[Qemu-devel] [PATCH v4 01/12] linux-user/syscall: Verify recvfrom(addr) is user-writable

["Philippe Mathieu-Daudé" <f4bug@amsat.org>]

Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Tested-By: Guido Günther <agx@sigxcpu.org>
Reviewed-by: Laurent Vivier <laurent@vivier.eu>
---
 linux-user/syscall.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index 2117fb13b4..ad40682cee 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -4154,6 +4154,11 @@ static abi_long do_recvfrom(int fd, abi_ulong msg, size_t len, int flags,
             ret = -TARGET_EINVAL;
             goto fail;
         }
+        if (!access_ok(VERIFY_WRITE, target_addr, addrlen)) {
+            ret = -TARGET_EFAULT;
+            goto fail;
+        }
+
         addr = alloca(addrlen);
         ret = get_errno(safe_recvfrom(fd, host_msg, len, flags,
                                       addr, &addrlen));
-- 
2.18.0