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[JFFS2] Check for all-zero node headers

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Due to a poor choice of CRC32 seed, a node header which is all zeroes
would pass the CRC32 check. Explicitly check for this case, and treat it
as we do a CRC failure.

Signed-off-by: David Woodhouse <dwmw2@infradead.org>
This commit is contained in:
David Woodhouse 2007-03-09 11:44:00 +00:00
parent 470bc84436
commit c7258a4477
2 changed files with 24 additions and 1 deletions
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16
fs/jffs2/readinode.c
View File

@ -373,7 +373,14 @@ free_out:
static inline int read_unknown(struct jffs2_sb_info *c, struct jffs2_raw_node_ref *ref, struct jffs2_unknown_node *un)
{
/* We don't mark unknown nodes as REF_UNCHECKED */
BUG_ON(ref_flags(ref) == REF_UNCHECKED);
if (ref_flags(ref) == REF_UNCHECKED) {
JFFS2_ERROR("REF_UNCHECKED but unknown node at %#08x\n",
ref_offset(ref));
JFFS2_ERROR("Node is {%04x,%04x,%08x,%08x}. Please report this error.\n",
je16_to_cpu(un->magic), je16_to_cpu(un->nodetype),
je32_to_cpu(un->totlen), je32_to_cpu(un->hdr_crc));
return 1;
}
un->nodetype = cpu_to_je16(JFFS2_NODE_ACCURATE | je16_to_cpu(un->nodetype));
@ -576,6 +583,13 @@ static int jffs2_get_inode_nodes(struct jffs2_sb_info *c, struct jffs2_inode_inf
jffs2_mark_node_obsolete(c, ref);
goto cont;
}
/* Due to poor choice of crc32 seed, an all-zero node will have a correct CRC */
if (!je32_to_cpu(node->u.hdr_crc) && !je16_to_cpu(node->u.nodetype) &&
!je16_to_cpu(node->u.magic) && !je32_to_cpu(node->u.totlen)) {
JFFS2_NOTICE("All zero node header at %#08x.\n", ref_offset(ref));
jffs2_mark_node_obsolete(c, ref);
goto cont;
}
switch (je16_to_cpu(node->u.nodetype)) {

9
fs/jffs2/scan.c
View File

@ -734,6 +734,15 @@ scan_more:
ofs += 4;
continue;
}
/* Due to poor choice of crc32 seed, an all-zero node will have a correct CRC */
if (!je32_to_cpu(node->hdr_crc) && !je16_to_cpu(node->nodetype) &&
!je16_to_cpu(node->magic) && !je32_to_cpu(node->totlen)) {
noisy_printk(&noise, "jffs2_scan_eraseblock(): All zero node header at 0x%08x.\n", ofs);
if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
return err;
ofs += 4;
continue;
}
if (ofs + je32_to_cpu(node->totlen) >
jeb->offset + c->sector_size) {