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strssndktndavem330
strssndktn
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davem330
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inet: prevent leakage of uninitialized memory to user in recv syscalls
Only update *addr_len when we actually fill in sockaddr, otherwise we can return uninitialized memory from the stack to the caller in the recvfrom, recvmmsg and recvmsg syscalls. Drop the the (addr_len == NULL) checks because we only get called with a valid addr_len pointer either from sock_common_recvmsg or inet_recvmsg. If a blocking read waits on a socket which is concurrently shut down we now return zero and set msg_msgnamelen to 0. Reported-by: mpb <mpb.mail@gmail.com> Suggested-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org> Signed-off-by: David S. Miller <davem@davemloft.net>
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8 files changed

+17
-38
lines changed

8 files changed

+17
-38
lines changed

‎net/ieee802154/dgram.c

Lines changed: 1 addition & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -315,9 +315,8 @@ static int dgram_recvmsg(struct kiocb *iocb, struct sock *sk,
315315
if (saddr) {
316316
saddr->family = AF_IEEE802154;
317317
saddr->addr = mac_cb(skb)->sa;
318-
}
319-
if (addr_len)
320318
*addr_len = sizeof(*saddr);
319+
}
321320

322321
if (flags & MSG_TRUNC)
323322
copied = skb->len;

‎net/ipv4/ping.c

Lines changed: 7 additions & 12 deletions
Original file line numberDiff line numberDiff line change
@@ -830,8 +830,6 @@ int ping_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
830830
{
831831
struct inet_sock *isk = inet_sk(sk);
832832
int family = sk->sk_family;
833-
struct sockaddr_in *sin;
834-
struct sockaddr_in6 *sin6;
835833
struct sk_buff *skb;
836834
int copied, err;
837835

@@ -841,13 +839,6 @@ int ping_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
841839
if (flags & MSG_OOB)
842840
goto out;
843841

844-
if (addr_len) {
845-
if (family == AF_INET)
846-
*addr_len = sizeof(*sin);
847-
else if (family == AF_INET6 && addr_len)
848-
*addr_len = sizeof(*sin6);
849-
}
850-
851842
if (flags & MSG_ERRQUEUE) {
852843
if (family == AF_INET) {
853844
return ip_recv_error(sk, msg, len);
@@ -877,11 +868,13 @@ int ping_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
877868

878869
/* Copy the address and add cmsg data. */
879870
if (family == AF_INET) {
880-
sin = (struct sockaddr_in *) msg->msg_name;
871+
struct sockaddr_in *sin = (struct sockaddr_in *)msg->msg_name;
872+
881873
sin->sin_family = AF_INET;
882874
sin->sin_port = 0 /* skb->h.uh->source */;
883875
sin->sin_addr.s_addr = ip_hdr(skb)->saddr;
884876
memset(sin->sin_zero, 0, sizeof(sin->sin_zero));
877+
*addr_len = sizeof(*sin);
885878

886879
if (isk->cmsg_flags)
887880
ip_cmsg_recv(msg, skb);
@@ -890,17 +883,19 @@ int ping_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
890883
} else if (family == AF_INET6) {
891884
struct ipv6_pinfo *np = inet6_sk(sk);
892885
struct ipv6hdr *ip6 = ipv6_hdr(skb);
893-
sin6 = (struct sockaddr_in6 *) msg->msg_name;
886+
struct sockaddr_in6 *sin6 =
887+
(struct sockaddr_in6 *)msg->msg_name;
888+
894889
sin6->sin6_family = AF_INET6;
895890
sin6->sin6_port = 0;
896891
sin6->sin6_addr = ip6->saddr;
897-
898892
sin6->sin6_flowinfo = 0;
899893
if (np->sndflow)
900894
sin6->sin6_flowinfo = ip6_flowinfo(ip6);
901895

902896
sin6->sin6_scope_id = ipv6_iface_scope_id(&sin6->sin6_addr,
903897
IP6CB(skb)->iif);
898+
*addr_len = sizeof(*sin6);
904899

905900
if (inet6_sk(sk)->rxopt.all)
906901
pingv6_ops.ip6_datagram_recv_ctl(sk, msg, skb);

‎net/ipv4/raw.c

Lines changed: 1 addition & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -696,9 +696,6 @@ static int raw_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
696696
if (flags & MSG_OOB)
697697
goto out;
698698

699-
if (addr_len)
700-
*addr_len = sizeof(*sin);
701-
702699
if (flags & MSG_ERRQUEUE) {
703700
err = ip_recv_error(sk, msg, len);
704701
goto out;
@@ -726,6 +723,7 @@ static int raw_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
726723
sin->sin_addr.s_addr = ip_hdr(skb)->saddr;
727724
sin->sin_port = 0;
728725
memset(&sin->sin_zero, 0, sizeof(sin->sin_zero));
726+
*addr_len = sizeof(*sin);
729727
}
730728
if (inet->cmsg_flags)
731729
ip_cmsg_recv(msg, skb);

