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| author | Andy Whitcroft <apw@canonical.com> | 2011-11-02 09:44:39 +0100 |
|---|---|---|
| committer | Christoph Hellwig <hch@serles.lst.de> | 2011-11-02 12:53:42 +0100 |
| commit | 1fa1e7f615f4d3ae436fa319af6e4eebdd4026a8 (patch) | |
| tree | aa3521aaa762424cc7fb38dbf924a34dac1b03c2 /fs/namei.c | |
| parent | 32096ea1aac14e6f29d4744924092eca52b937b0 (diff) | |
| download | linux-1fa1e7f615f4d3ae436fa319af6e4eebdd4026a8.tar.gz linux-1fa1e7f615f4d3ae436fa319af6e4eebdd4026a8.tar.bz2 linux-1fa1e7f615f4d3ae436fa319af6e4eebdd4026a8.zip | |
readlinkat: ensure we return ENOENT for the empty pathname for normal lookups
Since the commit below which added O_PATH support to the *at() calls, the
error return for readlink/readlinkat for the empty pathname has switched
from ENOENT to EINVAL:
commit 65cfc6722361570bfe255698d9cd4dccaf47570d
Author: Al Viro <viro@zeniv.linux.org.uk>
Date: Sun Mar 13 15:56:26 2011 -0400
readlinkat(), fchownat() and fstatat() with empty relative pathnames
This is both unexpected for userspace and makes readlink/readlinkat
inconsistant with all other interfaces; and inconsistant with our stated
return for these pathnames.
As the readlinkat call does not have a flags parameter we cannot use the
AT_EMPTY_PATH approach used in the other calls. Therefore expose whether
the original path is infact entry via a new user_path_at_empty() path
lookup function. Use this to determine whether to default to EINVAL or
ENOENT for failures.
Addresses http://bugs.launchpad.net/bugs/817187
[akpm@linux-foundation.org: remove unused getname_flags()]
Signed-off-by: Andy Whitcroft <apw@canonical.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: <stable@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Diffstat (limited to 'fs/namei.c')
| -rw-r--r-- | fs/namei.c | 18 |
1 files changed, 13 insertions, 5 deletions
diff --git a/fs/namei.c b/fs/namei.c index 7657be4352bf..ac6d214da827 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -137,7 +137,7 @@ static int do_getname(const char __user *filename, char *page) return retval; } -static char *getname_flags(const char __user * filename, int flags) +static char *getname_flags(const char __user *filename, int flags, int *empty) { char *tmp, *result; @@ -148,6 +148,8 @@ static char *getname_flags(const char __user * filename, int flags) result = tmp; if (retval < 0) { + if (retval == -ENOENT && empty) + *empty = 1; if (retval != -ENOENT || !(flags & LOOKUP_EMPTY)) { __putname(tmp); result = ERR_PTR(retval); @@ -160,7 +162,7 @@ static char *getname_flags(const char __user * filename, int flags) char *getname(const char __user * filename) { - return getname_flags(filename, 0); + return getname_flags(filename, 0, 0); } #ifdef CONFIG_AUDITSYSCALL @@ -1798,11 +1800,11 @@ struct dentry *lookup_one_len(const char *name, struct dentry *base, int len) return __lookup_hash(&this, base, NULL); } -int user_path_at(int dfd, const char __user *name, unsigned flags, - struct path *path) +int user_path_at_empty(int dfd, const char __user *name, unsigned flags, + struct path *path, int *empty) { struct nameidata nd; - char *tmp = getname_flags(name, flags); + char *tmp = getname_flags(name, flags, empty); int err = PTR_ERR(tmp); if (!IS_ERR(tmp)) { @@ -1816,6 +1818,12 @@ int user_path_at(int dfd, const char __user *name, unsigned flags, return err; } +int user_path_at(int dfd, const char __user *name, unsigned flags, + struct path *path) +{ + return user_path_at_empty(dfd, name, flags, path, 0); +} + static int user_path_parent(int dfd, const char __user *path, struct nameidata *nd, char **name) { |