Commit c7258a44 authored by David Woodhouse's avatar David Woodhouse
Browse files

[JFFS2] Check for all-zero node headers 



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: default avatarDavid Woodhouse <dwmw2@infradead.org>
parent 470bc844

fs/jffs2/readinode.c

+15 −1
Original line number Diff line number Diff line
@@ -373,7 +373,14 @@ static inline int read_dnode(struct jffs2_sb_info *c, struct jffs2_raw_node_ref 
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)) {

fs/jffs2/scan.c

+9 −0
Original line number Diff line number Diff line
@@ -734,6 +734,15 @@ static int jffs2_scan_eraseblock (struct jffs2_sb_info *c, struct jffs2_eraseblo 
			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) {