diff options
| -rw-r--r-- | fs/anon_inodes.c | 36 | ||||
| -rw-r--r-- | fs/internal.h | 3 | ||||
| -rw-r--r-- | fs/libfs.c | 8 |
3 files changed, 46 insertions, 1 deletions
diff --git a/fs/anon_inodes.c b/fs/anon_inodes.c index 583ac81669c2..42e4b9c34f89 100644 --- a/fs/anon_inodes.c +++ b/fs/anon_inodes.c @@ -24,10 +24,44 @@ #include <linux/uaccess.h> +#include "internal.h" + static struct vfsmount *anon_inode_mnt __ro_after_init; static struct inode *anon_inode_inode __ro_after_init; /* + * User space expects anonymous inodes to have no file type in st_mode. + * + * In particular, 'lsof' has this legacy logic: + * + * type = s->st_mode & S_IFMT; + * switch (type) { + * ... + * case 0: + * if (!strcmp(p, "anon_inode")) + * Lf->ntype = Ntype = N_ANON_INODE; + * + * to detect our old anon_inode logic. + * + * Rather than mess with our internal sane inode data, just fix it + * up here in getattr() by masking off the format bits. + */ +int anon_inode_getattr(struct mnt_idmap *idmap, const struct path *path, + struct kstat *stat, u32 request_mask, + unsigned int query_flags) +{ + struct inode *inode = d_inode(path->dentry); + + generic_fillattr(&nop_mnt_idmap, request_mask, inode, stat); + stat->mode &= ~S_IFMT; + return 0; +} + +static const struct inode_operations anon_inode_operations = { + .getattr = anon_inode_getattr, +}; + +/* * anon_inodefs_dname() is called from d_path(). */ static char *anon_inodefs_dname(struct dentry *dentry, char *buffer, int buflen) @@ -66,6 +100,7 @@ static struct inode *anon_inode_make_secure_inode( if (IS_ERR(inode)) return inode; inode->i_flags &= ~S_PRIVATE; + inode->i_op = &anon_inode_operations; error = security_inode_init_security_anon(inode, &QSTR(name), context_inode); if (error) { @@ -313,6 +348,7 @@ static int __init anon_inode_init(void) anon_inode_inode = alloc_anon_inode(anon_inode_mnt->mnt_sb); if (IS_ERR(anon_inode_inode)) panic("anon_inode_init() inode allocation failed (%ld)\n", PTR_ERR(anon_inode_inode)); + anon_inode_inode->i_op = &anon_inode_operations; return 0; } diff --git a/fs/internal.h b/fs/internal.h index b9b3e29a73fd..717dc9eb6185 100644 --- a/fs/internal.h +++ b/fs/internal.h @@ -343,3 +343,6 @@ static inline bool path_mounted(const struct path *path) void file_f_owner_release(struct file *file); bool file_seek_cur_needs_f_lock(struct file *file); int statmount_mnt_idmap(struct mnt_idmap *idmap, struct seq_file *seq, bool uid_map); +int anon_inode_getattr(struct mnt_idmap *idmap, const struct path *path, + struct kstat *stat, u32 request_mask, + unsigned int query_flags); diff --git a/fs/libfs.c b/fs/libfs.c index 6393d7c49ee6..e1146620346e 100644 --- a/fs/libfs.c +++ b/fs/libfs.c @@ -1647,7 +1647,13 @@ struct inode *alloc_anon_inode(struct super_block *s) * that it already _is_ on the dirty list. */ inode->i_state = I_DIRTY; - inode->i_mode = S_IRUSR | S_IWUSR; + /* + * Historically anonymous inodes didn't have a type at all and + * userspace has come to rely on this. Internally they're just + * regular files but S_IFREG is masked off when reporting + * information to userspace. + */ + inode->i_mode = S_IFREG | S_IRUSR | S_IWUSR; inode->i_uid = current_fsuid(); inode->i_gid = current_fsgid(); inode->i_flags |= S_PRIVATE; |