netdev - [PATCH] net/af_unix: don't create a path for a binded socket

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-Id: <20201124122421.9859-1-kda@linux-powerpc.org>
Date:   Tue, 24 Nov 2020 15:24:21 +0300
From:   Denis Kirjanov <kda@...ux-powerpc.org>
To:     netdev@...r.kernel.org
Cc:     kuba@...nel.org, davem@...emloft.net
Subject: [PATCH] net/af_unix: don't create a path for a binded socket

in the case of the socket which is bound to an adress
there is no sense to create a path in the next attempts

here is a program that shows the issue:

int main()
{
    int s;
    struct sockaddr_un a;

    s = socket(AF_UNIX, SOCK_STREAM, 0);
    if (s<0)
        perror("socket() failed\n");

    printf("First bind()\n");

    memset(&a, 0, sizeof(a));
    a.sun_family = AF_UNIX;
    strncpy(a.sun_path, "/tmp/.first_bind", sizeof(a.sun_path));

    if ((bind(s, (const struct sockaddr*) &a, sizeof(a))) == -1)
        perror("bind() failed\n");

    printf("Second bind()\n");

    memset(&a, 0, sizeof(a));
    a.sun_family = AF_UNIX;
    strncpy(a.sun_path, "/tmp/.first_bind_failed", sizeof(a.sun_path));

    if ((bind(s, (const struct sockaddr*) &a, sizeof(a))) == -1)
        perror("bind() failed\n");
}

kda@...S15-SP2:~> ./test
First bind()
Second bind()
bind() failed
: Invalid argument

kda@...S15-SP2:~> ls -la /tmp/.first_bind
.first_bind         .first_bind_failed

Signed-off-by: Denis Kirjanov <kda@...ux-powerpc.org>
---
 net/unix/af_unix.c | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index 41c3303c3357..fd76a8fe3907 100644
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -1021,7 +1021,7 @@ static int unix_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
 
 	err = -EINVAL;
 	if (addr_len < offsetofend(struct sockaddr_un, sun_family) ||
-	    sunaddr->sun_family != AF_UNIX)
+	    sunaddr->sun_family != AF_UNIX || u->addr)
 		goto out;
 
 	if (addr_len == sizeof(short)) {
@@ -1049,10 +1049,6 @@ static int unix_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
 	if (err)
 		goto out_put;
 
-	err = -EINVAL;
-	if (u->addr)
-		goto out_up;
-
 	err = -ENOMEM;
 	addr = kmalloc(sizeof(*addr)+addr_len, GFP_KERNEL);
 	if (!addr)
-- 
2.16.4