[PATCH 1/4] tipc: Fix bugs in tipc_msg_calc_data_size()

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From: Allan Stephens <Allan.Stephens@xxxxxxxxxxxxx>

Enhances TIPC's computation of the amount of data to be sent so that
it works properly when large values are involved. Calculations are now
done using "size_t" instead of "int", and a check has been added to
handle cases where the total amount of data exceeds the range of "size_t".

Signed-off-by: Allan Stephens <Allan.Stephens@xxxxxxxxxxxxx>
---
 net/tipc/msg.c |   17 ++++++++++++-----
 net/tipc/msg.h |    2 +-
 2 files changed, 13 insertions(+), 6 deletions(-)

diff --git a/net/tipc/msg.c b/net/tipc/msg.c
index ecb532f..38360a9 100644
--- a/net/tipc/msg.c
+++ b/net/tipc/msg.c
@@ -72,15 +72,22 @@ void tipc_msg_init(struct tipc_msg *m, u32 user, u32 type,
 
 /**
  * tipc_msg_calc_data_size - determine total data size for message
+ *
+ * Note: If total exceeds range of size_t returns largest possible value
  */
 
-int tipc_msg_calc_data_size(struct iovec const *msg_sect, u32 num_sect)
+size_t tipc_msg_calc_data_size(struct iovec const *msg_sect, size_t num_sect)
 {
-	int dsz = 0;
-	int i;
+	size_t dsz = 0;
+	size_t len;
+	size_t i;
 
-	for (i = 0; i < num_sect; i++)
-		dsz += msg_sect[i].iov_len;
+	for (i = 0; i < num_sect; i++) {
+		len = msg_sect[i].iov_len;
+		if (len > (size_t)LONG_MAX - dsz)
+			return (size_t)LONG_MAX;
+		dsz += len;
+	}
 	return dsz;
 }
 
diff --git a/net/tipc/msg.h b/net/tipc/msg.h
index 031aad1..a132800 100644
--- a/net/tipc/msg.h
+++ b/net/tipc/msg.h
@@ -711,7 +711,7 @@ static inline void msg_set_dataoctet(struct tipc_msg *m, u32 pos)
 u32 tipc_msg_tot_importance(struct tipc_msg *m);
 void tipc_msg_init(struct tipc_msg *m, u32 user, u32 type,
 			    u32 hsize, u32 destnode);
-int tipc_msg_calc_data_size(struct iovec const *msg_sect, u32 num_sect);
+size_t tipc_msg_calc_data_size(struct iovec const *msg_sect, size_t num_sect);
 int tipc_msg_build(struct tipc_msg *hdr,
 			    struct iovec const *msg_sect, u32 num_sect,
 			    int max_size, int usrmem, struct sk_buff** buf);
-- 
1.7.1.GIT

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