From: Prasad J Pandit <p...@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-sys...@rub.de> Suggested-by: Philippe Mathieu-Daudé <f4...@amsat.org> Signed-off-by: Prasad J Pandit <p...@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; -- 2.26.2
