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authorPaulo Alcantara <pc@manguebit.com>2023-11-09 18:01:48 +0300
committerSteve French <stfrench@microsoft.com>2023-11-09 21:59:36 +0300
commit5e2fd17f434d2fed78efb123e2fc6711e4f598f1 (patch)
tree88e367dddba8103f114d732ce5f12be35f85a960 /fs
parent5923d6686a100c2b4cabd4c2ca9d5a12579c7614 (diff)
downloadlinux-5e2fd17f434d2fed78efb123e2fc6711e4f598f1.tar.xz
smb: client: fix mount when dns_resolver key is not available
There was a wrong assumption that with CONFIG_CIFS_DFS_UPCALL=y there would always be a dns_resolver key set up so we could unconditionally upcall to resolve UNC hostname rather than using the value provided by mount(2). Only require it when performing automount of junctions within a DFS share so users that don't have dns_resolver key still can mount their regular shares with server hostname resolved by mount.cifs(8). Fixes: 348a04a8d113 ("smb: client: get rid of dfs code dep in namespace.c") Cc: stable@vger.kernel.org Tested-by: Eduard Bachmakov <e.bachmakov@gmail.com> Reported-by: Eduard Bachmakov <e.bachmakov@gmail.com> Closes: https://lore.kernel.org/all/CADCRUiNvZuiUZ0VGZZO9HRyPyw6x92kiA7o7Q4tsX5FkZqUkKg@mail.gmail.com/ Signed-off-by: Paulo Alcantara (SUSE) <pc@manguebit.com> Signed-off-by: Steve French <stfrench@microsoft.com>
Diffstat (limited to 'fs')
-rw-r--r--fs/smb/client/dfs.c18
-rw-r--r--fs/smb/client/fs_context.h1
-rw-r--r--fs/smb/client/namespace.c17
3 files changed, 29 insertions, 7 deletions
diff --git a/fs/smb/client/dfs.c b/fs/smb/client/dfs.c
index 81b84151450d..a8a1d386da65 100644
--- a/fs/smb/client/dfs.c
+++ b/fs/smb/client/dfs.c
@@ -263,15 +263,23 @@ out:
return rc;
}
-/* Resolve UNC hostname in @ctx->source and set ip addr in @ctx->dstaddr */
+/*
+ * If @ctx->dfs_automount, then update @ctx->dstaddr earlier with the DFS root
+ * server from where we'll start following any referrals. Otherwise rely on the
+ * value provided by mount(2) as the user might not have dns_resolver key set up
+ * and therefore failing to upcall to resolve UNC hostname under @ctx->source.
+ */
static int update_fs_context_dstaddr(struct smb3_fs_context *ctx)
{
struct sockaddr *addr = (struct sockaddr *)&ctx->dstaddr;
- int rc;
+ int rc = 0;
- rc = dns_resolve_server_name_to_ip(ctx->source, addr, NULL);
- if (!rc)
- cifs_set_port(addr, ctx->port);
+ if (!ctx->nodfs && ctx->dfs_automount) {
+ rc = dns_resolve_server_name_to_ip(ctx->source, addr, NULL);
+ if (!rc)
+ cifs_set_port(addr, ctx->port);
+ ctx->dfs_automount = false;
+ }
return rc;
}
diff --git a/fs/smb/client/fs_context.h b/fs/smb/client/fs_context.h
index 9d8d34af0211..cf46916286d0 100644
--- a/fs/smb/client/fs_context.h
+++ b/fs/smb/client/fs_context.h
@@ -268,6 +268,7 @@ struct smb3_fs_context {
bool witness:1; /* use witness protocol */
char *leaf_fullpath;
struct cifs_ses *dfs_root_ses;
+ bool dfs_automount:1; /* set for dfs automount only */
};
extern const struct fs_parameter_spec smb3_fs_parameters[];
diff --git a/fs/smb/client/namespace.c b/fs/smb/client/namespace.c
index c8f5ed8a69f1..a6968573b775 100644
--- a/fs/smb/client/namespace.c
+++ b/fs/smb/client/namespace.c
@@ -117,6 +117,18 @@ cifs_build_devname(char *nodename, const char *prepath)
return dev;
}
+static bool is_dfs_mount(struct dentry *dentry)
+{
+ struct cifs_sb_info *cifs_sb = CIFS_SB(dentry->d_sb);
+ struct cifs_tcon *tcon = cifs_sb_master_tcon(cifs_sb);
+ bool ret;
+
+ spin_lock(&tcon->tc_lock);
+ ret = !!tcon->origin_fullpath;
+ spin_unlock(&tcon->tc_lock);
+ return ret;
+}
+
/* Return full path out of a dentry set for automount */
static char *automount_fullpath(struct dentry *dentry, void *page)
{
@@ -212,8 +224,9 @@ static struct vfsmount *cifs_do_automount(struct path *path)
ctx->source = NULL;
goto out;
}
- cifs_dbg(FYI, "%s: ctx: source=%s UNC=%s prepath=%s\n",
- __func__, ctx->source, ctx->UNC, ctx->prepath);
+ ctx->dfs_automount = is_dfs_mount(mntpt);
+ cifs_dbg(FYI, "%s: ctx: source=%s UNC=%s prepath=%s dfs_automount=%d\n",
+ __func__, ctx->source, ctx->UNC, ctx->prepath, ctx->dfs_automount);
mnt = fc_mount(fc);
out: