[Qemu-devel] [PATCH] linux-user: Check array bounds in errno conversion

[Peter Maydell]

From: Timothy E Baldwin <t.e.baldwi...@members.leeds.ac.uk>

Check array bounds in host_to_target_errno() and target_to_host_errno().

Signed-off-by: Timothy Edward Baldwin <t.e.baldwi...@members.leeds.ac.uk>
Message-id: 1441497448-32489-2-git-send-email-t.e.baldwi...@members.leeds.ac.uk
[PMM: Add a lower-bound check, use braces on if(), tweak commit message]
Signed-off-by: Peter Maydell <peter.mayd...@linaro.org>
---
This is a bugfix patch fished out of Timothy's signal-race-fixes
patch series. We had a previous go-around doing this with unsigned
integers, but that doesn't work.

 linux-user/syscall.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index 9517531..f9dcdd4 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -617,15 +617,19 @@ static uint16_t 
host_to_target_errno_table[ERRNO_TABLE_SIZE] = {
 
 static inline int host_to_target_errno(int err)
 {
-    if(host_to_target_errno_table[err])
+    if (err >= 0 && err < ERRNO_TABLE_SIZE &&
+        host_to_target_errno_table[err]) {
         return host_to_target_errno_table[err];
+    }
     return err;
 }
 
 static inline int target_to_host_errno(int err)
 {
-    if (target_to_host_errno_table[err])
+    if (err >= 0 && err < ERRNO_TABLE_SIZE &&
+        target_to_host_errno_table[err]) {
         return target_to_host_errno_table[err];
+    }
     return err;
 }
 
-- 
1.9.1