staging/lustre/llite: check for integer overflow in hsm user request

Check to make sure total size of request does not overflow when
calculated.  Return -1 from hur_len() if it does overflow.

Signed-off-by: Nathaniel Clark <nathaniel.l.clark@intel.com>
Reviewed-on: http://review.whamcloud.com/10615
Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-4984
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: John L. Hammond <john.hammond@intel.com>
Signed-off-by: Oleg Drokin <oleg.drokin@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/lustre/lustre/include/lustre/lustre_user.h b/drivers/staging/lustre/lustre/include/lustre/lustre_user.h
index a69b27a..4c1b3cb 100644 (file)
--- a/drivers/staging/lustre/lustre/include/lustre/lustre_user.h
+++ b/drivers/staging/lustre/lustre/include/lustre/lustre_user.h
@@ -997,12 +997,25 @@ static inline void *hur_data(struct hsm_user_request *hur)
        return &(hur->hur_user_item[hur->hur_request.hr_itemcount]);
 }
 
-/** Compute the current length of the provided hsm_user_request. */
-static inline int hur_len(struct hsm_user_request *hur)
+/**
+ * Compute the current length of the provided hsm_user_request.  This returns -1
+ * instead of an errno because ssize_t is defined to be only [ -1, SSIZE_MAX ]
+ *
+ * return -1 on bounds check error.
+ */
+static inline ssize_t hur_len(struct hsm_user_request *hur)
 {
-       return offsetof(struct hsm_user_request,
-                       hur_user_item[hur->hur_request.hr_itemcount]) +
-               hur->hur_request.hr_data_len;
+       __u64   size;
+
+       /* can't overflow a __u64 since hr_itemcount is only __u32 */
+       size = offsetof(struct hsm_user_request, hur_user_item[0]) +
+               (__u64)hur->hur_request.hr_itemcount *
+               sizeof(hur->hur_user_item[0]) + hur->hur_request.hr_data_len;
+
+       if (size != (ssize_t)size)
+               return -1;
+
+       return size;
 }
 
 /****** HSM RPCs to copytool *****/

diff --git a/drivers/staging/lustre/lustre/llite/dir.c b/drivers/staging/lustre/lustre/llite/dir.c
index efa2faf..de5892c 100644 (file)
--- a/drivers/staging/lustre/lustre/llite/dir.c
+++ b/drivers/staging/lustre/lustre/llite/dir.c
@@ -1787,7 +1787,7 @@ out_quotactl:
                return ll_fid2path(inode, (void *)arg);
        case LL_IOC_HSM_REQUEST: {
                struct hsm_user_request *hur;
-               int                      totalsize;
+               ssize_t                  totalsize;
 
                OBD_ALLOC_PTR(hur);
                if (hur == NULL)
@@ -1802,6 +1802,8 @@ out_quotactl:
                /* Compute the whole struct size */
                totalsize = hur_len(hur);
                OBD_FREE_PTR(hur);
+               if (totalsize < 0)
+                       return -E2BIG;
 
                /* Final size will be more than double totalsize */
                if (totalsize >= MDS_MAXREQSIZE / 3)