Commit f52e0c11305aa09ed56cad97ffc8f0cdc3d78b5d
1 parent
5fe0c23788
Exists in
master
and in
20 other branches
New AT_... flag: AT_EMPTY_PATH
For name_to_handle_at(2) we'll want both ...at()-style syscall that would be usable for non-directory descriptors (with empty relative pathname). Introduce new flag (AT_EMPTY_PATH) to deal with that and corresponding LOOKUP_EMPTY; teach user_path_at() and path_init() to deal with the latter. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Showing 3 changed files with 21 additions and 10 deletions Side-by-side Diff
fs/namei.c
| ... | ... | @@ -136,7 +136,7 @@ |
| 136 | 136 | return retval; |
| 137 | 137 | } |
| 138 | 138 | |
| 139 | -char * getname(const char __user * filename) | |
| 139 | +static char *getname_flags(const char __user * filename, int flags) | |
| 140 | 140 | { |
| 141 | 141 | char *tmp, *result; |
| 142 | 142 | |
| 143 | 143 | |
| ... | ... | @@ -147,14 +147,21 @@ |
| 147 | 147 | |
| 148 | 148 | result = tmp; |
| 149 | 149 | if (retval < 0) { |
| 150 | - __putname(tmp); | |
| 151 | - result = ERR_PTR(retval); | |
| 150 | + if (retval != -ENOENT || !(flags & LOOKUP_EMPTY)) { | |
| 151 | + __putname(tmp); | |
| 152 | + result = ERR_PTR(retval); | |
| 153 | + } | |
| 152 | 154 | } |
| 153 | 155 | } |
| 154 | 156 | audit_getname(result); |
| 155 | 157 | return result; |
| 156 | 158 | } |
| 157 | 159 | |
| 160 | +char *getname(const char __user * filename) | |
| 161 | +{ | |
| 162 | + return getname_flags(filename, 0); | |
| 163 | +} | |
| 164 | + | |
| 158 | 165 | #ifdef CONFIG_AUDITSYSCALL |
| 159 | 166 | void putname(const char *name) |
| 160 | 167 | { |
| 161 | 168 | |
| ... | ... | @@ -1544,13 +1551,15 @@ |
| 1544 | 1551 | |
| 1545 | 1552 | dentry = file->f_path.dentry; |
| 1546 | 1553 | |
| 1547 | - retval = -ENOTDIR; | |
| 1548 | - if (!S_ISDIR(dentry->d_inode->i_mode)) | |
| 1549 | - goto fput_fail; | |
| 1554 | + if (*name) { | |
| 1555 | + retval = -ENOTDIR; | |
| 1556 | + if (!S_ISDIR(dentry->d_inode->i_mode)) | |
| 1557 | + goto fput_fail; | |
| 1550 | 1558 | |
| 1551 | - retval = file_permission(file, MAY_EXEC); | |
| 1552 | - if (retval) | |
| 1553 | - goto fput_fail; | |
| 1559 | + retval = file_permission(file, MAY_EXEC); | |
| 1560 | + if (retval) | |
| 1561 | + goto fput_fail; | |
| 1562 | + } | |
| 1554 | 1563 | |
| 1555 | 1564 | nd->path = file->f_path; |
| 1556 | 1565 | if (flags & LOOKUP_RCU) { |
| ... | ... | @@ -1759,7 +1768,7 @@ |
| 1759 | 1768 | struct path *path) |
| 1760 | 1769 | { |
| 1761 | 1770 | struct nameidata nd; |
| 1762 | - char *tmp = getname(name); | |
| 1771 | + char *tmp = getname_flags(name, flags); | |
| 1763 | 1772 | int err = PTR_ERR(tmp); |
| 1764 | 1773 | if (!IS_ERR(tmp)) { |
| 1765 | 1774 |
include/linux/fcntl.h
| ... | ... | @@ -46,6 +46,7 @@ |
| 46 | 46 | unlinking file. */ |
| 47 | 47 | #define AT_SYMLINK_FOLLOW 0x400 /* Follow symbolic links. */ |
| 48 | 48 | #define AT_NO_AUTOMOUNT 0x800 /* Suppress terminal automount traversal */ |
| 49 | +#define AT_EMPTY_PATH 0x1000 /* Allow empty relative pathname */ | |
| 49 | 50 | |
| 50 | 51 | #ifdef __KERNEL__ |
| 51 | 52 |