diff mbox series

[v2,2/8] io_uring/cmd: Introduce SOCKET_URING_OP_GETSOCKOPT

Message ID 20230808134049.1407498-3-leitao@debian.org (mailing list archive)
State Superseded
Headers show
Series io_uring: Initial support for {s,g}etsockopt commands | expand

Checks

Context Check Description
netdev/tree_selection success Guessing tree name failed - patch did not apply
bpf/vmtest-bpf-PR success PR summary
bpf/vmtest-bpf-VM_Test-1 success Logs for ShellCheck
bpf/vmtest-bpf-VM_Test-2 success Logs for build for aarch64 with gcc
bpf/vmtest-bpf-VM_Test-3 pending Logs for build for s390x with gcc
bpf/vmtest-bpf-VM_Test-4 success Logs for build for x86_64 with gcc
bpf/vmtest-bpf-VM_Test-5 success Logs for build for x86_64 with llvm-16
bpf/vmtest-bpf-VM_Test-6 success Logs for set-matrix

Commit Message

Breno Leitao Aug. 8, 2023, 1:40 p.m. UTC
Add support for getsockopt command (SOCKET_URING_OP_GETSOCKOPT), where
level is SOL_SOCKET. This is leveraging the sockptr_t infrastructure,
where a sockptr_t is either userspace or kernel space, and handled as
such.

Function io_uring_cmd_getsockopt() is inspired by __sys_getsockopt().

Differently from the getsockopt(2), the optlen field is not a userspace
pointers. In getsockopt(2), userspace provides optlen pointer, which is
overwritten by the kernel.  In this implementation, userspace passes a
u32, and the new value is returned in cqe->res. I.e., optlen is not a
pointer.

Important to say that userspace needs to keep the pointer alive until
the CQE is completed.

Signed-off-by: Breno Leitao <leitao@debian.org>
---
 include/uapi/linux/io_uring.h |  7 +++++++
 io_uring/uring_cmd.c          | 28 ++++++++++++++++++++++++++++
 2 files changed, 35 insertions(+)

Comments

kernel test robot Aug. 9, 2023, 4:07 a.m. UTC | #1
Hi Breno,

kernel test robot noticed the following build errors:

[auto build test ERROR on next-20230808]
[cannot apply to bpf-next/master bpf/master net/main net-next/main linus/master horms-ipvs/master v6.5-rc5 v6.5-rc4 v6.5-rc3 v6.5-rc5]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Breno-Leitao/net-expose-sock_use_custom_sol_socket/20230809-011901
base:   next-20230808
patch link:    https://lore.kernel.org/r/20230808134049.1407498-3-leitao%40debian.org
patch subject: [PATCH v2 2/8] io_uring/cmd: Introduce SOCKET_URING_OP_GETSOCKOPT
config: hexagon-randconfig-r041-20230808 (https://download.01.org/0day-ci/archive/20230809/202308091103.ylvbuCww-lkp@intel.com/config)
compiler: clang version 15.0.7 (https://github.com/llvm/llvm-project.git 8dfdcc7b7bf66834a761bd8de445840ef68e4d1a)
reproduce: (https://download.01.org/0day-ci/archive/20230809/202308091103.ylvbuCww-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202308091103.ylvbuCww-lkp@intel.com/

All errors (new ones prefixed by >>):

>> ld.lld: error: undefined symbol: sk_getsockopt
   >>> referenced by uring_cmd.c
   >>>               io_uring/uring_cmd.o:(io_uring_cmd_sock) in archive vmlinux.a
   >>> referenced by uring_cmd.c
   >>>               io_uring/uring_cmd.o:(io_uring_cmd_sock) in archive vmlinux.a
kernel test robot Aug. 9, 2023, 10:27 a.m. UTC | #2
Hi Breno,

kernel test robot noticed the following build errors:

