scsi: esp: check TI buffer index before read/write
The 53C9X Fast SCSI Controller(FSC) comes with internal 16-byte
FIFO buffers. One is used to handle commands and other is for
information transfer. Three control variables 'ti_rptr',
'ti_wptr' and 'ti_size' are used to control r/w access to the
information transfer buffer ti_buf[TI_BUFSZ=16]. In that,
'ti_rptr' is used as read index, where read occurs.
'ti_wptr' is a write index, where write would occur.
'ti_size' indicates total bytes to be read from the buffer.
While reading/writing to this buffer, index could exceed its
size. Add check to avoid OOB r/w access.
Reported-by: Huawei PSIRT <psirt@huawei.com>
Reported-by: Li Qiang <liqiang6-s@360.cn>
Signed-off-by: Prasad J Pandit <pjp@fedoraproject.org>
Message-Id: <1465230883-22303-1-git-send-email-ppandit@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
(cherry picked from commit ff589551c8
)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
stable-2.6
parent
407fb6fce9
commit
236039b89d
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@ -402,19 +402,17 @@ uint64_t esp_reg_read(ESPState *s, uint32_t saddr)
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trace_esp_mem_readb(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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qemu_log_mask(LOG_UNIMP, "esp: 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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qemu_log_mask(LOG_UNIMP,
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"esp: 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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@ -458,7 +456,7 @@ void esp_reg_write(ESPState *s, uint32_t saddr, uint64_t val)
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} else {
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trace_esp_error_fifo_overrun();
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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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trace_esp_error_fifo_overrun();
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} else {
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s->ti_size++;
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