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authorJeff Layton <jlayton@redhat.com>2010-02-10 16:18:26 -0500
committerSteve French <sfrench@us.ibm.com>2010-02-23 20:47:11 +0000
commit0cd126b504cede8a74acf7583a44eba32f9a1da1 (patch)
treec62a5835dbc50a2d5958a29ef511b349dff2842d /fs
parente529614ad0c2bf1f3a6fcf1402aa77430ecfaa2c (diff)
downloadconfigs-0cd126b504cede8a74acf7583a44eba32f9a1da1.tar.gz
cifs: verify lengths of QueryAllEAs reply
Make sure the lengths in a QUERY_ALL_EAS reply don't make the parser walk off the end of the SMB. Signed-off-by: Jeff Layton <jlayton@redhat.com> Signed-off-by: Steve French <sfrench@us.ibm.com>
Diffstat (limited to 'fs')
-rw-r--r--fs/cifs/cifssmb.c49
1 files changed, 31 insertions, 18 deletions
diff --git a/fs/cifs/cifssmb.c b/fs/cifs/cifssmb.c
index 4f24f83ce62..e197e1647d5 100644
--- a/fs/cifs/cifssmb.c
+++ b/fs/cifs/cifssmb.c
@@ -5285,6 +5285,7 @@ CIFSSMBQAllEAs(const int xid, struct cifsTconInfo *tcon,
struct fealist *ea_response_data;
struct fea *temp_fea;
char *temp_ptr;
+ char *end_of_smb;
__u16 params, byte_count, data_offset;
cFYI(1, ("In Query All EAs path %s", searchName));
@@ -5368,22 +5369,47 @@ QAllEAsRetry:
goto QAllEAsOut;
}
+ /* make sure list_len doesn't go past end of SMB */
+ end_of_smb = (char *)pByteArea(&pSMBr->hdr) + BCC(&pSMBr->hdr);
+ if ((char *)ea_response_data + list_len > end_of_smb) {
+ cFYI(1, ("EA list appears to go beyond SMB"));
+ rc = -EIO;
+ goto QAllEAsOut;
+ }
+
/* account for ea list len */
list_len -= 4;
temp_fea = ea_response_data->list;
temp_ptr = (char *)temp_fea;
while (list_len > 0) {
+ __u8 name_len;
__u16 value_len;
+
list_len -= 4;
temp_ptr += 4;
- rc += temp_fea->name_len;
+ /* make sure we can read name_len and value_len */
+ if (list_len < 0) {
+ cFYI(1, ("EA entry goes beyond length of list"));
+ rc = -EIO;
+ goto QAllEAsOut;
+ }
+
+ name_len = temp_fea->name_len;
+ value_len = le16_to_cpu(temp_fea->value_len);
+ list_len -= name_len + 1 + value_len;
+ if (list_len < 0) {
+ cFYI(1, ("EA entry goes beyond length of list"));
+ rc = -EIO;
+ goto QAllEAsOut;
+ }
+
/* account for prefix user. and trailing null */
- rc = rc + 5 + 1;
+ rc += (5 + 1 + name_len);
if (rc < (int) buf_size) {
memcpy(EAData, "user.", 5);
EAData += 5;
- memcpy(EAData, temp_ptr, temp_fea->name_len);
- EAData += temp_fea->name_len;
+ memcpy(EAData, temp_ptr, name_len);
+ EAData += name_len;
/* null terminate name */
*EAData = 0;
++EAData;
@@ -5394,20 +5420,7 @@ QAllEAsRetry:
rc = -ERANGE;
break;
}
- list_len -= temp_fea->name_len;
- temp_ptr += temp_fea->name_len;
- /* account for trailing null */
- list_len--;
- temp_ptr++;
- value_len = le16_to_cpu(temp_fea->value_len);
- list_len -= value_len;
- temp_ptr += value_len;
- /* BB check that temp_ptr is still
- within the SMB BB*/
-
- /* no trailing null to account for
- in value len */
- /* go on to next EA */
+ temp_ptr += name_len + 1 + value_len;
temp_fea = (struct fea *)temp_ptr;
}