trafgen: Fix for ipv6 header generation when L3-only devices are present #233
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tklauser
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Apr 21, 2022
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Thanks for the contribution @MatPerin!
One small nit inline. Also, could you please add the change description to the commit message as well and add a Signed-off-by line as outlined in SubmittingPatches?
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The getifaddrs function returns a linked list node for L2 even in the case of L3 interfaces (e.g. a TUN device), but with the pointer to the address structure set to NULL. This causes a segfault when trying to access the address family from it when such network interfaces are present in the system. The issue is solved by checking the validity of the pointer beforehand: if the address structure is present the address family can be fetched and the current iteration can go on safely, otherwise the node is skipped (as it is not linked to any address). Signed-off-by: Matteo Perin <[email protected]>
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Sure, sorry for not including the commit message and the |
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When trying to run trafgen with a config which included the ipv6() header generation helper function, I noticed the tool halting without sending any traffic.
By further inspection I found out that the issue was a segmentation fault caused by NULL pointer deferencing inside the lookup function for the device ipv6 address.
Apparently, the getifaddrs function returns a linked list node for L2 even in the case of L3 interfaces (in my case, it was a TUN device created in the network) but with the pointer to the address structure set to NULL. This causes a segfault when trying to access the address family from it.
I solved the issue by checking the validity of the pointer beforehand.