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Subject[PATCH 2/8] unix_bind(): allocate addr earlier
From 24439dbb7b78cb301c73254b364020e6a3f31902 Mon Sep 17 00:00:00 2001
From: Al Viro <viro@zeniv.linux.org.uk>
Date: Thu, 18 Feb 2021 15:52:53 -0500
Subject: [PATCH 2/8] unix_bind(): allocate addr earlier

makes it easier to massage; we do pay for that by extra work
(kmalloc+memcpy+kfree) in some error cases, but those are not
on the hot paths anyway.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
net/unix/af_unix.c | 26 ++++++++++++++------------
1 file changed, 14 insertions(+), 12 deletions(-)

diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index 179b4fe837e6..451d81f405c0 100644
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -1039,6 +1039,15 @@ static int unix_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
if (err < 0)
goto out;
addr_len = err;
+ err = -ENOMEM;
+ addr = kmalloc(sizeof(*addr)+addr_len, GFP_KERNEL);
+ if (!addr)
+ goto out;
+
+ memcpy(addr->name, sunaddr, addr_len);
+ addr->len = addr_len;
+ addr->hash = hash ^ sk->sk_type;
+ refcount_set(&addr->refcnt, 1);

if (sun_path[0]) {
umode_t mode = S_IFSOCK |
@@ -1047,7 +1056,7 @@ static int unix_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
if (err) {
if (err == -EEXIST)
err = -EADDRINUSE;
- goto out;
+ goto out_addr;
}
}

@@ -1059,16 +1068,6 @@ static int unix_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
if (u->addr)
goto out_up;

- err = -ENOMEM;
- addr = kmalloc(sizeof(*addr)+addr_len, GFP_KERNEL);
- if (!addr)
- goto out_up;
-
- memcpy(addr->name, sunaddr, addr_len);
- addr->len = addr_len;
- addr->hash = hash ^ sk->sk_type;
- refcount_set(&addr->refcnt, 1);
-
if (sun_path[0]) {
addr->hash = UNIX_HASH_SIZE;
hash = d_backing_inode(path.dentry)->i_ino & (UNIX_HASH_SIZE - 1);
@@ -1080,19 +1079,22 @@ static int unix_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
if (__unix_find_socket_byname(net, sunaddr, addr_len,
sk->sk_type, hash)) {
spin_unlock(&unix_table_lock);
- unix_release_addr(addr);
goto out_up;
}
hash = addr->hash;
}

__unix_set_addr(sk, addr, hash);
+ addr = NULL;
err = 0;
out_up:
mutex_unlock(&u->bindlock);
out_put:
if (err)
path_put(&path);
+out_addr:
+ if (addr)
+ unix_release_addr(addr);
out:
return err;
}
--
2.11.0
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