66 lines
2.5 KiB
Diff
66 lines
2.5 KiB
Diff
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References: bsc#983984 CVE-2016-5338
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The 53C9X Fast SCSI Controller(FSC) comes with internal 16-byte
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FIFO buffers. One is used to handle commands and other is for
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information transfer. Three control variables 'ti_rptr',
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'ti_wptr' and 'ti_size' are used to control r/w access to the
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information transfer buffer ti_buf[TI_BUFSZ=16]. In that,
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'ti_rptr' is used as read index, where read occurs.
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'ti_wptr' is a write index, where write would occur.
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'ti_size' indicates total bytes to be read from the buffer.
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While reading/writing to this buffer, index could exceed its
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size. Add check to avoid OOB r/w access.
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Reported-by: Huawei PSIRT <address@hidden>
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Reported-by: Li Qiang <address@hidden>
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Signed-off-by: Prasad J Pandit <address@hidden>
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---
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hw/scsi/esp.c | 20 +++++++++-----------
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1 file changed, 9 insertions(+), 11 deletions(-)
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Update as per:
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-> https://lists.gnu.org/archive/html/qemu-devel/2016-06/msg01326.html
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Index: xen-4.7.0-testing/tools/qemu-xen-traditional-dir-remote/hw/esp.c
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===================================================================
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--- xen-4.7.0-testing.orig/tools/qemu-xen-traditional-dir-remote/hw/esp.c
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+++ xen-4.7.0-testing/tools/qemu-xen-traditional-dir-remote/hw/esp.c
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@@ -435,18 +435,17 @@ static uint32_t esp_mem_readb(void *opaq
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DPRINTF("read reg[%d]: 0x%2.2x\n", saddr, s->rregs[saddr]);
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switch (saddr) {
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case ESP_FIFO:
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- if (s->ti_size > 0) {
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+ if ((s->rregs[ESP_RSTAT] & STAT_PIO_MASK) == 0) {
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+ /* Data out. */
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+ ESP_ERROR("PIO data read not implemented\n");
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+ s->rregs[ESP_FIFO] = 0;
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+ esp_raise_irq(s);
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+ } else if (s->ti_rptr < s->ti_wptr) {
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s->ti_size--;
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- if ((s->rregs[ESP_RSTAT] & STAT_PIO_MASK) == 0) {
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- /* Data out. */
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- ESP_ERROR("PIO data read not implemented\n");
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- s->rregs[ESP_FIFO] = 0;
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- } else {
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- s->rregs[ESP_FIFO] = s->ti_buf[s->ti_rptr++];
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- }
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+ s->rregs[ESP_FIFO] = s->ti_buf[s->ti_rptr++];
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esp_raise_irq(s);
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}
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- if (s->ti_size == 0) {
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+ if (s->ti_rptr == s->ti_wptr) {
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s->ti_rptr = 0;
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s->ti_wptr = 0;
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}
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@@ -482,7 +481,7 @@ static void esp_mem_writeb(void *opaque,
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} else {
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ESP_ERROR("fifo overrun\n");
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}
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- } else if (s->ti_size == TI_BUFSZ - 1) {
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+ } else if (s->ti_wptr == TI_BUFSZ - 1) {
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ESP_ERROR("fifo overrun\n");
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} else {
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s->ti_size++;
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