Commit 5149fa47 authored by Michael Ellerman's avatar Michael Ellerman Committed by Paul Mackerras

[PATCH] powerpc: Cope with duplicate node & property names in /proc/device-tree

Various dodgy firmware might give us nodes and/or properties in the device
tree with conflicting names. That's generally ok, except for when we export
the device tree via /proc, so check when we're creating the proc device tree
and munge names accordingly.

Tested on a faked device tree with kexec, would be good if someone with
actual bogus firmware could try it, but just for completeness.
Signed-off-by: default avatarMichael Ellerman <michael@ellerman.id.au>
Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
parent d0160bf0
......@@ -52,7 +52,8 @@ static int property_read_proc(char *page, char **start, off_t off,
* Add a property to a node
*/
static struct proc_dir_entry *
__proc_device_tree_add_prop(struct proc_dir_entry *de, struct property *pp)
__proc_device_tree_add_prop(struct proc_dir_entry *de, struct property *pp,
const char *name)
{
struct proc_dir_entry *ent;
......@@ -60,14 +61,14 @@ __proc_device_tree_add_prop(struct proc_dir_entry *de, struct property *pp)
* Unfortunately proc_register puts each new entry
* at the beginning of the list. So we rearrange them.
*/
ent = create_proc_read_entry(pp->name,
strncmp(pp->name, "security-", 9)
ent = create_proc_read_entry(name,
strncmp(name, "security-", 9)
? S_IRUGO : S_IRUSR, de,
property_read_proc, pp);
if (ent == NULL)
return NULL;
if (!strncmp(pp->name, "security-", 9))
if (!strncmp(name, "security-", 9))
ent->size = 0; /* don't leak number of password chars */
else
ent->size = pp->length;
......@@ -78,7 +79,7 @@ __proc_device_tree_add_prop(struct proc_dir_entry *de, struct property *pp)
void proc_device_tree_add_prop(struct proc_dir_entry *pde, struct property *prop)
{
__proc_device_tree_add_prop(pde, prop);
__proc_device_tree_add_prop(pde, prop, prop->name);
}
void proc_device_tree_remove_prop(struct proc_dir_entry *pde,
......@@ -105,6 +106,69 @@ void proc_device_tree_update_prop(struct proc_dir_entry *pde,
}
}
/*
* Various dodgy firmware might give us nodes and/or properties with
* conflicting names. That's generally ok, except for exporting via /proc,
* so munge names here to ensure they're unique.
*/
static int duplicate_name(struct proc_dir_entry *de, const char *name)
{
struct proc_dir_entry *ent;
int found = 0;
spin_lock(&proc_subdir_lock);
for (ent = de->subdir; ent != NULL; ent = ent->next) {
if (strcmp(ent->name, name) == 0) {
found = 1;
break;
}
}
spin_unlock(&proc_subdir_lock);
return found;
}
static const char *fixup_name(struct device_node *np, struct proc_dir_entry *de,
const char *name)
{
char *fixed_name;
int fixup_len = strlen(name) + 2 + 1; /* name + #x + \0 */
int i = 1, size;
realloc:
fixed_name = kmalloc(fixup_len, GFP_KERNEL);
if (fixed_name == NULL) {
printk(KERN_ERR "device-tree: Out of memory trying to fixup "
"name \"%s\"\n", name);
return name;
}
retry:
size = snprintf(fixed_name, fixup_len, "%s#%d", name, i);
size++; /* account for NULL */
if (size > fixup_len) {
/* We ran out of space, free and reallocate. */
kfree(fixed_name);
fixup_len = size;
goto realloc;
}
if (duplicate_name(de, fixed_name)) {
/* Multiple duplicates. Retry with a different offset. */
i++;
goto retry;
}
printk(KERN_WARNING "device-tree: Duplicate name in %s, "
"renamed to \"%s\"\n", np->full_name, fixed_name);
return fixed_name;
}
/*
* Process a node, adding entries for its children and its properties.
*/
......@@ -118,37 +182,30 @@ void proc_device_tree_add_node(struct device_node *np,
set_node_proc_entry(np, de);
for (child = NULL; (child = of_get_next_child(np, child));) {
/* Use everything after the last slash, or the full name */
p = strrchr(child->full_name, '/');
if (!p)
p = child->full_name;
else
++p;
if (duplicate_name(de, p))
p = fixup_name(np, de, p);
ent = proc_mkdir(p, de);
if (ent == 0)
break;
proc_device_tree_add_node(child, ent);
}
of_node_put(child);
for (pp = np->properties; pp != 0; pp = pp->next) {
/*
* Yet another Apple device-tree bogosity: on some machines,
* they have properties & nodes with the same name. Those
* properties are quite unimportant for us though, thus we
* simply "skip" them here, but we do have to check.
*/
spin_lock(&proc_subdir_lock);
for (ent = de->subdir; ent != NULL; ent = ent->next)
if (!strcmp(ent->name, pp->name))
break;
spin_unlock(&proc_subdir_lock);
if (ent != NULL) {
printk(KERN_WARNING "device-tree: property \"%s\" name"
" conflicts with node in %s\n", pp->name,
np->full_name);
continue;
}
p = pp->name;
if (duplicate_name(de, p))
p = fixup_name(np, de, p);
ent = __proc_device_tree_add_prop(de, pp);
ent = __proc_device_tree_add_prop(de, pp, p);
if (ent == 0)
break;
}
......
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