Messages in this thread Patch in this message | | | Date | Fri, 16 Jun 2006 14:41:57 +0200 | From | Petr Baudis <> | Subject | [RESEND][PATCH] Let even non-dumpable tasks access /proc/self/fd |
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All tasks calling setuid() from root to non-root during their lifetime will not be able to access their /proc/self/fd. This is troublesome because the fstatat() and other *at() routines are emulated by accessing /proc/self/fd/*/path and that will break with setuid()ing programs, leading to various weird consequences (e.g. with the latest glibc, nftw() does not work with setuid()ing programs on ppc and furthermore causes the LSB testsuite to fail because of this).
This kernel patch fixes the problem by letting the process access its own /proc/self/fd - as far as I can see, this should be reasonably safe since for the process, this does not reveal "anything new". Feel free to comment on this.
Signed-off-by: Petr Baudis <pasky@suse.cz>
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So far it's got one positive review on LKML and not much attention otherwise; Pavel Machek hinted me to steer it your way...
diff --git a/fs/proc/base.c b/fs/proc/base.c index 6cc77dc..ea36a25 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -1368,7 +1368,9 @@ static struct inode *proc_pid_make_inode ei->type = ino; inode->i_uid = 0; inode->i_gid = 0; - if (ino == PROC_TGID_INO || ino == PROC_TID_INO || task_dumpable(task)) { + if (ino == PROC_TGID_INO || ino == PROC_TID_INO || + ((ino == PROC_TGID_FD || ino == PROC_TID_FD || ino >= PROC_TID_FD_DIR) && task == current) || + task_dumpable(task)) { inode->i_uid = task->euid; inode->i_gid = task->egid; } @@ -1398,7 +1400,9 @@ static int pid_revalidate(struct dentry struct inode *inode = dentry->d_inode; struct task_struct *task = proc_task(inode); if (pid_alive(task)) { - if (proc_type(inode) == PROC_TGID_INO || proc_type(inode) == PROC_TID_INO || task_dumpable(task)) { + if (proc_type(inode) == PROC_TGID_INO || proc_type(inode) == PROC_TID_INO || + ((proc_type(inode) == PROC_TGID_FD || proc_type(inode) == PROC_TID_FD) && task == current) || + task_dumpable(task)) { inode->i_uid = task->euid; inode->i_gid = task->egid; } else { @@ -1425,7 +1429,7 @@ static int tid_fd_revalidate(struct dent if (fcheck_files(files, fd)) { rcu_read_unlock(); put_files_struct(files); - if (task_dumpable(task)) { + if (task_dumpable(task) || task == current) { inode->i_uid = task->euid; inode->i_gid = task->egid; } else {
-- Petr "Pasky" Baudis Stuff: http://pasky.or.cz/ Right now I am having amnesia and deja-vu at the same time. I think I have forgotten this before. - 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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