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
If two or more suitable entries with the same filename are found in
__uc_fw_auto_select's fw_blobs, and that filename fails to load in the
first attempt and in the retry, when __uc_fw_auto_select is called for
the third time, the coincidence of strings will cause it to clear
file_selected.path at the first hit, so it will return the second hit
over and over again, indefinitely.
Of course this doesn't occur with the pristine blob lists, but a
modified version could run into this, e.g., patching in a duplicate
entry, or (as in our case) disarming blob loading by remapping their
names to "/*(DEBLOBBED)*/", given a toolchain that unifies identical
string literals.
Of course I'm ready to carry a patchlet to avoid this problem
triggered by our (GNU Linux-libre's) intentional changes, but I
figured you might be interested in fail-safing it even in accidental
backporting circumstances. I realize it's not entirely foolproof: if
the same string appears in two entries separated by a different one,
the infinite loop might still occur. Catching that even more unlikely
situation seemed too expensive.
Link: https://www.fsfla.org/pipermail/linux-libre/2023-March/003506.html
Cc: intel-gfx(a)lists.freedesktop.org
Cc: stable(a)vger.kernel.org # 6.[12].x
Signed-off-by: Alexandre Oliva <lxoliva(a)fsfla.org>
---
drivers/gpu/drm/i915/gt/uc/intel_uc_fw.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/i915/gt/uc/intel_uc_fw.c b/drivers/gpu/drm/i915/gt/uc/intel_uc_fw.c
index 9d6f571097e6..2b7564a3ed82 100644
--- a/drivers/gpu/drm/i915/gt/uc/intel_uc_fw.c
+++ b/drivers/gpu/drm/i915/gt/uc/intel_uc_fw.c
@@ -259,7 +259,10 @@ __uc_fw_auto_select(struct drm_i915_private *i915, struct intel_uc_fw *uc_fw)
uc_fw->file_selected.path = NULL;
continue;
- }
+ } else if (uc_fw->file_wanted.path == blob->path)
+ /* Avoid retrying forever when neighbor
+ entries point to the same path. */
+ continue;
uc_fw->file_selected.path = blob->path;
uc_fw->file_wanted.path = blob->path;
--
2.25.1
--
Alexandre Oliva, happy hacker https://FSFLA.org/blogs/lxo/
Free Software Activist GNU Toolchain Engineer
Disinformation flourishes because many people care deeply about injustice
but very few check the facts. Ask me about <https://stallmansupport.org>