| From | Luis Henriques <> | Subject | [PATCH 3.16.y-ckt 060/110] net: socket: Fix the wrong returns for recvmsg and sendmsg | Date | Fri, 5 Jun 2015 14:57:43 +0100 |
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3.16.7-ckt13 -stable review patch. If anyone has any objections, please let me know.
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From: Junling Zheng <zhengjunling@huawei.com>
Based on 08adb7dabd4874cc5666b4490653b26534702ce0 upstream.
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: Luis Henriques <luis.henriques@canonical.com> --- net/socket.c | 24 ++++++++++-------------- 1 file changed, 10 insertions(+), 14 deletions(-)
diff --git a/net/socket.c b/net/socket.c index 4980af97d87c..fc7ba8cabb72 100644 --- a/net/socket.c +++ b/net/socket.c @@ -2011,14 +2011,12 @@ 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; @@ -2223,14 +2221,12 @@ 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;
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