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-rw-r--r--Documentation/networking/filter.txt11
-rw-r--r--arch/alpha/include/uapi/asm/socket.h1
-rw-r--r--arch/avr32/include/uapi/asm/socket.h2
-rw-r--r--arch/cris/include/uapi/asm/socket.h2
-rw-r--r--arch/frv/include/uapi/asm/socket.h2
-rw-r--r--arch/h8300/include/uapi/asm/socket.h2
-rw-r--r--arch/ia64/include/uapi/asm/socket.h2
-rw-r--r--arch/m32r/include/uapi/asm/socket.h2
-rw-r--r--arch/mips/include/uapi/asm/socket.h1
-rw-r--r--arch/mn10300/include/uapi/asm/socket.h2
-rw-r--r--arch/parisc/include/uapi/asm/socket.h1
-rw-r--r--arch/powerpc/include/uapi/asm/socket.h2
-rw-r--r--arch/s390/include/uapi/asm/socket.h2
-rw-r--r--arch/sparc/include/uapi/asm/socket.h1
-rw-r--r--arch/xtensa/include/uapi/asm/socket.h2
-rw-r--r--include/net/sock.h1
-rw-r--r--include/uapi/asm-generic/socket.h2
-rw-r--r--net/core/filter.c6
-rw-r--r--net/core/sock.c11
19 files changed, 53 insertions, 2 deletions
diff --git a/Documentation/networking/filter.txt b/Documentation/networking/filter.txt
index bbf2005270b..cdb3e40b9d1 100644
--- a/Documentation/networking/filter.txt
+++ b/Documentation/networking/filter.txt
@@ -17,12 +17,12 @@ creating filters.
LSF is much simpler than BPF. One does not have to worry about
devices or anything like that. You simply create your filter
-code, send it to the kernel via the SO_ATTACH_FILTER ioctl and
+code, send it to the kernel via the SO_ATTACH_FILTER option and
if your filter code passes the kernel check on it, you then
immediately begin filtering data on that socket.
You can also detach filters from your socket via the
-SO_DETACH_FILTER ioctl. This will probably not be used much
+SO_DETACH_FILTER option. This will probably not be used much
since when you close a socket that has a filter on it the
filter is automagically removed. The other less common case
may be adding a different filter on the same socket where you had another
@@ -31,12 +31,19 @@ the old one and placing your new one in its place, assuming your
filter has passed the checks, otherwise if it fails the old filter
will remain on that socket.
+SO_LOCK_FILTER option allows to lock the filter attached to a
+socket. Once set, a filter cannot be removed or changed. This allows
+one process to setup a socket, attach a filter, lock it then drop
+privileges and be assured that the filter will be kept until the
+socket is closed.
+
Examples
========
Ioctls-
setsockopt(sockfd, SOL_SOCKET, SO_ATTACH_FILTER, &Filter, sizeof(Filter));
setsockopt(sockfd, SOL_SOCKET, SO_DETACH_FILTER, &value, sizeof(value));
+setsockopt(sockfd, SOL_SOCKET, SO_LOCK_FILTER, &value, sizeof(value));
See the BSD bpf.4 manpage and the BSD Packet Filter paper written by
Steven McCanne and Van Jacobson of Lawrence Berkeley Laboratory.
diff --git a/arch/alpha/include/uapi/asm/socket.h b/arch/alpha/include/uapi/asm/socket.h
index 097c1577735..755702eefd9 100644
--- a/arch/alpha/include/uapi/asm/socket.h
+++ b/arch/alpha/include/uapi/asm/socket.h
@@ -77,5 +77,6 @@
/* Instruct lower device to use last 4-bytes of skb data as FCS */
#define SO_NOFCS 43
+#define SO_LOCK_FILTER 44
#endif /* _UAPI_ASM_SOCKET_H */
diff --git a/arch/avr32/include/uapi/asm/socket.h b/arch/avr32/include/uapi/asm/socket.h
index 486df68abee..f3f38a0e2ef 100644
--- a/arch/avr32/include/uapi/asm/socket.h
+++ b/arch/avr32/include/uapi/asm/socket.h
@@ -70,4 +70,6 @@
/* Instruct lower device to use last 4-bytes of skb data as FCS */
#define SO_NOFCS 43
+#define SO_LOCK_FILTER 44
+
#endif /* __ASM_AVR32_SOCKET_H */
diff --git a/arch/cris/include/uapi/asm/socket.h b/arch/cris/include/uapi/asm/socket.h
index b681b043f6c..406b5838def 100644
--- a/arch/cris/include/uapi/asm/socket.h
+++ b/arch/cris/include/uapi/asm/socket.h
@@ -72,6 +72,8 @@
/* Instruct lower device to use last 4-bytes of skb data as FCS */
#define SO_NOFCS 43
+#define SO_LOCK_FILTER 44
+
#endif /* _ASM_SOCKET_H */
diff --git a/arch/frv/include/uapi/asm/socket.h b/arch/frv/include/uapi/asm/socket.h
index 871f89b7fbd..d8e1132a1ab 100644
--- a/arch/frv/include/uapi/asm/socket.h
+++ b/arch/frv/include/uapi/asm/socket.h
@@ -70,5 +70,7 @@
/* Instruct lower device to use last 4-bytes of skb data as FCS */
#define SO_NOFCS 43
+#define SO_LOCK_FILTER 44
+
#endif /* _ASM_SOCKET_H */
diff --git a/arch/h8300/include/uapi/asm/socket.h b/arch/h8300/include/uapi/asm/socket.h
index 90a2e573c7e..c8b87a82820 100644
--- a/arch/h8300/include/uapi/asm/socket.h
+++ b/arch/h8300/include/uapi/asm/socket.h
@@ -70,4 +70,6 @@
/* Instruct lower device to use last 4-bytes of skb data as FCS */
#define SO_NOFCS 43
+#define SO_LOCK_FILTER 44
+
#endif /* _ASM_SOCKET_H */
diff --git a/arch/ia64/include/uapi/asm/socket.h b/arch/ia64/include/uapi/asm/socket.h
index 23d6759bb57..f390896c310 100644
--- a/arch/ia64/include/uapi/asm/socket.h
+++ b/arch/ia64/include/uapi/asm/socket.h
@@ -79,4 +79,6 @@
/* Instruct lower device to use last 4-bytes of skb data as FCS */
#define SO_NOFCS 43
+#define SO_LOCK_FILTER 44
+
#endif /* _ASM_IA64_SOCKET_H */
diff --git a/arch/m32r/include/uapi/asm/socket.h b/arch/m32r/include/uapi/asm/socket.h
index 5e7088a2672..6a895155e7a 100644
--- a/arch/m32r/include/uapi/asm/socket.h
+++ b/arch/m32r/include/uapi/asm/socket.h
@@ -70,4 +70,6 @@
/* Instruct lower device to use last 4-bytes of skb data as FCS */
#define SO_NOFCS 43
+#define SO_LOCK_FILTER 44
+
#endif /* _ASM_M32R_SOCKET_H */
diff --git a/arch/mips/include/uapi/asm/socket.h b/arch/mips/include/uapi/asm/socket.h
index 17307ab9047..9d11a771392 100644
--- a/arch/mips/include/uapi/asm/socket.h
+++ b/arch/mips/include/uapi/asm/socket.h
@@ -90,5 +90,6 @@ To add: #define SO_REUSEPORT 0x0200 /* Allow local address and port reuse. */
/* Instruct lower device to use last 4-bytes of skb data as FCS */
#define SO_NOFCS 43
+#define SO_LOCK_FILTER 44
#endif /* _UAPI_ASM_SOCKET_H */
diff --git a/arch/mn10300/include/uapi/asm/socket.h b/arch/mn10300/include/uapi/asm/socket.h
index af5366bbfe6..ab702c40b30 100644
--- a/arch/mn10300/include/uapi/asm/socket.h
+++ b/arch/mn10300/include/uapi/asm/socket.h
@@ -70,4 +70,6 @@
/* Instruct lower device to use last 4-bytes of skb data as FCS */
#define SO_NOFCS 43
+#define SO_LOCK_FILTER 44
+
#endif /* _ASM_SOCKET_H */
diff --git a/arch/parisc/include/uapi/asm/socket.h b/arch/parisc/include/uapi/asm/socket.h
index d9ff4731253..da2c8d3c209 100644
--- a/arch/parisc/include/uapi/asm/socket.h
+++ b/arch/parisc/include/uapi/asm/socket.h
@@ -69,6 +69,7 @@
/* Instruct lower device to use last 4-bytes of skb data as FCS */
#define SO_NOFCS 0x4024
+#define SO_LOCK_FILTER 0x4025
/* O_NONBLOCK clashes with the bits used for socket types. Therefore we
* have to define SOCK_NONBLOCK to a different value here.
