From: NeilBrown <neilb@suse.de>
Date: Thu, 2 Sep 2021 09:30:37 +1000
Subject: [PATCH] SUNRPC: improve error response to over-size gss credential
Git-commit: 0c217d5066c84f67cd672cf03ec8f682e5d013c2
Patch-mainline: v5.15-rc1
References: bsc#1190022
When the NFS server receives a large gss (kerberos) credential and tries
to pass it up to rpc.svcgssd (which is deprecated), it triggers an
infinite loop in cache_read().
cache_request() always returns -EAGAIN, and this causes a "goto again".
This patch:
- changes the error to -E2BIG to avoid the infinite loop, and
- generates a WARN_ONCE when rsi_request first sees an over-sized
credential. The warning suggests switching to gssproxy.
Link: https://bugzilla.kernel.org/show_bug.cgi?id=196583
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Acked-by: NeilBrown <neilb@suse.com>
---
net/sunrpc/auth_gss/svcauth_gss.c | 2 ++
net/sunrpc/cache.c | 2 +-
2 files changed, 3 insertions(+), 1 deletion(-)
--- a/net/sunrpc/auth_gss/svcauth_gss.c
+++ b/net/sunrpc/auth_gss/svcauth_gss.c
@@ -180,6 +180,8 @@ static void rsi_request(struct cache_det
qword_addhex(bpp, blen, rsii->in_handle.data, rsii->in_handle.len);
qword_addhex(bpp, blen, rsii->in_token.data, rsii->in_token.len);
(*bpp)[-1] = '\n';
+ WARN_ONCE(*blen < 0,
+ "RPCSEC/GSS credential too large - please use gssproxy\n");
}
static int rsi_parse(struct cache_detail *cd,
--- a/net/sunrpc/cache.c
+++ b/net/sunrpc/cache.c
@@ -770,7 +770,7 @@ static int cache_request(struct cache_de
detail->cache_request(detail, crq->item, &bp, &len);
if (len < 0)
- return -EAGAIN;
+ return -E2BIG;
return PAGE_SIZE - len;
}