From 8c744fb83da0771afa04695028e3550b798dad90 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Tue, 8 Nov 2005 21:35:04 -0800 Subject: [PATCH] [PATCH] add a file_permission helper A few more callers of permission() just want to check for a different access pattern on an already open file. This patch adds a wrapper for permission() that takes a file in preparation of per-mount read-only support and to clean up the callers a little. The helper is not intended for new code, everything without the interface set in stone should use vfs_permission() Signed-off-by: Christoph Hellwig Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/block/floppy.c | 3 +-- fs/binfmt_misc.c | 2 +- fs/exec.c | 2 +- fs/namei.c | 18 ++++++++++++++++++ fs/ncpfs/ioctl.c | 34 +++++++++++++++++++--------------- fs/open.c | 2 +- fs/udf/file.c | 2 +- include/linux/fs.h | 5 +++++ 8 files changed, 47 insertions(+), 21 deletions(-) diff --git a/drivers/block/floppy.c b/drivers/block/floppy.c index dd1935d55424..28002de783b6 100644 --- a/drivers/block/floppy.c +++ b/drivers/block/floppy.c @@ -3776,8 +3776,7 @@ static int floppy_open(struct inode *inode, struct file *filp) /* Allow ioctls if we have write-permissions even if read-only open. * Needed so that programs such as fdrawcmd still can work on write * protected disks */ - if (filp->f_mode & 2 - || permission(filp->f_dentry->d_inode, 2, NULL) == 0) + if ((filp->f_mode & FMODE_WRITE) || !file_permission(filp, MAY_WRITE)) filp->private_data = (void *)8; if (UFDCS->rawcmd == 1) diff --git a/fs/binfmt_misc.c b/fs/binfmt_misc.c index 8ae0db6cd69c..2568eb41cb3a 100644 --- a/fs/binfmt_misc.c +++ b/fs/binfmt_misc.c @@ -150,7 +150,7 @@ static int load_misc_binary(struct linux_binprm *bprm, struct pt_regs *regs) /* if the binary is not readable than enforce mm->dumpable=0 regardless of the interpreter's permissions */ - if (permission(bprm->file->f_dentry->d_inode, MAY_READ, NULL)) + if (file_permission(bprm->file, MAY_READ)) bprm->interp_flags |= BINPRM_FLAGS_ENFORCE_NONDUMP; allow_write_access(bprm->file); diff --git a/fs/exec.c b/fs/exec.c index 7bbb781b9ac6..c466fec5de20 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -896,7 +896,7 @@ int flush_old_exec(struct linux_binprm * bprm) flush_thread(); if (bprm->e_uid != current->euid || bprm->e_gid != current->egid || - permission(bprm->file->f_dentry->d_inode,MAY_READ, NULL) || + file_permission(bprm->file, MAY_READ) || (bprm->interp_flags & BINPRM_FLAGS_ENFORCE_NONDUMP)) { suid_keys(current); current->mm->dumpable = suid_dumpable; diff --git a/fs/namei.c b/fs/namei.c index 25e4ab4ce8b7..b69f6ebadb95 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -271,6 +271,23 @@ int vfs_permission(struct nameidata *nd, int mask) return permission(nd->dentry->d_inode, mask, nd); } +/** + * file_permission - check for additional access rights to a given file + * @file: file to check access rights for + * @mask: right to check for (%MAY_READ, %MAY_WRITE, %MAY_EXEC) + * + * Used to check for read/write/execute permissions on an already opened + * file. + * + * Note: + * Do not use this function in new code. All access checks should + * be done using vfs_permission(). + */ +int file_permission(struct file *file, int mask) +{ + return permission(file->f_dentry->d_inode, mask, NULL); +} + /* * get_write_access() gets write permission for a file. * put_write_access() releases this write permission. @@ -2551,6 +2568,7 @@ EXPORT_SYMBOL(path_release); EXPORT_SYMBOL(path_walk); EXPORT_SYMBOL(permission); EXPORT_SYMBOL(vfs_permission); +EXPORT_SYMBOL(file_permission); EXPORT_SYMBOL(unlock_rename); EXPORT_SYMBOL(vfs_create); EXPORT_SYMBOL(vfs_follow_link); diff --git a/fs/ncpfs/ioctl.c b/fs/ncpfs/ioctl.c index 88df79356a1f..fd3efdca5ae3 100644 --- a/fs/ncpfs/ioctl.c +++ b/fs/ncpfs/ioctl.c @@ -30,11 +30,13 @@ #define NCP_PACKET_SIZE_INTERNAL 65536 static int -ncp_get_fs_info(struct ncp_server* server, struct inode* inode, struct ncp_fs_info __user *arg) +ncp_get_fs_info(struct ncp_server * server, struct file *file, + struct ncp_fs_info __user *arg) { + struct inode *inode = file->f_dentry->d_inode; struct ncp_fs_info info; - if ((permission(inode, MAY_WRITE, NULL) != 0) + if ((file_permission(file, MAY_WRITE) != 0) && (current->uid != server->m.mounted_uid)) { return -EACCES; } @@ -58,11 +60,13 @@ ncp_get_fs_info(struct ncp_server* server, struct