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authorDavid Howells <dhowells@redhat.com>2018-06-13 21:43:19 +0300
committerAl Viro <viro@zeniv.linux.org.uk>2018-06-15 07:48:57 +0300
commit24074a35c5c975c94cd9691ae962855333aac47f (patch)
tree1b59ef017c85f158edf696564fe441fa2356ca3e
parentde52cf922a4a17d0a4cd34d697db62a01c1bd092 (diff)
downloadlinux-24074a35c5c975c94cd9691ae962855333aac47f.tar.xz
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: Al Viro <viro@ZenIV.linux.org.uk> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
-rw-r--r--fs/proc/generic.c2
-rw-r--r--fs/proc/inode.c5
-rw-r--r--fs/proc/internal.h18
-rw-r--r--fs/proc/root.c3
4 files changed, 16 insertions, 12 deletions
diff --git a/fs/proc/generic.c b/fs/proc/generic.c
index d0e5a68ae14a..210bd4b16947 100644
--- a/fs/proc/generic.c
+++ b/fs/proc/generic.c
@@ -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);
diff --git a/fs/proc/inode.c b/fs/proc/inode.c
index 2cf3b74391ca..85ffbd27f288 100644
--- a/fs/proc/inode.c
+++ b/fs/proc/inode.c
@@ -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)
diff --git a/fs/proc/internal.h b/fs/proc/internal.h
index 916ccc39073d..d8d11fd9fdb0 100644
--- a/fs/proc/internal.h
+++ b/fs/proc/internal.h
@@ -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);
diff --git a/fs/proc/root.c b/fs/proc/root.c
index 61b7340b357a..f4b1a9d2eca6 100644
--- a/fs/proc/root.c
+++ b/fs/proc/root.c
@@ -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)