[Qemu-devel] [PATCH V2 2/3] spapr: Fix integer overflow during migration (TCG)

[Samuel Mendoza-Jonas <sam.mj@au1.ibm.com>]

The n_valid and n_invalid fields are unsigned short integers but it is
possible to have more than 65535 entries in a contiguous hunk, overflowing
the field. This results in an incorrect HTAB being sent to the destination
during migration.

Signed-off-by: Samuel Mendoza-Jonas <sam.mj@au1.ibm.com>
---
 hw/ppc/spapr.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index eb07343..10b7b00 100644
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -1045,7 +1045,7 @@ static void htab_save_first_pass(QEMUFile *f, sPAPREnvironment *spapr,
 
         /* Consume valid HPTEs */
         chunkstart = index;
-        while ((index < htabslots)
+        while ((index < htabslots) && (index - chunkstart < USHRT_MAX)
                && HPTE_VALID(HPTE(spapr->htab, index))) {
             index++;
             CLEAN_HPTE(HPTE(spapr->htab, index));
@@ -1097,7 +1097,7 @@ static int htab_save_later_pass(QEMUFile *f, sPAPREnvironment *spapr,
 
         chunkstart = index;
         /* Consume valid dirty HPTEs */
-        while ((index < htabslots)
+        while ((index < htabslots) && (index - chunkstart < USHRT_MAX)
                && HPTE_DIRTY(HPTE(spapr->htab, index))
                && HPTE_VALID(HPTE(spapr->htab, index))) {
             CLEAN_HPTE(HPTE(spapr->htab, index));
@@ -1107,7 +1107,7 @@ static int htab_save_later_pass(QEMUFile *f, sPAPREnvironment *spapr,
 
         invalidstart = index;
         /* Consume invalid dirty HPTEs */
-        while ((index < htabslots)
+        while ((index < htabslots) && (index - invalidstart < USHRT_MAX)
                && HPTE_DIRTY(HPTE(spapr->htab, index))
                && !HPTE_VALID(HPTE(spapr->htab, index))) {
             CLEAN_HPTE(HPTE(spapr->htab, index));
-- 
1.9.3