[Qemu-devel] [PATCH v2 18/19] linux-user: Avoid possible misalignment in host_to_target_siginfo()

[Peter Maydell]

host_to_target_siginfo() is implemented by a combination of
host_to_target_siginfo_noswap() followed by tswap_siginfo().
The first of these two functions assumes that the target_siginfo_t
it is writing to is correctly aligned, but the pointer passed
into host_to_target_siginfo() is directly from the guest and
might be misaligned. Use a local variable to avoid this problem.
(tswap_siginfo() does now correctly handle a misaligned destination.)

Signed-off-by: Peter Maydell <address@hidden>
---
 linux-user/signal.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/linux-user/signal.c b/linux-user/signal.c
index 8ea0cbf..7e2a80f 100644
--- a/linux-user/signal.c
+++ b/linux-user/signal.c
@@ -400,8 +400,9 @@ static void tswap_siginfo(target_siginfo_t *tinfo,
 
 void host_to_target_siginfo(target_siginfo_t *tinfo, const siginfo_t *info)
 {
-    host_to_target_siginfo_noswap(tinfo, info);
-    tswap_siginfo(tinfo, tinfo);
+    target_siginfo_t tgt_tmp;
+    host_to_target_siginfo_noswap(&tgt_tmp, info);
+    tswap_siginfo(tinfo, &tgt_tmp);
 }
 
 /* XXX: we support only POSIX RT signals are used. */
-- 
1.9.1