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authorJan Kara <jack@suse.cz>2015-05-21 16:05:55 +0200
committerAl Viro <viro@zeniv.linux.org.uk>2015-06-23 18:01:09 -0400
commit45f147a1bc97c743c6101a8d2741c69a51f583e4 (patch)
treeb7919ca80674bc1793b4423957f4d61c8100408d /fs
parentdbfae0cdcd87602737101d4417811f4323156b54 (diff)
downloadop-kernel-dev-45f147a1bc97c743c6101a8d2741c69a51f583e4.zip
op-kernel-dev-45f147a1bc97c743c6101a8d2741c69a51f583e4.tar.gz
fs: Call security_ops->inode_killpriv on truncate
Comment in include/linux/security.h says that ->inode_killpriv() should be called when setuid bit is being removed and that similar security labels (in fact this applies only to file capabilities) should be removed at this time as well. However we don't call ->inode_killpriv() when we remove suid bit on truncate. We fix the problem by calling ->inode_need_killpriv() and subsequently ->inode_killpriv() on truncate the same way as we do it on file write. After this patch there's only one user of should_remove_suid() - ocfs2 - and indeed it's buggy because it doesn't call ->inode_killpriv() on write. However fixing it is difficult because of special locking constraints. Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'fs')
-rw-r--r--fs/inode.c5
-rw-r--r--fs/open.c6
2 files changed, 6 insertions, 5 deletions
diff --git a/fs/inode.c b/fs/inode.c
index 8c2dd74..0401d2c 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -1678,9 +1678,8 @@ EXPORT_SYMBOL(should_remove_suid);
* response to write or truncate. Return 0 if nothing has to be changed.
* Negative value on error (change should be denied).
*/
-int file_needs_remove_privs(struct file *file)
+int dentry_needs_remove_privs(struct dentry *dentry)
{
- struct dentry *dentry = file->f_path.dentry;
struct inode *inode = d_inode(dentry);
int mask = 0;
int ret;
@@ -1696,7 +1695,7 @@ int file_needs_remove_privs(struct file *file)
mask |= ATTR_KILL_PRIV;
return mask;
}
-EXPORT_SYMBOL(file_needs_remove_privs);
+EXPORT_SYMBOL(dentry_needs_remove_privs);
static int __remove_privs(struct dentry *dentry, int kill)
{
diff --git a/fs/open.c b/fs/open.c
index 1dbc793..e33dab2 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -51,8 +51,10 @@ int do_truncate(struct dentry *dentry, loff_t length, unsigned int time_attrs,
newattrs.ia_valid |= ATTR_FILE;
}
- /* Remove suid/sgid on truncate too */
- ret = should_remove_suid(dentry);
+ /* Remove suid, sgid, and file capabilities on truncate too */
+ ret = dentry_needs_remove_privs(dentry);
+ if (ret < 0)
+ return ret;
if (ret)
newattrs.ia_valid |= ret | ATTR_FORCE;
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