diff mbox series

[v2,3/7] linux-user: Pass ka_restorer to do_sigaction

Message ID 20210422230227.314751-4-richard.henderson@linaro.org
State New
Headers show
Series linux-user: sigaction fixes/cleanups | expand

Commit Message

Richard Henderson April 22, 2021, 11:02 p.m. UTC 
The value of ka_restorer needs to be saved in sigact_table.
At the moment, the attempt to save it in do_syscall is
improperly clobbering user memory.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

---
 linux-user/syscall_defs.h |  2 +-
 linux-user/signal.c       |  5 ++++-
 linux-user/syscall.c      | 19 ++++++-------------
 3 files changed, 11 insertions(+), 15 deletions(-)

-- 
2.25.1

Comments

Alex Bennée April 23, 2021, 12:55 p.m. UTC | #1 
Richard Henderson <richard.henderson@linaro.org> writes:

> The value of ka_restorer needs to be saved in sigact_table.


It would be nice to add a comment to sigact_table to describe what it
is. This is some of the oldest code in the tree so there seems to be a
fair bit of implicit knowledge is the way things are done.

> At the moment, the attempt to save it in do_syscall is

> improperly clobbering user memory.


Otherwise to my slightly confused eyes it looks pretty sane:

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>


-- 
Alex Bennée
diff mbox series

Patch

diff --git a/linux-user/syscall_defs.h b/linux-user/syscall_defs.h
index 693d4f3788..e4aaf8412f 100644
--- a/linux-user/syscall_defs.h
+++ b/linux-user/syscall_defs.h
@@ -492,7 +492,7 @@  void target_to_host_old_sigset(sigset_t *sigset,
                                const abi_ulong *old_sigset);
 struct target_sigaction;
 int do_sigaction(int sig, const struct target_sigaction *act,
-                 struct target_sigaction *oact);
+                 struct target_sigaction *oact, abi_ulong ka_restorer);
 
 #include "target_signal.h"
 
diff --git a/linux-user/signal.c b/linux-user/signal.c
index 7eecec46c4..44a5012930 100644
--- a/linux-user/signal.c
+++ b/linux-user/signal.c
@@ -830,7 +830,7 @@  out:
 
 /* do_sigaction() return target values and host errnos */
 int do_sigaction(int sig, const struct target_sigaction *act,
-                 struct target_sigaction *oact)
+                 struct target_sigaction *oact, abi_ulong ka_restorer)
 {
     struct target_sigaction *k;
     struct sigaction act1;
@@ -863,6 +863,9 @@  int do_sigaction(int sig, const struct target_sigaction *act,
         __get_user(k->sa_flags, &act->sa_flags);
 #ifdef TARGET_ARCH_HAS_SA_RESTORER
         __get_user(k->sa_restorer, &act->sa_restorer);
+#endif
+#ifdef TARGET_ARCH_HAS_KA_RESTORER
+        k->ka_restorer = ka_restorer;
 #endif
         /* To be swapped in target_to_host_sigset.  */
         k->sa_mask = act->sa_mask;
diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index ee21eb5e6f..36169a0ded 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -8989,11 +8989,10 @@  static abi_long do_syscall1(void *cpu_env, int num, abi_long arg1,
                 act._sa_handler = old_act->_sa_handler;
                 target_siginitset(&act.sa_mask, old_act->sa_mask);
                 act.sa_flags = old_act->sa_flags;
-                act.ka_restorer = 0;
                 unlock_user_struct(old_act, arg2, 0);
                 pact = &act;
             }
-            ret = get_errno(do_sigaction(arg1, pact, &oact));
+            ret = get_errno(do_sigaction(arg1, pact, &oact, 0));
             if (!is_error(ret) && arg3) {
                 if (!lock_user_struct(VERIFY_WRITE, old_act, arg3, 0))
                     return -TARGET_EFAULT;
@@ -9017,7 +9016,7 @@  static abi_long do_syscall1(void *cpu_env, int num, abi_long arg1,
 		pact = NULL;
 	    }
 
-	    ret = get_errno(do_sigaction(arg1, pact, &oact));
+	    ret = get_errno(do_sigaction(arg1, pact, &oact, 0));
 
 	    if (!is_error(ret) && arg3) {
                 if (!lock_user_struct(VERIFY_WRITE, old_act, arg3, 0))
@@ -9040,15 +9039,12 @@  static abi_long do_syscall1(void *cpu_env, int num, abi_long arg1,
                 target_siginitset(&act.sa_mask, old_act->sa_mask);
                 act.sa_flags = old_act->sa_flags;
                 act.sa_restorer = old_act->sa_restorer;
-#ifdef TARGET_ARCH_HAS_KA_RESTORER
-                act.ka_restorer = 0;
-#endif
                 unlock_user_struct(old_act, arg2, 0);
                 pact = &act;
             } else {
                 pact = NULL;
             }
-            ret = get_errno(do_sigaction(arg1, pact, &oact));
+            ret = get_errno(do_sigaction(arg1, pact, &oact, 0));
             if (!is_error(ret) && arg3) {
                 if (!lock_user_struct(VERIFY_WRITE, old_act, arg3, 0))
                     return -TARGET_EFAULT;
@@ -9085,11 +9081,10 @@  static abi_long do_syscall1(void *cpu_env, int num, abi_long arg1,
                 act._sa_handler = rt_act->_sa_handler;
                 act.sa_mask = rt_act->sa_mask;
                 act.sa_flags = rt_act->sa_flags;
-                act.ka_restorer = arg5;
                 unlock_user_struct(rt_act, arg2, 0);
                 pact = &act;
             }
-            ret = get_errno(do_sigaction(arg1, pact, &oact));
+            ret = get_errno(do_sigaction(arg1, pact, &oact, arg5));
             if (!is_error(ret) && arg3) {
                 if (!lock_user_struct(VERIFY_WRITE, rt_act, arg3, 0))
                     return -TARGET_EFAULT;
@@ -9104,6 +9099,7 @@  static abi_long do_syscall1(void *cpu_env, int num, abi_long arg1,
             target_ulong sigsetsize = arg5;
 #else
             target_ulong sigsetsize = arg4;
+            target_ulong restorer = 0;
 #endif
             struct target_sigaction *act;
             struct target_sigaction *oact;
@@ -9115,9 +9111,6 @@  static abi_long do_syscall1(void *cpu_env, int num, abi_long arg1,
                 if (!lock_user_struct(VERIFY_READ, act, arg2, 1)) {
                     return -TARGET_EFAULT;
                 }
-#ifdef TARGET_ARCH_HAS_KA_RESTORER
-                act->ka_restorer = restorer;
-#endif
             } else {
                 act = NULL;
             }
@@ -9128,7 +9121,7 @@  static abi_long do_syscall1(void *cpu_env, int num, abi_long arg1,
                 }
             } else
                 oact = NULL;
-            ret = get_errno(do_sigaction(arg1, act, oact));
+            ret = get_errno(do_sigaction(arg1, act, oact, restorer));
 	rt_sigaction_fail:
             if (act)
                 unlock_user_struct(act, arg2, 0);