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authorAlexey Dobriyan <adobriyan@openvz.org>2007-05-08 00:23:35 -0700
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-05-08 11:14:58 -0700
commit8948e11f450e6189a79e47d6051c3d5a0b98e3f3 (patch)
tree8cc904873cc1a8506970cf1e4a328c318a7fc4d7
parentab1b6f03a10ba1f5638188ab06bf46e33ac3a160 (diff)
Allow access to /proc/$PID/fd after setuid()
/proc/$PID/fd has r-x------ permissions, so if process does setuid(), it will not be able to access /proc/*/fd/. This breaks fstatat() emulation in glibc. open("foo", O_RDONLY|O_DIRECTORY) = 4 setuid32(65534) = 0 stat64("/proc/self/fd/4/bar", 0xbfafb298) = -1 EACCES (Permission denied) Signed-off-by: Alexey Dobriyan <adobriyan@openvz.org> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: James Morris <jmorris@namei.org> Cc: Chris Wright <chrisw@sous-sol.org> Cc: Ulrich Drepper <drepper@redhat.com> Cc: Oleg Nesterov <oleg@tv-sign.ru> Acked-By: Kirill Korotaev <dev@openvz.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--fs/proc/base.c18
1 files changed, 18 insertions, 0 deletions
diff --git a/fs/proc/base.c b/fs/proc/base.c
index ec158dd02b3..a721acfd4fd 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -1448,10 +1448,28 @@ static const struct file_operations proc_fd_operations = {
};
/*
+ * /proc/pid/fd needs a special permission handler so that a process can still
+ * access /proc/self/fd after it has executed a setuid().
+ */
+static int proc_fd_permission(struct inode *inode, int mask,
+ struct nameidata *nd)
+{
+ int rv;
+
+ rv = generic_permission(inode, mask, NULL);
+ if (rv == 0)
+ return 0;
+ if (task_pid(current) == proc_pid(inode))
+ rv = 0;
+ return rv;
+}
+
+/*
* proc directories can do almost nothing..
*/
static const struct inode_operations proc_fd_inode_operations = {
.lookup = proc_lookupfd,
+ .permission = proc_fd_permission,
.setattr = proc_setattr,
};