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spapr: fix out of bounds write in spapr_populate_drmem_v2

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buf_len is uint8_t which is not large enough to hold the result of:

  nr_entries * sizeof(struct sPAPRDrconfCellV2) + sizeof(uint32_t);

for a nr_entries greater than 10.

This causes the allocated buffer 'int_buf' to be smaller than expected
and we eventually overwrite some of glibc's control structures (see
"chunk" in https://sourceware.org/glibc/wiki/MallocInternals)

The following error is seen while trying to free int_buf:

  "free(): invalid next size (fast)"

Fixes: a324d6f166 "spapr: Support ibm,dynamic-memory-v2 property"
Signed-off-by: Fabiano Rosas <farosas@linux.ibm.com>
Message-Id: <20190213172926.21740-1-farosas@linux.ibm.com>
Reviewed-by: Greg Kurz <groug@kaod.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
This commit is contained in:
Fabiano Rosas 2019-02-13 15:29:26 -02:00 committed by David Gibson
parent 316aed6482
commit cc941111a5
1 changed files with 2 additions and 2 deletions
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4
hw/ppc/spapr.c
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@ -687,14 +687,14 @@ static int spapr_populate_drmem_v2(sPAPRMachineState *spapr, void *fdt,
int offset, MemoryDeviceInfoList *dimms)
{
MachineState *machine = MACHINE(spapr);
uint8_t *int_buf, *cur_index, buf_len;
uint8_t *int_buf, *cur_index;
int ret;
uint64_t lmb_size = SPAPR_MEMORY_BLOCK_SIZE;
uint64_t addr, cur_addr, size;
uint32_t nr_boot_lmbs = (machine->device_memory->base / lmb_size);
uint64_t mem_end = machine->device_memory->base +
memory_region_size(&machine->device_memory->mr);
uint32_t node, nr_entries = 0;
uint32_t node, buf_len, nr_entries = 0;
sPAPRDRConnector *drc;
DrconfCellQueue *elem, *next;
MemoryDeviceInfoList *info;