| Message ID | 20200903070842.2125083-1-ppandit@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v1] sd: sdhci: assert data_count is within fifo_buffer | expand |
On 9/3/20 9:08 AM, P J P wrote: > From: Prasad J Pandit <pjp@fedoraproject.org> > > While doing multi block SDMA, transfer block size may exceed > the 's->fifo_buffer[s->buf_maxsz]' size. It may leave the > current element pointer 's->data_count' pointing out of bounds. > Leading the subsequent DMA r/w operation to OOB access issue. > Assert that 's->data_count' is within fifo_buffer. > > -> https://ruhr-uni-bochum.sciebo.de/s/NNWP2GfwzYKeKwE?path=%2Fsdhci_oob_write1 > ==1459837==ERROR: AddressSanitizer: heap-buffer-overflow > WRITE of size 54722048 at 0x61500001e280 thread T3 > #0 __interceptor_memcpy (/lib64/libasan.so.6+0x3a71d) > #1 flatview_read_continue ../exec.c:3245 > #2 flatview_read ../exec.c:3278 > #3 address_space_read_full ../exec.c:3291 > #4 address_space_rw ../exec.c:3319 > #5 dma_memory_rw_relaxed ../include/sysemu/dma.h:87 > #6 dma_memory_rw ../include/sysemu/dma.h:110 > #7 dma_memory_read ../include/sysemu/dma.h:116 > #8 sdhci_sdma_transfer_multi_blocks ../hw/sd/sdhci.c:629 > #9 sdhci_write ../hw/sd/sdhci.c:1097 > #10 memory_region_write_accessor ../softmmu/memory.c:483 > ... > > Reported-by: Ruhr-University <bugs-syssec@rub.de> > Suggested-by: Philippe Mathieu-Daudé <f4bug@amsat.org> > Signed-off-by: Prasad J Pandit <pjp@fedoraproject.org> > --- > hw/sd/sdhci.c | 2 ++ > 1 file changed, 2 insertions(+) > > Update v1: use assert(3) calls > -> https://lists.nongnu.org/archive/html/qemu-devel/2020-09/msg00966.html > > diff --git a/hw/sd/sdhci.c b/hw/sd/sdhci.c > index 1785d7e1f7..023acbed41 100644 > --- a/hw/sd/sdhci.c > +++ b/hw/sd/sdhci.c > @@ -604,6 +604,7 @@ static void sdhci_sdma_transfer_multi_blocks(SDHCIState *s) > s->blkcnt--; > } > } > + assert(s->data_count <= s->buf_maxsz && s->data_count > begin); > dma_memory_write(s->dma_as, s->sdmasysad, > &s->fifo_buffer[begin], s->data_count - begin); > s->sdmasysad += s->data_count - begin; > @@ -626,6 +627,7 @@ static void sdhci_sdma_transfer_multi_blocks(SDHCIState *s) > s->data_count = block_size; > boundary_count -= block_size - begin; > } > + assert(s->data_count <= s->buf_maxsz && s->data_count > begin); > dma_memory_read(s->dma_as, s->sdmasysad, > &s->fifo_buffer[begin], s->data_count - begin); > s->sdmasysad += s->data_count - begin; > qemu-system-i386: hw/sd/sdhci.c:632: void sdhci_sdma_transfer_multi_blocks(SDHCIState *): Assertion `s->data_count <= s->buf_maxsz && s->data_count > begin' failed. Tested-by: Philippe Mathieu-Daudé <f4bug@amsat.org> If you don't mind I might split the assert in 2 when applying: - assert(s->data_count <= s->buf_maxsz && s->data_count > begin); + assert(s->data_count <= s->buf_maxsz); + assert(s->data_count > begin); To directly display the problem straight: qemu-system-i386: hw/sd/sdhci.c:635: void sdhci_sdma_transfer_multi_blocks(SDHCIState *): Assertion `s->data_count > begin' failed. Thanks, Phil.
