[PATCH AUTOSEL 5.13 39/59] cifs: fix check of dfs interlinks

From: Sasha Levin
Date: Mon Jul 05 2021 - 11:29:59 EST


From: Paulo Alcantara <pc@xxxxxx>

[ Upstream commit 889c2a700799f3b6f82210925e1faf4a9b833c4a ]

Interlink is a special type of DFS link that resolves to a different
DFS domain-based namespace. To determine whether it is an interlink
or not, check if ReferralServers and StorageServers bits are set to 1
and 0 respectively in ReferralHeaderFlags, as specified in MS-DFSC
3.1.5.4.5 Determining Whether a Referral Response is an Interlink.

Signed-off-by: Paulo Alcantara (SUSE) <pc@xxxxxx>
Reviewed-by: Aurelien Aptel <aaptel@xxxxxxxx>
Signed-off-by: Steve French <stfrench@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
fs/cifs/dfs_cache.c | 7 +++----
1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/fs/cifs/dfs_cache.c b/fs/cifs/dfs_cache.c
index b1fa30fefe1f..8e16ee1e5fd1 100644
--- a/fs/cifs/dfs_cache.c
+++ b/fs/cifs/dfs_cache.c
@@ -25,8 +25,7 @@
#define CACHE_HTABLE_SIZE 32
#define CACHE_MAX_ENTRIES 64

-#define IS_INTERLINK_SET(v) ((v) & (DFSREF_REFERRAL_SERVER | \
- DFSREF_STORAGE_SERVER))
+#define IS_DFS_INTERLINK(v) (((v) & DFSREF_REFERRAL_SERVER) && !((v) & DFSREF_STORAGE_SERVER))

struct cache_dfs_tgt {
char *name;
@@ -171,7 +170,7 @@ static int dfscache_proc_show(struct seq_file *m, void *v)
"cache entry: path=%s,type=%s,ttl=%d,etime=%ld,hdr_flags=0x%x,ref_flags=0x%x,interlink=%s,path_consumed=%d,expired=%s\n",
ce->path, ce->srvtype == DFS_TYPE_ROOT ? "root" : "link",
ce->ttl, ce->etime.tv_nsec, ce->ref_flags, ce->hdr_flags,
- IS_INTERLINK_SET(ce->hdr_flags) ? "yes" : "no",
+ IS_DFS_INTERLINK(ce->hdr_flags) ? "yes" : "no",
ce->path_consumed, cache_entry_expired(ce) ? "yes" : "no");

list_for_each_entry(t, &ce->tlist, list) {
@@ -240,7 +239,7 @@ static inline void dump_ce(const struct cache_entry *ce)
ce->srvtype == DFS_TYPE_ROOT ? "root" : "link", ce->ttl,
ce->etime.tv_nsec,
ce->hdr_flags, ce->ref_flags,
- IS_INTERLINK_SET(ce->hdr_flags) ? "yes" : "no",
+ IS_DFS_INTERLINK(ce->hdr_flags) ? "yes" : "no",
ce->path_consumed,
cache_entry_expired(ce) ? "yes" : "no");
dump_tgts(ce);
--
2.30.2