kernel/net/socket.c, branch linux-3.4.y

net: Fix use after free in the recvmmsg exit path

2016-10-26T15:15:47Z

commit 34b88a68f26a75e4fded796f1a49c40f82234b7d upstream. The syzkaller fuzzer hit the following use-after-free: Call Trace: [] __asan_report_load8_noabort+0x3e/0x40 mm/kasan/report.c:295 [] __sys_recvmmsg+0x6fa/0x7f0 net/socket.c:2261 [< inline >] SYSC_recvmmsg net/socket.c:2281 [] SyS_recvmmsg+0x16f/0x180 net/socket.c:2270 [] entry_SYSCALL_64_fastpath+0x16/0x7a arch/x86/entry/entry_64.S:185 And, as Dmitry rightly assessed, that is because we can drop the reference and then touch it when the underlying recvmsg calls return some packets and then hit an error, which will make recvmmsg to set sock->sk->sk_err, oops, fix it. Reported-and-Tested-by: Dmitry Vyukov Cc: Alexander Potapenko Cc: Eric Dumazet Cc: Kostya Serebryany Cc: Sasha Levin Fixes: a2e2725541fa ("net: Introduce recvmmsg socket syscall") http://lkml.kernel.org/r/20160122211644.GC2470@redhat.com Signed-off-by: Arnaldo Carvalho de Melo Signed-off-by: David S. Miller Signed-off-by: Zefan Li

net: socket: Fix the wrong returns for recvmsg and sendmsg

2015-09-18T01:20:46Z

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 Signed-off-by: Hanbing Xu Cc: Li Zefan Cc: Al Viro Cc: David Miller Signed-off-by: Greg Kroah-Hartman Signed-off-by: Zefan Li

net:socket: set msg_namelen to 0 if msg_name is passed as NULL in msghdr struct from userland.

2015-04-14T09:34:03Z

commit 6a2a2b3ae0759843b22c929881cc184b00cc63ff upstream. Linux manpage for recvmsg and sendmsg calls does not explicitly mention setting msg_namelen to 0 when msg_name passed set as NULL. When developers don't set msg_namelen member in msghdr, it might contain garbage value which will fail the validation check and sendmsg and recvmsg calls from kernel will return EINVAL. This will break old binaries and any code for which there is no access to source code. To fix this, we set msg_namelen to 0 when msg_name is passed as NULL from userland. Signed-off-by: Ani Sinha Signed-off-by: David S. Miller Cc: Michal Marek Signed-off-by: Zefan Li

net: socket: error on a negative msg_namelen

2014-04-27T00:13:17Z

[ Upstream commit dbb490b96584d4e958533fb637f08b557f505657 ] When copying in a struct msghdr from the user, if the user has set the msg_namelen parameter to a negative value it gets clamped to a valid size due to a comparison between signed and unsigned values. Ensure the syscall errors when the user passes in a negative value. Signed-off-by: Matthew Leach Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

net: clamp ->msg_namelen instead of returning an error

2013-12-08T15:29:42Z

[ Upstream commit db31c55a6fb245fdbb752a2ca4aefec89afabb06 ] If kmsg->msg_namelen > sizeof(struct sockaddr_storage) then in the original code that would lead to memory corruption in the kernel if you had audit configured. If you didn't have audit configured it was harmless. There are some programs such as beta versions of Ruby which use too large of a buffer and returning an error code breaks them. We should clamp the ->msg_namelen value instead. Fixes: 1661bf364ae9 ("net: heap overflow in __audit_sockaddr()") Reported-by: Eric Wong Signed-off-by: Dan Carpenter Tested-by: Eric Wong Acked-by: Eric Dumazet Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

net: add BUG_ON if kernel advertises msg_namelen > sizeof(struct sockaddr_storage)

2013-12-08T15:29:41Z

[ Upstream commit 68c6beb373955da0886d8f4f5995b3922ceda4be ] In that case it is probable that kernel code overwrote part of the stack. So we should bail out loudly here. The BUG_ON may be removed in future if we are sure all protocols are conformant. Suggested-by: Eric Dumazet Signed-off-by: Hannes Frederic Sowa Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

net: rework recvmsg handler msg_name and msg_namelen logic

2013-12-08T15:29:41Z

[ Upstream commit f3d3342602f8bcbf37d7c46641cb9bca7618eb1c ] 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 Signed-off-by: Greg Kroah-Hartman

net: heap overflow in __audit_sockaddr()

2013-11-04T12:23:40Z

[ 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 Signed-off-by: Dan Carpenter Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

net: Block MSG_CMSG_COMPAT in send(m)msg and recv(m)msg

2013-06-27T18:27:32Z

[ Upstream commits 1be374a0518a288147c6a7398792583200a67261 and a7526eb5d06b0084ef12d7b168d008fcf516caab ] MSG_CMSG_COMPAT is (AFAIK) not intended to be part of the API -- it's a hack that steals a bit to indicate to other networking code that a compat entry was used. So don't allow it from a non-compat syscall. This prevents an oops when running this code: int main() { int s; struct sockaddr_in addr; struct msghdr *hdr; char *highpage = mmap((void*)(TASK_SIZE_MAX - 4096), 4096, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS | MAP_FIXED, -1, 0); if (highpage == MAP_FAILED) err(1, "mmap"); s = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP); if (s == -1) err(1, "socket"); addr.sin_family = AF_INET; addr.sin_port = htons(1); addr.sin_addr.s_addr = htonl(INADDR_LOOPBACK); if (connect(s, (struct sockaddr*)&addr, sizeof(addr)) != 0) err(1, "connect"); void *evil = highpage + 4096 - COMPAT_MSGHDR_SIZE; printf("Evil address is %p\n", evil); if (syscall(__NR_sendmmsg, s, evil, 1, MSG_CMSG_COMPAT) < 0) err(1, "sendmmsg"); return 0; } Signed-off-by: Andy Lutomirski Cc: David S. Miller Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

net: fix info leak in compat dev_ifconf()

2012-10-02T17:29:37Z

[ Upstream commit 43da5f2e0d0c69ded3d51907d9552310a6b545e8 ] The implementation of dev_ifconf() for the compat ioctl interface uses an intermediate ifc structure allocated in userland for the duration of the syscall. Though, it fails to initialize the padding bytes inserted for alignment and that for leaks four bytes of kernel stack. Add an explicit memset(0) before filling the structure to avoid the info leak. Signed-off-by: Mathias Krause Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman