kernel.git/net/sunrpc/auth_gss, branch linux-4.5.y

sunrpc: fix stripping of padded MIC tokens

2016-06-08T01:18:51Z

commit c0cb8bf3a8e4bd82e640862cdd8891400405cb89 upstream. The length of the GSS MIC token need not be a multiple of four bytes. It is then padded by XDR to a multiple of 4 B, but unwrap_integ_data() would previously only trim mic.len + 4 B. The remaining up to three bytes would then trigger a check in nfs4svc_decode_compoundargs(), leading to a "garbage args" error and mount failure: nfs4svc_decode_compoundargs: compound not properly padded! nfsd: failed to decode arguments! This would prevent older clients using the pre-RFC 4121 MIC format (37-byte MIC including a 9-byte OID) from mounting exports from v3.9+ servers using krb5i. The trimming was introduced by commit 4c190e2f913f ("sunrpc: trim off trailing checksum before returning decrypted or integrity authenticated buffer"). Fixes: 4c190e2f913f "unrpc: trim off trailing checksum..." Signed-off-by: Tomáš Trnka Acked-by: Jeff Layton Signed-off-by: J. Bruce Fields Signed-off-by: Greg Kroah-Hartman

auth_gss: fix panic in gss_pipe_downcall() in fips mode

2016-02-17T16:50:10Z

On Mon, 15 Feb 2016, Trond Myklebust wrote: > Hi Scott, > > On Mon, Feb 15, 2016 at 2:28 PM, Scott Mayhew wrote: > > md5 is disabled in fips mode, and attempting to import a gss context > > using md5 while in fips mode will result in crypto_alg_mod_lookup() > > returning -ENOENT, which will make its way back up to > > gss_pipe_downcall(), where the BUG() is triggered. Handling the -ENOENT > > allows for a more graceful failure. > > > > Signed-off-by: Scott Mayhew > > --- > > net/sunrpc/auth_gss/auth_gss.c | 3 +++ > > 1 file changed, 3 insertions(+) > > > > diff --git a/net/sunrpc/auth_gss/auth_gss.c b/net/sunrpc/auth_gss/auth_gss.c > > index 799e65b..c30fc3b 100644 > > --- a/net/sunrpc/auth_gss/auth_gss.c > > +++ b/net/sunrpc/auth_gss/auth_gss.c > > @@ -737,6 +737,9 @@ gss_pipe_downcall(struct file *filp, const char __user *src, size_t mlen) > > case -ENOSYS: > > gss_msg->msg.errno = -EAGAIN; > > break; > > + case -ENOENT: > > + gss_msg->msg.errno = -EPROTONOSUPPORT; > > + break; > > default: > > printk(KERN_CRIT "%s: bad return from " > > "gss_fill_context: %zd\n", __func__, err); > > -- > > 2.4.3 > > > > Well debugged, but I unfortunately do have to ask if this patch is > sufficient? In addition to -ENOENT, and -ENOMEM, it looks to me as if > crypto_alg_mod_lookup() can also fail with -EINTR, -ETIMEDOUT, and > -EAGAIN. Don't we also want to handle those? You're right, I was focusing on the panic that I could easily reproduce. I'm still not sure how I could trigger those other conditions. > > In fact, peering into the rats nest that is > gss_import_sec_context_kerberos(), it looks as if that is just a tiny > subset of all the errors that we might run into. Perhaps the right > thing to do here is to get rid of the BUG() (but keep the above > printk) and just return a generic error? That sounds fine to me -- updated patch attached. -Scott >From d54c6b64a107a90a38cab97577de05f9a4625052 Mon Sep 17 00:00:00 2001 From: Scott Mayhew Date: Mon, 15 Feb 2016 15:12:19 -0500 Subject: [PATCH] auth_gss: remove the BUG() from gss_pipe_downcall() Instead return a generic error via gss_msg->msg.errno. None of the errors returned by gss_fill_context() should necessarily trigger a kernel panic. Signed-off-by: Scott Mayhew Signed-off-by: Trond Myklebust

nfsd4: fix gss-proxy 4.1 mounts for some AD principals

2015-11-24T18:36:31Z

The principal name on a gss cred is used to setup the NFSv4.0 callback, which has to have a client principal name to authenticate to. That code wants the name to be in the form servicetype@hostname. rpc.svcgssd passes down such names (and passes down no principal name at all in the case the principal isn't a service principal). gss-proxy always passes down the principal name, and passes it down in the form servicetype/hostname@REALM. So we've been munging the name gss-proxy passes down into the format the NFSv4.0 callback code expects, or throwing away the name if we can't. Since the introduction of the MACH_CRED enforcement in NFSv4.1, we've also been using the principal name to verify that certain operations are done as the same principal as was used on the original EXCHANGE_ID call. For that application, the original name passed down by gss-proxy is also useful. Lack of that name in some cases was causing some kerberized NFSv4.1 mount failures in an Active Directory environment. This fix only works in the gss-proxy case. The fix for legacy rpc.svcgssd would be more involved, and rpc.svcgssd already has other problems in the AD case. Reported-and-tested-by: James Ralston Acked-by: Simo Sorce Signed-off-by: J. Bruce Fields

sunrpc: avoid warning in gss_key_timeout

2015-10-23T19:57:28Z

The gss_key_timeout() function causes a harmless warning in some configurations, e.g. ARM imx_v6_v7_defconfig with gcc-5.2, if the compiler cannot figure out the state of the 'expire' variable across an rcu_read_unlock(): net/sunrpc/auth_gss/auth_gss.c: In function 'gss_key_timeout': net/sunrpc/auth_gss/auth_gss.c:1422:211: warning: 'expire' may be used uninitialized in this function [-Wmaybe-uninitialized] To avoid this warning without adding a bogus initialization, this rewrites the function so the comparison is done inside of the critical section. As a side-effect, it also becomes slightly easier to understand because the implementation now more closely resembles the comment above it. Signed-off-by: Arnd Bergmann Fixes: c5e6aecd034e7 ("sunrpc: fix RCU handling of gc_ctx field") Signed-off-by: J. Bruce Fields

sunrpc: use sg_init_one() in krb5_rc4_setup_enc/seq_key()

2015-06-22T18:15:06Z

Don't opencode sg_init_one() Signed-off-by: Fabian Frederick Signed-off-by: J. Bruce Fields

svcrpc: fix potential GSSX_ACCEPT_SEC_CONTEXT decoding failures

2015-05-04T16:02:40Z

In an environment where the KDC is running Active Directory, the exported composite name field returned in the context could be large enough to span a page boundary. Attaching a scratch buffer to the decoding xdr_stream helps deal with those cases. The case where we saw this was actually due to behavior that's been fixed in newer gss-proxy versions, but we're fixing it here too. Signed-off-by: Scott Mayhew Cc: stable@vger.kernel.org Reviewed-by: Simo Sorce Signed-off-by: J. Bruce Fields

sunrpc: integer underflow in rsc_parse()

2015-02-26T20:40:16Z

If we call groups_alloc() with invalid values then it's might lead to memory corruption. For example, with a negative value then we might not allocate enough for sizeof(struct group_info). (We're doing this in the caller for consistency with other callers of groups_alloc(). The other alternative might be to move the check out of all the callers into groups_alloc().) Signed-off-by: Dan Carpenter Reviewed-by: Simo Sorce Signed-off-by: J. Bruce Fields

svcrpc: fix memory leak in gssp_accept_sec_context_upcall

2015-02-17T23:09:02Z

Our UC-KLEE tool found a kernel memory leak of 512 bytes (on x86_64) for each call to gssp_accept_sec_context_upcall() (net/sunrpc/auth_gss/gss_rpc_upcall.c). Since it appears that this call can be triggered by remote connections (at least, from a cursory a glance at the call chain), it may be exploitable to cause kernel memory exhaustion. We found the bug in kernel 3.16.3, but it appears to date back to commit 9dfd87da1aeb0fd364167ad199f40fe96a6a87be (2013-08-20). The gssp_accept_sec_context_upcall() function performs a pair of calls to gssp_alloc_receive_pages() and gssp_free_receive_pages(). The first allocates memory for arg->pages. The second then frees the pages pointed to by the arg->pages array, but not the array itself. Reported-by: David A. Ramos Fixes: 9dfd87da1aeb ("rpc: fix huge kmalloc's in gss-proxy”) Signed-off-by: David A. Ramos Signed-off-by: J. Bruce Fields

sunrpc: move rq_splice_ok flag into rq_flags

2014-12-09T16:22:21Z

Signed-off-by: Jeff Layton Signed-off-by: J. Bruce Fields

sunrpc: eliminate RPC_DEBUG

2014-11-24T22:31:46Z

It's always set to whatever CONFIG_SUNRPC_DEBUG is, so just use that. Signed-off-by: Jeff Layton Signed-off-by: Trond Myklebust