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e835ada070
If sendmsg() or sendmmsg() is called on a connected socket that hasn't had
bind() called on it, then an oops will occur when the kernel tries to
connect the call because no local endpoint has been allocated.
Fix this by implicitly binding the socket if it is in the
RXRPC_CLIENT_UNBOUND state, just like it does for the RXRPC_UNBOUND state.
Further, the state should be transitioned to RXRPC_CLIENT_BOUND after this
to prevent further attempts to bind it.
This can be tested with:
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <linux/rxrpc.h>
static const unsigned char inet6_addr[16] = {
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -1, -1, 0xac, 0x14, 0x14, 0xaa
};
int main(void)
{
struct sockaddr_rxrpc srx;
struct cmsghdr *cm;
struct msghdr msg;
unsigned char control[16];
int fd;
memset(&srx, 0, sizeof(srx));
srx.srx_family = 0x21;
srx.srx_service = 0;
srx.transport_type = AF_INET;
srx.transport_len = 0x1c;
srx.transport.sin6.sin6_family = AF_INET6;
srx.transport.sin6.sin6_port = htons(0x4e22);
srx.transport.sin6.sin6_flowinfo = htons(0x4e22);
srx.transport.sin6.sin6_scope_id = htons(0xaa3b);
memcpy(&srx.transport.sin6.sin6_addr, inet6_addr, 16);
cm = (struct cmsghdr *)control;
cm->cmsg_len = CMSG_LEN(sizeof(unsigned long));
cm->cmsg_level = SOL_RXRPC;
cm->cmsg_type = RXRPC_USER_CALL_ID;
*(unsigned long *)CMSG_DATA(cm) = 0;
msg.msg_name = NULL;
msg.msg_namelen = 0;
msg.msg_iov = NULL;
msg.msg_iovlen = 0;
msg.msg_control = control;
msg.msg_controllen = cm->cmsg_len;
msg.msg_flags = 0;
fd = socket(AF_RXRPC, SOCK_DGRAM, AF_INET);
connect(fd, (struct sockaddr *)&srx, sizeof(srx));
sendmsg(fd, &msg, 0);
return 0;
}
Leading to the following oops:
BUG: kernel NULL pointer dereference, address: 0000000000000018
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
...
RIP: 0010:rxrpc_connect_call+0x42/0xa01
...
Call Trace:
? mark_held_locks+0x47/0x59
? __local_bh_enable_ip+0xb6/0xba
rxrpc_new_client_call+0x3b1/0x762
? rxrpc_do_sendmsg+0x3c0/0x92e
rxrpc_do_sendmsg+0x3c0/0x92e
rxrpc_sendmsg+0x16b/0x1b5
sock_sendmsg+0x2d/0x39
___sys_sendmsg+0x1a4/0x22a
? release_sock+0x19/0x9e
? reacquire_held_locks+0x136/0x160
? release_sock+0x19/0x9e
? find_held_lock+0x2b/0x6e
? __lock_acquire+0x268/0xf73
? rxrpc_connect+0xdd/0xe4
? __local_bh_enable_ip+0xb6/0xba
__sys_sendmsg+0x5e/0x94
do_syscall_64+0x7d/0x1bf
entry_SYSCALL_64_after_hwframe+0x49/0xbe
Fixes:
|
||
|---|---|---|
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.