[DCCP]: Unaligned pointer access

This fixes `unaligned (read) access' errors of the type

Kernel unaligned access at TPC[100f970c] dccp_parse_options+0x4f4/0x7e0 [dccp]
Kernel unaligned access at TPC[1011f2e4] ccid3_hc_tx_parse_options+0x1ac/0x380 [dccp_ccid3]
Kernel unaligned access at TPC[100f9898] dccp_parse_options+0x680/0x880 [dccp]

by using the get_unaligned macro for parsing options.

Commiter note: Preserved the sparse __be{16,32} annotations.

Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

2 files changed, 29 insertions, 15 deletions

diff --git a/net/dccp/ccids/ccid3.c b/net/dccp/ccids/ccid3.c
index 25772c326172..05f263e9160d 100644
--- a/net/dccp/ccids/ccid3.c
+++ b/net/dccp/ccids/ccid3.c
@@ -40,6 +40,8 @@
 #include "lib/tfrc.h"
 #include "ccid3.h"
 
+#include <asm/unaligned.h>
+
 #ifdef CONFIG_IP_DCCP_CCID3_DEBUG
 static int ccid3_debug;
 #define ccid3_pr_debug(format, a...)    DCCP_PR_DEBUG(ccid3_debug, format, ##a)
@@ -544,6 +546,7 @@ static int ccid3_hc_tx_parse_options(struct sock *sk, unsigned char option,
         const struct dccp_sock *dp = dccp_sk(sk);
         struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
         struct ccid3_options_received *opt_recv;
+        __be32 opt_val;
 
         opt_recv = &hctx->ccid3hctx_options_received;
 
@@ -563,8 +566,8 @@ static int ccid3_hc_tx_parse_options(struct sock *sk, unsigned char option,
                                   dccp_role(sk), sk, len);
                         rc = -EINVAL;
                 } else {
-                        opt_recv->ccid3or_loss_event_rate =
-                                                ntohl(*(__be32 *)value);
+                        opt_val = get_unaligned((__be32 *)value);
+                        opt_recv->ccid3or_loss_event_rate = ntohl(opt_val);
                         ccid3_pr_debug("%s(%p), LOSS_EVENT_RATE=%u\n",
                                        dccp_role(sk), sk,
                                        opt_recv->ccid3or_loss_event_rate);
@@ -585,8 +588,8 @@ static int ccid3_hc_tx_parse_options(struct sock *sk, unsigned char option,
                                   dccp_role(sk), sk, len);
                         rc = -EINVAL;
                 } else {
-                        opt_recv->ccid3or_receive_rate =
-                                                ntohl(*(__be32 *)value);
+                        opt_val = get_unaligned((__be32 *)value);
+                        opt_recv->ccid3or_receive_rate = ntohl(opt_val);
                         ccid3_pr_debug("%s(%p), RECEIVE_RATE=%u\n",
                                        dccp_role(sk), sk,
                                        opt_recv->ccid3or_receive_rate);
diff --git a/net/dccp/options.c b/net/dccp/options.c
index d361b5533309..d286cffe2c49 100644
--- a/net/dccp/options.c
+++ b/net/dccp/options.c
@@ -14,6 +14,7 @@
 #include <linux/dccp.h>
 #include <linux/module.h>
 #include <linux/types.h>
+#include <asm/unaligned.h>
 #include <linux/kernel.h>
 #include <linux/skbuff.h>
 
@@ -59,6 +60,7 @@ int dccp_parse_options(struct sock *sk, struct sk_buff *skb)
         unsigned char opt, len;
         unsigned char *value;
         u32 elapsed_time;
+        __be32 opt_val;
         int rc;
         int mandatory = 0;
 
@@ -145,7 +147,8 @@ int dccp_parse_options(struct sock *sk, struct sk_buff *skb)
                         if (len != 4)
                                 goto out_invalid_option;
 
-                        opt_recv->dccpor_timestamp = ntohl(*(__be32 *)value);
+                        opt_val = get_unaligned((__be32 *)value);
+                        opt_recv->dccpor_timestamp = ntohl(opt_val);
 
                         dp->dccps_timestamp_echo = opt_recv->dccpor_timestamp;
                         dp->dccps_timestamp_time = ktime_get_real();
@@ -159,7 +162,8 @@ int dccp_parse_options(struct sock *sk, struct sk_buff *skb)
                         if (len != 4 && len != 6 && len != 8)
                                 goto out_invalid_option;
 
-                        opt_recv->dccpor_timestamp_echo = ntohl(*(__be32 *)value);
+                        opt_val = get_unaligned((__be32 *)value);
+                        opt_recv->dccpor_timestamp_echo = ntohl(opt_val);
 
                         dccp_pr_debug("%s rx opt: TIMESTAMP_ECHO=%u, len=%d, "
                                       "ackno=%llu", dccp_role(sk),
@@ -168,16 +172,20 @@ int dccp_parse_options(struct sock *sk, struct sk_buff *skb)
                                       (unsigned long long)
                                       DCCP_SKB_CB(skb)->dccpd_ack_seq);
 
+                        value += 4;
 
-                        if (len == 4) {
+                        if (len == 4) {         /* no elapsed time included */
                                 dccp_pr_debug_cat("\n");
                                 break;
                         }
 
-                        if (len == 6)
-                                elapsed_time = ntohs(*(__be16 *)(value + 4));
-                        else
-                                elapsed_time = ntohl(*(__be32 *)(value + 4));
+                        if (len == 6) {         /* 2-byte elapsed time */
+                                __be16 opt_val2 = get_unaligned((__be16 *)value);
+                                elapsed_time = ntohs(opt_val2);
+                        } else {                /* 4-byte elapsed time */
+                                opt_val = get_unaligned((__be32 *)value);
+                                elapsed_time = ntohl(opt_val);
+                        }
 
                         dccp_pr_debug_cat(", ELAPSED_TIME=%u\n", elapsed_time);
 
@@ -192,10 +200,13 @@ int dccp_parse_options(struct sock *sk, struct sk_buff *skb)
                         if (pkt_type == DCCP_PKT_DATA)
                                 continue;
 
-                        if (len == 2)
-                                elapsed_time = ntohs(*(__be16 *)value);
-                        else
-                                elapsed_time = ntohl(*(__be32 *)value);
+                        if (len == 2) {
+                                __be16 opt_val2 = get_unaligned((__be16 *)value);
+                                elapsed_time = ntohs(opt_val2);
+                        } else {
+                                opt_val = get_unaligned((__be32 *)value);
+                                elapsed_time = ntohl(opt_val);
+                        }
 
                         if (elapsed_time > opt_recv->dccpor_elapsed_time)
                                 opt_recv->dccpor_elapsed_time = elapsed_time;