[auto build test ERROR on next-20230808]
[cannot apply to bpf-next/master bpf/master net/main net-next/main linus/master horms-ipvs/master v6.5-rc5 v6.5-rc4 v6.5-rc3 v6.5-rc5]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Breno-Leitao/net-expose-sock_use_custom_sol_socket/20230809-011901
base:   next-20230808
patch link:    https://lore.kernel.org/r/20230808134049.1407498-3-leitao%40debian.org
patch subject: [PATCH v2 2/8] io_uring/cmd: Introduce SOCKET_URING_OP_GETSOCKOPT
config: m68k-randconfig-r036-20230809 (https://download.01.org/0day-ci/archive/20230809/202308091701.sGyLMOi2-lkp@intel.com/config)
compiler: m68k-linux-gcc (GCC) 12.3.0
reproduce: (https://download.01.org/0day-ci/archive/20230809/202308091701.sGyLMOi2-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202308091701.sGyLMOi2-lkp@intel.com/

All errors (new ones prefixed by >>):

   m68k-linux-ld: io_uring/uring_cmd.o: in function `io_uring_cmd_sock':
>> io_uring/uring_cmd.c:183: undefined reference to `sk_getsockopt'


vim +183 io_uring/uring_cmd.c

   168	
   169	static inline int io_uring_cmd_getsockopt(struct socket *sock,
   170						  struct io_uring_cmd *cmd)
   171	{
   172		void __user *optval = u64_to_user_ptr(READ_ONCE(cmd->sqe->optval));
   173		int optname = READ_ONCE(cmd->sqe->optname);
   174		int optlen = READ_ONCE(cmd->sqe->optlen);
   175		int level = READ_ONCE(cmd->sqe->level);
   176		int err;
   177	
   178		err = security_socket_getsockopt(sock, level, optname);
   179		if (err)
   180			return err;
   181	
   182		if (level == SOL_SOCKET) {
 > 183			err = sk_getsockopt(sock->sk, level, optname,
   184					    USER_SOCKPTR(optval),
   185					    KERNEL_SOCKPTR(&optlen));
   186			if (err)
   187				return err;
   188	
   189			return optlen;
   190		}
   191	
   192		return -EOPNOTSUPP;
   193	}
   194
Willem de Bruijn Aug. 9, 2023, 1:21 p.m. UTC | #3
Breno Leitao wrote:
> Add support for getsockopt command (SOCKET_URING_OP_GETSOCKOPT), where
> level is SOL_SOCKET. This is leveraging the sockptr_t infrastructure,
> where a sockptr_t is either userspace or kernel space, and handled as
> such.
> 
> Function io_uring_cmd_getsockopt() is inspired by __sys_getsockopt().
> 
> Differently from the getsockopt(2), the optlen field is not a userspace
> pointers. In getsockopt(2), userspace provides optlen pointer, which is
> overwritten by the kernel.  In this implementation, userspace passes a
> u32, and the new value is returned in cqe->res. I.e., optlen is not a
> pointer.
> 
> Important to say that userspace needs to keep the pointer alive until
> the CQE is completed.

What bad things can happen otherwise?

The kernel is not depending on a well behaved process for its
correctness here, is it? Any user pages have to be pinned while
kernel might refer to them, for instance.
 
> Signed-off-by: Breno Leitao <leitao@debian.org>
Pavel Begunkov Aug. 10, 2023, 12:57 p.m. UTC | #4
On 8/9/23 14:21, Willem de Bruijn wrote:
> Breno Leitao wrote:
>> Add support for getsockopt command (SOCKET_URING_OP_GETSOCKOPT), where
>> level is SOL_SOCKET. This is leveraging the sockptr_t infrastructure,
>> where a sockptr_t is either userspace or kernel space, and handled as
>> such.
>>
>> Function io_uring_cmd_getsockopt() is inspired by __sys_getsockopt().
>>
>> Differently from the getsockopt(2), the optlen field is not a userspace
>> pointers. In getsockopt(2), userspace provides optlen pointer, which is
>> overwritten by the kernel.  In this implementation, userspace passes a
>> u32, and the new value is returned in cqe->res. I.e., optlen is not a
>> pointer.
>>
>> Important to say that userspace needs to keep the pointer alive until
>> the CQE is completed.
> 
> What bad things can happen otherwise?
> 
> The kernel is not depending on a well behaved process for its
> correctness here, is it? Any user pages have to be pinned while

