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Commit 24074a35 authored by David Howells's avatar David Howells Committed by Al Viro
Browse files

proc: Make inline name size calculation automatic 



Make calculation of the size of the inline name in struct proc_dir_entry
automatic, rather than having to manually encode the numbers and failing to
allow for lockdep.

Require a minimum inline name size of 33+1 to allow for names that look
like two hex numbers with a dash between.

Reported-by: default avatarAl Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent de52cf92

fs/proc/generic.c

+1 −1
Original line number Diff line number Diff line
@@ -410,7 +410,7 @@ static struct proc_dir_entry *__proc_create(struct proc_dir_entry **parent, 
	if (!ent)

		goto out;



	if (qstr.len + 1 <= sizeof(ent->inline_name)) {

	if (qstr.len + 1 <= SIZEOF_PDE_INLINE_NAME) {

		ent->name = ent->inline_name;

	} else {

		ent->name = kmalloc(qstr.len + 1, GFP_KERNEL);

fs/proc/inode.c

+2 −3
Original line number Diff line number Diff line
@@ -105,9 +105,8 @@ void __init proc_init_kmemcache(void) 
		kmem_cache_create("pde_opener", sizeof(struct pde_opener), 0,

				  SLAB_ACCOUNT|SLAB_PANIC, NULL);

	proc_dir_entry_cache = kmem_cache_create_usercopy(

		"proc_dir_entry", sizeof(struct proc_dir_entry), 0, SLAB_PANIC,

		offsetof(struct proc_dir_entry, inline_name),

		sizeof_field(struct proc_dir_entry, inline_name), NULL);

		"proc_dir_entry", SIZEOF_PDE_SLOT, 0, SLAB_PANIC,

		OFFSETOF_PDE_NAME, SIZEOF_PDE_INLINE_NAME, NULL);

}



static int proc_show_options(struct seq_file *seq, struct dentry *root)

fs/proc/internal.h

+12 −6
Original line number Diff line number Diff line
@@ -62,14 +62,20 @@ struct proc_dir_entry { 
	char *name;

	umode_t mode;

	u8 namelen;

#ifdef CONFIG_64BIT

#define SIZEOF_PDE_INLINE_NAME	(192-155)

#else

#define SIZEOF_PDE_INLINE_NAME	(128-95)

#endif

	char inline_name[SIZEOF_PDE_INLINE_NAME];

	char inline_name[];

} __randomize_layout;



#define OFFSETOF_PDE_NAME offsetof(struct proc_dir_entry, inline_name)

#define SIZEOF_PDE_SLOT					\

	(OFFSETOF_PDE_NAME + 34 <= 64 ? 64 :		\

	 OFFSETOF_PDE_NAME + 34 <= 128 ? 128 :		\

	 OFFSETOF_PDE_NAME + 34 <= 192 ? 192 :		\

	 OFFSETOF_PDE_NAME + 34 <= 256 ? 256 :		\

	 OFFSETOF_PDE_NAME + 34 <= 512 ? 512 :		\

	 0)



#define SIZEOF_PDE_INLINE_NAME (SIZEOF_PDE_SLOT - OFFSETOF_PDE_NAME)



extern struct kmem_cache *proc_dir_entry_cache;

void pde_free(struct proc_dir_entry *pde);

fs/proc/root.c

+1 −2
Original line number Diff line number Diff line
@@ -204,8 +204,7 @@ struct proc_dir_entry proc_root = { 
	.proc_fops	= &proc_root_operations,

	.parent		= &proc_root,

	.subdir		= RB_ROOT,

	.name		= proc_root.inline_name,

	.inline_name	= "/proc",

	.name		= "/proc",

};



int pid_ns_prepare_proc(struct pid_namespace *ns)