kernel/linux.git/net/rds/recv.c, branch linux-4.4.y

net: rds: fix memory leak in rds_recvmsg

2021-06-30T12:49:32+00:00

[ Upstream commit 49bfcbfd989a8f1f23e705759a6bb099de2cff9f ] Syzbot reported memory leak in rds. The problem was in unputted refcount in case of error. int rds_recvmsg(struct socket *sock, struct msghdr *msg, size_t size, int msg_flags) { ... if (!rds_next_incoming(rs, &inc)) { ... } After this "if" inc refcount incremented and if (rds_cmsg_recv(inc, msg, rs)) { ret = -EFAULT; goto out; } ... out: return ret; } in case of rds_cmsg_recv() fail the refcount won't be decremented. And it's easy to see from ftrace log, that rds_inc_addref() don't have rds_inc_put() pair in rds_recvmsg() after rds_cmsg_recv() 1) | rds_recvmsg() { 1) 3.721 us | rds_inc_addref(); 1) 3.853 us | rds_message_inc_copy_to_user(); 1) + 10.395 us | rds_cmsg_recv(); 1) + 34.260 us | } Fixes: bdbe6fbc6a2f ("RDS: recv.c") Reported-and-tested-by: syzbot+5134cdf021c4ed5aaa5f@syzkaller.appspotmail.com Signed-off-by: Pavel Skripkin Reviewed-by: Håkon Bugge Acked-by: Santosh Shilimkar Signed-off-by: David S. Miller Signed-off-by: Sasha Levin

rds: Prevent kernel-infoleak in rds_notify_queue_get()

2020-08-21T08:52:53+00:00

commit bbc8a99e952226c585ac17477a85ef1194501762 upstream. rds_notify_queue_get() is potentially copying uninitialized kernel stack memory to userspace since the compiler may leave a 4-byte hole at the end of `cmsg`. In 2016 we tried to fix this issue by doing `= { 0 };` on `cmsg`, which unfortunately does not always initialize that 4-byte hole. Fix it by using memset() instead. Cc: stable@vger.kernel.org Fixes: f037590fff30 ("rds: fix a leak of kernel memory") Fixes: bdbe6fbc6a2f ("RDS: recv.c") Suggested-by: Dan Carpenter Signed-off-by: Peilin Ye Acked-by: Santosh Shilimkar Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

rds: avoid unenecessary cong_update in loop transport

2018-07-22T12:25:54+00:00

commit f1693c63ab133d16994cc50f773982b5905af264 upstream. Loop transport which is self loopback, remote port congestion update isn't relevant. Infact the xmit path already ignores it. Receive path needs to do the same. Reported-by: syzbot+4c20b3866171ce8441d2@syzkaller.appspotmail.com Reviewed-by: Sowmini Varadhan Signed-off-by: Santosh Shilimkar Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

rds: fix an infoleak in rds_inc_info_copy

2016-09-15T06:27:51+00:00

commit 4116def2337991b39919f3b448326e21c40e0dbb upstream. The last field "flags" of object "minfo" is not initialized. Copying this object out may leak kernel stack data. Assign 0 to it to avoid leak. Signed-off-by: Kangjie Lu Acked-by: Santosh Shilimkar Signed-off-by: David S. Miller Signed-off-by: Juerg Haefliger Signed-off-by: Greg Kroah-Hartman

net: Remove iocb argument from sendmsg and recvmsg

2015-03-02T18:06:31+00:00

After TIPC doesn't depend on iocb argument in its internal implementations of sendmsg() and recvmsg() hooks defined in proto structure, no any user is using iocb argument in them at all now. Then we can drop the redundant iocb argument completely from kinds of implementations of both sendmsg() and recvmsg() in the entire networking stack. Cc: Christoph Hellwig Suggested-by: Al Viro Signed-off-by: Ying Xue Signed-off-by: David S. Miller

put iov_iter into msghdr

2014-12-09T21:29:03+00:00

Note that the code _using_ ->msg_iter at that point will be very unhappy with anything other than unshifted iovec-backed iov_iter. We still need to convert users to proper primitives. Signed-off-by: Al Viro

