Re: [Wireshark-dev] [Wireshark-commits] rev 30846: /trunk/gtk/ /trunk/gtk/: capture_if_dlg.c
On Nov 7, 2009, at 10:38 AM, Gerald Combs wrote: > In capture_interface_list we don't set the interface description if we > get an empty string from dumpcap: > > if (strlen(if_parts[1]) > 0) > if_info->description = g_strdup(if_parts[1]); Hmm. Looking at capture_opts_list_interfaces(), which is what dumpcap uses to list the interfaces, if it's generating (more easily) machine- readable output, the output generated for a missing description (if_info->description is null) and the output generated for an empty description (if_info->description points to a null string) are the same. > This is apparently how we ended up with null description pointers in > capture_get_if_icon. Should we take out the if statement and set the > description no matter what? An empty description is no more useful than a null description, and, as indicated, pcap_findalldevs() doesn't guarantee that it will return a description for every adapter, so I wouldn't be inclined to do that; I'd be inclined to leave the if statement there. (I'm thinking of redoing the way that dumpcap communicates with its callers for various reasons, including adding support for all the new stuff I added in libpcap 1.0, so, for example, we can have a "monitor mode" checkbox for wireless adapters if the relevant APIs work; I'll see if I can distinguish between "no description" and "empty description".) I'm also curious how the description managed to be null - at least according to the bug report, Marvell *does* supply a description: Connection-specific DNS Suffix . : Description . . . . . . . . . . . : Marvell Yukon 88E8056 PCI-E Gigabit Ethernet Controller Physical Address. . . . . . . . . : 00-22-15-##-##-## DHCP Enabled. . . . . . . . . . . : Yes Autoconfiguration Enabled . . . . : Yes Link-local IPv6 Address . . . . . : fe80::::. IPv4 Address. . . . . . . . . . . : a.b.c.h(Preferred) Subnet Mask . . . . . . . . . . . : w.x.y.z Lease Obtained. . . . . . . . . . : 06 November 2009 18:38:00 Lease Expires . . . . . . . . . . : 09 November 2009 18:37:59 Default Gateway . . . . . . . . . : a.b.c.d DHCP Server . . . . . . . . . . . : a.b.c.d DNS Servers . . . . . . . . . . . : a.b.c.d NetBIOS over Tcpip. . . . . . . . : Enabled so there's presumably something odd going on in WinPcap here. ___ Sent via:Wireshark-dev mailing list Archives:http://www.wireshark.org/lists/wireshark-dev Unsubscribe: https://wireshark.org/mailman/options/wireshark-dev mailto:wireshark-dev-requ...@wireshark.org?subject=unsubscribe
Re: [Wireshark-dev] [Wireshark-commits] rev 30846: /trunk/gtk/ /trunk/gtk/: capture_if_dlg.c
Guy Harris wrote: > On Nov 6, 2009, at 10:09 AM, ger...@wireshark.org wrote: > >> http://anonsvn.wireshark.org/viewvc/viewvc.cgi?view=rev&revision=30846 >> >> User: gerald >> Date: 2009/11/06 10:09 AM >> >> Log: >> Add some null pointer checks. This is a blind attempt to fix bug 4155. > > Note that pcap_findalldevs() is not specified as guaranteeing that all > interfaces have a non-null description field. > > A quick look at the WinPcap 4.1.1 code doesn't seem to show any way > for any interfaces to have a null description field on Windows, but > perhaps I'm missing something. In any case, the checks for a null > pointer probably still belong there, just in case, in the future, > pcap_findalldevs() can return an interface with a null description > field. > > However, if the description field is null, no () will be printed. If > it points to a null *string*, () will be printed - but you won't get a > null-pointer dereference in that case. In capture_interface_list we don't set the interface description if we get an empty string from dumpcap: if (strlen(if_parts[1]) > 0) if_info->description = g_strdup(if_parts[1]); This is apparently how we ended up with null description pointers in capture_get_if_icon. Should we take out the if statement and set the description no matter what? ___ Sent via:Wireshark-dev mailing list Archives:http://www.wireshark.org/lists/wireshark-dev Unsubscribe: https://wireshark.org/mailman/options/wireshark-dev mailto:wireshark-dev-requ...@wireshark.org?subject=unsubscribe
Re: [Wireshark-dev] [Wireshark-commits] rev 30846: /trunk/gtk/ /trunk/gtk/: capture_if_dlg.c
On Nov 6, 2009, at 10:09 AM, ger...@wireshark.org wrote: > http://anonsvn.wireshark.org/viewvc/viewvc.cgi?view=rev&revision=30846 > > User: gerald > Date: 2009/11/06 10:09 AM > > Log: > Add some null pointer checks. This is a blind attempt to fix bug 4155. Note that pcap_findalldevs() is not specified as guaranteeing that all interfaces have a non-null description field. A quick look at the WinPcap 4.1.1 code doesn't seem to show any way for any interfaces to have a null description field on Windows, but perhaps I'm missing something. In any case, the checks for a null pointer probably still belong there, just in case, in the future, pcap_findalldevs() can return an interface with a null description field. However, if the description field is null, no () will be printed. If it points to a null *string*, () will be printed - but you won't get a null-pointer dereference in that case. ___ Sent via:Wireshark-dev mailing list Archives:http://www.wireshark.org/lists/wireshark-dev Unsubscribe: https://wireshark.org/mailman/options/wireshark-dev mailto:wireshark-dev-requ...@wireshark.org?subject=unsubscribe
