From linux-kernel Thu Oct 23 14:50:56 2008 From: Daniel Gollub Date: Thu, 23 Oct 2008 14:50:56 +0000 To: linux-kernel Subject: [patch 1/3] [RFC] Change sys_readlink/sys_readlinkat buffer size parameter to size_t (POSIX mismatch Message-Id: <20081023150548.447457340 () marvin ! suse ! de> X-MARC-Message: https://marc.info/?l=linux-kernel&m=122477442001057 man-page for readlink syscalls prototype with buffer size as type of size_t: "ssize_t readlink(const char *path, char *buf, size_t bufsiz);" Kernel readlink syscall interface has signed buffer size and doesn't match with man-page described prototype. POSIX and glibc implementation of the readlink interface have an unsigned buffer size. This patch changes the syscall interface of sys_readlink and sys_readlinkat, by changing the buffer size argument type to "size_t". A buffer size of 0 will end in return value 0. This is _different_ behavior to original sys_readlink/sys_readlinkat interface. But equal/similar to POSIXs one. Signed-off-by: Daniel Gollub --- fs/9p/vfs_inode.c | 4 ++-- fs/bad_inode.c | 2 +- fs/ecryptfs/inode.c | 2 +- fs/gfs2/ops_inode.c | 2 +- fs/hppfs/hppfs.c | 2 +- fs/namei.c | 8 ++++---- fs/ocfs2/symlink.c | 2 +- fs/proc/base.c | 6 +++--- fs/stat.c | 8 ++++---- include/linux/fs.h | 8 ++++---- include/linux/syscalls.h | 4 ++-- 11 files changed, 24 insertions(+), 24 deletions(-) diff --git a/fs/9p/vfs_inode.c b/fs/9p/vfs_inode.c index e83aa5e..dd70525 100644 --- a/fs/9p/vfs_inode.c +++ b/fs/9p/vfs_inode.c @@ -898,7 +898,7 @@ ino_t v9fs_qid2ino(struct p9_qid *qid) * */ -static int v9fs_readlink(struct dentry *dentry, char *buffer, int buflen) +static int v9fs_readlink(struct dentry *dentry, char *buffer, size_t buflen) { int retval; @@ -952,7 +952,7 @@ done: */ static int v9fs_vfs_readlink(struct dentry *dentry, char __user * buffer, - int buflen) + size_t buflen) { int retval; int ret; diff --git a/fs/bad_inode.c b/fs/bad_inode.c index 5f1538c..5342a55 100644 --- a/fs/bad_inode.c +++ b/fs/bad_inode.c @@ -238,7 +238,7 @@ static int bad_inode_rename (struct inode *old_dir, struct dentry *old_dentry, } static int bad_inode_readlink(struct dentry *dentry, char __user *buffer, - int buflen) + size_t buflen) { return -EIO; } diff --git a/fs/ecryptfs/inode.c b/fs/ecryptfs/inode.c index 89209f0..378a1e2 100644 --- a/fs/ecryptfs/inode.c +++ b/fs/ecryptfs/inode.c @@ -602,7 +602,7 @@ out_lock: } static int -ecryptfs_readlink(struct dentry *dentry, char __user * buf, int bufsiz) +ecryptfs_readlink(struct dentry *dentry, char __user * buf, size_t bufsiz) { int rc; struct dentry *lower_dentry; diff --git a/fs/gfs2/ops_inode.c b/fs/gfs2/ops_inode.c index 534e1e2..8680062 100644 --- a/fs/gfs2/ops_inode.c +++ b/fs/gfs2/ops_inode.c @@ -894,7 +894,7 @@ out: */ static int gfs2_readlink(struct dentry *dentry, char __user *user_buf, - int user_size) + size_t user_size) { struct gfs2_inode *ip = GFS2_I(dentry->d_inode); char array[GFS2_FAST_NAME_SIZE], *buf = array; diff --git a/fs/hppfs/hppfs.c b/fs/hppfs/hppfs.c index 2b3d182..488f95d 100644 --- a/fs/hppfs/hppfs.c +++ b/fs/hppfs/hppfs.c @@ -637,7 +637,7 @@ static const struct super_operations hppfs_sbops = { }; static int hppfs_readlink(struct dentry *dentry, char __user *buffer, - int buflen) + size_t buflen) { struct dentry *proc_dentry; diff --git a/fs/namei.c b/fs/namei.c index 4ea63ed..63e01e4 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -2712,7 +2712,7 @@ asmlinkage long sys_rename(const char __user *oldname, const char __user *newnam return sys_renameat(AT_FDCWD, oldname, AT_FDCWD, newname); } -int vfs_readlink(struct dentry *dentry, char __user *buffer, int buflen, const char *link) +int vfs_readlink(struct dentry *dentry, char __user *buffer, size_t buflen, const char *link) { int len; @@ -2721,7 +2721,7 @@ int vfs_readlink(struct dentry *dentry, char __user *buffer, int buflen, const c goto out; len = strlen(link); - if (len > (unsigned) buflen) + if (len > buflen) len = buflen; if (copy_to_user(buffer, link, len)) len = -EFAULT; @@ -2734,7 +2734,7 @@ out: * have ->follow_link() touching nd only in nd_set_link(). Using (or not * using) it for any given inode is up to filesystem. */ -int generic_readlink(struct dentry *dentry, char __user *buffer, int buflen) +int generic_readlink(struct dentry *dentry, char __user *buffer, size_t buflen) { struct nameidata nd; void *cookie; @@ -2768,7 +2768,7 @@ static char *page_getlink(struct dentry * dentry, struct page **ppage) return kmap(page); } -int page_readlink(struct dentry *dentry, char __user *buffer, int buflen) +int page_readlink(struct dentry *dentry, char __user *buffer, size_t buflen) { struct page *page = NULL; char *s = page_getlink(dentry, &page); diff --git a/fs/ocfs2/symlink.c b/fs/ocfs2/symlink.c index cbd03df..3295ff7 100644 --- a/fs/ocfs2/symlink.c +++ b/fs/ocfs2/symlink.c @@ -101,7 +101,7 @@ bail: static int