This is a note to let you know that I've just added the patch titled af_unix: fix hard linked sockets on overlay to the 4.6-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: af_unix-fix-hard-linked-sockets-on-overlay.patch and it can be found in the queue-4.6 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From eb0a4a47ae89aaa0674ab3180de6a162f3be2ddf Mon Sep 17 00:00:00 2001 From: Miklos Szeredi <mszeredi@xxxxxxxxxx> Date: Fri, 20 May 2016 22:13:45 +0200 Subject: af_unix: fix hard linked sockets on overlay From: Miklos Szeredi <mszeredi@xxxxxxxxxx> 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@xxxxxxxxxx> Signed-off-by: Miklos Szeredi <mszeredi@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- net/unix/af_unix.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) --- a/net/unix/af_unix.c +++ b/net/unix/af_unix.c @@ -315,7 +315,7 @@ static struct sock *unix_find_socket_byi &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(stru 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 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]; Patches currently in stable-queue which might be from mszeredi@xxxxxxxxxx are queue-4.6/vfs-add-d_real_inode-helper.patch queue-4.6/af_unix-fix-hard-linked-sockets-on-overlay.patch -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html