From 4c77a51256e0b05b0948c1f5dd06dfb2b5abe489 Mon Sep 17 00:00:00 2001 From: Vegard Nossum Date: Wed, 16 Dec 2015 21:59:56 +0100 Subject: [PATCH] uml: fix hostfs mknod() commit 9f2dfda2f2f1c6181c3732c16b85c59ab2d195e0 upstream. An inverted return value check in hostfs_mknod() caused the function to return success after handling it as an error (and cleaning up). It resulted in the following segfault when trying to bind() a named unix socket: Pid: 198, comm: a.out Not tainted 4.4.0-rc4 RIP: 0033:[<0000000061077df6>] RSP: 00000000daae5d60 EFLAGS: 00010202 RAX: 0000000000000000 RBX: 000000006092a460 RCX: 00000000dfc54208 RDX: 0000000061073ef1 RSI: 0000000000000070 RDI: 00000000e027d600 RBP: 00000000daae5de0 R08: 00000000da980ac0 R09: 0000000000000000 R10: 0000000000000003 R11: 00007fb1ae08f72a R12: 0000000000000000 R13: 000000006092a460 R14: 00000000daaa97c0 R15: 00000000daaa9a88 Kernel panic - not syncing: Kernel mode fault at addr 0x40, ip 0x61077df6 CPU: 0 PID: 198 Comm: a.out Not tainted 4.4.0-rc4 #1 Stack: e027d620 dfc54208 0000006f da981398 61bee000 0000c1ed daae5de0 0000006e e027d620 dfcd4208 00000005 6092a460 Call Trace: [<60dedc67>] SyS_bind+0xf7/0x110 [<600587be>] handle_syscall+0x7e/0x80 [<60066ad7>] userspace+0x3e7/0x4e0 [<6006321f>] ? save_registers+0x1f/0x40 [<6006c88e>] ? arch_prctl+0x1be/0x1f0 [<60054985>] fork_handler+0x85/0x90 Let's also get rid of the "cosmic ray protection" while we're at it. Fixes: e9193059b1b3 "hostfs: fix races in dentry_name() and inode_name()" Signed-off-by: Vegard Nossum Cc: Jeff Dike Cc: Al Viro Signed-off-by: Richard Weinberger Signed-off-by: Greg Kroah-Hartman --- fs/hostfs/hostfs_kern.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/fs/hostfs/hostfs_kern.c b/fs/hostfs/hostfs_kern.c index 32f35f187989..b58a9cbb9695 100644 --- a/fs/hostfs/hostfs_kern.c +++ b/fs/hostfs/hostfs_kern.c @@ -720,15 +720,13 @@ static int hostfs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, init_special_inode(inode, mode, dev); err = do_mknod(name, mode, MAJOR(dev), MINOR(dev)); - if (!err) + if (err) goto out_free; err = read_name(inode, name); __putname(name); if (err) goto out_put; - if (err) - goto out_put; d_instantiate(dentry, inode); return 0;