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authorMiklos Szeredi <mszeredi@redhat.com>2016-05-20 22:13:45 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2016-07-27 09:47:33 -0700
commit0da3127a76c2cf7ad2c56e88841fa83613a67a77 (patch)
tree358bb6338c60a01a855560207116c74e5f9cb9f5 /net/unix
parentc65170792047969e2b129dbf6cdc633503a4087d (diff)
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')
-rw-r--r--net/unix/af_unix.c6
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];