[PATCH v2 0/6] Fixes multiple sysctl bound checks

nicolas.bouchinet
2025-02-24T09:58:57Z

From: Nicolas Bouchinet <nicolas.bouchinet@ssi.gouv.fr>

Hi,

This patchset adds some bound checks to sysctls to avoid negative
value writes.

The patched sysctls were storing the result of the proc_dointvec
proc_handler into an unsigned int data. proc_dointvec being able to
parse negative value, and it return value being a signed int, this could
lead to undefined behaviors.
This has led to kernel crash in the past as described in commit
3b3376f222e3 ("sysctl.c: fix underflow value setting risk in vm_table")

They are now bounded between SYSCTL_ZERO and SYSCTL_INT_MAX.
The proc_handlers have thus been updated to proc_dointvec_minmax.

This patchset has been written over sysctl-testing branch [1].
See [2] for similar sysctl fixes currently in review.

[1]: https://git.kernel.org/pub/scm/linux/kernel/git/sysctl/sysctl.git/log/?h=sysctl-testing
[2]: https://lore.kernel.org/all/20250115132211.25400-1-nicolas.bouchinet@clip-os.org/

Best regards,

Nicolas

---

Changes since v1:
https://lore.kernel.org/all/20250127142014.37834-1-nicolas.bouchinet@clip-os.org/

* Detached patches 1/9, 2/9 [3] and 3/9 [4]
* Adapted the cover-letter message to match the reduced patchset

[3]: https://lore.kernel.org/all/20250129170633.88574-1-nicolas.bouchinet@clip-os.org/
[4]: https://lore.kernel.org/all/20250128103821.29745-1-nicolas.bouchinet@clip-os.org/

---

Nicolas Bouchinet (6):
sysctl: Fixes idmap_cache_timeout bounds
sysctl: Fixes nsm_local_state bounds
sysctl/coda: Fixes timeout bounds
sysctl: Fixes scsi_logging_level bounds
sysctl/infiniband: Fixes infiniband sysctl bounds
sysctl: Fixes max-user-freq bounds

drivers/char/hpet.c | 4 +++-
drivers/infiniband/core/iwcm.c | 4 +++-
drivers/infiniband/core/ucma.c | 4 +++-
drivers/scsi/scsi_sysctl.c | 4 +++-
fs/coda/sysctl.c | 4 +++-
fs/lockd/svc.c | 4 +++-
fs/nfs/nfs4sysctl.c | 4 +++-
7 files changed, 21 insertions(+), 7 deletions(-)

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2.48.1