[PATCH 05/15] spl: legacy: Honor bl_len when decompressing

Sean Anderson
2023-10-29T03:50:20Z

When allocating a buffer to load compressed data into, we need to ensure we
have enough space for over- and under-flow due to alignment. Otherwise we
will clobber the malloc bookkeeping data. Calculate the correct amount of
overhead and use it when determining the size.

Signed-off-by: Sean Anderson <seanga2@gmail.com>
---

common/spl/spl_legacy.c | 18 ++++++++++++------
1 file changed, 12 insertions(+), 6 deletions(-)

diff --git a/common/spl/spl_legacy.c b/common/spl/spl_legacy.c
index 51656fb9617..9189576b774 100644
--- a/common/spl/spl_legacy.c
+++ b/common/spl/spl_legacy.c
@@ -133,25 +133,31 @@ int spl_load_legacy_img(struct spl_image_info *spl_image,
map_sysmem(spl_image->load_addr, spl_image->size));
break;

- case IH_COMP_LZMA:
+ case IH_COMP_LZMA: {
+ ulong overhead, size;
+
lzma_len = LZMA_LEN;

/* dataptr points to compressed payload */
- dataptr = offset + sizeof(*hdr);
+ dataptr = ALIGN_DOWN(sizeof(*hdr), load->bl_len);
+ overhead = sizeof(*hdr) - dataptr;
+ size = ALIGN(spl_image->size + overhead, load->bl_len);
+ dataptr += offset;

debug("LZMA: Decompressing %08lx to %08lx\n",
dataptr, spl_image->load_addr);
- src = malloc(spl_image->size);
+ src = malloc(size);
if (!src) {
printf("Unable to allocate %d bytes for LZMA\n",
spl_image->size);
return -ENOMEM;
}

- load->read(load, dataptr, spl_image->size, src);
+ load->read(load, dataptr, size, src);
ret = lzmaBuffToBuffDecompress(map_sysmem(spl_image->load_addr,
spl_image->size),
- &lzma_len, src, spl_image->size);
+ &lzma_len, src + overhead,
+ spl_image->size);
if (ret) {
printf("LZMA decompression error: %d\n", ret);
return ret;
@@ -159,7 +165,7 @@ int spl_load_legacy_img(struct spl_image_info *spl_image,

spl_image->size = lzma_len;
break;
-
+ }
default:
debug("Compression method %s is not supported\n",
genimg_get_comp_short_name(image_get_comp(hdr)));
--
2.37.1