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Blame 0213-scsi-disk-introduce-check_lba_range.patch

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From dd43bce420668dcde639c55bc792cedb1bb8c950 Mon Sep 17 00:00:00 2001
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From: Paolo Bonzini <pbonzini@redhat.com>
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Date: Wed, 5 Sep 2012 17:46:18 +0200
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Subject: [PATCH] scsi-disk: introduce check_lba_range
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Abstract the test for an out-of-range (starting block, block count)
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pair.
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Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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(cherry picked from commit 444bc908611ccaf4512dc37c33ac3b54d873a62b)
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Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
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---
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 hw/scsi-disk.c | 24 ++++++++++++++++--------
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 1 file changed, 16 insertions(+), 8 deletions(-)
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diff --git a/hw/scsi-disk.c b/hw/scsi-disk.c
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index 1585683..3959603 100644
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--- a/hw/scsi-disk.c
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+++ b/hw/scsi-disk.c
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@@ -1449,6 +1449,18 @@ invalid_field:
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     return;
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 }
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+static inline bool check_lba_range(SCSIDiskState *s,
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+                                   uint64_t sector_num, uint32_t nb_sectors)
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+{
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+    /*
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+     * The first line tests that no overflow happens when computing the last
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+     * sector.  The second line tests that the last accessed sector is in
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+     * range.
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+     */
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+    return (sector_num <= sector_num + nb_sectors &&
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+            sector_num + nb_sectors - 1 <= s->qdev.max_lba);
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+}
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+
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 typedef struct UnmapCBData {
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     SCSIDiskReq *r;
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     uint8_t *inbuf;
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@@ -1473,8 +1485,7 @@ static void scsi_unmap_complete(void *opaque, int ret)
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     if (data->count > 0 && !r->req.io_canceled) {
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         sector_num = ldq_be_p(&data->inbuf[0]);
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         nb_sectors = ldl_be_p(&data->inbuf[8]) & 0xffffffffULL;
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-        if (sector_num > sector_num + nb_sectors ||
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-            sector_num + nb_sectors - 1 > s->qdev.max_lba) {
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+        if (!check_lba_range(s, sector_num, nb_sectors)) {
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             scsi_check_condition(r, SENSE_CODE(LBA_OUT_OF_RANGE));
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             goto done;
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         }
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@@ -1802,8 +1813,7 @@ static int32_t scsi_disk_emulate_command(SCSIRequest *req, uint8_t *buf)
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             scsi_check_condition(r, SENSE_CODE(WRITE_PROTECTED));
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             return 0;
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         }
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-        if (r->req.cmd.lba > r->req.cmd.lba + nb_sectors ||
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-            r->req.cmd.lba + nb_sectors - 1 > s->qdev.max_lba) {
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+        if (!check_lba_range(s, r->req.cmd.lba, nb_sectors)) {
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             goto illegal_lba;
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         }
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@@ -1878,8 +1888,7 @@ static int32_t scsi_disk_dma_command(SCSIRequest *req, uint8_t *buf)
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         if (r->req.cmd.buf[1] & 0xe0) {
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             goto illegal_request;
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         }
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-        if (r->req.cmd.lba > r->req.cmd.lba + len ||
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-            r->req.cmd.lba + len - 1 > s->qdev.max_lba) {
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+        if (!check_lba_range(s, r->req.cmd.lba, len)) {
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             goto illegal_lba;
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         }
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         r->sector = r->req.cmd.lba * (s->qdev.blocksize / 512);
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@@ -1907,8 +1916,7 @@ static int32_t scsi_disk_dma_command(SCSIRequest *req, uint8_t *buf)
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         if (r->req.cmd.buf[1] & 0xe0) {
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             goto illegal_request;
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         }
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-        if (r->req.cmd.lba > r->req.cmd.lba + len ||
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-            r->req.cmd.lba + len - 1 > s->qdev.max_lba) {
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+        if (!check_lba_range(s, r->req.cmd.lba, len)) {
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             goto illegal_lba;
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         }
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         r->sector = r->req.cmd.lba * (s->qdev.blocksize / 512);
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-- 
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1.7.12.1
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