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batman-adv: Only write requested number of byte to user buffer

Don't write more than the requested number of bytes of an batman-adv icmp
packet to the userspace buffer. Otherwise unrelated userspace memory might get
overridden by the kernel.

Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Marek Lindner <lindner_marek@yahoo.de>
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1 parent d18eb45 commit b5a1eeef04cc7859f34dec9b72ea1b28e4aba07c @ecsv ecsv committed with Marek Lindner Dec 10, 2011
Showing with 2 additions and 3 deletions.
  1. +2 −3 net/batman-adv/icmp_socket.c
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5 net/batman-adv/icmp_socket.c
@@ -136,10 +136,9 @@ static ssize_t bat_socket_read(struct file *file, char __user *buf,
spin_unlock_bh(&socket_client->lock);
- error = copy_to_user(buf, &socket_packet->icmp_packet,
- socket_packet->icmp_len);
+ packet_len = min(count, socket_packet->icmp_len);
+ error = copy_to_user(buf, &socket_packet->icmp_packet, packet_len);
- packet_len = socket_packet->icmp_len;
kfree(socket_packet);
if (error)

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