rds: switch ->inc_copy_to_user() to passing iov_iter

2014-11-24T10:16:43+00:00

instances get considerably simpler from that... Signed-off-by: Al Viro

net: add build-time checks for msg->msg_name size

2014-01-19T07:04:16+00:00

This is a follow-up patch to f3d3342602f8bc ("net: rework recvmsg handler msg_name and msg_namelen logic"). DECLARE_SOCKADDR validates that the structure we use for writing the name information to is not larger than the buffer which is reserved for msg->msg_name (which is 128 bytes). Also use DECLARE_SOCKADDR consistently in sendmsg code paths. Signed-off-by: Steffen Hurrle Suggested-by: Hannes Frederic Sowa Acked-by: Hannes Frederic Sowa Signed-off-by: David S. Miller

net: rework recvmsg handler msg_name and msg_namelen logic

2013-11-21T02:52:30+00:00

This patch now always passes msg->msg_namelen as 0. recvmsg handlers must set msg_namelen to the proper size <= sizeof(struct sockaddr_storage) to return msg_name to the user. This prevents numerous uninitialized memory leaks we had in the recvmsg handlers and makes it harder for new code to accidentally leak uninitialized memory. Optimize for the case recvfrom is called with NULL as address. We don't need to copy the address at all, so set it to NULL before invoking the recvmsg handler. We can do so, because all the recvmsg handlers must cope with the case a plain read() is called on them. read() also sets msg_name to NULL. Also document these changes in include/linux/net.h as suggested by David Miller. Changes since RFC: Set msg->msg_name = NULL if user specified a NULL in msg_name but had a non-null msg_namelen in verify_iovec/verify_compat_iovec. This doesn't affect sendto as it would bail out earlier while trying to copy-in the address. It also more naturally reflects the logic by the callers of verify_iovec. With this change in place I could remove " if (!uaddr || msg_sys->msg_namelen == 0) msg->msg_name = NULL ". This change does not alter the user visible error logic as we ignore msg_namelen as long as msg_name is NULL. Also remove two unnecessary curly brackets in ___sys_recvmsg and change comments to netdev style. Cc: David Miller Suggested-by: Eric Dumazet Signed-off-by: Hannes Frederic Sowa Signed-off-by: David S. Miller

