Bugs item #2234923, was opened at 2008-11-07 16:04
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Category: libcurl
Group: crash
Status: Open
Resolution: None
Priority: 5
Private: No
Submitted By: Adam Sampson (adamsampson)
Assigned to: Daniel Stenberg (bagder)
Summary: Curl_if2ip crashes on NULL ifa_addr

Initial Comment:
On my Linux 2.6.26.6 machine, getifaddrs() returns a struct iface with a NULL ifa_addr field for the teql0 interface -- presumably because it doesn't really have an address (it's a virtual interface for load-balancing that you can bind other interfaces to). In gdb, the struct looks like this:

$3 = {ifa_next = 0x9242418, ifa_name = 0x9242404 "teql0", ifa_flags = 128,
      ifa_addr = 0x0, ifa_netmask = 0x0, ifa_ifu = { ifu_broadaddr = 0x0,
      ifu_dstaddr = 0x0}, ifa_data = 0x9242d38}

which corresponds to what "ip link show teql0" displays:

2: teql0: <NOARP> mtu 1500 qdisc noop qlen 100
    link/void

(That "/void" would normally be a hardware address of some kind for a real interface.)

This causes Curl_if2ip to crash, because it enumerates all the interfaces, assuming ifa_addr is a valid pointer for each one. I've attached a patch against curl-7.19.1 to make it check for this.

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Received on 2008-11-07