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authorJeff Layton <jlayton@redhat.com>2011-12-01 20:23:34 -0500
committerSteve French <smfrench@gmail.com>2011-12-08 22:04:47 -0600
commit7023676f9ee851d94f0942e879243fc1f9081c47 (patch)
tree6aac4d2bbaae57306fa320beb4282c380171a8e2
parent95edcff497b126a3f3e079e94b20fe2ca7e5a63d (diff)
cifs: check for NULL last_entry before calling cifs_save_resume_key
Prior to commit eaf35b1, cifs_save_resume_key had some NULL pointer checks at the top. It turns out that at least one of those NULL pointer checks is needed after all. When the LastNameOffset in a FIND reply appears to be beyond the end of the buffer, CIFSFindFirst and CIFSFindNext will set srch_inf.last_entry to NULL. Since eaf35b1, the code will now oops in this situation. Fix this by having the callers check for a NULL last entry pointer before calling cifs_save_resume_key. No change is needed for the call site in cifs_readdir as it's not reachable with a NULL current_entry pointer. This should fix: https://bugzilla.redhat.com/show_bug.cgi?id=750247 Cc: stable@vger.kernel.org Cc: Christoph Hellwig <hch@infradead.org> Reported-by: Adam G. Metzler <adamgmetzler@gmail.com> Signed-off-by: Jeff Layton <jlayton@redhat.com> Signed-off-by: Steve French <smfrench@gmail.com>
-rw-r--r--fs/cifs/readdir.c10
1 files changed, 8 insertions, 2 deletions
diff --git a/fs/cifs/readdir.c b/fs/cifs/readdir.c
index 5de03ec20144..a090bbe6ee29 100644
--- a/fs/cifs/readdir.c
+++ b/fs/cifs/readdir.c
@@ -554,7 +554,10 @@ static int find_cifs_entry(const int xid, struct cifs_tcon *pTcon,
rc);
return rc;
}
- cifs_save_resume_key(cifsFile->srch_inf.last_entry, cifsFile);
+ /* FindFirst/Next set last_entry to NULL on malformed reply */
+ if (cifsFile->srch_inf.last_entry)
+ cifs_save_resume_key(cifsFile->srch_inf.last_entry,
+ cifsFile);
}
while ((index_to_find >= cifsFile->srch_inf.index_of_last_entry) &&
@@ -562,7 +565,10 @@ static int find_cifs_entry(const int xid, struct cifs_tcon *pTcon,
cFYI(1, "calling findnext2");
rc = CIFSFindNext(xid, pTcon, cifsFile->netfid,
&cifsFile->srch_inf);
- cifs_save_resume_key(cifsFile->srch_inf.last_entry, cifsFile);
+ /* FindFirst/Next set last_entry to NULL on malformed reply */
+ if (cifsFile->srch_inf.last_entry)
+ cifs_save_resume_key(cifsFile->srch_inf.last_entry,
+ cifsFile);
if (rc)
return -ENOENT;
}