diff --git a/arch/powerpc/include/uapi/asm/socket.h b/arch/powerpc/include/uapi/asm/socket.h
index eb0b1864d40..e6ca31816cc 100644
--- a/arch/powerpc/include/uapi/asm/socket.h
+++ b/arch/powerpc/include/uapi/asm/socket.h
@@ -77,4 +77,6 @@
/* Instruct lower device to use last 4-bytes of skb data as FCS */
#define SO_NOFCS 43
+#define SO_LOCK_FILTER 44
+
#endif /* _ASM_POWERPC_SOCKET_H */
diff --git a/arch/s390/include/uapi/asm/socket.h b/arch/s390/include/uapi/asm/socket.h
index 436d07c23be..9ce60b68f07 100644
--- a/arch/s390/include/uapi/asm/socket.h
+++ b/arch/s390/include/uapi/asm/socket.h
@@ -76,4 +76,6 @@
/* Instruct lower device to use last 4-bytes of skb data as FCS */
#define SO_NOFCS 43
+#define SO_LOCK_FILTER 44
+
#endif /* _ASM_SOCKET_H */
diff --git a/arch/sparc/include/uapi/asm/socket.h b/arch/sparc/include/uapi/asm/socket.h
index c83a937ead0..fbbba57547d 100644
--- a/arch/sparc/include/uapi/asm/socket.h
+++ b/arch/sparc/include/uapi/asm/socket.h
@@ -66,6 +66,7 @@
/* Instruct lower device to use last 4-bytes of skb data as FCS */
#define SO_NOFCS 0x0027
+#define SO_LOCK_FILTER 0x0028
/* Security levels - as per NRL IPv6 - don't actually do anything */
#define SO_SECURITY_AUTHENTICATION 0x5001
diff --git a/arch/xtensa/include/uapi/asm/socket.h b/arch/xtensa/include/uapi/asm/socket.h
index 38079be1cf1..dbf316487b5 100644
--- a/arch/xtensa/include/uapi/asm/socket.h
+++ b/arch/xtensa/include/uapi/asm/socket.h
@@ -81,4 +81,6 @@
/* Instruct lower device to use last 4-bytes of skb data as FCS */
#define SO_NOFCS 43
+#define SO_LOCK_FILTER 44
+
#endif /* _XTENSA_SOCKET_H */
diff --git a/include/net/sock.h b/include/net/sock.h
index 182ca99405a..5a34e2f0365 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -664,6 +664,7 @@ enum sock_flags {
* Will use last 4 bytes of packet sent from
* user-space instead.
*/
+ SOCK_FILTER_LOCKED, /* Filter cannot be changed anymore */
};
static inline void sock_copy_flags(struct sock *nsk, struct sock *osk)
diff --git a/include/uapi/asm-generic/socket.h b/include/uapi/asm-generic/socket.h
index 2d32d073a6f..3f6a9920141 100644
--- a/include/uapi/asm-generic/socket.h
+++ b/include/uapi/asm-generic/socket.h
@@ -73,4 +73,6 @@
/* Instruct lower device to use last 4-bytes of skb data as FCS */
#define SO_NOFCS 43
+#define SO_LOCK_FILTER 44
+
#endif /* __ASM_GENERIC_SOCKET_H */
diff --git a/net/core/filter.c b/net/core/filter.c
index 2ead2a9b185..2e20b55a783 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -721,6 +721,9 @@ int sk_attach_filter(struct sock_fprog *fprog, struct sock *sk)
unsigned int fsize = sizeof(struct sock_filter) * fprog->len;
int err;
+ if (sock_flag(sk, SOCK_FILTER_LOCKED))
+ return -EPERM;
+
/* Make sure new filter is there and in the right amounts. */
if (fprog->filter == NULL)
return -EINVAL;
@@ -757,6 +760,9 @@ int sk_detach_filter(struct sock *sk)
int ret = -ENOENT;
struct sk_filter *filter;
+ if (sock_flag(sk, SOCK_FILTER_LOCKED))
+ return -EPERM;
+
filter = rcu_dereference_protected(sk->sk_filter,
sock_owned_by_user(sk));
if (filter) {
diff --git a/net/core/sock.c b/net/core/sock.c
index bc131d41968..8258fb741e9 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -861,6 +861,13 @@ set_rcvbuf:
ret = sk_detach_filter(sk);
break;
+ case SO_LOCK_FILTER:
+ if (sock_flag(sk, SOCK_FILTER_LOCKED) && !valbool)
+ ret = -EPERM;
+ else
+ sock_valbool_flag(sk, SOCK_FILTER_LOCKED, valbool);
+ break;
+
case SO_PASSSEC:
if (valbool)
set_bit(SOCK_PASSSEC, &sock->flags);
@@ -1140,6 +1147,10 @@ int sock_getsockopt(struct socket *sock, int level, int optname,
goto lenout;
+ case SO_LOCK_FILTER:
+ v.val = sock_flag(sk, SOCK_FILTER_LOCKED);
+ break;
+
default:
return -ENOPROTOOPT;
}
generated by cgit v1.2.3 (git 2.25.1) at 2024-05-10 00:56:08 +0000