Don't allow chmod() on the /proc// files This just turns off chmod() on the /proc// files, since there is no good reason to allow it, and had we disallowed it originally, the nasty /proc race exploit wouldn't have been possible. The other patches already fixed the problem chmod() could cause, so this is really just some final mop-up.. This particular version is based off a patch by Eugene and Marcel which had much better naming than my original equivalent one. Signed-off-by: Eugene Teo Signed-off-by: Marcel Holtmann Signed-off-by: Linus Torvalds --- commit 5aa433ab7de5110cc76d19763e2e6424279bcf79 tree 51ce3e286807c56567eb05ec835e7c3d84f42eba parent 245b3c810f1d09ac27f326346cb58451556ecc0b author Marcel Holtmann Sun, 16 Jul 2006 02:13:16 +0200 committer Marcel Holtmann Sun, 16 Jul 2006 02:13:16 +0200 fs/proc/base.c | 33 ++++++++++++++++++++++++++++++++- 1 files changed, 32 insertions(+), 1 deletions(-) diff --git a/fs/proc/base.c b/fs/proc/base.c index f801693..a3b825f 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -596,6 +596,27 @@ static int proc_permission(struct inode return proc_check_root(inode); } +static int proc_setattr(struct dentry *dentry, struct iattr *attr) +{ + int error; + struct inode *inode = dentry->d_inode; + + if (attr->ia_valid & ATTR_MODE) + return -EPERM; + + error = inode_change_ok(inode, attr); + if (!error) { + error = security_inode_setattr(dentry, attr); + if (!error) + error = inode_setattr(inode, attr); + } + return error; +} + +static struct inode_operations proc_def_inode_operations = { + .setattr = proc_setattr, +}; + static int proc_task_permission(struct inode *inode, int mask, struct nameidata *nd) { struct dentry *root; @@ -987,6 +1008,7 @@ static struct file_operations proc_oom_a static struct inode_operations proc_mem_inode_operations = { .permission = proc_permission, + .setattr = proc_setattr, }; #ifdef CONFIG_AUDITSYSCALL @@ -1184,7 +1206,8 @@ out: static struct inode_operations proc_pid_link_inode_operations = { .readlink = proc_pid_readlink, - .follow_link = proc_pid_follow_link + .follow_link = proc_pid_follow_link, + .setattr = proc_setattr, }; #define NUMBUF 10 @@ -1356,6 +1379,7 @@ static struct inode *proc_pid_make_inode ei->task = NULL; inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME; inode->i_ino = fake_ino(task->pid, ino); + inode->i_op = &proc_def_inode_operations; if (!pid_alive(task)) goto out_unlock; @@ -1579,11 +1603,13 @@ static struct file_operations proc_task_ static struct inode_operations proc_fd_inode_operations = { .lookup = proc_lookupfd, .permission = proc_permission, + .setattr = proc_setattr, }; static struct inode_operations proc_task_inode_operations = { .lookup = proc_task_lookup, .permission = proc_task_permission, + .setattr = proc_setattr, }; #ifdef CONFIG_SECURITY @@ -1873,10 +1899,12 @@ static struct file_operations proc_tid_b static struct inode_operations proc_tgid_base_inode_operations = { .lookup = proc_tgid_base_lookup, + .setattr = proc_setattr, }; static struct inode_operations proc_tid_base_inode_operations = { .lookup = proc_tid_base_lookup, + .setattr = proc_setattr, }; #ifdef CONFIG_SECURITY @@ -1918,10 +1946,12 @@ static struct dentry *proc_tid_attr_look static struct inode_operations proc_tgid_attr_inode_operations = { .lookup = proc_tgid_attr_lookup, + .setattr = proc_setattr, }; static struct inode_operations proc_tid_attr_inode_operations = { .lookup = proc_tid_attr_lookup, + .setattr = proc_setattr, }; #endif @@ -1946,6 +1976,7 @@ static void *proc_self_follow_link(struc static struct inode_operations proc_self_inode_operations = { .readlink = proc_self_readlink, .follow_link = proc_self_follow_link, + .setattr = proc_setattr, }; /**