The fragmented files were not correctly read because of two issues:
- The squashfs_file_info struct has a field named 'comp', which tells if the file's fragment is compressed or not. This field was always set to 'true' in sqfs_get_regfile_info and sqfs_get_lregfile_info. It should actually take sqfs_frag_lookup's return value. This patch addresses these two assignments.
- In sqfs_read, the fragments (compressed or not) were copied to the output buffer through a for loop which was reading data at the wrong offset. Replace these loops by equivalent calls to memcpy, with the right parameters.
I tested this patch by comparing the MD5 checksum of a few fragmented files with the respective md5sum output in sandbox, considering both compressed and uncompressed fragments.
Signed-off-by: Joao Marcos Costa jmcosta944@gmail.com --- fs/squashfs/sqfs.c | 16 ++++++---------- 1 file changed, 6 insertions(+), 10 deletions(-)
diff --git a/fs/squashfs/sqfs.c b/fs/squashfs/sqfs.c index 29805c3c6f..22ef4f2691 100644 --- a/fs/squashfs/sqfs.c +++ b/fs/squashfs/sqfs.c @@ -1253,7 +1253,7 @@ static int sqfs_get_regfile_info(struct squashfs_reg_inode *reg, fentry); if (ret < 0) return -EINVAL; - finfo->comp = true; + finfo->comp = ret; if (fentry->size < 1 || fentry->start == 0x7FFFFFFF) return -EINVAL; } else { @@ -1291,7 +1291,7 @@ static int sqfs_get_lregfile_info(struct squashfs_lreg_inode *lreg, fentry); if (ret < 0) return -EINVAL; - finfo->comp = true; + finfo->comp = ret; if (fentry->size < 1 || fentry->start == 0x7FFFFFFF) return -EINVAL; } else { @@ -1547,20 +1547,16 @@ int sqfs_read(const char *filename, void *buf, loff_t offset, loff_t len, goto out; }
- for (j = *actread; j < finfo.size; j++) { - memcpy(buf + j, &fragment_block[finfo.offset + j], 1); - (*actread)++; - } + memcpy(buf + *actread, &fragment_block[finfo.offset], finfo.size - *actread); + *actread = finfo.size;
free(fragment_block);
} else if (finfo.frag && !finfo.comp) { fragment_block = (void *)fragment + table_offset;
- for (j = *actread; j < finfo.size; j++) { - memcpy(buf + j, &fragment_block[finfo.offset + j], 1); - (*actread)++; - } + memcpy(buf + *actread, &fragment_block[finfo.offset], finfo.size - *actread); + *actread = finfo.size; }
out: