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-rw-r--r--fs/coredump.c139
-rw-r--r--include/linux/net.h1
-rw-r--r--net/unix/af_unix.c54
3 files changed, 177 insertions, 17 deletions
diff --git a/fs/coredump.c b/fs/coredump.c
index 4b9ea455a59c..af4aa57353ba 100644
--- a/fs/coredump.c
+++ b/fs/coredump.c
@@ -44,7 +44,11 @@
#include <linux/sysctl.h>
#include <linux/elf.h>
#include <linux/pidfs.h>
+#include <linux/net.h>
+#include <linux/socket.h>
+#include <net/net_namespace.h>
#include <uapi/linux/pidfd.h>
+#include <uapi/linux/un.h>
#include <linux/uaccess.h>
#include <asm/mmu_context.h>
@@ -79,6 +83,7 @@ unsigned int core_file_note_size_limit = CORE_FILE_NOTE_SIZE_DEFAULT;
enum coredump_type_t {
COREDUMP_FILE = 1,
COREDUMP_PIPE = 2,
+ COREDUMP_SOCK = 3,
};
struct core_name {
@@ -232,13 +237,16 @@ static int format_corename(struct core_name *cn, struct coredump_params *cprm,
cn->corename = NULL;
if (*pat_ptr == '|')
cn->core_type = COREDUMP_PIPE;
+ else if (*pat_ptr == '@')
+ cn->core_type = COREDUMP_SOCK;
else
cn->core_type = COREDUMP_FILE;
if (expand_corename(cn, core_name_size))
return -ENOMEM;
cn->corename[0] = '\0';
- if (cn->core_type == COREDUMP_PIPE) {
+ switch (cn->core_type) {
+ case COREDUMP_PIPE: {
int argvs = sizeof(core_pattern) / 2;
(*argv) = kmalloc_array(argvs, sizeof(**argv), GFP_KERNEL);
if (!(*argv))
@@ -247,6 +255,45 @@ static int format_corename(struct core_name *cn, struct coredump_params *cprm,
++pat_ptr;
if (!(*pat_ptr))
return -ENOMEM;
+ break;
+ }
+ case COREDUMP_SOCK: {
+ /* skip the @ */
+ pat_ptr++;
+ if (!(*pat_ptr))
+ return -ENOMEM;
+
+ err = cn_printf(cn, "%s", pat_ptr);
+ if (err)
+ return err;
+
+ /* Require absolute paths. */
+ if (cn->corename[0] != '/')
+ return -EINVAL;
+
+ /*
+ * Ensure we can uses spaces to indicate additional
+ * parameters in the future.
+ */
+ if (strchr(cn->corename, ' ')) {
+ coredump_report_failure("Coredump socket may not %s contain spaces", cn->corename);
+ return -EINVAL;
+ }
+
+ /*
+ * Currently no need to parse any other options.
+ * Relevant information can be retrieved from the peer
+ * pidfd retrievable via SO_PEERPIDFD by the receiver or
+ * via /proc/<pid>, using the SO_PEERPIDFD to guard
+ * against pid recycling when opening /proc/<pid>.
+ */
+ return 0;
+ }
+ case COREDUMP_FILE:
+ break;
+ default:
+ WARN_ON_ONCE(true);
+ return -EINVAL;
}
/* Repeat as long as we have more pattern to process and more output
@@ -395,6 +442,7 @@ out:
* the filename. Do not do this for piped commands. */
if (cn->core_type == COREDUMP_FILE && !pid_in_pattern && core_uses_pid)
return cn_printf(cn, ".%d", task_tgid_vnr(current));
+
return 0;
}
@@ -798,6 +846,53 @@ void do_coredump(const kernel_siginfo_t *siginfo)
}
break;
}
+ 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)
+ goto close_fail;
+
+ file = sock_alloc_file(socket, 0, NULL);
+ if (IS_ERR(file))
+ goto close_fail;
+
+ retval = kernel_connect(socket, (struct sockaddr *)(&addr),
+ addr_len, O_NONBLOCK | SOCK_COREDUMP);
+ 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;
+ }
+
+ cprm.limit = RLIM_INFINITY;
+ cprm.file = no_free_ptr(file);
+#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;
@@ -835,8 +930,44 @@ void do_coredump(const kernel_siginfo_t *siginfo)
file_end_write(cprm.file);
free_vma_snapshot(&cprm);
}
- if ((cn.core_type == COREDUMP_PIPE) && core_pipe_limit)
- wait_for_dump_helpers(cprm.file);
+
+#ifdef CONFIG_UNIX
+ /* Let userspace know we're done processing the coredump. */
+ if (sock_from_file(cprm.file))
+ kernel_sock_shutdown(sock_from_file(cprm.file), SHUT_WR);
+#endif
+
+ /*
+ * When core_pipe_limit is set we wait for the coredump server
+ * or usermodehelper to finish before exiting so it can e.g.,
+ * inspect /proc/<pid>.
+ */
+ if (core_pipe_limit) {
+ switch (cn.core_type) {
+ case COREDUMP_PIPE:
+ wait_for_dump_helpers(cprm.file);
+ break;
+#ifdef CONFIG_UNIX
+ case COREDUMP_SOCK: {
+ ssize_t n;
+
+ /*
+ * We use a simple read to wait for the coredump
+ * processing to finish. Either the socket is
+ * closed or we get sent unexpected data. In
+ * both cases, we're done.
