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firewire: fw-sbp2: add a boundary check

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Add rudimentary check for the case that the page table overflows due to
merging of s/g elements by the IOMMU.  This would have lead to
overwriting of arbitrary memory.

After this change I expect that an offending command will be
unsuccessfully retried until the scsi_device is taken offline by SCSI
core.  It's a border case and not worth to implement a recovery
strategy.

Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Acked-by: Kristian Høgsberg <krh@redhat.com>
This commit is contained in:
Stefan Richter 2007-07-01 13:56:03 +02:00
parent 9fb2dd12c0
commit 332ef3310b
1 changed files with 5 additions and 0 deletions
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5
drivers/firewire/fw-sbp2.c
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@ -937,6 +937,11 @@ static int sbp2_command_orb_map_scatterlist(struct sbp2_command_orb *orb)
sg_len = sg_dma_len(sg + i);
sg_addr = sg_dma_address(sg + i);
while (sg_len) {
/* FIXME: This won't get us out of the pinch. */
if (unlikely(j >= ARRAY_SIZE(orb->page_table))) {
fw_error("page table overflow\n");
goto fail_page_table;
}
l = min(sg_len, SBP2_MAX_SG_ELEMENT_LENGTH);
orb->page_table[j].low = sg_addr;
orb->page_table[j].high = (l << 16);