rds: set correct msg_namelen

2012-07-23T08:01:44+00:00

Jay Fenlason (fenlason@redhat.com) found a bug, that recvfrom() on an RDS socket can return the contents of random kernel memory to userspace if it was called with a address length larger than sizeof(struct sockaddr_in). rds_recvmsg() also fails to set the addr_len paramater properly before returning, but that's just a bug. There are also a number of cases wher recvfrom() can return an entirely bogus address. Anything in rds_recvmsg() that returns a non-negative value but does not go through the "sin = (struct sockaddr_in *)msg->msg_name;" code path at the end of the while(1) loop will return up to 128 bytes of kernel memory to userspace. And I write two test programs to reproduce this bug, you will see that in rds_server, fromAddr will be overwritten and the following sock_fd will be destroyed. Yes, it is the programmer's fault to set msg_namelen incorrectly, but it is better to make the kernel copy the real length of address to user space in such case. How to run the test programs ? I test them on 32bit x86 system, 3.5.0-rc7. 1 compile gcc -o rds_client rds_client.c gcc -o rds_server rds_server.c 2 run ./rds_server on one console 3 run ./rds_client on another console 4 you will see something like: server is waiting to receive data... old socket fd=3 server received data from client:data from client msg.msg_namelen=32 new socket fd=-1067277685 sendmsg() : Bad file descriptor /***************** rds_client.c ********************/ int main(void) { int sock_fd; struct sockaddr_in serverAddr; struct sockaddr_in toAddr; char recvBuffer[128] = "data from client"; struct msghdr msg; struct iovec iov; sock_fd = socket(AF_RDS, SOCK_SEQPACKET, 0); if (sock_fd < 0) { perror("create socket error\n"); exit(1); } memset(&serverAddr, 0, sizeof(serverAddr)); serverAddr.sin_family = AF_INET; serverAddr.sin_addr.s_addr = inet_addr("127.0.0.1"); serverAddr.sin_port = htons(4001); if (bind(sock_fd, (struct sockaddr*)&serverAddr, sizeof(serverAddr)) < 0) { perror("bind() error\n"); close(sock_fd); exit(1); } memset(&toAddr, 0, sizeof(toAddr)); toAddr.sin_family = AF_INET; toAddr.sin_addr.s_addr = inet_addr("127.0.0.1"); toAddr.sin_port = htons(4000); msg.msg_name = &toAddr; msg.msg_namelen = sizeof(toAddr); msg.msg_iov = &iov; msg.msg_iovlen = 1; msg.msg_iov->iov_base = recvBuffer; msg.msg_iov->iov_len = strlen(recvBuffer) + 1; msg.msg_control = 0; msg.msg_controllen = 0; msg.msg_flags = 0; if (sendmsg(sock_fd, &msg, 0) == -1) { perror("sendto() error\n"); close(sock_fd); exit(1); } printf("client send data:%s\n", recvBuffer); memset(recvBuffer, '\0', 128); msg.msg_name = &toAddr; msg.msg_namelen = sizeof(toAddr); msg.msg_iov = &iov; msg.msg_iovlen = 1; msg.msg_iov->iov_base = recvBuffer; msg.msg_iov->iov_len = 128; msg.msg_control = 0; msg.msg_controllen = 0; msg.msg_flags = 0; if (recvmsg(sock_fd, &msg, 0) == -1) { perror("recvmsg() error\n"); close(sock_fd); exit(1); } printf("receive data from server:%s\n", recvBuffer); close(sock_fd); return 0; } /***************** rds_server.c ********************/ int main(void) { struct sockaddr_in fromAddr; int sock_fd; struct sockaddr_in serverAddr; unsigned int addrLen; char recvBuffer[128]; struct msghdr msg; struct iovec iov; sock_fd = socket(AF_RDS, SOCK_SEQPACKET, 0); if(sock_fd < 0) { perror("create socket error\n"); exit(0); } memset(&serverAddr, 0, sizeof(serverAddr)); serverAddr.sin_family = AF_INET; serverAddr.sin_addr.s_addr = inet_addr("127.0.0.1"); serverAddr.sin_port = htons(4000); if (bind(sock_fd, (struct sockaddr*)&serverAddr, sizeof(serverAddr)) < 0) { perror("bind error\n"); close(sock_fd); exit(1); } printf("server is waiting to receive data...\n"); msg.msg_name = &fromAddr; /* * I add 16 to sizeof(fromAddr), ie 32, * and pay attention to the definition of fromAddr, * recvmsg() will overwrite sock_fd, * since kernel will copy 32 bytes to userspace. * * If you just use sizeof(fromAddr), it works fine. * */ msg.msg_namelen = sizeof(fromAddr) + 16; /* msg.msg_namelen = sizeof(fromAddr); */ msg.msg_iov = &iov; msg.msg_iovlen = 1; msg.msg_iov->iov_base = recvBuffer; msg.msg_iov->iov_len = 128; msg.msg_control = 0; msg.msg_controllen = 0; msg.msg_flags = 0; while (1) { printf("old socket fd=%d\n", sock_fd); if (recvmsg(sock_fd, &msg, 0) == -1) { perror("recvmsg() error\n"); close(sock_fd); exit(1); } printf("server received data from client:%s\n", recvBuffer); printf("msg.msg_namelen=%d\n", msg.msg_namelen); printf("new socket fd=%d\n", sock_fd); strcat(recvBuffer, "--data from server"); if (sendmsg(sock_fd, &msg, 0) == -1) { perror("sendmsg()\n"); close(sock_fd); exit(1); } } close(sock_fd); return 0; } Signed-off-by: Weiping Pan Signed-off-by: David S. Miller