diff options
| -rw-r--r-- | fs/pidfs.c | 107 |
1 files changed, 103 insertions, 4 deletions
diff --git a/fs/pidfs.c b/fs/pidfs.c index df5bc69ea1c0..bde19614ef8b 100644 --- a/fs/pidfs.c +++ b/fs/pidfs.c @@ -21,6 +21,7 @@ #include <linux/utsname.h> #include <net/net_namespace.h> #include <linux/coredump.h> +#include <linux/xattr.h> #include "internal.h" #include "mount.h" @@ -28,6 +29,7 @@ #define PIDFS_PID_DEAD ERR_PTR(-ESRCH) static struct kmem_cache *pidfs_attr_cachep __ro_after_init; +static struct kmem_cache *pidfs_xattr_cachep __ro_after_init; /* * Stashes information that userspace needs to access even after the @@ -40,6 +42,7 @@ struct pidfs_exit_info { }; struct pidfs_attr { + struct simple_xattrs *xattrs; struct pidfs_exit_info __pei; struct pidfs_exit_info *exit_info; }; @@ -138,14 +141,27 @@ void pidfs_remove_pid(struct pid *pid) void pidfs_free_pid(struct pid *pid) { + struct pidfs_attr *attr __free(kfree) = no_free_ptr(pid->attr); + struct simple_xattrs *xattrs __free(kfree) = NULL; + /* * Any dentry must've been wiped from the pid by now. * Otherwise there's a reference count bug. */ VFS_WARN_ON_ONCE(pid->stashed); - if (!IS_ERR(pid->attr)) - kfree(pid->attr); + if (IS_ERR(attr)) + return; + + /* + * Any dentry must've been wiped from the pid by now. Otherwise + * there's a reference count bug. + */ + VFS_WARN_ON_ONCE(pid->stashed); + + xattrs = attr->xattrs; + if (xattrs) + simple_xattrs_free(attr->xattrs, NULL); } #ifdef CONFIG_PROC_FS @@ -663,9 +679,24 @@ static int pidfs_getattr(struct mnt_idmap *idmap, const struct path *path, return anon_inode_getattr(idmap, path, stat, request_mask, query_flags); } +static ssize_t pidfs_listxattr(struct dentry *dentry, char *buf, size_t size) +{ + struct inode *inode = d_inode(dentry); + struct pid *pid = inode->i_private; + struct pidfs_attr *attr = pid->attr; + struct simple_xattrs *xattrs; + + xattrs = READ_ONCE(attr->xattrs); + if (!xattrs) + return 0; + + return simple_xattr_list(inode, xattrs, buf, size); +} + static const struct inode_operations pidfs_inode_operations = { - .getattr = pidfs_getattr, - .setattr = pidfs_setattr, + .getattr = pidfs_getattr, + .setattr = pidfs_setattr, + .listxattr = pidfs_listxattr, }; static void pidfs_evict_inode(struct inode *inode) @@ -905,6 +936,67 @@ static const struct stashed_operations pidfs_stashed_ops = { .put_data = pidfs_put_data, }; +static int pidfs_xattr_get(const struct xattr_handler *handler, + struct dentry *unused, struct inode *inode, + const char *suffix, void *value, size_t size) +{ + struct pid *pid = inode->i_private; + struct pidfs_attr *attr = pid->attr; + const char *name; + struct simple_xattrs *xattrs; + + xattrs = READ_ONCE(attr->xattrs); + if (!xattrs) + return 0; + + name = xattr_full_name(handler, suffix); + return simple_xattr_get(xattrs, name, value, size); +} + +static int pidfs_xattr_set(const struct xattr_handler *handler, + struct mnt_idmap *idmap, struct dentry *unused, + struct inode *inode, const char *suffix, + const void *value, size_t size, int flags) +{ + struct pid *pid = inode->i_private; + struct pidfs_attr *attr = pid->attr; + const char *name; + struct simple_xattrs *xattrs; + struct simple_xattr *old_xattr; + + /* Ensure we're the only one to set @attr->xattrs. */ + WARN_ON_ONCE(!inode_is_locked(inode)); + + xattrs = READ_ONCE(attr->xattrs); + if (!xattrs) { + xattrs = kmem_cache_zalloc(pidfs_xattr_cachep, GFP_KERNEL); + if (!xattrs) + return -ENOMEM; + + simple_xattrs_init(xattrs); + smp_store_release(&pid->attr->xattrs, xattrs); + } + + name = xattr_full_name(handler, suffix); + old_xattr = simple_xattr_set(xattrs, name, value, size, flags); + if (IS_ERR(old_xattr)) + return PTR_ERR(old_xattr); + + simple_xattr_free(old_xattr); + return 0; +} + +static const struct xattr_handler pidfs_trusted_xattr_handler = { + .prefix = XATTR_TRUSTED_PREFIX, + .get = pidfs_xattr_get, + .set = pidfs_xattr_set, +}; + +static const struct xattr_handler *const pidfs_xattr_handlers[] = { + &pidfs_trusted_xattr_handler, + NULL +}; + static int pidfs_init_fs_context(struct fs_context *fc) { struct pseudo_fs_context *ctx; @@ -918,6 +1010,7 @@ static int pidfs_init_fs_context(struct fs_context *fc) ctx->ops = &pidfs_sops; ctx->eops = &pidfs_export_operations; ctx->dops = &pidfs_dentry_operations; + ctx->xattr = pidfs_xattr_handlers; fc->s_fs_info = (void *)&pidfs_stashed_ops; return 0; } @@ -960,6 +1053,12 @@ void __init pidfs_init(void) pidfs_attr_cachep = kmem_cache_create("pidfs_attr_cache", sizeof(struct pidfs_attr), 0, (SLAB_HWCACHE_ALIGN | SLAB_RECLAIM_ACCOUNT | SLAB_ACCOUNT | SLAB_PANIC), NULL); + + pidfs_xattr_cachep = kmem_cache_create("pidfs_xattr_cache", + sizeof(struct simple_xattrs), 0, + (SLAB_HWCACHE_ALIGN | SLAB_RECLAIM_ACCOUNT | + SLAB_ACCOUNT | SLAB_PANIC), NULL); + pidfs_mnt = kern_mount(&pidfs_type); if (IS_ERR(pidfs_mnt)) panic("Failed to mount pidfs pseudo filesystem"); |