| Message ID | 1296840411-29109-2-git-send-email-brad.figg@canonical.com |
|---|---|
| State | Accepted |
| Commit | 52f9e7f06dd1ef26c9103c07aa574c08bd9c11c3 |
| Headers | show |
On 02/04/2011 10:26 AM, Brad Figg wrote: > From: Dan Rosenberg<drosenberg@vsecurity.com> > > CVE-2010-4083 > > BugLink: http://bugs.launchpad.net/bugs/712749 > > 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> > > (cherry-picked from commit 982f7c2b2e6a28f8f266e075d92e19c0dd4c6e56) > Signed-off-by: Brad Figg<brad.figg@canonical.com> > --- > ipc/sem.c | 2 ++ > 1 files changed, 2 insertions(+), 0 deletions(-) > > diff --git a/ipc/sem.c b/ipc/sem.c > index 40a8f46..0e0d49b 100644 > --- a/ipc/sem.c > +++ b/ipc/sem.c > @@ -743,6 +743,8 @@ 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; Acked-by: Tim Gardner <tim.gardner@canonical.com>
On 02/04/2011 06:26 PM, Brad Figg wrote: > From: Dan Rosenberg <drosenberg@vsecurity.com> > > CVE-2010-4083 > > BugLink: http://bugs.launchpad.net/bugs/712749 > > 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> > > (cherry-picked from commit 982f7c2b2e6a28f8f266e075d92e19c0dd4c6e56) > Signed-off-by: Brad Figg <brad.figg@canonical.com> Acked-by: Stefan Bader <stefan.bader@canonical.com> > --- > ipc/sem.c | 2 ++ > 1 files changed, 2 insertions(+), 0 deletions(-) > > diff --git a/ipc/sem.c b/ipc/sem.c > index 40a8f46..0e0d49b 100644 > --- a/ipc/sem.c > +++ b/ipc/sem.c > @@ -743,6 +743,8 @@ 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;
diff --git a/ipc/sem.c b/ipc/sem.c index 40a8f46..0e0d49b 100644 --- a/ipc/sem.c +++ b/ipc/sem.c @@ -743,6 +743,8 @@ 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;