+ */
+ n = __kernel_read(cprm.file, &(char){ 0 }, 1, NULL);
+ if (n != 0)
+ coredump_report_failure("Unexpected data on coredump socket");
+ break;
+ }
+#endif
+ default:
+ break;
+ }
+ }
+
close_fail:
if (cprm.file)
filp_close(cprm.file, NULL);
@@ -1066,7 +1197,7 @@ EXPORT_SYMBOL(dump_align);
void validate_coredump_safety(void)
{
if (suid_dumpable == SUID_DUMP_ROOT &&
- core_pattern[0] != '/' && core_pattern[0] != '|') {
+ core_pattern[0] != '/' && core_pattern[0] != '|' && core_pattern[0] != '@') {
coredump_report_failure("Unsafe core_pattern used with fs.suid_dumpable=2: "
"pipe handler or fully qualified core dump path required. "
diff --git a/include/linux/net.h b/include/linux/net.h
index 0ff950eecc6b..139c85d0f2ea 100644
--- a/include/linux/net.h
+++ b/include/linux/net.h
@@ -81,6 +81,7 @@ enum sock_type {
#ifndef SOCK_NONBLOCK
#define SOCK_NONBLOCK O_NONBLOCK
#endif
+#define SOCK_COREDUMP O_NOCTTY
#endif /* ARCH_HAS_SOCKET_TYPES */
diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index 472f8aa9ea15..59a64b2ced6e 100644
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -85,10 +85,13 @@
#include <linux/file.h>
#include <linux/filter.h>
#include <linux/fs.h>
+#include <linux/fs_struct.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/mount.h>
#include <linux/namei.h>
+#include <linux/net.h>
+#include <linux/pidfs.h>
#include <linux/poll.h>
#include <linux/proc_fs.h>
#include <linux/sched/signal.h>
@@ -100,7 +103,6 @@
#include <linux/splice.h>
#include <linux/string.h>
#include <linux/uaccess.h>
-#include <linux/pidfs.h>
#include <net/af_unix.h>
#include <net/net_namespace.h>
#include <net/scm.h>
@@ -1146,7 +1148,7 @@ static int unix_release(struct socket *sock)
}
static struct sock *unix_find_bsd(struct sockaddr_un *sunaddr, int addr_len,
- int type)
+ int type, int flags)
{
struct inode *inode;
struct path path;
@@ -1154,13 +1156,39 @@ static struct sock *unix_find_bsd(struct sockaddr_un *sunaddr, int addr_len,
int err;
unix_mkname_bsd(sunaddr, addr_len);
- err = kern_path(sunaddr->sun_path, LOOKUP_FOLLOW, &path);
- if (err)
- goto fail;
- err = path_permission(&path, MAY_WRITE);
- if (err)
- goto path_put;
+ if (flags & SOCK_COREDUMP) {
+ const struct cred *cred;
+ struct cred *kcred;
+ struct path root;
+
+ kcred = prepare_kernel_cred(&init_task);
+ if (!kcred) {
+ err = -ENOMEM;
+ goto fail;
+ }
+
+ task_lock(&init_task);
+ get_fs_root(init_task.fs, &root);
+ task_unlock(&init_task);
+
+ cred = override_creds(kcred);
+ err = vfs_path_lookup(root.dentry, root.mnt, sunaddr->sun_path,
+ LOOKUP_BENEATH | LOOKUP_NO_SYMLINKS |
+ LOOKUP_NO_MAGICLINKS, &path);
+ put_cred(revert_creds(cred));
+ path_put(&root);
+ if (err)
+ goto fail;
+ } else {
+ err = kern_path(sunaddr->sun_path, LOOKUP_FOLLOW, &path);
+ if (err)
+ goto fail;
+
+ err = path_permission(&path, MAY_WRITE);
+ if (err)
+ goto path_put;
+ }
err = -ECONNREFUSED;
inode = d_backing_inode(path.dentry);
@@ -1210,12 +1238,12 @@ static struct sock *unix_find_abstract(struct net *net,
static struct sock *unix_find_other(struct net *net,
struct sockaddr_un *sunaddr,
- int addr_len, int type)
+ int addr_len, int type, int flags)
{
struct sock *sk;
if (sunaddr->sun_path[0])
- sk = unix_find_bsd(sunaddr, addr_len, type);
+ sk = unix_find_bsd(sunaddr, addr_len, type, flags);
else
sk = unix_find_abstract(net, sunaddr, addr_len, type);
@@ -1473,7 +1501,7 @@ static int unix_dgram_connect(struct socket *sock, struct sockaddr *addr,
}
restart:
- other = unix_find_other(sock_net(sk), sunaddr, alen, sock->type);
+ other = unix_find_other(sock_net(sk), sunaddr, alen, sock->type, 0);
if (IS_ERR(other)) {
err = PTR_ERR(other);
goto out;
@@ -1620,7 +1648,7 @@ static int unix_stream_connect(struct socket *sock, struct sockaddr *uaddr,
restart:
/* Find listening sock. */
- other = unix_find_other(net, sunaddr, addr_len, sk->sk_type);
+ other = unix_find_other(net, sunaddr, addr_len, sk->sk_type, flags);
if (IS_ERR(other)) {
err = PTR_ERR(other);
goto out_free_skb;
@@ -2089,7 +2117,7 @@ static int unix_dgram_sendmsg(struct socket *sock, struct msghdr *msg,
if (msg->msg_namelen) {
lookup:
other = unix_find_other(sock_net(sk), msg->msg_name,
- msg->msg_namelen, sk->sk_type);
+ msg->msg_namelen, sk->sk_type, 0);
if (IS_ERR(other)) {
err = PTR_ERR(other);
goto out_free;
generated by cgit v1.2.3 (git 2.39.1) at 2025-06-18 18:48:11 +0000