| Message ID | 1466012179-31839-1-git-send-email-ppandit@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Hi, On (Wed) 15 Jun 2016 [23:06:19], P J P wrote: > From: Prasad J Pandit <pjp@fedoraproject.org> > > While doing DMA read into ESP command buffer 's->cmdbuf', it could > write past the 's->cmdbuf' area, if it was partially filled; > ie. 's->cmdlen' wasn't set at the start of the buffer. > Check 'len' to avoid OOB access. Also increase the command buffer > size to 32, which is maximum when 's->do_cmd' is set. > > Reported-by: Li Qiang <liqiang6-s@360.cn> > Signed-off-by: Prasad J Pandit <pjp@fedoraproject.org> [...] > diff --git a/include/hw/scsi/esp.h b/include/hw/scsi/esp.h > index 6c79527..d2c4886 100644 > --- a/include/hw/scsi/esp.h > +++ b/include/hw/scsi/esp.h > @@ -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]; This was flagged as an incompatibility in the vmstate by a nightly run of the vmstate checker: Section "esp" Description "esp" Field "cmdbuf" size mismatch: 16 , 32 Section "dc390" Description "esp" Field "cmdbuf" size mismatch: 16 , 32 Section "am53c974" Description "esp" Field "cmdbuf" size mismatch: 16 , 32 Amit
+-- On Fri, 17 Jun 2016, Amit Shah wrote --+ | This was flagged as an incompatibility in the vmstate by a nightly run | of the vmstate checker: | | Section "esp" Description "esp" Field "cmdbuf" size mismatch: 16 , 32 | Section "dc390" Description "esp" Field "cmdbuf" size mismatch: 16 , 32 | Section "am53c974" Description "esp" Field "cmdbuf" size mismatch: 16 , 32 Probably vmstate file needs to be regenerated? -- Prasad J Pandit / Red Hat Product Security Team 47AF CE69 3A90 54AA 9045 1053 DD13 3D32 FE5B 041F
On 17/06/2016 06:19, Amit Shah wrote: > Hi, > > On (Wed) 15 Jun 2016 [23:06:19], P J P wrote: >> From: Prasad J Pandit <pjp@fedoraproject.org> >> >> While doing DMA read into ESP command buffer 's->cmdbuf', it could >> write past the 's->cmdbuf' area, if it was partially filled; >> ie. 's->cmdlen' wasn't set at the start of the buffer. >> Check 'len' to avoid OOB access. Also increase the command buffer >> size to 32, which is maximum when 's->do_cmd' is set. >> >> Reported-by: Li Qiang <liqiang6-s@360.cn> >> Signed-off-by: Prasad J Pandit <pjp@fedoraproject.org> > > [...] > >> diff --git a/include/hw/scsi/esp.h b/include/hw/scsi/esp.h >> index 6c79527..d2c4886 100644 >> --- a/include/hw/scsi/esp.h >> +++ b/include/hw/scsi/esp.h >> @@ -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]; > > This was flagged as an incompatibility in the vmstate by a nightly run > of the vmstate checker: > > Section "esp" Description "esp" Field "cmdbuf" size mismatch: 16 , 32 > Section "dc390" Description "esp" Field "cmdbuf" size mismatch: 16 , 32 > Section "am53c974" Description "esp" Field "cmdbuf" size mismatch: 16 , 32 Oh, good catch. But from reading the spec the implementation was completely busted. Let's just drop handle_satn_stop, cmdbuf, cmdlen and do_cmd. Paolo
On 17/06/2016 10:16, P J P wrote: > +-- On Fri, 17 Jun 2016, Amit Shah wrote --+ > | This was flagged as an incompatibility in the vmstate by a nightly run > | of the vmstate checker: > | > | Section "esp" Description "esp" Field "cmdbuf" size mismatch: 16 , 32 > | Section "dc390" Description "esp" Field "cmdbuf" size mismatch: 16 , 32 > | Section "am53c974" Description "esp" Field "cmdbuf" size mismatch: 16 , 32 > > Probably vmstate file needs to be regenerated? No, that's not what that means. It means that your patch broke migration compatibility. I've posted a patch to just remove the code (which also has the effect of reverting your patch and mine). Paolo
diff --git a/hw/scsi/esp.c b/hw/scsi/esp.c index 4b94bbc..cc74ba8 100644 --- a/hw/scsi/esp.c +++ b/hw/scsi/esp.c @@ -249,6 +249,8 @@ 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); s->ti_size = 0; s->cmdlen = 0; @@ -348,7 +350,7 @@ 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 @@ -452,7 +454,7 @@ 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(); diff --git a/include/hw/scsi/esp.h b/include/hw/scsi/esp.h index 6c79527..d2c4886 100644 --- a/include/hw/scsi/esp.h +++ b/include/hw/scsi/esp.h @@ -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;