2.6.32-longterm review patch. If anyone has any objections, please let me know.
------------------ From: Dan Carpenter <[email protected]> [ Upstream commit 1661bf364ae9c506bc8795fef70d1532931be1e8 ] We need to cap ->msg_namelen or it leads to a buffer overflow when we to the memcpy() in __audit_sockaddr(). It requires CAP_AUDIT_CONTROL to exploit this bug. The call tree is: ___sys_recvmsg() move_addr_to_user() audit_sockaddr() __audit_sockaddr() Reported-by: Jüri Aedla <[email protected]> Signed-off-by: Dan Carpenter <[email protected]> Signed-off-by: David S. Miller <[email protected]> [wt: 2.6.32: msg_sys is a struct, not a pointer] Signed-off-by: Willy Tarreau <[email protected]> --- net/compat.c | 2 ++ net/socket.c | 24 ++++++++++++++++++++---- 2 files changed, 22 insertions(+), 4 deletions(-) diff --git a/net/compat.c b/net/compat.c index 9559afc..da3d0fc 100644 --- a/net/compat.c +++ b/net/compat.c @@ -69,6 +69,8 @@ int get_compat_msghdr(struct msghdr *kmsg, struct compat_msghdr __user *umsg) __get_user(kmsg->msg_controllen, &umsg->msg_controllen) || __get_user(kmsg->msg_flags, &umsg->msg_flags)) return -EFAULT; + if (kmsg->msg_namelen > sizeof(struct sockaddr_storage)) + return -EINVAL; kmsg->msg_name = compat_ptr(tmp1); kmsg->msg_iov = compat_ptr(tmp2); kmsg->msg_control = compat_ptr(tmp3); diff --git a/net/socket.c b/net/socket.c index bf9fc68..9f8cd74 100644 --- a/net/socket.c +++ b/net/socket.c @@ -1863,6 +1863,16 @@ SYSCALL_DEFINE2(shutdown, int, fd, int, how) #define COMPAT_NAMELEN(msg) COMPAT_MSG(msg, msg_namelen) #define COMPAT_FLAGS(msg) COMPAT_MSG(msg, msg_flags) +static int copy_msghdr_from_user(struct msghdr *kmsg, + struct msghdr __user *umsg) +{ + if (copy_from_user(kmsg, umsg, sizeof(struct msghdr))) + return -EFAULT; + if (kmsg->msg_namelen > sizeof(struct sockaddr_storage)) + return -EINVAL; + return 0; +} + /* * BSD sendmsg interface */ @@ -1887,8 +1897,11 @@ SYSCALL_DEFINE3(sendmsg, int, fd, struct msghdr __user *, msg, unsigned, flags) if (get_compat_msghdr(&msg_sys, msg_compat)) return -EFAULT; } - else if (copy_from_user(&msg_sys, msg, sizeof(struct msghdr))) - return -EFAULT; + else { + err = copy_msghdr_from_user(&msg_sys, msg); + if (err) + return err; + } sock = sockfd_lookup_light(fd, &err, &fput_needed); if (!sock) @@ -1997,8 +2010,11 @@ SYSCALL_DEFINE3(recvmsg, int, fd, struct msghdr __user *, msg, if (get_compat_msghdr(&msg_sys, msg_compat)) return -EFAULT; } - else if (copy_from_user(&msg_sys, msg, sizeof(struct msghdr))) - return -EFAULT; + else { + err = copy_msghdr_from_user(&msg_sys, msg); + if (err) + return err; + } sock = sockfd_lookup_light(fd, &err, &fput_needed); if (!sock) -- 1.7.12.2.21.g234cd45.dirty -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
