| Message ID | CAN5uoS_GfCgWCc7QLPhtYkRzXfV+5Xy-TJobC7-NopQe5MGwMw@mail.gmail.com |
|---|---|
| State | Superseded |
| Headers | show |
| Series | tee: check shm references are consistent in offset/size | expand |
On 04/27/2018 06:53 AM, Etienne Carriere wrote: > This change prevents userland from referencing TEE shared memory > outside the area initially allocated by its owner. Prior this change an > application could not reference or access memory it did not own but > it could reference memory not explicitly allocated by owner. > > Reported-by: Alexandre Jutras <alexandre.jutras@nxp.com> > Signed-off-by: Etienne Carriere <etienne.carriere@linaro.org> > > --- > drivers/tee/tee_core.c | 11 +++++++++++ > 1 file changed, 11 insertions(+) > > diff --git a/drivers/tee/tee_core.c b/drivers/tee/tee_core.c > index 0124a91..dd46b75 100644 > --- a/drivers/tee/tee_core.c > +++ b/drivers/tee/tee_core.c > @@ -238,6 +238,17 @@ static int params_from_user(struct tee_context > *ctx, struct tee_param *params, Those 2 lines above should be only one line. > if (IS_ERR(shm)) > return PTR_ERR(shm); > > + /* > + * Ensure offset + size does not overflow offset > + * and does not overflow the size of the referred > + * shared memory object. > + */ > + if ((ip.a + ip.b) < ip.a || > + (ip.a + ip.b) > shm->size) { > + tee_shm_put(shm); > + return -EINVAL; > + } > + Hi, The patch makes sense but the whitespace and indentation are all mucked up. Could be your email client. Please check/fix and test by emailing it to yourself. > params[n].u.memref.shm_offs = ip.a; > params[n].u.memref.size = ip.b; > params[n].u.memref.shm = shm; > thanks, -- ~Randy
diff --git a/drivers/tee/tee_core.c b/drivers/tee/tee_core.c index 0124a91..dd46b75 100644 --- a/drivers/tee/tee_core.c +++ b/drivers/tee/tee_core.c @@ -238,6 +238,17 @@ static int params_from_user(struct tee_context *ctx, struct tee_param *params, if (IS_ERR(shm)) return PTR_ERR(shm); + /* + * Ensure offset + size does not overflow offset + * and does not overflow the size of the referred + * shared memory object. + */ + if ((ip.a + ip.b) < ip.a || + (ip.a + ip.b) > shm->size) { + tee_shm_put(shm); + return -EINVAL; + } + params[n].u.memref.shm_offs = ip.a; params[n].u.memref.size = ip.b;
This change prevents userland from referencing TEE shared memory outside the area initially allocated by its owner. Prior this change an application could not reference or access memory it did not own but it could reference memory not explicitly allocated by owner. Reported-by: Alexandre Jutras <alexandre.jutras@nxp.com> Signed-off-by: Etienne Carriere <etienne.carriere@linaro.org> --- drivers/tee/tee_core.c | 11 +++++++++++ 1 file changed, 11 insertions(+) params[n].u.memref.shm = shm; -- 1.9.1