Fix denial of service - memory corruption.

CVE-2011-0719

Fix bug #7949 (DoS in Winbind and smbd with many file descriptors open).

All current released versions of Samba are vulnerable to
a denial of service caused by memory corruption. Range
checks on file descriptors being used in the FD_SET macro
were not present allowing stack corruption. This can cause
the Samba code to crash or to loop attempting to select
on a bad file descriptor set.

A connection to a file share, or a local account is needed
to exploit this problem, either authenticated or unauthenticated
(guest connection).

Currently we do not believe this flaw is exploitable
beyond a crash or causing the code to loop, but on the
advice of our security reviewers we are releasing fixes
in case an exploit is discovered at a later date.

1 files changed, 5 insertions, 0 deletions

diff --git a/source/smbd/oplock_irix.c b/source/smbd/oplock_irix.c
index 8c287c9836e..6e86fac65b2 100644
--- a/source/smbd/oplock_irix.c
+++ b/source/smbd/oplock_irix.c
@@ -284,6 +284,11 @@ struct kernel_oplocks *irix_init_kernel_oplocks(void)
 		return False;
 	}
 
+	if (pfd[0] < 0 || pfd[0] >= FD_SETSIZE) {
+		DEBUG(0,("setup_kernel_oplock_pipe: fd out of range.\n"));
+		return False;
+	}
+
 	oplock_pipe_read = pfd[0];
 	oplock_pipe_write = pfd[1];