[SCSI] scsi_debug: fix buffer overrun when DIF/DIX is enabled and virtual_gb > 0
If the module parameter virtual_gb is greater than 0, the READ command
may request the blocks which exceed actual ramdisk storage (fake_storep).
prot_verify_read() should treat those blocks as wrap around the end of
fake_storep. But it actually causes fake_storep and dif_storep buffer
overruns.
This fixes these buffer overruns. In order to simplify the fix,
this also introduces fake_store() and dif_store() which return
corresponding wrap around addresses.
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Acked-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
diff --git a/drivers/scsi/scsi_debug.c b/drivers/scsi/scsi_debug.c
index 01c0ffa..f640b6b 100644
--- a/drivers/scsi/scsi_debug.c
+++ b/drivers/scsi/scsi_debug.c
@@ -293,6 +293,20 @@
static unsigned char iec_m_pg[] = {0x1c, 0xa, 0x08, 0, 0, 0, 0, 0,
0, 0, 0x0, 0x0};
+static void *fake_store(unsigned long long lba)
+{
+ lba = do_div(lba, sdebug_store_sectors);
+
+ return fake_storep + lba * scsi_debug_sector_size;
+}
+
+static struct sd_dif_tuple *dif_store(sector_t sector)
+{
+ sector = do_div(sector, sdebug_store_sectors);
+
+ return dif_storep + sector;
+}
+
static int sdebug_add_adapter(void);
static void sdebug_remove_adapter(void);
@@ -1782,24 +1796,19 @@
struct scatterlist *psgl;
struct sd_dif_tuple *sdt;
sector_t sector;
- sector_t tmp_sec = start_sec;
void *paddr;
+ const void *dif_store_end = dif_storep + sdebug_store_sectors;
- start_sec = do_div(tmp_sec, sdebug_store_sectors);
-
- sdt = dif_storep + start_sec;
-
- for (i = 0 ; i < sectors ; i++) {
+ for (i = 0; i < sectors; i++) {
int ret;
- if (sdt[i].app_tag == 0xffff)
+ sector = start_sec + i;
+ sdt = dif_store(sector);
+
+ if (sdt->app_tag == 0xffff)
continue;
- sector = start_sec + i;
-
- ret = dif_verify(&sdt[i],
- fake_storep + sector * scsi_debug_sector_size,
- sector, ei_lba);
+ ret = dif_verify(sdt, fake_store(sector), sector, ei_lba);
if (ret) {
dif_errors++;
return ret;
@@ -1814,16 +1823,19 @@
scsi_for_each_prot_sg(SCpnt, psgl, scsi_prot_sg_count(SCpnt), i) {
int len = min(psgl->length, resid);
+ void *start = dif_store(sector);
+ int rest = 0;
+
+ if (dif_store_end < start + len)
+ rest = start + len - dif_store_end;
paddr = kmap_atomic(sg_page(psgl)) + psgl->offset;
- memcpy(paddr, dif_storep + sector, len);
+ memcpy(paddr, start, len - rest);
+
+ if (rest)
+ memcpy(paddr + len - rest, dif_storep, rest);
sector += len / sizeof(*dif_storep);
- if (sector >= sdebug_store_sectors) {
- /* Force wrap */
- tmp_sec = sector;
- sector = do_div(tmp_sec, sdebug_store_sectors);
- }
resid -= len;
kunmap_atomic(paddr);
}