From c7258a4477b5ed0243c28ec107b98bb946757448 Mon Sep 17 00:00:00 2001 From: David Woodhouse Date: Fri, 9 Mar 2007 11:44:00 +0000 Subject: [PATCH] [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: David Woodhouse --- fs/jffs2/readinode.c | 16 +++++++++++++++- fs/jffs2/scan.c | 9 +++++++++ 2 files changed, 24 insertions(+), 1 deletion(-) diff --git a/fs/jffs2/readinode.c b/fs/jffs2/readinode.c index 58a0b912e9d0..717a48cf7df2 100644 --- a/fs/jffs2/readinode.c +++ b/fs/jffs2/readinode.c @@ -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)) { diff --git a/fs/jffs2/scan.c b/fs/jffs2/scan.c index 31c1475d922a..7fb45bd4915c 100644 --- a/fs/jffs2/scan.c +++ b/fs/jffs2/scan.c @@ -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) { -- GitLab