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[PATCH] permission checks for chdir need special treatment only on the last step

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... so we ought to pass MAY_CHDIR to vfs_permission() instead of having
it triggered on every step of preceding pathname resolution.  LOOKUP_CHDIR
is killed by that.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro
2008-07-16 09:51:03 -04:00
parent db2e747b14
commit 8bb79224b8
3 changed files with 2 additions and 6 deletions
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2
fs/namei.c
View File

@@ -268,8 +268,6 @@ int permission(struct inode *inode, int mask, struct nameidata *nd)
if (nd) { if (nd) {
if (nd->flags & LOOKUP_ACCESS) if (nd->flags & LOOKUP_ACCESS)
extra |= MAY_ACCESS; extra |= MAY_ACCESS;
if (nd->flags & LOOKUP_CHDIR)
extra |= MAY_CHDIR;
if (nd->flags & LOOKUP_OPEN) if (nd->flags & LOOKUP_OPEN)
extra |= MAY_OPEN; extra |= MAY_OPEN;
} }

5
fs/open.c
View File

@@ -501,12 +501,11 @@ asmlinkage long sys_chdir(const char __user * filename)
struct nameidata nd; struct nameidata nd;
int error; int error;
error = __user_walk(filename, error = __user_walk(filename, LOOKUP_FOLLOW|LOOKUP_DIRECTORY, &nd);
LOOKUP_FOLLOW|LOOKUP_DIRECTORY|LOOKUP_CHDIR, &nd);
if (error) if (error)
goto out; goto out;
error = vfs_permission(&nd, MAY_EXEC); error = vfs_permission(&nd, MAY_EXEC | MAY_CHDIR);
if (error) if (error)
goto dput_and_out; goto dput_and_out;

1
include/linux/namei.h
View File

@@ -55,7 +55,6 @@ enum {LAST_NORM, LAST_ROOT, LAST_DOT, LAST_DOTDOT, LAST_BIND};
#define LOOKUP_OPEN (0x0100) #define LOOKUP_OPEN (0x0100)
#define LOOKUP_CREATE (0x0200) #define LOOKUP_CREATE (0x0200)
#define LOOKUP_ACCESS (0x0400) #define LOOKUP_ACCESS (0x0400)
#define LOOKUP_CHDIR (0x0800)
extern int __user_walk(const char __user *, unsigned, struct nameidata *); extern int __user_walk(const char __user *, unsigned, struct nameidata *);
extern int __user_walk_fd(int dfd, const char __user *, unsigned, struct nameidata *); extern int __user_walk_fd(int dfd, const char __user *, unsigned, struct nameidata *);