This is a proposal to revert commit 914eedcb9ba0ff53c33808.
I found this when writting a simple UFFDIO_API test to be the first unit
test in this set. Two things breaks with the commit:
- UFFDIO_API check was lost and missing. According to man page, the
kernel should reject ioctl(UFFDIO_API) if uffdio_api.api != 0xaa. This
check is needed if the api version will be extended in the future, or
user app won't be able to identify which is a new kernel.
- Feature flags checks were removed, which means UFFDIO_API with a
feature that does not exist will also succeed. According to the man
page, we should (and it makes sense) to reject ioctl(UFFDIO_API) if
unknown features passed in.
Link: https://lore.kernel.org/r/20220722201513.1624158-1-axelrasmussen@google.com
Cc: Axel Rasmussen <axelrasmussen(a)google.com>
Cc: linux-stable <stable(a)vger.kernel.org>
Signed-off-by: Peter Xu <peterx(a)redhat.com>
---
fs/userfaultfd.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c
index 8395605790f6..3b2a41c330e6 100644
--- a/fs/userfaultfd.c
+++ b/fs/userfaultfd.c
@@ -1977,8 +1977,10 @@ static int userfaultfd_api(struct userfaultfd_ctx *ctx,
ret = -EFAULT;
if (copy_from_user(&uffdio_api, buf, sizeof(uffdio_api)))
goto out;
- /* Ignore unsupported features (userspace built against newer kernel) */
- features = uffdio_api.features & UFFD_API_FEATURES;
+ features = uffdio_api.features;
+ ret = -EINVAL;
+ if (uffdio_api.api != UFFD_API || (features & ~UFFD_API_FEATURES))
+ goto err_out;
ret = -EPERM;
if ((features & UFFD_FEATURE_EVENT_FORK) && !capable(CAP_SYS_PTRACE))
goto err_out;
--
2.39.1
Hello my beloved, good morning from here, how are you doing today? My
name is Mrs. Rabi Juanni Marcus, I have something very important that
i want to discuss with you.
If the value read from the CHDBOFF and ERDBOFF registers is outside the
range of the MHI register space then an invalid address might be computed
which later causes a kernel panic. Range check the read value to prevent
a crash due to bad data from the device.
Fixes: 6cd330ae76ff ("bus: mhi: core: Add support for ringing channel/event ring doorbells")
Cc: stable(a)vger.kernel.org
Signed-off-by: Jeffrey Hugo <quic_jhugo(a)quicinc.com>
Reviewed-by: Pranjal Ramajor Asha Kanojiya <quic_pkanojiy(a)quicinc.com>
---
v2:
-CC stable
-Use ERANGE for the error code
drivers/bus/mhi/host/init.c | 12 ++++++++++++
1 file changed, 12 insertions(+)
diff --git a/drivers/bus/mhi/host/init.c b/drivers/bus/mhi/host/init.c
index 3d779ee..b46a082 100644
--- a/drivers/bus/mhi/host/init.c
+++ b/drivers/bus/mhi/host/init.c
@@ -516,6 +516,12 @@ int mhi_init_mmio(struct mhi_controller *mhi_cntrl)
return -EIO;
}
+ if (val >= mhi_cntrl->reg_len - (8 * MHI_DEV_WAKE_DB)) {
+ dev_err(dev, "CHDB offset: 0x%x is out of range: 0x%zx\n",
+ val, mhi_cntrl->reg_len - (8 * MHI_DEV_WAKE_DB));
+ return -ERANGE;
+ }
+
/* Setup wake db */
mhi_cntrl->wake_db = base + val + (8 * MHI_DEV_WAKE_DB);
mhi_cntrl->wake_set = false;
@@ -532,6 +538,12 @@ int mhi_init_mmio(struct mhi_controller *mhi_cntrl)
return -EIO;
}
+ if (val >= mhi_cntrl->reg_len - (8 * mhi_cntrl->total_ev_rings)) {
+ dev_err(dev, "ERDB offset: 0x%x is out of range: 0x%zx\n",
+ val, mhi_cntrl->reg_len - (8 * mhi_cntrl->total_ev_rings));
+ return -ERANGE;
+ }
+
/* Setup event db address for each ev_ring */
mhi_event = mhi_cntrl->mhi_event;
for (i = 0; i < mhi_cntrl->total_ev_rings; i++, val += 8, mhi_event++) {
--
2.7.4