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fs/squashfs: fix reading of fragmented files

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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>
Tested-by: Richard Genoud <richard.genoud@posteo.net>
Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com>
This commit is contained in:
Joao Marcos Costa 2021-05-17 18:20:38 -03:00 committed by Tom Rini
parent 46704165f5
commit 0008d80866
1 changed files with 6 additions and 10 deletions
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16
fs/squashfs/sqfs.c
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@ -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: