From 21d8a15ac333b05f1fecdf9fdc30996be2e11d60 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Thu, 29 Nov 2012 22:17:21 -0500 Subject: lookup_one_len: don't accept . and .. Signed-off-by: Al Viro --- fs/namei.c | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'fs/namei.c') diff --git a/fs/namei.c b/fs/namei.c index 937f9d5..5f4cdf3 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -2131,6 +2131,11 @@ struct dentry *lookup_one_len(const char *name, struct dentry *base, int len) if (!len) return ERR_PTR(-EACCES); + if (unlikely(name[0] == '.')) { + if (len < 2 || (len == 2 && name[1] == '.')) + return ERR_PTR(-EACCES); + } + while (len--) { c = *(const unsigned char *)name++; if (c == '/' || c == '\0') -- cgit v1.1 From 582aa64a04a579d47d05e4a0ee85bf047978ef4d Mon Sep 17 00:00:00 2001 From: Jeff Layton Date: Tue, 11 Dec 2012 08:56:16 -0500 Subject: vfs: remove unneeded permission check from path_init When path_init is called with a valid dfd, that code checks permissions on the open directory fd and returns an error if the check fails. This permission check is redundant, however. Both callers of path_init immediately call link_path_walk afterward. The first thing that link_path_walk does for pathnames that do not consist only of slashes is to check for exec permissions at the starting point of the path walk. And this check in path_init() is on the path taken only when *name != '/' && *name != '\0'. In most cases, these checks are very quick, but when the dfd is for a file on a NFS mount with the actimeo=0, each permission check goes out onto the wire. The result is 2 identical ACCESS calls. Given that these codepaths are fairly "hot", I think it makes sense to eliminate the permission check in path_init and simply assume that the caller will eventually check the permissions before proceeding. Reported-by: Dave Wysochanski Signed-off-by: Jeff Layton Signed-off-by: Al Viro --- fs/namei.c | 7 +------ 1 file changed, 1 insertion(+), 6 deletions(-) (limited to 'fs/namei.c') diff --git a/fs/namei.c b/fs/namei.c index 5f4cdf3..e245d88 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -1903,6 +1903,7 @@ static int path_init(int dfd, const char *name, unsigned int flags, get_fs_pwd(current->fs, &nd->path); } } else { + /* Caller must check execute permissions on the starting path component */ struct fd f = fdget_raw(dfd); struct dentry *dentry; @@ -1916,12 +1917,6 @@ static int path_init(int dfd, const char *name, unsigned int flags, fdput(f); return -ENOTDIR; } - - retval = inode_permission(dentry->d_inode, MAY_EXEC); - if (retval) { - fdput(f); - return retval; - } } nd->path = f.file->f_path; -- cgit v1.1 From 741b7c3f77937b2fb7c10aeb4c5c621463582583 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Thu, 20 Dec 2012 13:41:28 -0500 Subject: path_init(): make -ENOTDIR failure exits consistent Signed-off-by: Al Viro --- fs/namei.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'fs/namei.c') diff --git a/fs/namei.c b/fs/namei.c index e245d88..35195ff 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -1859,7 +1859,7 @@ static int path_init(int dfd, const char *name, unsigned int flags, if (flags & LOOKUP_ROOT) { struct inode *inode = nd->root.dentry->d_inode; if (*name) { - if (!inode->i_op->lookup) + if (!can_lookup(inode)) return -ENOTDIR; retval = inode_permission(inode, MAY_EXEC); if (retval) @@ -1913,7 +1913,7 @@ static int path_init(int dfd, const char *name, unsigned int flags, dentry = f.file->f_path.dentry; if (*name) { - if (!S_ISDIR(dentry->d_inode->i_mode)) { + if (!can_lookup(dentry->d_inode)) { fdput(f); return -ENOTDIR; } -- cgit v1.1 From 39e3c9553f34381a1b664c27b0c696a266a5735e Mon Sep 17 00:00:00 2001 From: Jeff Layton Date: Wed, 28 Nov 2012 11:30:53 -0500 Subject: vfs: remove DCACHE_NEED_LOOKUP The code that relied on that flag was ripped out of btrfs quite some time ago, and never added back. Josef indicated that he was going to take a different approach to the problem in btrfs, and that we could just eliminate this flag. Cc: Josef Bacik Signed-off-by: Jeff Layton Signed-off-by: Al Viro --- fs/namei.c | 11 +---------- 1 file changed, 1 insertion(+), 10 deletions(-) (limited to 'fs/namei.c') diff --git a/fs/namei.c b/fs/namei.c index 35195ff..25a41e0 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -1275,9 +1275,7 @@ static struct dentry *lookup_dcache(struct qstr *name, struct dentry *dir, *need_lookup = false; dentry = d_lookup(dir, name); if (dentry) { - if (d_need_lookup(dentry)) { - *need_lookup = true; - } else if (dentry->d_flags & DCACHE_OP_REVALIDATE) { + if (dentry->d_flags & DCACHE_OP_REVALIDATE) { error = d_revalidate(dentry, flags); if (unlikely(error <= 0)) { if (error < 0) { @@ -1383,8 +1381,6 @@ static int lookup_fast(struct nameidata *nd, struct qstr *name, return -ECHILD; nd->seq = seq; - if (unlikely(d_need_lookup(dentry))) - goto unlazy; if (unlikely(dentry->d_flags & DCACHE_OP_REVALIDATE)) { status = d_revalidate(dentry, nd->flags); if (unlikely(status <= 0)) { @@ -1410,11 +1406,6 @@ unlazy: if (unlikely(!dentry)) goto need_lookup; - if (unlikely(d_need_lookup(dentry))) { - dput(dentry); - goto need_lookup; - } - if (unlikely(dentry->d_flags & DCACHE_OP_REVALIDATE) && need_reval) status = d_revalidate(dentry, nd->flags); if (unlikely(status <= 0)) { -- cgit v1.1 From 1ac12b4b6d707937f9de6d09622823b2fd0c93ef Mon Sep 17 00:00:00 2001 From: Jeff Layton Date: Tue, 11 Dec 2012 12:10:06 -0500 Subject: vfs: turn is_dir argument to kern_path_create into a lookup_flags arg Where we can pass in LOOKUP_DIRECTORY or LOOKUP_REVAL. Any other flags passed in here are currently ignored. Signed-off-by: Jeff Layton Signed-off-by: Al Viro --- fs/namei.c | 21 ++++++++++++++++----- 1 file changed, 16 insertions(+), 5 deletions(-) (limited to 'fs/namei.c') diff --git a/fs/namei.c b/fs/namei.c index 25a41e0..8f8e41f 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -3030,12 +3030,22 @@ struct file *do_file_open_root(struct dentry *dentry, struct vfsmount *mnt, return file; } -struct dentry *kern_path_create(int dfd, const char *pathname, struct path *path, int is_dir) +struct dentry *kern_path_create(int dfd, const char *pathname, + struct path *path, unsigned int lookup_flags) { struct dentry *dentry = ERR_PTR(-EEXIST); struct nameidata nd; int err2; - int error = do_path_lookup(dfd, pathname, LOOKUP_PARENT, &nd); + int error; + bool is_dir = (lookup_flags & LOOKUP_DIRECTORY); + + /* + * Note that only LOOKUP_REVAL and LOOKUP_DIRECTORY matter here. Any + * other flags passed in are ignored! + */ + lookup_flags &= LOOKUP_REVAL; + + error = do_path_lookup(dfd, pathname, LOOKUP_PARENT|lookup_flags, &nd); if (error) return ERR_PTR(error); @@ -3099,13 +3109,14 @@ void done_path_create(struct path *path, struct dentry *dentry) } EXPORT_SYMBOL(done_path_create); -struct dentry *user_path_create(int dfd, const char __user *pathname, struct path *path, int is_dir) +struct dentry *user_path_create(int dfd, const char __user *pathname, + struct path *path, unsigned int lookup_flags) { struct filename *tmp = getname(pathname); struct dentry *res; if (IS_ERR(tmp)) return ERR_CAST(tmp); - res = kern_path_create(dfd, tmp->name, path, is_dir); + res = kern_path_create(dfd, tmp->name, path, lookup_flags); putname(tmp); return res; } @@ -3228,7 +3239,7 @@ SYSCALL_DEFINE3(mkdirat, int, dfd, const char __user *, pathname, umode_t, mode) struct path path; int error; - dentry = user_path_create(dfd, pathname, &path, 1); + dentry = user_path_create(dfd, pathname, &path, LOOKUP_DIRECTORY); if (IS_ERR(dentry)) return PTR_ERR(dentry); -- cgit v1.1 From 972567f14cbcd437e9a88a73836bbc2ee0720b5f Mon Sep 17 00:00:00 2001 From: Jeff Layton Date: Thu, 20 Dec 2012 16:00:10 -0500 Subject: vfs: fix mknodat to retry on ESTALE errors Signed-off-by: Jeff Layton Signed-off-by: Al Viro --- fs/namei.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) (limited to 'fs/namei.c') diff --git a/fs/namei.c b/fs/namei.c index 8f8e41f..b70c191 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -3172,12 +3172,13 @@ SYSCALL_DEFINE4(mknodat, int, dfd, const char __user *, filename, umode_t, mode, struct dentry *dentry; struct path path; int error; + unsigned int lookup_flags = 0; error = may_mknod(mode); if (error) return error; - - dentry = user_path_create(dfd, filename, &path, 0); +retry: + dentry = user_path_create(dfd, filename, &path, lookup_flags); if (IS_ERR(dentry)) return PTR_ERR(dentry); @@ -3200,6 +3201,10 @@ SYSCALL_DEFINE4(mknodat, int, dfd, const char __user *, filename, umode_t, mode, } out: done_path_create(&path, dentry); + if (retry_estale(error, lookup_flags)) { + lookup_flags |= LOOKUP_REVAL; + goto retry; + } return error; } -- cgit v1.1 From b76d8b82266077dc7098dd13f321a616099a1bd8 Mon Sep 17 00:00:00 2001 From: Jeff Layton Date: Thu, 20 Dec 2012 16:04:09 -0500 Subject: vfs: fix mkdirat to retry once on an ESTALE error Signed-off-by: Jeff Layton Signed-off-by: Al Viro --- fs/namei.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) (limited to 'fs/namei.c') diff --git a/fs/namei.c b/fs/namei.c index b70c191..1beebc1 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -3243,8 +3243,10 @@ SYSCALL_DEFINE3(mkdirat, int, dfd, const char __user *, pathname, umode_t, mode) struct dentry *dentry; struct path path; int error; + unsigned int lookup_flags = LOOKUP_DIRECTORY; - dentry = user_path_create(dfd, pathname, &path, LOOKUP_DIRECTORY); +retry: + dentry = user_path_create(dfd, pathname, &path, lookup_flags); if (IS_ERR(dentry)) return PTR_ERR(dentry); @@ -3254,6 +3256,10 @@ SYSCALL_DEFINE3(mkdirat, int, dfd, const char __user *, pathname, umode_t, mode) if (!error) error = vfs_mkdir(path.dentry->d_inode, dentry, mode); done_path_create(&path, dentry); + if (retry_estale(error, lookup_flags)) { + lookup_flags |= LOOKUP_REVAL; + goto retry; + } return error; } -- cgit v1.1 From f46d3567b223e41e1f2faeb82d3b74a6d84fc508 Mon Sep 17 00:00:00 2001 From: Jeff Layton Date: Tue, 11 Dec 2012 12:10:08 -0500 Subject: vfs: fix symlinkat to retry on ESTALE errors Signed-off-by: Jeff Layton Signed-off-by: Al Viro --- fs/namei.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) (limited to 'fs/namei.c') diff --git a/fs/namei.c b/fs/namei.c index 1beebc1..b06a111 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -3521,12 +3521,13 @@ SYSCALL_DEFINE3(symlinkat, const char __user *, oldname, struct filename *from; struct dentry *dentry; struct path path; + unsigned int lookup_flags = 0; from = getname(oldname); if (IS_ERR(from)) return PTR_ERR(from); - - dentry = user_path_create(newdfd, newname, &path, 0); +retry: + dentry = user_path_create(newdfd, newname, &path, lookup_flags); error = PTR_ERR(dentry); if (IS_ERR(dentry)) goto out_putname; @@ -3535,6 +3536,10 @@ SYSCALL_DEFINE3(symlinkat, const char __user *, oldname, if (!error) error = vfs_symlink(path.dentry->d_inode, dentry, from->name); done_path_create(&path, dentry); + if (retry_estale(error, lookup_flags)) { + lookup_flags |= LOOKUP_REVAL; + goto retry; + } out_putname: putname(from); return error; -- cgit v1.1 From 442e31ca5a49e398351b2954b51f578353fdf210 Mon Sep 17 00:00:00 2001 From: Jeff Layton Date: Thu, 20 Dec 2012 16:15:38 -0500 Subject: vfs: fix linkat to retry once on ESTALE errors Signed-off-by: Jeff Layton Signed-off-by: Al Viro --- fs/namei.