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From 7262d3c7280343601ab3b0be0d469ffb867b86d7 Mon Sep 17 00:00:00 2001
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From: Markus Armbruster <armbru@redhat.com>
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Date: Fri, 31 Oct 2014 16:29:55 +0100
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Subject: [PATCH 18/19] ide: Treat read/write beyond end as invalid
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Message-id: <1414772996-17272-5-git-send-email-armbru@redhat.com>
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Patchwork-id: 62015
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O-Subject: [PATCH RHEL-7.1 qemu-kvm 4/5] ide: Treat read/write beyond end as invalid
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Bugzilla: 1085232
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RH-Acked-by: Paolo Bonzini <pbonzini@redhat.com>
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RH-Acked-by: Fam Zheng <famz@redhat.com>
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The block layer fails such reads and writes just fine.  However, they
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then get treated like valid operations that fail: the error action
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gets executed.  Unwanted; reporting the error to the guest is the only
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sensible action.
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Reject them before passing them to the block layer.  This bypasses the
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error action and I/O accounting.  Not quite correct for DMA, because
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DMA can fail after some success, and when that happens, the part that
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succeeded isn't counted.  Tolerable, because I/O accounting is an
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inconsistent mess anyway.
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Signed-off-by: Markus Armbruster <armbru@redhat.com>
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Signed-off-by: Kevin Wolf <kwolf@redhat.com>
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(cherry picked from commit 58ac321135af890b503ebe56d0d00e184779918f)
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Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
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---
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 hw/ide/core.c | 28 ++++++++++++++++++++++++++++
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 1 file changed, 28 insertions(+)
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diff --git a/hw/ide/core.c b/hw/ide/core.c
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index 98128fb..4c36f52 100644
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--- a/hw/ide/core.c
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+++ b/hw/ide/core.c
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@@ -513,6 +513,18 @@ static void ide_rw_error(IDEState *s) {
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     ide_set_irq(s->bus);
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 }
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+static bool ide_sect_range_ok(IDEState *s,
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+                              uint64_t sector, uint64_t nb_sectors)
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+{
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+    uint64_t total_sectors;
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+
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+    bdrv_get_geometry(s->bs, &total_sectors);
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+    if (sector > total_sectors || nb_sectors > total_sectors - sector) {
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+        return false;
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+    }
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+    return true;
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+}
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+
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 static void ide_sector_read_cb(void *opaque, int ret)
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 {
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     IDEState *s = opaque;
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@@ -568,6 +580,11 @@ void ide_sector_read(IDEState *s)
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     printf("sector=%" PRId64 "\n", sector_num);
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 #endif
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+    if (!ide_sect_range_ok(s, sector_num, n)) {
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+        ide_rw_error(s);
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+        return;
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+    }
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+
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     s->iov.iov_base = s->io_buffer;
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     s->iov.iov_len  = n * BDRV_SECTOR_SIZE;
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     qemu_iovec_init_external(&s->qiov, &s->iov, 1);
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@@ -685,6 +702,12 @@ void ide_dma_cb(void *opaque, int ret)
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            sector_num, n, s->dma_cmd);
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 #endif
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+    if (!ide_sect_range_ok(s, sector_num, n)) {
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+        dma_buf_commit(s);
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+        ide_dma_error(s);
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+        return;
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+    }
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+
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     switch (s->dma_cmd) {
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     case IDE_DMA_READ:
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         s->bus->dma->aiocb = dma_bdrv_read(s->bs, &s->sg, sector_num,
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@@ -804,6 +827,11 @@ void ide_sector_write(IDEState *s)
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         n = s->req_nb_sectors;
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     }
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+    if (!ide_sect_range_ok(s, sector_num, n)) {
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+        ide_rw_error(s);
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+        return;
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+    }
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+
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     s->iov.iov_base = s->io_buffer;
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     s->iov.iov_len  = n * BDRV_SECTOR_SIZE;
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     qemu_iovec_init_external(&s->qiov, &s->iov, 1);
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-- 
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1.8.3.1
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