ss: Allow ssfilter_bytecompile to return 0

Allow ssfilter_bytecompile to return 0 for filter ops the kernel
does not support. If such an op is in the filter string then all
filtering is done in userspace.

Signed-off-by: David Ahern <dsa@cumulusnetworks.com>

diff --git a/misc/ss.c b/misc/ss.c
index f164ca92030884748e1f4055f589e046e044312a..0510701619ac6ef8db8fd5ac33f133719e6d36aa 100644 (file)
--- a/misc/ss.c
+++ b/misc/ss.c
@@ -1273,11 +1273,16 @@ static int ssfilter_bytecompile(struct ssfilter *f, char **bytecode)
 
                case SSF_AND:
        {
-               char *a1, *a2, *a;
+               char *a1 = NULL, *a2 = NULL, *a;
                int l1, l2;
 
                l1 = ssfilter_bytecompile(f->pred, &a1);
                l2 = ssfilter_bytecompile(f->post, &a2);
+               if (!l1 || !l2) {
+                       free(a1);
+                       free(a2);
+                       return 0;
+               }
                if (!(a = malloc(l1+l2))) abort();
                memcpy(a, a1, l1);
                memcpy(a+l1, a2, l2);
@@ -1288,11 +1293,16 @@ static int ssfilter_bytecompile(struct ssfilter *f, char **bytecode)
        }
                case SSF_OR:
        {
-               char *a1, *a2, *a;
+               char *a1 = NULL, *a2 = NULL, *a;
                int l1, l2;
 
                l1 = ssfilter_bytecompile(f->pred, &a1);
                l2 = ssfilter_bytecompile(f->post, &a2);
+               if (!l1 || !l2) {
+                       free(a1);
+                       free(a2);
+                       return 0;
+               }
                if (!(a = malloc(l1+l2+4))) abort();
                memcpy(a, a1, l1);
                memcpy(a+l1+4, a2, l2);
@@ -1303,10 +1313,14 @@ static int ssfilter_bytecompile(struct ssfilter *f, char **bytecode)
        }
                case SSF_NOT:
        {
-               char *a1, *a;
+               char *a1 = NULL, *a;
                int l1;
 
                l1 = ssfilter_bytecompile(f->pred, &a1);
+               if (!l1) {
+                       free(a1);
+                       return 0;
+               }
                if (!(a = malloc(l1+4))) abort();
                memcpy(a, a1, l1);
                free(a1);
@@ -2127,6 +2141,7 @@ static int tcpdiag_send(int fd, int protocol, struct filter *f)
        struct msghdr msg;
        struct rtattr rta;
        struct iovec iov[3];
+       int iovlen = 1;
 
        if (protocol == IPPROTO_UDP)
                return -1;
@@ -2162,18 +2177,21 @@ static int tcpdiag_send(int fd, int protocol, struct filter *f)
        };
        if (f->f) {
                bclen = ssfilter_bytecompile(f->f, &bc);
-               rta.rta_type = INET_DIAG_REQ_BYTECODE;
-               rta.rta_len = RTA_LENGTH(bclen);
-               iov[1] = (struct iovec){ &rta, sizeof(rta) };
-               iov[2] = (struct iovec){ bc, bclen };
-               req.nlh.nlmsg_len += RTA_LENGTH(bclen);
+               if (bclen) {
+                       rta.rta_type = INET_DIAG_REQ_BYTECODE;
+                       rta.rta_len = RTA_LENGTH(bclen);
+                       iov[1] = (struct iovec){ &rta, sizeof(rta) };
+                       iov[2] = (struct iovec){ bc, bclen };
+                       req.nlh.nlmsg_len += RTA_LENGTH(bclen);
+                       iovlen = 3;
+               }
        }
 
        msg = (struct msghdr) {
                .msg_name = (void *)&nladdr,
                .msg_namelen = sizeof(nladdr),
                .msg_iov = iov,
-               .msg_iovlen = f->f ? 3 : 1,
+               .msg_iovlen = iovlen,
        };
 
        if (sendmsg(fd, &msg, 0) < 0) {
@@ -2194,6 +2212,7 @@ static int sockdiag_send(int family, int fd, int protocol, struct filter *f)
        struct msghdr msg;
        struct rtattr rta;
        struct iovec iov[3];
+       int iovlen = 1;
 
        if (family == PF_UNSPEC)
                return tcpdiag_send(fd, protocol, f);
@@ -2222,18 +2241,21 @@ static int sockdiag_send(int family, int fd, int protocol, struct filter *f)
        };
        if (f->f) {
                bclen = ssfilter_bytecompile(f->f, &bc);
-               rta.rta_type = INET_DIAG_REQ_BYTECODE;
-               rta.rta_len = RTA_LENGTH(bclen);
-               iov[1] = (struct iovec){ &rta, sizeof(rta) };
-               iov[2] = (struct iovec){ bc, bclen };
-               req.nlh.nlmsg_len += RTA_LENGTH(bclen);
+               if (bclen) {
+                       rta.rta_type = INET_DIAG_REQ_BYTECODE;
+                       rta.rta_len = RTA_LENGTH(bclen);
+                       iov[1] = (struct iovec){ &rta, sizeof(rta) };
+                       iov[2] = (struct iovec){ bc, bclen };
+                       req.nlh.nlmsg_len += RTA_LENGTH(bclen);
+                       iovlen = 3;
+               }
        }
 
        msg = (struct msghdr) {
                .msg_name = (void *)&nladdr,
                .msg_namelen = sizeof(nladdr),
                .msg_iov = iov,
-               .msg_iovlen = f->f ? 3 : 1,
+               .msg_iovlen = iovlen,
        };
 
        if (sendmsg(fd, &msg, 0) < 0) {