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coredump: cleanup coredump socket functions 

We currently use multiple CONFIG_UNIX guards. This looks messy and makes
the code harder to follow and maintain. Use a helper function
coredump_sock_connect() that handles the connect portion. This allows us
to remove the CONFIG_UNIX guard in the main do_coredump() function.

Link: https://lore.kernel.org/20250605-schlamm-touren-720ba2b60a85@brauner
Signed-off-by: Christian Brauner <brauner@kernel.org>
This commit is contained in:
Christian Brauner 2025-06-05 11:53:15 +02:00
parent c8e7ce2aa1
commit e04f97c8be
No known key found for this signature in database
GPG Key ID: 91C61BC06578DCA2
1 changed files with 83 additions and 74 deletions
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157
fs/coredump.c
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@ -646,6 +646,77 @@ static int umh_coredump_setup(struct subprocess_info *info, struct cred *new)
}
#ifdef CONFIG_UNIX
static bool coredump_sock_connect(struct core_name *cn, struct coredump_params *cprm)
{
struct file *file __free(fput) = NULL;
struct sockaddr_un addr = {
.sun_family = AF_UNIX,
};
ssize_t addr_len;
int retval;
struct socket *socket;
addr_len = strscpy(addr.sun_path, cn->corename);
if (addr_len < 0)
return false;
addr_len += offsetof(struct sockaddr_un, sun_path) + 1;
/*
* It is possible that the userspace process which is supposed
* to handle the coredump and is listening on the AF_UNIX socket
* coredumps. Userspace should just mark itself non dumpable.
*/
retval = sock_create_kern(&init_net, AF_UNIX, SOCK_STREAM, 0, &socket);
if (retval < 0)
return false;
file = sock_alloc_file(socket, 0, NULL);
if (IS_ERR(file))
return false;
/*
* Set the thread-group leader pid which is used for the peer
* credentials during connect() below. Then immediately register
* it in pidfs...
*/
cprm->pid = task_tgid(current);
retval = pidfs_register_pid(cprm->pid);
if (retval)
return false;
/*
* ... and set the coredump information so userspace has it
* available after connect()...
*/
pidfs_coredump(cprm);
retval = kernel_connect(socket, (struct sockaddr *)(&addr), addr_len,
O_NONBLOCK | SOCK_COREDUMP);
/*
* ... Make sure to only put our reference after connect() took
* its own reference keeping the pidfs entry alive ...
*/
pidfs_put_pid(cprm->pid);
if (retval) {
if (retval == -EAGAIN)
coredump_report_failure("Coredump socket %s receive queue full", addr.sun_path);
else
coredump_report_failure("Coredump socket connection %s failed %d", addr.sun_path, retval);
return false;
}
/* ... and validate that @sk_peer_pid matches @cprm.pid. */
if (WARN_ON_ONCE(unix_peer(socket->sk)->sk_peer_pid != cprm->pid))
return false;
cprm->limit = RLIM_INFINITY;
cprm->file = no_free_ptr(file);
return true;
}
static inline bool coredump_sock_recv(struct file *file, struct coredump_ack *ack, size_t size, int flags)
{
struct msghdr msg = {};
@ -707,7 +778,7 @@ static inline void coredump_sock_shutdown(struct file *file)
kernel_sock_shutdown(socket, SHUT_WR);
}
static bool coredump_request(struct core_name *cn, struct coredump_params *cprm)
static bool coredump_sock_request(struct core_name *cn, struct coredump_params *cprm)
{
struct coredump_req req = {
.size = sizeof(struct coredump_req),
@ -770,6 +841,14 @@ static bool coredump_request(struct core_name *cn, struct coredump_params *cprm)
return coredump_sock_mark(cprm->file, COREDUMP_MARK_REQACK);
}
#else
static bool coredump_sock_connect(struct core_name *cn,
struct coredump_params *cprm)
{
coredump_report_failure("Core dump socket support %s disabled", cn->corename);
return false;
}
static bool coredump_sock_request(struct core_name *cn,
struct coredump_params *cprm) { return false; }
static inline void coredump_sock_wait(struct file *file) { }
static inline void coredump_sock_shutdown(struct file *file) { }
#endif
@ -994,83 +1073,13 @@ void do_coredump(const kernel_siginfo_t *siginfo)
}
case COREDUMP_SOCK_REQ:
fallthrough;
case COREDUMP_SOCK: {
#ifdef CONFIG_UNIX
struct file *file __free(fput) = NULL;
struct sockaddr_un addr = {
.sun_family = AF_UNIX,
};
ssize_t addr_len;
struct socket *socket;
addr_len = strscpy(addr.sun_path, cn.corename);
if (addr_len < 0)
goto close_fail;
addr_len += offsetof(struct sockaddr_un, sun_path) + 1;
/*
* It is possible that the userspace process which is
* supposed to handle the coredump and is listening on
* the AF_UNIX socket coredumps. Userspace should just
* mark itself non dumpable.
*/
retval = sock_create_kern(&init_net, AF_UNIX, SOCK_STREAM, 0, &socket);
if (retval < 0)
case COREDUMP_SOCK:
if (!coredump_sock_connect(&cn, &cprm))
goto close_fail;
file = sock_alloc_file(socket, 0, NULL);
if (IS_ERR(file))
if (!coredump_sock_request(&cn, &cprm))
goto close_fail;
/*
* Set the thread-group leader pid which is used for the
* peer credentials during connect() below. Then
* immediately register it in pidfs...
*/
cprm.pid = task_tgid(current);
retval = pidfs_register_pid(cprm.pid);
if (retval)
goto close_fail;
/*
* ... and set the coredump information so userspace
* has it available after connect()...
*/
pidfs_coredump(&cprm);
retval = kernel_connect(socket, (struct sockaddr *)(&addr),
addr_len, O_NONBLOCK | SOCK_COREDUMP);
/*
* ... Make sure to only put our reference after connect() took
* its own reference keeping the pidfs entry alive ...
*/
pidfs_put_pid(cprm.pid);
if (retval) {
if (retval == -EAGAIN)
coredump_report_failure("Coredump socket %s receive queue full", addr.sun_path);
else
coredump_report_failure("Coredump socket connection %s failed %d", addr.sun_path, retval);
goto close_fail;
}
/* ... and validate that @sk_peer_pid matches @cprm.pid. */
if (WARN_ON_ONCE(unix_peer(socket->sk)->sk_peer_pid != cprm.pid))
goto close_fail;
cprm.limit = RLIM_INFINITY;
cprm.file = no_free_ptr(file);
if (!coredump_request(&cn, &cprm))
goto close_fail;
#else
coredump_report_failure("Core dump socket support %s disabled", cn.corename);
goto close_fail;
#endif
break;
}
default:
WARN_ON_ONCE(true);
goto close_fail;