On Wed, 15 Aug 2007 12:22:51 -0700 (PDT) [EMAIL PROTECTED] wrote: > http://bugzilla.kernel.org/show_bug.cgi?id=8891 > > Summary: in-kernel rpc generates broken RPCBPROC_GETVERSADDR v4 > requests > Product: Networking > Version: 2.5 > KernelVersion: 2.6.22.1 > Platform: All > OS/Version: Linux > Tree: Mainline > Status: NEW > Severity: normal > Priority: P1 > Component: Other > AssignedTo: [EMAIL PROTECTED] > ReportedBy: [EMAIL PROTECTED] > > > Most recent kernel where this bug did not occur: 2.6.20
Apparently a regression. > Distribution: Fedora Core 6 > Hardware Environment: x86_64 > Software Environment: NFS > Problem Description: When locking a file, an invalid RPCBPROC_GETVERSADDR > procedure call is sent out > > Steps to reproduce: > on the NFS server, run: tcpdump -xX -pni eth0 -s0 port 111 and src host > theNFSclient > on a client running 2.6.22.1, run: flock -x /nfsmount/somefile ls > tcpdump will show: > > 17:10:01.290655 IP 141.2.15.141.34572 > 141.2.1.1.sunrpc: P 0:168(168) ack 1 > win 183 <nop,nop,timestamp 966695 115079499> > 0x0000: 4500 00dc 53ad 4000 3f06 bcdc 8d02 0f8d [EMAIL PROTECTED] > 0x0010: 8d02 0101 870c 006f cdcd 938d db00 c8a7 > .......o........ > 0x0020: 8018 00b7 e59d 0000 0101 080a 000e c027 ...............' > 0x0030: 06db f94b 8000 00a4 fd48 2a07 0000 0000 ...K.....H*..... > 0x0040: 0000 0002 0001 86a0 0000 0004 0000 0009 ................ > 0x0050: 0000 0001 0000 0054 0000 03c6 0000 0007 .......T........ > 0x0060: 6572 6964 796b 6500 0000 0000 0000 0000 eridyke......... > 0x0070: 0000 000e 0000 0000 0000 0001 0000 0002 ................ > 0x0080: 0000 0003 0000 0004 0000 0005 0000 0006 ................ > 0x0090: 0000 0007 0000 0007 0000 0009 0000 000a ................ > 0x00a0: 0000 000c 0000 0014 0000 001c 0000 0000 ................ > 0x00b0: 0000 0000 0001 86b5 0000 0004 0000 0003 ................ > 0x00c0: 7463 7000 0000 0009 3134 312e 322e 312e tcp.....141.2.1. > 0x00d0: 3100 0000 0000 0004 7270 6362 1.......rpcb > > Note the "141.2.1.1" in the output. > > According to RFC 1833, you can read here the following fields: > > RPCBPROC_GETVERSADDR version 4 procedure is being called > r_prog == 0x000186b5 == 100021 == nfs.lockd > r_vers == 4 > r_netid == (length 3) "tcp" > r_addr == (length 9) "141.2.1.1" > r_owner == (length 4) "rpcb" > > This r_addr member is supposed to contain an universal address. Although I > have > no source for that, the RFC clearly says a service can listen to an address, > and RPCBPROC_GETVERSADDR is supposed to return an universal address too. From > this I can conclude that an universal address is supposed to contain the port > number, and other operating systems are using the format > a.b.c.d.PortHighByte.PortLowByte (like in FTP, but with . instead of ,). I > interpret the RFC 1833 so that the port number of the rpcbind, that is, 111, > is > to be appended, so the correct value of r_addr would be "141.2.1.1.0.111". > This > matches other implementations. > > Of course, all this does sound like nitpicking, and as the callee is not even > supposed to look at the port number (this argument is only there so the callee > can decide correctly which interface address to use for the response). > However, > this omission triggers an apparently unpatched denial of service vulnerability > against HP-UX 11.11's rpcbind and causes it to quit with a core dump and a bus > error. When using a correctly formed universal address, or the empty string, > there is no crash of HP-UX's rpcbind. > > And of course it is HP who has to fix the DoS bug - but Linux 2.6.22 triggers > it by a RFC violation, which is a minor bug to be fixed on Linux's side. By > the > way, does anyone have the right contacts to HP to report this bug? I do not > have a HP service contract any more, and the only other support place I found > is their public forum, where I of course can only provide limited information > about the bug (basically, the same I am posting here). > > Maybe the bug is fixed in a more current kernel, I was only using Fedora's > highly patched distribution kernel and compared it to the sources of the base > version in the main tree, where I see the very same problem in the source > code. > So I do not think it was Fedora who caused the problem, and am assigning it to > mainline. > - To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html