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Diffstat (limited to 'fs/namei.c')
-rw-r--r--fs/namei.c110
1 files changed, 60 insertions, 50 deletions
diff --git a/fs/namei.c b/fs/namei.c
index f3c5b278895a..d11f404667e9 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -169,19 +169,10 @@ void putname(const char *name)
EXPORT_SYMBOL(putname);
#endif
-
-/**
- * generic_permission - check for access rights on a Posix-like filesystem
- * @inode: inode to check access rights for
- * @mask: right to check for (%MAY_READ, %MAY_WRITE, %MAY_EXEC)
- * @check_acl: optional callback to check for Posix ACLs
- *
- * Used to check for read/write/execute permissions on a file.
- * We use "fsuid" for this, letting us set arbitrary permissions
- * for filesystem access without changing the "normal" uids which
- * are used for other things..
+/*
+ * This does basic POSIX ACL permission checking
*/
-int generic_permission(struct inode *inode, int mask,
+static int acl_permission_check(struct inode *inode, int mask,
int (*check_acl)(struct inode *inode, int mask))
{
umode_t mode = inode->i_mode;
@@ -193,9 +184,7 @@ int generic_permission(struct inode *inode, int mask,
else {
if (IS_POSIXACL(inode) && (mode & S_IRWXG) && check_acl) {
int error = check_acl(inode, mask);
- if (error == -EACCES)
- goto check_capabilities;
- else if (error != -EAGAIN)
+ if (error != -EAGAIN)
return error;
}
@@ -208,8 +197,32 @@ int generic_permission(struct inode *inode, int mask,
*/
if ((mask & ~mode) == 0)
return 0;
+ return -EACCES;
+}
+
+/**
+ * generic_permission - check for access rights on a Posix-like filesystem
+ * @inode: inode to check access rights for
+ * @mask: right to check for (%MAY_READ, %MAY_WRITE, %MAY_EXEC)
+ * @check_acl: optional callback to check for Posix ACLs
+ *
+ * Used to check for read/write/execute permissions on a file.
+ * We use "fsuid" for this, letting us set arbitrary permissions
+ * for filesystem access without changing the "normal" uids which
+ * are used for other things..
+ */
+int generic_permission(struct inode *inode, int mask,
+ int (*check_acl)(struct inode *inode, int mask))
+{
+ int ret;
+
+ /*
+ * Do the basic POSIX ACL permission checks.
+ */
+ ret = acl_permission_check(inode, mask, check_acl);
+ if (ret != -EACCES)
+ return ret;
- check_capabilities:
/*
* Read/write DACs are always overridable.
* Executable DACs are overridable if at least one exec bit is set.
@@ -262,7 +275,7 @@ int inode_permission(struct inode *inode, int mask)
if (inode->i_op->permission)
retval = inode->i_op->permission(inode, mask);
else
- retval = generic_permission(inode, mask, NULL);
+ retval = generic_permission(inode, mask, inode->i_op->check_acl);
if (retval)
return retval;
@@ -432,29 +445,22 @@ static struct dentry * cached_lookup(struct dentry * parent, struct qstr * name,
*/
static int exec_permission_lite(struct inode *inode)
{
- umode_t mode = inode->i_mode;
+ int ret;
- if (inode->i_op->permission)
- return -EAGAIN;
-
- if (current_fsuid() == inode->i_uid)
- mode >>= 6;
- else if (in_group_p(inode->i_gid))
- mode >>= 3;
-
- if (mode & MAY_EXEC)
- goto ok;
-
- if ((inode->i_mode & S_IXUGO) && capable(CAP_DAC_OVERRIDE))
- goto ok;
-
- if (S_ISDIR(inode->i_mode) && capable(CAP_DAC_OVERRIDE))
+ if (inode->i_op->permission) {
+ ret = inode->i_op->permission(inode, MAY_EXEC);
+ if (!ret)
+ goto ok;
+ return ret;
+ }
+ ret = acl_permission_check(inode, MAY_EXEC, inode->i_op->check_acl);
+ if (!ret)
goto ok;
- if (S_ISDIR(inode->i_mode) && capable(CAP_DAC_READ_SEARCH))
+ if (capable(CAP_DAC_OVERRIDE) || capable(CAP_DAC_READ_SEARCH))
goto ok;
- return -EACCES;
+ return ret;
ok:
return security_inode_permission(inode, MAY_EXEC);
}
@@ -853,12 +859,6 @@ static int __link_path_walk(const char *name, struct nameidata *nd)
nd->flags |= LOOKUP_CONTINUE;
err = exec_permission_lite(inode);
- if (err == -EAGAIN)
- err = inode_permission(nd->path.dentry->d_inode,
- MAY_EXEC);
- if (!err)
- err = ima_path_check(&nd->path, MAY_EXEC,
- IMA_COUNT_UPDATE);
if (err)
break;
@@ -1533,37 +1533,42 @@ int may_open(struct path *path, int acc_mode, int flag)
if (error)
return error;
- error = ima_path_check(path,
- acc_mode & (MAY_READ | MAY_WRITE | MAY_EXEC),
+ error = ima_path_check(path, acc_mode ?
+ acc_mode & (MAY_READ | MAY_WRITE | MAY_EXEC) :
+ ACC_MODE(flag) & (MAY_READ | MAY_WRITE),
IMA_COUNT_UPDATE);
+
if (error)
return error;
/*
* An append-only file must be opened in append mode for writing.
*/
if (IS_APPEND(inode)) {
+ error = -EPERM;
if ((flag & FMODE_WRITE) && !(flag & O_APPEND))
- return -EPERM;
+ goto err_out;
if (flag & O_TRUNC)
- return -EPERM;
+ goto err_out;
}
/* O_NOATIME can only be set by the owner or superuser */
if (flag & O_NOATIME)
- if (!is_owner_or_cap(inode))
- return -EPERM;
+ if (!is_owner_or_cap(inode)) {
+ error = -EPERM;
+ goto err_out;
+ }
/*
* Ensure there are no outstanding leases on the file.
*/
error = break_lease(inode, flag);
if (error)
- return error;
+ goto err_out;
if (flag & O_TRUNC) {
error = get_write_access(inode);
if (error)
- return error;
+ goto err_out;
/*
* Refuse to truncate files with mandatory locks held on them.
@@ -1581,12 +1586,17 @@ int may_open(struct path *path, int acc_mode, int flag)
}
put_write_access(inode);
if (error)
- return error;
+ goto err_out;
} else
if (flag & FMODE_WRITE)
vfs_dq_init(inode);
return 0;
+err_out:
+ ima_counts_put(path, acc_mode ?
+ acc_mode & (MAY_READ | MAY_WRITE | MAY_EXEC) :
+ ACC_MODE(flag) & (MAY_READ | MAY_WRITE));
+ return error;
}
/*