Messages in this thread Patch in this message | | | Date | Sat, 3 Jul 2004 22:22:42 +0200 | From | Herbert Poetzl <> | Subject | procfs permissions on 2.6.x |
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Hi Andrew!
stumbled over the following detail ...
usually when somebody tries to modify an inode, notify_change() calls inode_change_ok() to verify the user's permissions ... now it seems that somewhere around 2.5.41, a patch similar to this one was included into the mainline, and remained almost unmodified ...
http://www.uwsg.iu.edu/hypermail/linux/kernel/0210.1/1002.html
this probably unintentionally circumvents the inode_change_ok() check, so that now any user can modify inodes of the procfs.
example:
$ chmod a-rwx /proc/cmdline
the following patch hopefully fixes this, so please consider for inclusion ...
TIA, Herbert
diff -NurpP --minimal linux-2.6.7/fs/proc/generic.c linux-2.6.7-fix/fs/proc/generic.c --- linux-2.6.7/fs/proc/generic.c 2004-06-16 07:20:26.000000000 +0200 +++ linux-2.6.7-fix/fs/proc/generic.c 2004-07-03 21:50:30.000000000 +0200 @@ -241,8 +241,20 @@ static int proc_notify_change(struct den return error; } +static int proc_setattr(struct dentry *dentry, struct iattr *iattr) +{ + struct inode *inode = dentry->d_inode; + int error; + + error = inode_change_ok(inode, iattr); + if (error) + return error; + error = proc_notify_change(dentry, iattr); + return error; +} + static struct inode_operations proc_file_inode_operations = { - .setattr = proc_notify_change, + .setattr = proc_setattr, }; /* @@ -472,7 +484,7 @@ static struct file_operations proc_dir_o */ static struct inode_operations proc_dir_inode_operations = { .lookup = proc_lookup, - .setattr = proc_notify_change, + .setattr = proc_setattr, }; static int proc_register(struct proc_dir_entry * dir, struct proc_dir_entry * dp) - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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