Add two simple helpers to check permissions on a file and path respectively and convert over some callers. It simplifies quite a few codepaths and also reduces the churn in later patches quite a bit. Christoph also correctly points out that this makes codepaths (e.g. ioctls) way easier to follow that would otherwise have to do more complex argument passing than necessary. Link: https://lore.kernel.org/r/20210112220124.837960-16-christian.brauner@xxxxxxxxxx Cc: David Howells <dhowells@xxxxxxxxxx> Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx> Cc: linux-fsdevel@xxxxxxxxxxxxxxx Suggested-by: Christoph Hellwig <hch@xxxxxx> Reviewed-by: Christoph Hellwig <hch@xxxxxx> Signed-off-by: Christian Brauner <christian.brauner@xxxxxxxxxx> --- /* v2 */ patch not present /* v3 */ patch not present /* v4 */ patch not present /* v5 */ patch not present /* v6 */ base-commit: 19c329f6808995b142b3966301f217c831e7cf31 - Christoph Hellwig <hch@xxxxxx>: - Make file_user_ns() static inline. - Add file_permission() and path_permission() helpers. --- fs/init.c | 6 +++--- fs/notify/fanotify/fanotify_user.c | 2 +- fs/notify/inotify/inotify_user.c | 2 +- fs/open.c | 6 +++--- fs/udf/file.c | 2 +- fs/verity/enable.c | 2 +- include/linux/fs.h | 8 ++++++++ kernel/bpf/inode.c | 2 +- kernel/sys.c | 2 +- mm/madvise.c | 2 +- mm/memcontrol.c | 2 +- mm/mincore.c | 2 +- net/unix/af_unix.c | 2 +- 13 files changed, 24 insertions(+), 16 deletions(-) diff --git a/fs/init.c b/fs/init.c index e9c320a48cf1..02723bea8499 100644 --- a/fs/init.c +++ b/fs/init.c @@ -49,7 +49,7 @@ int __init init_chdir(const char *filename) error = kern_path(filename, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, &path); if (error) return error; - error = inode_permission(path.dentry->d_inode, MAY_EXEC | MAY_CHDIR); + error = path_permission(&path, MAY_EXEC | MAY_CHDIR); if (!error) set_fs_pwd(current->fs, &path); path_put(&path); @@ -64,7 +64,7 @@ int __init init_chroot(const char *filename) error = kern_path(filename, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, &path); if (error) return error; - error = inode_permission(path.dentry->d_inode, MAY_EXEC | MAY_CHDIR); + error = path_permission(&path, MAY_EXEC | MAY_CHDIR); if (error) goto dput_and_out; error = -EPERM; @@ -118,7 +118,7 @@ int __init init_eaccess(const char *filename) error = kern_path(filename, LOOKUP_FOLLOW, &path); if (error) return error; - error = inode_permission(d_inode(path.dentry), MAY_ACCESS); + error = path_permission(&path, MAY_ACCESS); path_put(&path); return error; } diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c index dcab112e1f00..64cfc1a3015d 100644 --- a/fs/notify/fanotify/fanotify_user.c +++ b/fs/notify/fanotify/fanotify_user.c @@ -702,7 +702,7 @@ static int fanotify_find_path(int dfd, const char __user *filename, } /* you can only watch an inode if you have read permissions on it */ - ret = inode_permission(path->dentry->d_inode, MAY_READ); + ret = path_permission(path, MAY_READ); if (ret) { path_put(path); goto out; diff --git a/fs/notify/inotify/inotify_user.c b/fs/notify/inotify/inotify_user.c index 59c177011a0f..e1155d32ef6f 100644 --- a/fs/notify/inotify/inotify_user.c +++ b/fs/notify/inotify/inotify_user.c @@ -352,7 +352,7 @@ static int inotify_find_inode(const char __user *dirname, struct path *path, if (error) return error; /* you can only watch an inode if you have read permissions on it */ - error = inode_permission(path->dentry->d_inode, MAY_READ); + error = path_permission(path, MAY_READ); if (error) { path_put(path); return error; diff --git a/fs/open.c b/fs/open.c index 1e06e443a565..cd1efd254cad 100644 --- a/fs/open.c +++ b/fs/open.c @@ -492,7 +492,7 @@ SYSCALL_DEFINE1(chdir, const char __user *, filename) if (error) goto out; - error = inode_permission(path.dentry->d_inode, MAY_EXEC | MAY_CHDIR); + error = path_permission(&path, MAY_EXEC | MAY_CHDIR); if (error) goto dput_and_out; @@ -521,7 +521,7 @@ SYSCALL_DEFINE1(fchdir, unsigned int, fd) if (!d_can_lookup(f.file->f_path.dentry)) goto out_putf; - error = inode_permission(file_inode(f.file), MAY_EXEC | MAY_CHDIR); + error = file_permission(f.file, MAY_EXEC | MAY_CHDIR); if (!error) set_fs_pwd(current->fs, &f.file->f_path); out_putf: @@ -540,7 +540,7 @@ SYSCALL_DEFINE1(chroot, const char __user *, filename) if (error) goto out; - error = inode_permission(path.dentry->d_inode, MAY_EXEC | MAY_CHDIR); + error = path_permission(&path, MAY_EXEC | MAY_CHDIR); if (error) goto dput_and_out; diff --git a/fs/udf/file.c b/fs/udf/file.c index ad8eefad27d7..3671a40ed3c3 100644 --- a/fs/udf/file.c +++ b/fs/udf/file.c @@ -183,7 +183,7 @@ long udf_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) long old_block, new_block; int result; - if (inode_permission(inode, MAY_READ) != 0) { + if (file_permission(filp, MAY_READ) != 0) { udf_debug("no permission to access inode %lu\n", inode->i_ino); return -EPERM; } diff --git a/fs/verity/enable.c b/fs/verity/enable.c index f7e997a01ad0..77e159a0346b 100644 --- a/fs/verity/enable.c +++ b/fs/verity/enable.c @@ -369,7 +369,7 @@ int fsverity_ioctl_enable(struct file *filp, const void __user *uarg) * has verity enabled, and to stabilize the data being hashed. */ - err = inode_permission(inode, MAY_WRITE); + err = file_permission(filp, MAY_WRITE); if (err) return err; diff --git a/include/linux/fs.h b/include/linux/fs.h index 3165998e2294..bcd17097d441 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -2812,6 +2812,14 @@ static inline int bmap(struct inode *inode, sector_t *block) extern int notify_change(struct dentry *, struct iattr *, struct inode **); extern int inode_permission(struct inode *, int); extern int generic_permission(struct inode *, int); +static inline int file_permission(struct file *file, int mask) +{ + return inode_permission(file_inode(file), mask); +} +static inline int path_permission(const struct path *path, int mask) +{ + return inode_permission(d_inode(path->dentry), mask); +} extern int __check_sticky(struct inode *dir, struct inode *inode); static inline bool execute_ok(struct inode *inode) diff --git a/kernel/bpf/inode.c b/kernel/bpf/inode.c index dd4b7fd60ee7..8962f139521e 100644 --- a/kernel/bpf/inode.c +++ b/kernel/bpf/inode.c @@ -507,7 +507,7 @@ static void *bpf_obj_do_get(const char __user *pathname, return ERR_PTR(ret); inode = d_backing_inode(path.dentry); - ret = inode_permission(inode, ACC_MODE(flags)); + ret = path_permission(&path, ACC_MODE(flags)); if (ret) goto out; diff --git a/kernel/sys.c b/kernel/sys.c index 51f00fe20e4d..138fb253b344 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -1848,7 +1848,7 @@ static int prctl_set_mm_exe_file(struct mm_struct *mm, unsigned int fd) if (!S_ISREG(inode->i_mode) || path_noexec(&exe.file->f_path)) goto exit; - err = inode_permission(inode, MAY_EXEC); + err = file_permission(exe.file, MAY_EXEC); if (err) goto exit; diff --git a/mm/madvise.c b/mm/madvise.c index 6a660858784b..175c5582d8a9 100644 --- a/mm/madvise.c +++ b/mm/madvise.c @@ -540,7 +540,7 @@ static inline bool can_do_pageout(struct vm_area_struct *vma) * opens a side channel. */ return inode_owner_or_capable(file_inode(vma->vm_file)) || - inode_permission(file_inode(vma->vm_file), MAY_WRITE) == 0; + file_permission(vma->vm_file, MAY_WRITE) == 0; } static long madvise_pageout(struct vm_area_struct *vma, diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 605f671203ef..cf9076f58582 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -4899,7 +4899,7 @@ static ssize_t memcg_write_event_control(struct kernfs_open_file *of, /* the process need read permission on control file */ /* AV: shouldn't we check that it's been opened for read instead? */ - ret = inode_permission(file_inode(cfile.file), MAY_READ); + ret = file_permission(cfile.file, MAY_READ); if (ret < 0) goto out_put_cfile; diff --git a/mm/mincore.c b/mm/mincore.c index 02db1a834021..7bdb4673f776 100644 --- a/mm/mincore.c +++ b/mm/mincore.c @@ -167,7 +167,7 @@ static inline bool can_do_mincore(struct vm_area_struct *vma) * mappings, which opens a side channel. */ return inode_owner_or_capable(file_inode(vma->vm_file)) || - inode_permission(file_inode(vma->vm_file), MAY_WRITE) == 0; + file_permission(vma->vm_file, MAY_WRITE) == 0; } static const struct mm_walk_ops mincore_walk_ops = { diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c index 41c3303c3357..18453d15dddf 100644 --- a/net/unix/af_unix.c +++ b/net/unix/af_unix.c @@ -936,7 +936,7 @@ static struct sock *unix_find_other(struct net *net, if (err) goto fail; inode = d_backing_inode(path.dentry); - err = inode_permission(inode, MAY_WRITE); + err = path_permission(&path, MAY_WRITE); if (err) goto put_fail; -- 2.30.0