Right, it's the user api thing. There are always userspace progs
that would try to do:

submit_async() {
	char buf[20];
	do_submit(sqe = {buf = buf, ...});
}

submit_async();
wait_completions();


> kernel might refer to them, for instance.

fwiw, it's passed down as a user ptr, which will be eventually
used in copy_[from,to]_user() or so.
diff mbox series

Patch

diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h
index 9fc7195f25df..8152151080db 100644
--- a/include/uapi/linux/io_uring.h
+++ b/include/uapi/linux/io_uring.h
@@ -43,6 +43,10 @@  struct io_uring_sqe {
 	union {
 		__u64	addr;	/* pointer to buffer or iovecs */
 		__u64	splice_off_in;
+		struct {
+			__u32	level;
+			__u32	optname;
+		};
 	};
 	__u32	len;		/* buffer size or number of iovecs */
 	union {
@@ -79,6 +83,7 @@  struct io_uring_sqe {
 	union {
 		__s32	splice_fd_in;
 		__u32	file_index;
+		__u32	optlen;
 		struct {
 			__u16	addr_len;
 			__u16	__pad3[1];
@@ -89,6 +94,7 @@  struct io_uring_sqe {
 			__u64	addr3;
 			__u64	__pad2[1];
 		};
+		__u64	optval;
 		/*
 		 * If the ring is initialized with IORING_SETUP_SQE128, then
 		 * this field is used for 80 bytes of arbitrary command data
@@ -729,6 +735,7 @@  struct io_uring_recvmsg_out {
 enum {
 	SOCKET_URING_OP_SIOCINQ		= 0,
 	SOCKET_URING_OP_SIOCOUTQ,
+	SOCKET_URING_OP_GETSOCKOPT,
 };
 
 #ifdef __cplusplus
diff --git a/io_uring/uring_cmd.c b/io_uring/uring_cmd.c
index 8e7a03c1b20e..582931879482 100644
--- a/io_uring/uring_cmd.c
+++ b/io_uring/uring_cmd.c
@@ -166,6 +166,32 @@  int io_uring_cmd_import_fixed(u64 ubuf, unsigned long len, int rw,
 }
 EXPORT_SYMBOL_GPL(io_uring_cmd_import_fixed);
 
+static inline int io_uring_cmd_getsockopt(struct socket *sock,
+					  struct io_uring_cmd *cmd)
+{
+	void __user *optval = u64_to_user_ptr(READ_ONCE(cmd->sqe->optval));
+	int optname = READ_ONCE(cmd->sqe->optname);
+	int optlen = READ_ONCE(cmd->sqe->optlen);
+	int level = READ_ONCE(cmd->sqe->level);
+	int err;
+
+	err = security_socket_getsockopt(sock, level, optname);
+	if (err)
+		return err;
+
+	if (level == SOL_SOCKET) {
+		err = sk_getsockopt(sock->sk, level, optname,
+				    USER_SOCKPTR(optval),
+				    KERNEL_SOCKPTR(&optlen));
+		if (err)
+			return err;
+
+		return optlen;
+	}
+
+	return -EOPNOTSUPP;
+}
+
 int io_uring_cmd_sock(struct io_uring_cmd *cmd, unsigned int issue_flags)
 {
 	struct socket *sock = cmd->file->private_data;
@@ -187,6 +213,8 @@  int io_uring_cmd_sock(struct io_uring_cmd *cmd, unsigned int issue_flags)
 		if (ret)
 			return ret;
 		return arg;
+	case SOCKET_URING_OP_GETSOCKOPT:
+		return io_uring_cmd_getsockopt(sock, cmd);
 	default:
 		return -EOPNOTSUPP;
 	}