cifs: fix name parsing in CIFSSMBQAllEAs

The code that matches EA names in CIFSSMBQAllEAs is incorrect. It
uses strncmp to do the comparison with the length limited to the
name_len sent in the response.

Problem: Suppose we're looking for an attribute named "foobar" and
have an attribute before it in the EA list named "foo". The
comparison will succeed since we're only looking at the first 3
characters. Fix this by also comparing the length of the provided
ea_name with the name_len in the response. If they're not equal then
it shouldn't match.

Reported-by: Jian Li <jiali@redhat.com>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Reviewed-by: Pavel Shilovsky <piastryyy@gmail.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>

1 files changed, 7 insertions, 1 deletions

diff --git a/fs/cifs/cifssmb.c b/fs/cifs/cifssmb.c
index 1a9fe7f816d1..0580da1cf34c 100644
--- a/fs/cifs/cifssmb.c
+++ b/fs/cifs/cifssmb.c
@@ -5720,6 +5720,7 @@ CIFSSMBQAllEAs(const int xid, struct cifs_tcon *tcon,
         char *temp_ptr;
         char *end_of_smb;
         __u16 params, byte_count, data_offset;
+        unsigned int ea_name_len;
 
         cFYI(1, "In Query All EAs path %s", searchName);
 QAllEAsRetry:
@@ -5814,6 +5815,10 @@ QAllEAsRetry:
         list_len -= 4;
         temp_fea = ea_response_data->list;
         temp_ptr = (char *)temp_fea;
+
+        if (ea_name)
+                ea_name_len = strlen(ea_name);
+
         while (list_len > 0) {
                 unsigned int name_len;
                 __u16 value_len;
@@ -5837,7 +5842,8 @@ QAllEAsRetry:
                 }
 
                 if (ea_name) {
-                        if (strncmp(ea_name, temp_ptr, name_len) == 0) {
+                        if (ea_name_len == name_len &&
+                            strncmp(ea_name, temp_ptr, name_len) == 0) {
                                 temp_ptr += name_len + 1;
                                 rc = value_len;
                                 if (buf_size == 0)