ocfs2_readlink(struct dentry *dentry, char __user *buffer, - int buflen) + size_t buflen) { int ret; char *link; diff --git a/fs/proc/base.c b/fs/proc/base.c index b5918ae..14b90b9 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -1333,7 +1333,7 @@ out: return ERR_PTR(error); } -static int do_proc_readlink(struct path *path, char __user *buffer, int buflen) +static int do_proc_readlink(struct path *path, char __user *buffer, size_t buflen) { char *tmp = (char*)__get_free_page(GFP_TEMPORARY); char *pathname; @@ -1357,7 +1357,7 @@ static int do_proc_readlink(struct path *path, char __user *buffer, int buflen) return len; } -static int proc_pid_readlink(struct dentry * dentry, char __user * buffer, int buflen) +static int proc_pid_readlink(struct dentry * dentry, char __user * buffer, size_t buflen) { int error = -EACCES; struct inode *inode = dentry->d_inode; @@ -2246,7 +2246,7 @@ static const struct file_operations proc_coredump_filter_operations = { * /proc/self: */ static int proc_self_readlink(struct dentry *dentry, char __user *buffer, - int buflen) + size_t buflen) { struct pid_namespace *ns = dentry->d_sb->s_fs_info; pid_t tgid = task_tgid_nr_ns(current, ns); diff --git a/fs/stat.c b/fs/stat.c index 7c46fbe..b521674 100644 --- a/fs/stat.c +++ b/fs/stat.c @@ -292,13 +292,13 @@ asmlinkage long sys_newfstat(unsigned int fd, struct stat __user *statbuf) } asmlinkage long sys_readlinkat(int dfd, const char __user *pathname, - char __user *buf, int bufsiz) + char __user *buf, size_t bufsiz) { struct path path; int error; - if (bufsiz <= 0) - return -EINVAL; + if (unlikely(!bufsiz)) + return 0; error = user_path_at(dfd, pathname, 0, &path); if (!error) { @@ -319,7 +319,7 @@ asmlinkage long sys_readlinkat(int dfd, const char __user *pathname, } asmlinkage long sys_readlink(const char __user *path, char __user *buf, - int bufsiz) + size_t bufsiz) { return sys_readlinkat(AT_FDCWD, path, buf, bufsiz); } diff --git a/include/linux/fs.h b/include/linux/fs.h index a6a625b..816dc29 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -1333,7 +1333,7 @@ struct inode_operations { int (*mknod) (struct inode *,struct dentry *,int,dev_t); int (*rename) (struct inode *, struct dentry *, struct inode *, struct dentry *); - int (*readlink) (struct dentry *, char __user *,int); + int (*readlink) (struct dentry *, char __user *,size_t); void * (*follow_link) (struct dentry *, struct nameidata *); void (*put_link) (struct dentry *, struct nameidata *, void *); void (*truncate) (struct inode *); @@ -2029,16 +2029,16 @@ extern const struct file_operations generic_ro_fops; #define special_file(m) (S_ISCHR(m)||S_ISBLK(m)||S_ISFIFO(m)||S_ISSOCK(m)) -extern int vfs_readlink(struct dentry *, char __user *, int, const char *); +extern int vfs_readlink(struct dentry *, char __user *, size_t, const char *); extern int vfs_follow_link(struct nameidata *, const char *); -extern int page_readlink(struct dentry *, char __user *, int); +extern int page_readlink(struct dentry *, char __user *, size_t); extern void *page_follow_link_light(struct dentry *, struct nameidata *); extern void page_put_link(struct dentry *, struct nameidata *, void *); extern int __page_symlink(struct inode *inode, const char *symname, int len, gfp_t gfp_mask); extern int page_symlink(struct inode *inode, const char *symname, int len); extern const struct inode_operations page_symlink_inode_operations; -extern int generic_readlink(struct dentry *, char __user *, int); +extern int generic_readlink(struct dentry *, char __user *, size_t); extern void generic_fillattr(struct inode *, struct kstat *); extern int vfs_getattr(struct vfsmount *, struct dentry *, struct kstat *); void inode_add_bytes(struct inode *inode, loff_t bytes); diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h index d6ff145..e9582d1 100644 --- a/include/linux/syscalls.h +++ b/include/linux/syscalls.h @@ -326,7 +326,7 @@ asmlinkage ssize_t sys_sendfile(int out_fd, int in_fd, asmlinkage ssize_t sys_sendfile64(int out_fd, int in_fd, loff_t __user *offset, size_t count); asmlinkage long sys_readlink(const char __user *path, - char __user *buf, int bufsiz); + char __user *buf, size_t bufsiz); asmlinkage long sys_creat(const char __user *pathname, int mode); asmlinkage long sys_open(const char __user *filename, int flags, int mode); @@ -581,7 +581,7 @@ asmlinkage long sys_newfstatat(int dfd, char __user *filename, asmlinkage long sys_fstatat64(int dfd, char __user *filename, struct stat64 __user *statbuf, int flag); asmlinkage long sys_readlinkat(int dfd, const char __user *path, char __user *buf, - int bufsiz); + size_t bufsiz); asmlinkage long sys_utimensat(int dfd, char __user *filename, struct timespec __user *utimes, int flags); asmlinkage long compat_sys_futimesat(unsigned int dfd, char __user *filename, -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/