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) (limited to 'fs/namei.c') diff --git a/fs/namei.c b/fs/namei.c index b06a111..6868699 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -3626,12 +3626,13 @@ SYSCALL_DEFINE5(linkat, int, olddfd, const char __user *, oldname, if (flags & AT_SYMLINK_FOLLOW) how |= LOOKUP_FOLLOW; - +retry: error = user_path_at(olddfd, oldname, how, &old_path); if (error) return error; - new_dentry = user_path_create(newdfd, newname, &new_path, 0); + new_dentry = user_path_create(newdfd, newname, &new_path, + (how & LOOKUP_REVAL)); error = PTR_ERR(new_dentry); if (IS_ERR(new_dentry)) goto out; @@ -3648,6 +3649,10 @@ SYSCALL_DEFINE5(linkat, int, olddfd, const char __user *, oldname, error = vfs_link(old_path.dentry, new_path.dentry->d_inode, new_dentry); out_dput: done_path_create(&new_path, new_dentry); + if (retry_estale(error, how)) { + how |= LOOKUP_REVAL; + goto retry; + } out: path_put(&old_path); -- cgit v1.1 From 9e790bd65ce4cbfdff305a57b67b1a2cbe5d4335 Mon Sep 17 00:00:00 2001 From: Jeff Layton Date: Tue, 11 Dec 2012 12:10:09 -0500 Subject: vfs: add a flags argument to user_path_parent ...so we can pass in LOOKUP_REVAL. For now, nothing does yet. Signed-off-by: Jeff Layton Signed-off-by: Al Viro --- fs/namei.c | 16 ++++++++++------ 1 file changed, 10 insertions(+), 6 deletions(-) (limited to 'fs/namei.c') diff --git a/fs/namei.c b/fs/namei.c index 6868699..1919061 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -2175,15 +2175,19 @@ int user_path_at(int dfd, const char __user *name, unsigned flags, * path-walking is complete. */ static struct filename * -user_path_parent(int dfd, const char __user *path, struct nameidata *nd) +user_path_parent(int dfd, const char __user *path, struct nameidata *nd, + unsigned int flags) { struct filename *s = getname(path); int error; + /* only LOOKUP_REVAL is allowed in extra flags */ + flags &= LOOKUP_REVAL; + if (IS_ERR(s)) return s; - error = filename_lookup(dfd, s, LOOKUP_PARENT, nd); + error = filename_lookup(dfd, s, flags | LOOKUP_PARENT, nd); if (error) { putname(s); return ERR_PTR(error); @@ -3336,7 +3340,7 @@ static long do_rmdir(int dfd, const char __user *pathname) struct dentry *dentry; struct nameidata nd; - name = user_path_parent(dfd, pathname, &nd); + name = user_path_parent(dfd, pathname, &nd, 0); if (IS_ERR(name)) return PTR_ERR(name); @@ -3432,7 +3436,7 @@ static long do_unlinkat(int dfd, const char __user *pathname) struct nameidata nd; struct inode *inode = NULL; - name = user_path_parent(dfd, pathname, &nd); + name = user_path_parent(dfd, pathname, &nd, 0); if (IS_ERR(name)) return PTR_ERR(name); @@ -3827,13 +3831,13 @@ SYSCALL_DEFINE4(renameat, int, olddfd, const char __user *, oldname, struct filename *to; int error; - from = user_path_parent(olddfd, oldname, &oldnd); + from = user_path_parent(olddfd, oldname, &oldnd, 0); if (IS_ERR(from)) { error = PTR_ERR(from); goto exit; } - to = user_path_parent(newdfd, newname, &newnd); + to = user_path_parent(newdfd, newname, &newnd, 0); if (IS_ERR(to)) { error = PTR_ERR(to); goto exit1; -- cgit v1.1 From c6ee920698301febdf10df0b57039173a1edbd43 Mon Sep 17 00:00:00 2001 From: Jeff Layton Date: Thu, 20 Dec 2012 16:28:33 -0500 Subject: vfs: make do_rmdir retry once on ESTALE errors Signed-off-by: Jeff Layton Signed-off-by: Al Viro --- fs/namei.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) (limited to 'fs/namei.c') diff --git a/fs/namei.c b/fs/namei.c index 1919061..fe06a2f 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -3339,8 +3339,9 @@ static long do_rmdir(int dfd, const char __user *pathname) struct filename *name; struct dentry *dentry; struct nameidata nd; - - name = user_path_parent(dfd, pathname, &nd, 0); + unsigned int lookup_flags = 0; +retry: + name = user_path_parent(dfd, pathname, &nd, lookup_flags); if (IS_ERR(name)) return PTR_ERR(name); @@ -3382,6 +3383,10 @@ exit2: exit1: path_put(&nd.path); putname(name); + if (retry_estale(error, lookup_flags)) { + lookup_flags |= LOOKUP_REVAL; + goto retry; + } return error; } -- cgit v1.1 From 5d18f8133cad85ccbb7fa6fd351d75025da32504 Mon Sep 17 00:00:00 2001 From: Jeff Layton Date: Thu, 20 Dec 2012 16:38:04 -0500 Subject: vfs: make do_unlinkat retry once on ESTALE errors Signed-off-by: Jeff Layton Signed-off-by: Al Viro --- fs/namei.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) (limited to 'fs/namei.c') diff --git a/fs/namei.c b/fs/namei.c index fe06a2f..8a262c2 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -3440,8 +3440,9 @@ static long do_unlinkat(int dfd, const char __user *pathname) struct dentry *dentry; struct nameidata nd; struct inode *inode = NULL; - - name = user_path_parent(dfd, pathname, &nd, 0); + unsigned int lookup_flags = 0; +retry: + name = user_path_parent(dfd, pathname, &nd, lookup_flags); if (IS_ERR(name)) return PTR_ERR(name); @@ -3479,6 +3480,11 @@ exit2: exit1: path_put(&nd.path); putname(name); + if (retry_estale(error, lookup_flags)) { + lookup_flags |= LOOKUP_REVAL; + inode = NULL; + goto retry; + } return error; slashes: -- cgit v1.1 From c6a9428401c00a27d3c17264934d14e284570c97 Mon Sep 17 00:00:00 2001 From: Jeff Layton Date: Tue, 11 Dec 2012 12:10:10 -0500 Subject: vfs: fix renameat to retry on ESTALE errors ...as always, rename is the messiest of the bunch. We have to track whether to retry or not via a separate flag since the error handling is already quite complex. Signed-off-by: Jeff Layton Signed-off-by: Al Viro --- fs/namei.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-) (limited to 'fs/namei.c') diff --git a/fs/namei.c b/fs/namei.c index 8a262c2..43a97ee 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -3840,15 +3840,17 @@ SYSCALL_DEFINE4(renameat, int, olddfd, const char __user *, oldname, struct nameidata oldnd, newnd; struct filename *from; struct filename *to; + unsigned int lookup_flags = 0; + bool should_retry = false; int error; - - from = user_path_parent(olddfd, oldname, &oldnd, 0); +retry: + from = user_path_parent(olddfd, oldname, &oldnd, lookup_flags); if (IS_ERR(from)) { error = PTR_ERR(from); goto exit; } - to = user_path_parent(newdfd, newname, &newnd, 0); + to = user_path_parent(newdfd, newname, &newnd, lookup_flags); if (IS_ERR(to)) { error = PTR_ERR(to); goto exit1; @@ -3920,11 +3922,18 @@ exit3: unlock_rename(new_dir, old_dir); mnt_drop_write(oldnd.path.mnt); exit2: + if (retry_estale(error, lookup_flags)) + should_retry = true; path_put(&newnd.path); putname(to); exit1: path_put(&oldnd.path); putname(from); + if (should_retry) { + should_retry = false; + lookup_flags |= LOOKUP_REVAL; + goto retry; + } exit: return error; } -- cgit v1.1