| Message ID | 1306426975-31462-2-git-send-email-apw@canonical.com |
|---|---|
| State | New |
| Headers | show |
On 05/26/2011 10:22 AM, Andy Whitcroft wrote: > From: Vasiliy Kulikov<segoon@openwall.com> > > page_count is copied from userspace. agp_allocate_memory() tries to > check whether this number is too big, but doesn't take into account the > wrap case. Also agp_create_user_memory() doesn't check whether > alloc_size is calculated from num_agp_pages variable without overflow. > This may lead to allocation of too small buffer with following buffer > overflow. > > Another problem in agp code is not addressed in the patch - kernel memory > exhaustion (AGPIOC_RESERVE and AGPIOC_ALLOCATE ioctls). It is not checked > whether requested pid is a pid of the caller (no check in agpioc_reserve_wrap()). > Each allocation is limited to 16KB, though, there is no per-process limit. > This might lead to OOM situation, which is not even solved in case of the > caller death by OOM killer - the memory is allocated for another (faked) process. > > Signed-off-by: Vasiliy Kulikov<segoon@openwall.com> > Signed-off-by: Dave Airlie<airlied@redhat.com> > > CVE-2011-1747 > BugLink: http://bugs.launchpad.net/bugs/788700 > (cherry picked from commit b522f02184b413955f3bc952e3776ce41edc6355) > Signed-off-by: Andy Whitcroft<apw@canonical.com> > --- > drivers/char/agp/generic.c | 8 +++++++- > 1 files changed, 7 insertions(+), 1 deletions(-) > > diff --git a/drivers/char/agp/generic.c b/drivers/char/agp/generic.c > index d2abf51..3d852bf 100644 > --- a/drivers/char/agp/generic.c > +++ b/drivers/char/agp/generic.c > @@ -122,6 +122,9 @@ static struct agp_memory *agp_create_user_memory(unsigned long num_agp_pages) > struct agp_memory *new; > unsigned long alloc_size = num_agp_pages*sizeof(struct page *); > > + if (INT_MAX/sizeof(struct page *)< num_agp_pages) > + return NULL; > + > new = kzalloc(sizeof(struct agp_memory), GFP_KERNEL); > if (new == NULL) > return NULL; > @@ -241,11 +244,14 @@ struct agp_memory *agp_allocate_memory(struct agp_bridge_data *bridge, > int scratch_pages; > struct agp_memory *new; > size_t i; > + int cur_memory; > > if (!bridge) > return NULL; > > - if ((atomic_read(&bridge->current_memory_agp) + page_count)> bridge->max_memory_agp) > + cur_memory = atomic_read(&bridge->current_memory_agp); > + if ((cur_memory + page_count> bridge->max_memory_agp) || > + (cur_memory + page_count< page_count)) > return NULL; > > if (type>= AGP_USER_TYPES) { Acked-by: Tim Gardner <tim.gardner@canonical.com>
On Thu, 2011-05-26 at 17:22 +0100, Andy Whitcroft wrote: > From: Vasiliy Kulikov <segoon@openwall.com> > > page_count is copied from userspace. agp_allocate_memory() tries to > check whether this number is too big, but doesn't take into account the > wrap case. Also agp_create_user_memory() doesn't check whether > alloc_size is calculated from num_agp_pages variable without overflow. > This may lead to allocation of too small buffer with following buffer > overflow. > > Another problem in agp code is not addressed in the patch - kernel memory > exhaustion (AGPIOC_RESERVE and AGPIOC_ALLOCATE ioctls). It is not checked > whether requested pid is a pid of the caller (no check in agpioc_reserve_wrap()). > Each allocation is limited to 16KB, though, there is no per-process limit. > This might lead to OOM situation, which is not even solved in case of the > caller death by OOM killer - the memory is allocated for another (faked) process. > > Signed-off-by: Vasiliy Kulikov <segoon@openwall.com> > Signed-off-by: Dave Airlie <airlied@redhat.com> > > CVE-2011-1747 > BugLink: http://bugs.launchpad.net/bugs/788700 > (cherry picked from commit b522f02184b413955f3bc952e3776ce41edc6355) > Signed-off-by: Andy Whitcroft <apw@canonical.com> Acked-by: Leann Ogasawara <leann.ogasawara@canonical.com> > --- > drivers/char/agp/generic.c | 8 +++++++- > 1 files changed, 7 insertions(+), 1 deletions(-) > > diff --git a/drivers/char/agp/generic.c b/drivers/char/agp/generic.c > index d2abf51..3d852bf 100644 > --- a/drivers/char/agp/generic.c > +++ b/drivers/char/agp/generic.c > @@ -122,6 +122,9 @@ static struct agp_memory *agp_create_user_memory(unsigned long num_agp_pages) > struct agp_memory *new; > unsigned long alloc_size = num_agp_pages*sizeof(struct page *); > > + if (INT_MAX/sizeof(struct page *) < num_agp_pages) > + return NULL; > + > new = kzalloc(sizeof(struct agp_memory), GFP_KERNEL); > if (new == NULL) > return NULL; > @@ -241,11 +244,14 @@ struct agp_memory *agp_allocate_memory(struct agp_bridge_data *bridge, > int scratch_pages; > struct agp_memory *new; > size_t i; > + int cur_memory; > > if (!bridge) > return NULL; > > - if ((atomic_read(&bridge->current_memory_agp) + page_count) > bridge->max_memory_agp) > + cur_memory = atomic_read(&bridge->current_memory_agp); > + if ((cur_memory + page_count > bridge->max_memory_agp) || > + (cur_memory + page_count < page_count)) > return NULL; > > if (type >= AGP_USER_TYPES) { > -- > 1.7.4.1 > >
diff --git a/drivers/char/agp/generic.c b/drivers/char/agp/generic.c index d2abf51..3d852bf 100644 --- a/drivers/char/agp/generic.c +++ b/drivers/char/agp/generic.c @@ -122,6 +122,9 @@ static struct agp_memory *agp_create_user_memory(unsigned long num_agp_pages) struct agp_memory *new; unsigned long alloc_size = num_agp_pages*sizeof(struct page *); + if (INT_MAX/sizeof(struct page *) < num_agp_pages) + return NULL; + new = kzalloc(sizeof(struct agp_memory), GFP_KERNEL); if (new == NULL) return NULL; @@ -241,11 +244,14 @@ struct agp_memory *agp_allocate_memory(struct agp_bridge_data *bridge, int scratch_pages; struct agp_memory *new; size_t i; + int cur_memory; if (!bridge) return NULL; - if ((atomic_read(&bridge->current_memory_agp) + page_count) > bridge->max_memory_agp) + cur_memory = atomic_read(&bridge->current_memory_agp); + if ((cur_memory + page_count > bridge->max_memory_agp) || + (cur_memory + page_count < page_count)) return NULL; if (type >= AGP_USER_TYPES) {