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@xxxxxxx> --- net/sunrpc/auth_gss/svcauth_gss.c | 2 ++ net/sunrpc/cache.c | 2 +- 2 files changed, 3 insertions(+), 1 deletion(-) diff --git a/net/sunrpc/auth_gss/svcauth_gss.c b/net/sunrpc/auth_gss/svcauth_gss.c index a81be45f40d9..e738c0182f09 100644 --- a/net/sunrpc/auth_gss/svcauth_gss.c +++ b/net/sunrpc/auth_gss/svcauth_gss.c @@ -194,6 +194,8 @@ static void rsi_request(struct cache_detail *cd, 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, diff --git a/net/sunrpc/cache.c b/net/sunrpc/cache.c index 1a2c1c44bb00..59641803472c 100644 --- a/net/sunrpc/cache.c +++ b/net/sunrpc/cache.c @@ -803,7 +803,7 @@ static int cache_request(struct cache_detail *detail, detail->cache_request(detail, crq->item, &bp, &len); if (len < 0) - return -EAGAIN; + return -E2BIG; return PAGE_SIZE - len; } -- 2.32.0
