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authorMichael Brown <mcb30@ipxe.org>2016-01-27 23:27:47 +0000
committerMichael Brown <mcb30@ipxe.org>2016-01-27 23:27:47 +0000
commit4ddd3d99c36d1fd3e8a4b31c1814e7d82ca91081 (patch)
tree2c240072efff9c20c97792d4b19750fefff2cd08 /src
parentfef8e34b6f990de651002e00b60b2a6212369fb5 (diff)
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[slam] Avoid potential division by zero
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Diffstat (limited to 'src')
-rw-r--r--src/net/udp/slam.c20
1 files changed, 13 insertions, 7 deletions
diff --git a/src/net/udp/slam.c b/src/net/udp/slam.c
index 8b26bfb..8fcc976 100644
--- a/src/net/udp/slam.c
+++ b/src/net/udp/slam.c
@@ -415,6 +415,8 @@ static int slam_pull_value ( struct slam_request *slam,
static int slam_pull_header ( struct slam_request *slam,
struct io_buffer *iobuf ) {
void *header = iobuf->data;
+ unsigned long total_bytes;
+ unsigned long block_size;
int rc;
/* If header matches cached header, just pull it and return */
@@ -431,22 +433,26 @@ static int slam_pull_header ( struct slam_request *slam,
*/
if ( ( rc = slam_pull_value ( slam, iobuf, NULL ) ) != 0 )
return rc;
- if ( ( rc = slam_pull_value ( slam, iobuf,
- &slam->total_bytes ) ) != 0 )
+ if ( ( rc = slam_pull_value ( slam, iobuf, &total_bytes ) ) != 0 )
return rc;
- if ( ( rc = slam_pull_value ( slam, iobuf,
- &slam->block_size ) ) != 0 )
+ if ( ( rc = slam_pull_value ( slam, iobuf, &block_size ) ) != 0 )
return rc;
+ /* Sanity check */
+ if ( block_size == 0 ) {
+ DBGC ( slam, "SLAM %p ignoring zero block size\n", slam );
+ return -EINVAL;
+ }
+
/* Update the cached header */
slam->header_len = ( iobuf->data - header );
assert ( slam->header_len <= sizeof ( slam->header ) );
memcpy ( slam->header, header, slam->header_len );
/* Calculate number of blocks */
- slam->num_blocks = ( ( slam->total_bytes + slam->block_size - 1 ) /
- slam->block_size );
-
+ slam->total_bytes = total_bytes;
+ slam->block_size = block_size;
+ slam->num_blocks = ( ( total_bytes + block_size - 1 ) / block_size );
DBGC ( slam, "SLAM %p has total bytes %ld, block size %ld, num "
"blocks %ld\n", slam, slam->total_bytes, slam->block_size,
slam->num_blocks );