| Message ID | 20210119112446.21180-1-kda@linux-powerpc.org |
|---|---|
| State | New |
| Headers | show |
| Series | [v5] net/af_unix: don't create a path for a bound socket | expand |
On Tue, 19 Jan 2021 14:24:46 +0300 Denis Kirjanov wrote: > In the case of a socket which is already bound to an adress > there is no sense to create a path in the next attempts > > here is a program that shows the issue: Appears to not build in allmodconfig net-next: ERROR: modpost: "kern_path_locked" [net/unix/unix.ko] undefined!
diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c index 41c3303c3357..d8b1cfd872a3 100644 --- a/net/unix/af_unix.c +++ b/net/unix/af_unix.c @@ -1091,8 +1091,23 @@ static int unix_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len) out_up: mutex_unlock(&u->bindlock); out_put: - if (err) + if (err) { + struct path parent = { }; + struct dentry *dentry; + int ret; + + dentry = kern_path_locked(sun_path, &parent); + if (IS_ERR(dentry)) + return PTR_ERR(dentry); + + ret = vfs_unlink(d_inode(parent.dentry), path.dentry, NULL); + if (ret) + err = ret; + dput(path.dentry); + inode_unlock(d_inode(parent.dentry)); + path_put(&parent); path_put(&path); + } out: return err; }
In the case of a socket which is already bound to an adress there is no sense to create a path in the next attempts here is a program that shows the issue: int main() { int s; struct sockaddr_un a; s = socket(AF_UNIX, SOCK_STREAM, 0); if (s<0) perror("socket() failed\n"); printf("First bind()\n"); memset(&a, 0, sizeof(a)); a.sun_family = AF_UNIX; strncpy(a.sun_path, "/tmp/.first_bind", sizeof(a.sun_path)); if ((bind(s, (const struct sockaddr*) &a, sizeof(a))) == -1) perror("bind() failed\n"); printf("Second bind()\n"); memset(&a, 0, sizeof(a)); a.sun_family = AF_UNIX; strncpy(a.sun_path, "/tmp/.first_bind_failed", sizeof(a.sun_path)); if ((bind(s, (const struct sockaddr*) &a, sizeof(a))) == -1) perror("bind() failed\n"); } kda@SLES15-SP2:~> ./test First bind() Second bind() bind() failed : Invalid argument kda@SLES15-SP2:~> ls -la /tmp/.first_bind .first_bind .first_bind_failed Signed-off-by: Denis Kirjanov <kda@linux-powerpc.org> --- net/unix/af_unix.c | 17 ++++++++++++++++- 1 file changed, 16 insertions(+), 1 deletion(-)