inode* inode, struct ncp_fs_in } static int -ncp_get_fs_info_v2(struct ncp_server* server, struct inode* inode, struct ncp_fs_info_v2 __user * arg) +ncp_get_fs_info_v2(struct ncp_server * server, struct file *file, + struct ncp_fs_info_v2 __user * arg) { + struct inode *inode = file->f_dentry->d_inode; struct ncp_fs_info_v2 info2; - if ((permission(inode, MAY_WRITE, NULL) != 0) + if ((file_permission(file, MAY_WRITE) != 0) && (current->uid != server->m.mounted_uid)) { return -EACCES; } @@ -190,7 +194,7 @@ int ncp_ioctl(struct inode *inode, struct file *filp, switch (cmd) { case NCP_IOC_NCPREQUEST: - if ((permission(inode, MAY_WRITE, NULL) != 0) + if ((file_permission(filp, MAY_WRITE) != 0) && (current->uid != server->m.mounted_uid)) { return -EACCES; } @@ -245,16 +249,16 @@ int ncp_ioctl(struct inode *inode, struct file *filp, return ncp_conn_logged_in(inode->i_sb); case NCP_IOC_GET_FS_INFO: - return ncp_get_fs_info(server, inode, argp); + return ncp_get_fs_info(server, filp, argp); case NCP_IOC_GET_FS_INFO_V2: - return ncp_get_fs_info_v2(server, inode, argp); + return ncp_get_fs_info_v2(server, filp, argp); case NCP_IOC_GETMOUNTUID2: { unsigned long tmp = server->m.mounted_uid; - if ( (permission(inode, MAY_READ, NULL) != 0) + if ((file_permission(filp, MAY_READ) != 0) && (current->uid != server->m.mounted_uid)) { return -EACCES; @@ -268,7 +272,7 @@ int ncp_ioctl(struct inode *inode, struct file *filp, { struct ncp_setroot_ioctl sr; - if ( (permission(inode, MAY_READ, NULL) != 0) + if ((file_permission(filp, MAY_READ) != 0) && (current->uid != server->m.mounted_uid)) { return -EACCES; @@ -343,7 +347,7 @@ int ncp_ioctl(struct inode *inode, struct file *filp, #ifdef CONFIG_NCPFS_PACKET_SIGNING case NCP_IOC_SIGN_INIT: - if ((permission(inode, MAY_WRITE, NULL) != 0) + if ((file_permission(filp, MAY_WRITE) != 0) && (current->uid != server->m.mounted_uid)) { return -EACCES; @@ -366,7 +370,7 @@ int ncp_ioctl(struct inode *inode, struct file *filp, return 0; case NCP_IOC_SIGN_WANTED: - if ( (permission(inode, MAY_READ, NULL) != 0) + if ((file_permission(filp, MAY_READ) != 0) && (current->uid != server->m.mounted_uid)) { return -EACCES; @@ -379,7 +383,7 @@ int ncp_ioctl(struct inode *inode, struct file *filp, { int newstate; - if ( (permission(inode, MAY_WRITE, NULL) != 0) + if ((file_permission(filp, MAY_WRITE) != 0) && (current->uid != server->m.mounted_uid)) { return -EACCES; @@ -400,7 +404,7 @@ int ncp_ioctl(struct inode *inode, struct file *filp, #ifdef CONFIG_NCPFS_IOCTL_LOCKING case NCP_IOC_LOCKUNLOCK: - if ( (permission(inode, MAY_WRITE, NULL) != 0) + if ((file_permission(filp, MAY_WRITE) != 0) && (current->uid != server->m.mounted_uid)) { return -EACCES; @@ -605,7 +609,7 @@ outrel: #endif /* CONFIG_NCPFS_NLS */ case NCP_IOC_SETDENTRYTTL: - if ((permission(inode, MAY_WRITE, NULL) != 0) && + if ((file_permission(filp, MAY_WRITE) != 0) && (current->uid != server->m.mounted_uid)) return -EACCES; { @@ -635,7 +639,7 @@ outrel: so we have this out of switch */ if (cmd == NCP_IOC_GETMOUNTUID) { __kernel_uid_t uid = 0; - if ((permission(inode, MAY_READ, NULL) != 0) + if ((file_permission(filp, MAY_READ) != 0) && (current->uid != server->m.mounted_uid)) { return -EACCES; } diff --git a/fs/open.c b/fs/open.c index baffc084580d..f53a5b9ffb7d 100644 --- a/fs/open.c +++ b/fs/open.c @@ -563,7 +563,7 @@ asmlinkage long sys_fchdir(unsigned int fd) if (!S_ISDIR(inode->i_mode)) goto out_putf; - error = permission(inode, MAY_EXEC, NULL); + error = file_permission(file, MAY_EXEC); if (!error) set_fs_pwd(current->fs, mnt, dentry); out_putf: diff --git a/fs/udf/file.c b/fs/udf/file.c index bb40d63f328f..01f520c71dc1 100644 --- a/fs/udf/file.c +++ b/fs/udf/file.c @@ -186,7 +186,7 @@ int udf_ioctl(struct inode *inode, struct file *filp, unsigned int cmd, { int result = -EINVAL; - if ( permission(inode, MAY_READ, NULL) != 0 ) + if ( file_permission(filp, MAY_READ) != 0 ) { udf_debug("no permission to access inode %lu\n", inode->i_ino); diff --git a/include/linux/fs.h b/include/linux/fs.h index c3b8c1dc7cdf..cc35b6ac778d 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -889,6 +889,11 @@ extern int vfs_rename(struct inode *, struct dentry *, struct inode *, struct de */ extern void dentry_unhash(struct dentry *dentry); +/* + * VFS file helper functions. + */ +extern int file_permission(struct file *, int); + /* * File types *