5.15-stable review patch. If anyone has any objections, please let me know.
------------------
From: Chris Mason <redacted>
commit f8870b9b75afb77986bc65940a231d54068ff2b1 upstream.
svcauth_gss_release() reads gc_proc and switches on gc_svc before
consulting rq_auth_stat. On the SVC_DENIED path after a failed
svcauth_gss_accept(), those fields may hold stale values from a
prior request or uninitialized slab residue: svcauth_gss_accept()
allocates gss_svc_data with non-zeroing kmalloc and clears only
gsd_databody_offset and rsci per request, not clcred.
Because RPC_GSS_PROC_DATA is zero, a zeroed or stale-zero gc_proc
passes the existing guard and falls through into the gc_svc switch,
which can dispatch to svcauth_gss_wrap_integ() or
svcauth_gss_wrap_priv(). Both wrap helpers call
svcauth_gss_prepare_to_wrap() before any rsci->mechctx dereference,
and that helper already returns early when rq_auth_stat is not
rpc_auth_ok, so the downstream NULL dereference is blocked. The
dispatch itself remains structurally wrong: it reads scalars that
the caller has no contract to have initialized after a failed
authentication.
Mirror the existing rq_auth_stat gate in
svcauth_gss_prepare_to_wrap() one frame up, so
svcauth_gss_release() skips the clcred dispatch entirely when
authentication has not succeeded. The cleanup tail that releases
rq_client, rq_gssclient, cr_group_info, and rsci still runs.
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Cc: <redacted>
Signed-off-by: Chris Mason <redacted>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Link: https://patch.msgid.link/20260528-tier2-v1-4-d026a1415e0b@oracle.com (local)
Signed-off-by: Chuck Lever <redacted>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
net/sunrpc/auth_gss/svcauth_gss.c | 2 ++
1 file changed, 2 insertions(+)
--- a/net/sunrpc/auth_gss/svcauth_gss.c
+++ b/net/sunrpc/auth_gss/svcauth_gss.c
@@ -1837,6 +1837,8 @@ svcauth_gss_release(struct svc_rqst *rqs
if (!gsd)
goto out;
+ if (rqstp->rq_auth_stat != rpc_auth_ok)
+ goto out;
gc = &gsd->clcred;
if (gc->gc_proc != RPC_GSS_PROC_DATA)
goto out;