diff options
| author | Dan Rosenberg <drosenberg@vsecurity.com> | 2010-09-30 15:15:31 -0700 |
|---|---|---|
| committer | Paul Gortmaker <paul.gortmaker@windriver.com> | 2011-04-17 16:15:41 -0400 |
| commit | cdae69720bf88450fabc93f1e2ded4a8e53b8dd4 (patch) | |
| tree | c9afe69a4819e96892a233ef95b59d036d2d34a6 /ipc | |
| parent | 3a0d44ddfa469f86c16c8daf005a372b19ea1f9e (diff) | |
sys_semctl: fix kernel stack leakage
commit 982f7c2b2e6a28f8f266e075d92e19c0dd4c6e56 upstream.
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>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Diffstat (limited to 'ipc')
| -rw-r--r-- | ipc/sem.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/ipc/sem.c b/ipc/sem.c index dbef95b15941..b4c1641a33a1 100644 --- a/ipc/sem.c +++ b/ipc/sem.c @@ -608,6 +608,8 @@ 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; |