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author | Miklos Szeredi <mszeredi@redhat.com> | 2016-05-20 23:13:45 +0300 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2016-07-27 19:47:33 +0300 |
commit | 0da3127a76c2cf7ad2c56e88841fa83613a67a77 (patch) | |
tree | 358bb6338c60a01a855560207116c74e5f9cb9f5 /net/unix/af_unix.c | |
parent | c65170792047969e2b129dbf6cdc633503a4087d (diff) | |
download | linux-0da3127a76c2cf7ad2c56e88841fa83613a67a77.tar.xz |
af_unix: fix hard linked sockets on overlay
commit eb0a4a47ae89aaa0674ab3180de6a162f3be2ddf upstream.
Overlayfs uses separate inodes even in the case of hard links on the
underlying filesystems. This is a problem for AF_UNIX socket
implementation which indexes sockets based on the inode. This resulted in
hard linked sockets not working.
The fix is to use the real, underlying inode.
Test case follows:
-- ovl-sock-test.c --
#include <unistd.h>
#include <err.h>
#include <sys/socket.h>
#include <sys/un.h>
#define SOCK "test-sock"
#define SOCK2 "test-sock2"
int main(void)
{
int fd, fd2;
struct sockaddr_un addr = {
.sun_family = AF_UNIX,
.sun_path = SOCK,
};
struct sockaddr_un addr2 = {
.sun_family = AF_UNIX,
.sun_path = SOCK2,
};
unlink(SOCK);
unlink(SOCK2);
if ((fd = socket(AF_UNIX, SOCK_STREAM, 0)) == -1)
err(1, "socket");
if (bind(fd, (struct sockaddr *) &addr, sizeof(addr)) == -1)
err(1, "bind");
if (listen(fd, 0) == -1)
err(1, "listen");
if (link(SOCK, SOCK2) == -1)
err(1, "link");
if ((fd2 = socket(AF_UNIX, SOCK_STREAM, 0)) == -1)
err(1, "socket");
if (connect(fd2, (struct sockaddr *) &addr2, sizeof(addr2)) == -1)
err (1, "connect");
return 0;
}
----
Reported-by: Alexander Morozov <alexandr.morozov@docker.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'net/unix/af_unix.c')
-rw-r--r-- | net/unix/af_unix.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c index 898a53a562b8..6579fd6e7459 100644 --- a/net/unix/af_unix.c +++ b/net/unix/af_unix.c @@ -315,7 +315,7 @@ static struct sock *unix_find_socket_byinode(struct inode *i) &unix_socket_table[i->i_ino & (UNIX_HASH_SIZE - 1)]) { struct dentry *dentry = unix_sk(s)->path.dentry; - if (dentry && d_backing_inode(dentry) == i) { + if (dentry && d_real_inode(dentry) == i) { sock_hold(s); goto found; } @@ -911,7 +911,7 @@ static struct sock *unix_find_other(struct net *net, err = kern_path(sunname->sun_path, LOOKUP_FOLLOW, &path); if (err) goto fail; - inode = d_backing_inode(path.dentry); + inode = d_real_inode(path.dentry); err = inode_permission(inode, MAY_WRITE); if (err) goto put_fail; @@ -1048,7 +1048,7 @@ static int unix_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len) goto out_up; } addr->hash = UNIX_HASH_SIZE; - hash = d_backing_inode(dentry)->i_ino & (UNIX_HASH_SIZE - 1); + hash = d_real_inode(dentry)->i_ino & (UNIX_HASH_SIZE - 1); spin_lock(&unix_table_lock); u->path = u_path; list = &unix_socket_table[hash]; |