From: Danny Feng <dfeng@redhat.com> Date: Fri, 12 Nov 2010 09:53:45 -0500 Subject: [ipc] sys_semctl: fix kernel stack leakage Message-id: <20101112095345.23651.17710.sendpatchset@danny.redhat> Patchwork-id: 29205 O-Subject: [PATCH RHEL5.6] sys_semctl: fix kernel stack leakage Bugzilla: 648722 CVE: CVE-2010-4083 RH-Acked-by: Amerigo Wang <amwang@redhat.com> RH-Acked-by: Dean Nelson <dnelson@redhat.com> RH-Acked-by: Jiri Pirko <jpirko@redhat.com> Backport of: commit 982f7c2b2e6a28f8f266e075d92e19c0dd4c6e56 Author: Dan Rosenberg <drosenberg@vsecurity.com> Date: Thu Sep 30 15:15:31 2010 -0700 sys_semctl: fix kernel stack leakage The semctl syscall has several code paths that lead to the leakage of uninitialized kernel stack memory (namely the IPC_INFO, SEM_INFO, IPC_STAT, and SEM_STAT commands) during the use of the older, obsolete version of the semid_ds struct. The copy_semid_to_user() function declares a semid_ds struct on the stack and copies it back to the user without initializing or zeroing the "sem_base", "sem_pending", "sem_pending_last", and "undo" pointers, allowing the leakage of 16 bytes of kernel stack memory. The code is still reachable on 32-bit systems - when calling semctl() newer glibc's automatically OR the IPC command with the IPC_64 flag, but invoking the syscall directly allows users to use the older versions of the struct. Signed-off-by: Dan Rosenberg <dan.j.rosenberg@gmail.com> Cc: Manfred Spraul <manfred@colorfullife.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Fixes bz648722 Aka CVE-2010-4083 diff --git a/ipc/sem.c b/ipc/sem.c index 6013c75..c6a8329 100644 --- a/ipc/sem.c +++ b/ipc/sem.c @@ -490,6 +490,8 @@ static unsigned long copy_semid_to_user(void __user *buf, struct semid64_ds *in, { struct semid_ds out; + memset(&out, 0, sizeof(out)); + ipc64_perm_to_ipc_perm(&in->sem_perm, &out.sem_perm); out.sem_otime = in->sem_otime;