Thank you for your contribution! Sashiko AI review found 4 potential issue(s) to consider:
New issues: - [High] Calling `add_taint_module()` unconditionally dereferences `drv->owner`, causing a kernel panic for built-in drivers where `drv->owner` is `NULL`. - [Low] The patch breaks the build when `CONFIG_MODULES` is disabled due to a syntactically invalid inline stub for `add_taint_module` introduced in the previous patch. - [Low] Malformed reStructuredText simple table and outdated `seq 20` script in the tainted-kernels documentation. Pre-existing issues: - [High] A race condition in `unbind_store` allows detaching an unintended driver if `dev->driver` changes concurrently. -- commit 4cfb386dac8b53407ce0309b005475cf263546f7 Author: Greg Kroah-Hartman <[email protected]> driver core: add TAINT_FORCED_BIND for when userspace manually messes with devices and drivers Add a new TAINT_FORCED_BIND taint flag to track when userspace successfully adds or removes devices from a driver via the sysfs bind and unbind files. This helps identify when userspace fuzzing or manual interference causes subsequent kernel crashes. > diff --git a/Documentation/admin-guide/tainted-kernels.rst > b/Documentation/admin-guide/tainted-kernels.rst > index 9ead927a37c0f..d4ca8b9e3819e 100644 > --- a/Documentation/admin-guide/tainted-kernels.rst > +++ b/Documentation/admin-guide/tainted-kernels.rst > @@ -79,30 +79,31 @@ which bits are set:: > Table for decoding tainted state > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > > -=== === ====== ======================================================== > -Bit Log Number Reason that got the kernel tainted > -=== === ====== ======================================================== > +=== === ====== ======================================================== > +Bit Log Number Reason that got the kernel tainted > +=== === ====== ======================================================== [ ... ] > + 19 _/J 524288 userspace used a mutating debug operation in fwctl > + 20 _/Y 1048576 device was manually bound or unbound from a driver > +=== === ======= ======================================================== [Severity: Low] The header separator for the Number column is 6 characters wide, but the footer separator is 7 characters wide. Can this mismatch break Sphinx reStructuredText table parsing? Also, does the quick-check script just above this table need to be updated? It uses seq 20, which fails to cover this newly added 20th taint bit (requires seq 21). > diff --git a/drivers/base/bus.c b/drivers/base/bus.c > index d17bd91490ee4..c51ad96d4de4b 100644 > --- a/drivers/base/bus.c > +++ b/drivers/base/bus.c [ ... ] > @@ -241,6 +242,7 @@ static ssize_t unbind_store(struct device_driver *drv, > const char *buf, > > dev = bus_find_device_by_name(bus, NULL, buf); > if (dev && dev->driver == drv) { [Severity: High] This is a pre-existing issue, but is there a race condition here? The check of dev->driver is performed without holding the device lock. If the driver is detached and a new driver attaches immediately after, could the subsequent call to device_driver_detach(dev) blindly detach the unintended new driver? > + add_taint_module(drv->owner, TAINT_FORCED_BIND, > LOCKDEP_STILL_OK); [Severity: High] For built-in drivers, drv->owner is NULL. Does calling add_taint_module unconditionally dereference drv->owner, causing a kernel panic when a user writes to the unbind sysfs file for a statically compiled driver? [Severity: Low] Will this unconditional call cause a compilation error when CONFIG_MODULES=n? The inline stub for add_taint_module in include/linux/module.h omits the parameter name for enum lockdep_ok, making it syntactically invalid, which is activated by this new call. > device_driver_detach(dev); > err = count; > } > @@ -264,6 +266,7 @@ static ssize_t bind_store(struct device_driver *drv, > const char *buf, > > dev = bus_find_device_by_name(bus, NULL, buf); > if (dev && driver_match_device(drv, dev)) { > + add_taint_module(drv->owner, TAINT_FORCED_BIND, > LOCKDEP_STILL_OK); [Severity: High] Similarly, for built-in drivers where drv->owner is NULL, does this unconditionally dereference it and cause a kernel panic here as well? > err = device_driver_attach(drv, dev); > if (!err) { > /* success */ -- Sashiko AI review ยท https://sashiko.dev/#/patchset/[email protected]?part=2
