From: Ronnie Sahlberg <lsahlber@redhat.com>
To: linux-cifs <linux-cifs@vger.kernel.org>
Cc: Steve French <smfrench@gmail.com>
Subject: [PATCH] cifs: Do not leak EDEADLK to dgetents64 for STATUS_USER_SESSION_DELETED
Date: Wed, 25 Aug 2021 21:16:56 +1000 [thread overview]
Message-ID: <20210825111656.1635954-2-lsahlber@redhat.com> (raw)
In-Reply-To: <20210825111656.1635954-1-lsahlber@redhat.com>
RHBZ: 1994393
If we hit a STATUS_USER_SESSION_DELETED for the Create part in the
Create/QueryDirectory compound that starts a directory scan
we will leak EDEADLK back to userspace and surprise glibc and the application.
Pick this up initiate_cifs_search() and retry a small number of tries before we
return an error to userspace.
Cc: stable@vger.kernel.org
Reported-by: Xiaoli Feng <xifeng@redhat.com>
Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
---
fs/cifs/readdir.c | 19 ++++++++++++++++++-
1 file changed, 18 insertions(+), 1 deletion(-)
diff --git a/fs/cifs/readdir.c b/fs/cifs/readdir.c
index bfee176b901d..4518e3ca64df 100644
--- a/fs/cifs/readdir.c
+++ b/fs/cifs/readdir.c
@@ -369,7 +369,7 @@ int get_symlink_reparse_path(char *full_path, struct cifs_sb_info *cifs_sb,
*/
static int
-initiate_cifs_search(const unsigned int xid, struct file *file,
+_initiate_cifs_search(const unsigned int xid, struct file *file,
const char *full_path)
{
__u16 search_flags;
@@ -451,6 +451,23 @@ initiate_cifs_search(const unsigned int xid, struct file *file,
return rc;
}
+static int
+initiate_cifs_search(const unsigned int xid, struct file *file,
+ const char *full_path)
+{
+ int rc, retry_count = 0;
+
+ do {
+ rc = _initiate_cifs_search(xid, file, full_path);
+ /*
+ * We don't have enough credits to start reading the
+ * directory so just try again.
+ */
+ } while (rc == -EDEADLK && retry_count++ < 5);
+
+ return rc;
+}
+
/* return length of unicode string in bytes */
static int cifs_unicode_bytelen(const char *str)
{
--
2.30.2
next prev parent reply other threads:[~2021-08-25 11:17 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-25 11:16 [PATCH 0/1] don't leak EDEADLK to userspace Ronnie Sahlberg
2021-08-25 11:16 ` Ronnie Sahlberg [this message]
2021-08-25 21:09 ` [PATCH] cifs: Do not leak EDEADLK to dgetents64 for STATUS_USER_SESSION_DELETED Steve French
2021-08-26 17:15 ` Shyam Prasad N
2021-08-26 18:07 ` ronnie sahlberg
-- strict thread matches above, loose matches on Subject: below --
2021-08-25 7:30 [PATCH 0/1] cifs: do not leak EDEADLK to dgetents64 Ronnie Sahlberg
2021-08-25 7:30 ` [PATCH] cifs: Do not leak EDEADLK to dgetents64 for STATUS_USER_SESSION_DELETED Ronnie Sahlberg
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