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scsi: esp: make cmdbuf big enough for maximum CDB size

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While doing DMA read into ESP command buffer 's->cmdbuf', it could
write past the 's->cmdbuf' area, if it was transferring more than 16
bytes.  Increase the command buffer size to 32, which is maximum when
's->do_cmd' is set, and add a check on 'len' to avoid OOB access.

Reported-by: Li Qiang <liqiang6-s@360.cn>
Signed-off-by: Prasad J Pandit <pjp@fedoraproject.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Prasad J Pandit 2016-06-16 00:22:35 +02:00 committed by Paolo Bonzini
parent 7f0b6e114a
commit 926cde5f3e
2 changed files with 6 additions and 3 deletions
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6
hw/scsi/esp.c
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@ -248,6 +248,8 @@ static void esp_do_dma(ESPState *s)
len = s->dma_left;
if (s->do_cmd) {
trace_esp_do_dma(s->cmdlen, len);
assert (s->cmdlen <= sizeof(s->cmdbuf) &&
len <= sizeof(s->cmdbuf) - s->cmdlen);
s->dma_memory_read(s->dma_opaque, &s->cmdbuf[s->cmdlen], len);
return;
}
@ -345,7 +347,7 @@ static void handle_ti(ESPState *s)
s->dma_counter = dmalen;
if (s->do_cmd)
minlen = (dmalen < 32) ? dmalen : 32;
minlen = (dmalen < ESP_CMDBUF_SZ) ? dmalen : ESP_CMDBUF_SZ;
else if (s->ti_size < 0)
minlen = (dmalen < -s->ti_size) ? dmalen : -s->ti_size;
else
@ -449,7 +451,7 @@ void esp_reg_write(ESPState *s, uint32_t saddr, uint64_t val)
break;
case ESP_FIFO:
if (s->do_cmd) {
if (s->cmdlen < TI_BUFSZ) {
if (s->cmdlen < ESP_CMDBUF_SZ) {
s->cmdbuf[s->cmdlen++] = val & 0xff;
} else {
trace_esp_error_fifo_overrun();

3
include/hw/scsi/esp.h
View File

@ -14,6 +14,7 @@ void esp_init(hwaddr espaddr, int it_shift,
#define ESP_REGS 16
#define TI_BUFSZ 16
#define ESP_CMDBUF_SZ 32
typedef struct ESPState ESPState;
@ -31,7 +32,7 @@ struct ESPState {
SCSIBus bus;
SCSIDevice *current_dev;
SCSIRequest *current_req;
uint8_t cmdbuf[TI_BUFSZ];
uint8_t cmdbuf[ESP_CMDBUF_SZ];
uint32_t cmdlen;
uint32_t do_cmd;