‎net/ipv4/udp.c

Lines changed: 1 addition & 6 deletions
Original file line numberDiff line numberDiff line change
@@ -1235,12 +1235,6 @@ int udp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
12351235
int is_udplite = IS_UDPLITE(sk);
12361236
bool slow;
12371237

1238-
/*
1239-
* Check any passed addresses
1240-
*/
1241-
if (addr_len)
1242-
*addr_len = sizeof(*sin);
1243-
12441238
if (flags & MSG_ERRQUEUE)
12451239
return ip_recv_error(sk, msg, len);
12461240

@@ -1302,6 +1296,7 @@ int udp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
13021296
sin->sin_port = udp_hdr(skb)->source;
13031297
sin->sin_addr.s_addr = ip_hdr(skb)->saddr;
13041298
memset(sin->sin_zero, 0, sizeof(sin->sin_zero));
1299+
*addr_len = sizeof(*sin);
13051300
}
13061301
if (inet->cmsg_flags)
13071302
ip_cmsg_recv(msg, skb);

‎net/ipv6/raw.c

Lines changed: 1 addition & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -465,9 +465,6 @@ static int rawv6_recvmsg(struct kiocb *iocb, struct sock *sk,
465465
if (flags & MSG_OOB)
466466
return -EOPNOTSUPP;
467467

468-
if (addr_len)
469-
*addr_len=sizeof(*sin6);
470-
471468
if (flags & MSG_ERRQUEUE)
472469
return ipv6_recv_error(sk, msg, len);
473470

@@ -506,6 +503,7 @@ static int rawv6_recvmsg(struct kiocb *iocb, struct sock *sk,
506503
sin6->sin6_flowinfo = 0;
507504
sin6->sin6_scope_id = ipv6_iface_scope_id(&sin6->sin6_addr,
508505
IP6CB(skb)->iif);
506+
*addr_len = sizeof(*sin6);
509507
}
510508

511509
sock_recv_ts_and_drops(msg, sk, skb);

‎net/ipv6/udp.c

Lines changed: 1 addition & 4 deletions
Original file line numberDiff line numberDiff line change
@@ -392,9 +392,6 @@ int udpv6_recvmsg(struct kiocb *iocb, struct sock *sk,
392392
int is_udp4;
393393
bool slow;
394394

395-
if (addr_len)
396-
*addr_len = sizeof(struct sockaddr_in6);
397-
398395
if (flags & MSG_ERRQUEUE)
399396
return ipv6_recv_error(sk, msg, len);
400397

@@ -480,7 +477,7 @@ int udpv6_recvmsg(struct kiocb *iocb, struct sock *sk,
480477
ipv6_iface_scope_id(&sin6->sin6_addr,
481478
IP6CB(skb)->iif);
482479
}
483-
480+
*addr_len = sizeof(*sin6);
484481
}
485482
if (is_udp4) {
486483
if (inet->cmsg_flags)

‎net/l2tp/l2tp_ip.c

Lines changed: 1 addition & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -518,9 +518,6 @@ static int l2tp_ip_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *m
518518
if (flags & MSG_OOB)
519519
goto out;
520520

521-
if (addr_len)
522-
*addr_len = sizeof(*sin);
523-
524521
skb = skb_recv_datagram(sk, flags, noblock, &err);
525522
if (!skb)
526523
goto out;
@@ -543,6 +540,7 @@ static int l2tp_ip_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *m
543540
sin->sin_addr.s_addr = ip_hdr(skb)->saddr;
544541
sin->sin_port = 0;
545542
memset(&sin->sin_zero, 0, sizeof(sin->sin_zero));
543+
*addr_len = sizeof(*sin);
546544
}
547545
if (inet->cmsg_flags)
548546
ip_cmsg_recv(msg, skb);

‎net/phonet/datagram.c

Lines changed: 4 additions & 5 deletions
Original file line numberDiff line numberDiff line change
@@ -139,9 +139,6 @@ static int pn_recvmsg(struct kiocb *iocb, struct sock *sk,
139139
MSG_CMSG_COMPAT))
140140
goto out_nofree;
141141

142-
if (addr_len)
143-
*addr_len = sizeof(sa);
144-
145142
skb = skb_recv_datagram(sk, flags, noblock, &rval);
146143
if (skb == NULL)
147144
goto out_nofree;
@@ -162,8 +159,10 @@ static int pn_recvmsg(struct kiocb *iocb, struct sock *sk,
162159

163160
rval = (flags & MSG_TRUNC) ? skb->len : copylen;
164161

165-
if (msg->msg_name != NULL)
166-
memcpy(msg->msg_name, &sa, sizeof(struct sockaddr_pn));
162+
if (msg->msg_name != NULL) {
163+
memcpy(msg->msg_name, &sa, sizeof(sa));
164+
*addr_len = sizeof(sa);
165+
}
167166

168167
out:
169168
skb_free_datagram(sk, skb);

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