esp: check dma length before reading scsi command(CVE-2016-4441)
The 53C9X Fast SCSI Controller(FSC) comes with an internal 16-byte
FIFO buffer. It is used to handle command and data transfer.
Routine get_cmd() uses DMA to read scsi commands into this buffer.
Add check to validate DMA length against buffer size to avoid any
overrun.
Fixes CVE-2016-4441.
Reported-by: Li Qiang <liqiang6-s@360.cn>
Cc: qemu-stable@nongnu.org
Signed-off-by: Prasad J Pandit <pjp@fedoraproject.org>
Message-Id: <1463654371-11169-3-git-send-email-ppandit@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
(cherry picked from commit 6c1fef6b59
)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
This commit is contained in:
parent
0a5e3685ea
commit
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@ -82,7 +82,7 @@ void esp_request_cancelled(SCSIRequest *req)
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}
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}
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static uint32_t get_cmd(ESPState *s, uint8_t *buf)
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static uint32_t get_cmd(ESPState *s, uint8_t *buf, uint8_t buflen)
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{
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uint32_t dmalen;
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int target;
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@ -92,6 +92,9 @@ static uint32_t get_cmd(ESPState *s, uint8_t *buf)
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dmalen = s->rregs[ESP_TCLO];
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dmalen |= s->rregs[ESP_TCMID] << 8;
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dmalen |= s->rregs[ESP_TCHI] << 16;
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if (dmalen > buflen) {
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return 0;
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}
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s->dma_memory_read(s->dma_opaque, buf, dmalen);
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} else {
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dmalen = s->ti_size;
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@ -166,7 +169,7 @@ static void handle_satn(ESPState *s)
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s->dma_cb = handle_satn;
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return;
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}
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len = get_cmd(s, buf);
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len = get_cmd(s, buf, sizeof(buf));
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if (len)
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do_cmd(s, buf);
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}
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@ -180,7 +183,7 @@ static void handle_s_without_atn(ESPState *s)
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s->dma_cb = handle_s_without_atn;
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return;
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}
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len = get_cmd(s, buf);
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len = get_cmd(s, buf, sizeof(buf));
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if (len) {
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do_busid_cmd(s, buf, 0);
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}
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@ -192,7 +195,7 @@ static void handle_satn_stop(ESPState *s)
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s->dma_cb = handle_satn_stop;
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return;
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}
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s->cmdlen = get_cmd(s, s->cmdbuf);
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s->cmdlen = get_cmd(s, s->cmdbuf, sizeof(s->cmdbuf));
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if (s->cmdlen) {
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trace_esp_handle_satn_stop(s->cmdlen);
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s->do_cmd = 1;
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