vfs: coredumping fix

fix: http://bugzilla.kernel.org/show_bug.cgi?id=3043

only allow coredumping to the same uid that the coredumping
task runs under.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Acked-by: Alan Cox <alan@redhat.com>
Acked-by: Christoph Hellwig <hch@lst.de>
Acked-by: Al Viro <viro@ftp.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/fs/exec.c b/fs/exec.c
index 4ccaaa4..282240a 100644 (file)
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -1780,6 +1780,12 @@ int do_coredump(long signr, int exit_code, struct pt_regs * regs)
           but keep the previous behaviour for now. */
        if (!ispipe && !S_ISREG(inode->i_mode))
                goto close_fail;
+       /*
+        * Dont allow local users get cute and trick others to coredump
+        * into their pre-created files:
+        */
+       if (inode->i_uid != current->fsuid)
+               goto close_fail;
        if (!file->f_op)
                goto close_fail;
        if (!file->f_op->write)