pid);
+ cs.last_ptid = ptid_t (pid);
current_thread = NULL;
}
@@ -1281,7 +1285,7 @@ handle_detach (char *own_buf)
/* If we are attached, then we can exit. Otherwise, we
need to hang around doing nothing, until the child is
gone. */
- join_inferior (process);
+ join_inferior (pid);
exit (0);
}
}
diff --git a/gdb/gdbserver/spu-low.c b/gdb/gdbserver/spu-low.c
index 83a31a2..239c212 100644
--- a/gdb/gdbserver/spu-low.c
+++ b/gdb/gdbserver/spu-low.c
@@ -362,12 +362,12 @@ spu_mourn (struct process_info *process)
}
static void
-spu_join (process_info *proc)
+spu_join (int pid)
{
int status, ret;
do {
- ret = waitpid (proc->pid, &status, 0);
+ ret = waitpid (pid, &status, 0);
if (WIFEXITED (status) || WIFSIGNALED (status))
break;
} while (ret != -1 || errno != ECHILD);
diff --git a/gdb/gdbserver/target.h b/gdb/gdbserver/target.h
index fce54e0..6f810b6 100644
--- a/gdb/gdbserver/target.h
+++ b/gdb/gdbserver/target.h
@@ -103,9 +103,9 @@ struct target_ops
void (*mourn) (struct process_info *proc);
- /* Wait for process PROC to exit. */
+ /* Wait for process PID to exit. */
- void (*join) (process_info *proc);
+ void (*join) (int pid);
/* Return 1 iff the thread with process ID PID is alive. */
@@ -530,8 +530,8 @@ int kill_inferior (process_info *proc);
#define store_inferior_registers(regcache, regno) \
(*the_target->store_registers) (regcache, regno)
-#define join_inferior(proc) \
- (*the_target->join) (proc)
+#define join_inferior(pid) \
+ (*the_target->join) (pid)
#define target_supports_non_stop() \
(the_target->supports_non_stop ? (*the_target->supports_non_stop ) () : 0)
diff --git a/gdb/gdbserver/win32-low.c b/gdb/gdbserver/win32-low.c
index 4aed58d..1ad71c7 100644
--- a/gdb/gdbserver/win32-low.c
+++ b/gdb/gdbserver/win32-low.c
@@ -873,9 +873,9 @@ win32_mourn (struct process_info *process)
/* Implementation of target_ops::join. */
static void
-win32_join (process_info *proc)
+win32_join (int pid)
{
- HANDLE h = OpenProcess (PROCESS_ALL_ACCESS, FALSE, proc->pid);
+ HANDLE h = OpenProcess (PROCESS_ALL_ACCESS, FALSE, pid);
if (h != NULL)
{
WaitForSingleObject (h, INFINITE);