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[JFFS2] Don't trust node headers before the CRC is checked. 

Especially when summary code is used, we can have in-memory data
structures referencing certain nodes without them actually being readable
on the flash. Discard the nodes gracefully in that case, rather than
triggering a BUG().

Signed-off-by: David Woodhouse <dwmw2@infradead.org>
This commit is contained in:
David Woodhouse 2006-06-18 00:05:26 +01:00
parent 21c8db9eff
commit 3877f0b6c9
1 changed files with 37 additions and 31 deletions
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68
fs/jffs2/readinode.c
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@ -343,7 +343,7 @@ static inline int read_dnode(struct jffs2_sb_info *c, struct jffs2_raw_node_ref
* Helper function for jffs2_get_inode_nodes().
* It is called every time an unknown node is found.
*
* Returns: 0 on succes;
* Returns: 0 on success;
* 1 if the node should be marked obsolete;
* negative error code on failure.
*/
@ -354,37 +354,30 @@ static inline int read_unknown(struct jffs2_sb_info *c, struct jffs2_raw_node_re
un->nodetype = cpu_to_je16(JFFS2_NODE_ACCURATE | je16_to_cpu(un->nodetype));
if (crc32(0, un, sizeof(struct jffs2_unknown_node) - 4) != je32_to_cpu(un->hdr_crc)) {
/* Hmmm. This should have been caught at scan time. */
JFFS2_NOTICE("node header CRC failed at %#08x. But it must have been OK earlier.\n", ref_offset(ref));
jffs2_dbg_dump_node(c, ref_offset(ref));
switch(je16_to_cpu(un->nodetype) & JFFS2_COMPAT_MASK) {
case JFFS2_FEATURE_INCOMPAT:
JFFS2_ERROR("unknown INCOMPAT nodetype %#04X at %#08x\n",
je16_to_cpu(un->nodetype), ref_offset(ref));
/* EEP */
BUG();
break;
case JFFS2_FEATURE_ROCOMPAT:
JFFS2_ERROR("unknown ROCOMPAT nodetype %#04X at %#08x\n",
je16_to_cpu(un->nodetype), ref_offset(ref));
BUG_ON(!(c->flags & JFFS2_SB_FLAG_RO));
break;
case JFFS2_FEATURE_RWCOMPAT_COPY:
JFFS2_NOTICE("unknown RWCOMPAT_COPY nodetype %#04X at %#08x\n",
je16_to_cpu(un->nodetype), ref_offset(ref));
break;
case JFFS2_FEATURE_RWCOMPAT_DELETE:
JFFS2_NOTICE("unknown RWCOMPAT_DELETE nodetype %#04X at %#08x\n",
je16_to_cpu(un->nodetype), ref_offset(ref));
return 1;
} else {
switch(je16_to_cpu(un->nodetype) & JFFS2_COMPAT_MASK) {
case JFFS2_FEATURE_INCOMPAT:
JFFS2_ERROR("unknown INCOMPAT nodetype %#04X at %#08x\n",
je16_to_cpu(un->nodetype), ref_offset(ref));
/* EEP */
BUG();
break;
case JFFS2_FEATURE_ROCOMPAT:
JFFS2_ERROR("unknown ROCOMPAT nodetype %#04X at %#08x\n",
je16_to_cpu(un->nodetype), ref_offset(ref));
BUG_ON(!(c->flags & JFFS2_SB_FLAG_RO));
break;
case JFFS2_FEATURE_RWCOMPAT_COPY:
JFFS2_NOTICE("unknown RWCOMPAT_COPY nodetype %#04X at %#08x\n",
je16_to_cpu(un->nodetype), ref_offset(ref));
break;
case JFFS2_FEATURE_RWCOMPAT_DELETE:
JFFS2_NOTICE("unknown RWCOMPAT_DELETE nodetype %#04X at %#08x\n",
je16_to_cpu(un->nodetype), ref_offset(ref));
return 1;
}
}
return 0;
@ -549,6 +542,18 @@ static int jffs2_get_inode_nodes(struct jffs2_sb_info *c, struct jffs2_inode_inf
node = (union jffs2_node_union *)bufstart;
/* No need to mask in the valid bit; it shouldn't be invalid */
if (je32_to_cpu(node->u.hdr_crc) != crc32(0, node, sizeof(node->u)-4)) {
JFFS2_NOTICE("Node header CRC failed at %#08x. {%04x,%04x,%08x,%08x}\n",
ref_offset(ref), je16_to_cpu(node->u.magic),
je16_to_cpu(node->u.nodetype),
je32_to_cpu(node->u.totlen),
je32_to_cpu(node->u.hdr_crc));
jffs2_dbg_dump_node(c, ref_offset(ref));
jffs2_mark_node_obsolete(c, ref);
goto cont;
}
switch (je16_to_cpu(node->u.nodetype)) {
case JFFS2_NODETYPE_DIRENT:
@ -606,6 +611,7 @@ static int jffs2_get_inode_nodes(struct jffs2_sb_info *c, struct jffs2_inode_inf
goto free_out;
}
cont:
spin_lock(&c->erase_completion_lock);
}