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authorJunling Zheng <zhengjunling@huawei.com>2015-06-01 09:28:00 +0000
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2015-06-06 08:19:31 -0700
commit5ca74d43d929e6ecaba677a411f0e81371d61f76 (patch)
tree09fc91b770cdb07c826d5a9f94a35acc0c96c773
parent2917b458441b54eaf677f440005dc2635ca0e1ec (diff)
downloadlinux-linaro-stable-5ca74d43d929e6ecaba677a411f0e81371d61f76.tar.gz
net: socket: Fix the wrong returns for recvmsg and sendmsg
Based on 08adb7dabd4874cc5666b4490653b26534702ce0 upstream. We found that after v3.10.73, recvmsg might return -EFAULT while -EINVAL was expected. We tested it through the recvmsg01 testcase come from LTP testsuit. It set msg->msg_namelen to -1 and the recvmsg syscall returned errno 14, which is unexpected (errno 22 is expected): recvmsg01 4 TFAIL : invalid socket length ; returned -1 (expected -1), errno 14 (expected 22) Linux mainline has no this bug for commit 08adb7dab fixes it accidentally. However, it is too large and complex to be backported to LTS 3.10. Commit 281c9c36 (net: compat: Update get_compat_msghdr() to match copy_msghdr_from_user() behaviour) made get_compat_msghdr() return error if msg_sys->msg_namelen was negative, which changed the behaviors of recvmsg and sendmsg syscall in a lib32 system: Before commit 281c9c36, get_compat_msghdr() wouldn't fail and it would return -EINVAL in move_addr_to_user() or somewhere if msg_sys->msg_namelen was invalid and then syscall returned -EINVAL, which is correct. And now, when msg_sys->msg_namelen is negative, get_compat_msghdr() will fail and wants to return -EINVAL, however, the outer syscall will return -EFAULT directly, which is unexpected. This patch gets the return value of get_compat_msghdr() as well as copy_msghdr_from_user(), then returns this expected value if get_compat_msghdr() fails. Fixes: 281c9c36 (net: compat: Update get_compat_msghdr() to match copy_msghdr_from_user() behaviour) Signed-off-by: Junling Zheng <zhengjunling@huawei.com> Signed-off-by: Hanbing Xu <xuhanbing@huawei.com> Cc: Li Zefan <lizefan@huawei.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: David Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--net/socket.c24
1 files changed, 10 insertions, 14 deletions
diff --git a/net/socket.c b/net/socket.c
index 1b2c2d62ff20..b72fc137e1a6 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -2007,14 +2007,12 @@ static int ___sys_sendmsg(struct socket *sock, struct msghdr __user *msg,
int err, ctl_len, total_len;
err = -EFAULT;
- if (MSG_CMSG_COMPAT & flags) {
- if (get_compat_msghdr(msg_sys, msg_compat))
- return -EFAULT;
- } else {
+ if (MSG_CMSG_COMPAT & flags)
+ err = get_compat_msghdr(msg_sys, msg_compat);
+ else
err = copy_msghdr_from_user(msg_sys, msg);
- if (err)
- return err;
- }
+ if (err)
+ return err;
if (msg_sys->msg_iovlen > UIO_FASTIOV) {
err = -EMSGSIZE;
@@ -2219,14 +2217,12 @@ static int ___sys_recvmsg(struct socket *sock, struct msghdr __user *msg,
struct sockaddr __user *uaddr;
int __user *uaddr_len;
- if (MSG_CMSG_COMPAT & flags) {
- if (get_compat_msghdr(msg_sys, msg_compat))
- return -EFAULT;
- } else {
+ if (MSG_CMSG_COMPAT & flags)
+ err = get_compat_msghdr(msg_sys, msg_compat);
+ else
err = copy_msghdr_from_user(msg_sys, msg);
- if (err)
- return err;
- }
+ if (err)
+ return err;
if (msg_sys->msg_iovlen > UIO_FASTIOV) {
err = -EMSGSIZE;