On 9/3/20 4:01 PM, Philippe Mathieu-Daudé wrote: > On 9/3/20 9:08 AM, P J P wrote: >> From: Prasad J Pandit <pjp@fedoraproject.org> >> >> While doing multi block SDMA, transfer block size may exceed >> the 's->fifo_buffer[s->buf_maxsz]' size. It may leave the >> current element pointer 's->data_count' pointing out of bounds. >> Leading the subsequent DMA r/w operation to OOB access issue. >> Assert that 's->data_count' is within fifo_buffer. >> >> -> https://ruhr-uni-bochum.sciebo.de/s/NNWP2GfwzYKeKwE?path=%2Fsdhci_oob_write1 >> ==1459837==ERROR: AddressSanitizer: heap-buffer-overflow >> WRITE of size 54722048 at 0x61500001e280 thread T3 >> #0 __interceptor_memcpy (/lib64/libasan.so.6+0x3a71d) >> #1 flatview_read_continue ../exec.c:3245 >> #2 flatview_read ../exec.c:3278 >> #3 address_space_read_full ../exec.c:3291 >> #4 address_space_rw ../exec.c:3319 >> #5 dma_memory_rw_relaxed ../include/sysemu/dma.h:87 >> #6 dma_memory_rw ../include/sysemu/dma.h:110 >> #7 dma_memory_read ../include/sysemu/dma.h:116 >> #8 sdhci_sdma_transfer_multi_blocks ../hw/sd/sdhci.c:629 >> #9 sdhci_write ../hw/sd/sdhci.c:1097 >> #10 memory_region_write_accessor ../softmmu/memory.c:483 >> ... >> >> Reported-by: Ruhr-University <bugs-syssec@rub.de> >> Suggested-by: Philippe Mathieu-Daudé <f4bug@amsat.org> >> Signed-off-by: Prasad J Pandit <pjp@fedoraproject.org> >> --- >> hw/sd/sdhci.c | 2 ++ >> 1 file changed, 2 insertions(+) >> >> Update v1: use assert(3) calls >> -> https://lists.nongnu.org/archive/html/qemu-devel/2020-09/msg00966.html >> >> diff --git a/hw/sd/sdhci.c b/hw/sd/sdhci.c >> index 1785d7e1f7..023acbed41 100644 >> --- a/hw/sd/sdhci.c >> +++ b/hw/sd/sdhci.c >> @@ -604,6 +604,7 @@ static void sdhci_sdma_transfer_multi_blocks(SDHCIState *s) >> s->blkcnt--; >> } >> } >> + assert(s->data_count <= s->buf_maxsz && s->data_count > begin); >> dma_memory_write(s->dma_as, s->sdmasysad, >> &s->fifo_buffer[begin], s->data_count - begin); >> s->sdmasysad += s->data_count - begin; >> @@ -626,6 +627,7 @@ static void sdhci_sdma_transfer_multi_blocks(SDHCIState *s) >> s->data_count = block_size; >> boundary_count -= block_size - begin; >> } >> + assert(s->data_count <= s->buf_maxsz && s->data_count > begin); >> dma_memory_read(s->dma_as, s->sdmasysad, >> &s->fifo_buffer[begin], s->data_count - begin); >> s->sdmasysad += s->data_count - begin; >> > > qemu-system-i386: hw/sd/sdhci.c:632: void > sdhci_sdma_transfer_multi_blocks(SDHCIState *): Assertion `s->data_count > <= s->buf_maxsz && s->data_count > begin' failed. > > Tested-by: Philippe Mathieu-Daudé <f4bug@amsat.org> > > If you don't mind I might split the assert in 2 when applying: > > - assert(s->data_count <= s->buf_maxsz && s->data_count > begin); > + assert(s->data_count <= s->buf_maxsz); > + assert(s->data_count > begin); Doesn't seem enough, guest crash here, having: (gdb) p begin $1 = 0 (gdb) p s->data_count $2 = 0 (gdb) p s->blksize $3 = 0 Beh, something is wrong in this model, because when using ADMA2 length 0 means 65536 bytes (see '1.13.4. Descriptor Table' in "SD Host Controller Simplified Specification Version 2.00").
+-- On Thu, 3 Sep 2020, Philippe Mathieu-Daudé wrote --+
| > - assert(s->data_count <= s->buf_maxsz && s->data_count > begin);
| > + assert(s->data_count <= s->buf_maxsz);
| > + assert(s->data_count > begin);
|
| Doesn't seem enough, guest crash here, having:
|
| (gdb) p begin
| $1 = 0
| (gdb) p s->data_count
| $2 = 0
I was actually thinking of a case if 's->data_count' and 'begin' are same? It
may lead to an infinite loop condition.
| (gdb) p s->blksize
| $3 = 0
This is strange.
| Beh, something is wrong in this model, because when using ADMA2
| length 0 means 65536 bytes (see '1.13.4. Descriptor Table' in
| "SD Host Controller Simplified Specification Version 2.00").
* DMA length 's->data_count - begin'?
* if s->blksize is 65536, it'd set 'block_size = 0' in transfer_multi_blocks()
#define BLOCK_SIZE_MASK (4 * KiB - 1) <== 0xFFF
static void sdhci_sdma_transfer_multi_blocks(SDHCIState *s)
{
...
const uint16_t block_size = s->blksize & BLOCK_SIZE_MASK; <== 0
Thank you.
--
Prasad J Pandit / Red Hat Product Security Team
8685 545E B54C 486B C6EB 271E E285 8B5A F050 DE8D
+-- On Thu, 3 Sep 2020, Philippe Mathieu-Daudé wrote --+ | If you don't mind I might split the assert in 2 when applying: | | - assert(s->data_count <= s->buf_maxsz && s->data_count > begin); | + assert(s->data_count <= s->buf_maxsz); | + assert(s->data_count > begin); Sure, np. Thank you. -- Prasad J Pandit / Red Hat Product Security Team 8685 545E B54C 486B C6EB 271E E285 8B5A F050 DE8D
diff --git a/hw/sd/sdhci.c b/hw/sd/sdhci.c index 1785d7e1f7..023acbed41 100644 --- a/hw/sd/sdhci.c +++ b/hw/sd/sdhci.c @@ -604,6 +604,7 @@ static void sdhci_sdma_transfer_multi_blocks(SDHCIState *s) s->blkcnt--; } } + assert(s->data_count <= s->buf_maxsz && s->data_count > begin); dma_memory_write(s->dma_as, s->sdmasysad, &s->fifo_buffer[begin], s->data_count - begin); s->sdmasysad += s->data_count - begin; @@ -626,6 +627,7 @@ static void sdhci_sdma_transfer_multi_blocks(SDHCIState *s) s->data_count = block_size; boundary_count -= block_size - begin; } + assert(s->data_count <= s->buf_maxsz && s->data_count > begin); dma_memory_read(s->dma_as, s->sdmasysad, &s->fifo_buffer[begin], s->data_count - begin); s->sdmasysad += s->data_count - begin;