Hi,
Thank's for your reply.
On 1/27/25 19:05, Joe Damato wrote:
On Mon, Jan 27, 2025 at 03:19:57PM +0100, nicolas.bouchinet@xxxxxxxxxxx wrote:
From: Nicolas Bouchinet <nicolas.bouchinet@xxxxxxxxxxx>
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")
Most of them are now bounded between SYSCTL_ZERO and SYSCTL_INT_MAX.
nf_conntrack_expect_max is bounded between SYSCTL_ONE and SYSCTL_INT_MAX
as defined by its documentation.
I noticed that none of the patches have a Fixes tags. Do any of
these fix existing crashes or is this just cleanup?
I've just saw that xfrm{4,6}_gc_thresh sysctls where obsolete since 4.14
in the documentation...
Also, ipv4_dst_ops.gc_thresh is set to `~0` since commit 4ff3885262d0
("ipv4: Delete routing cache.").
Wich will be printed as -1 when this syctl is read.
```
$ cat /proc/sys/net/ipv4/route/gc_thresh
-1
```
IIUC, it seems to be used in order to disable the garbage collection,
hence, this patch would make it impossible
to a user to disable it this way.
It should thus be bounded it between SYSCTL_NEG_ONE and SYSCTL_INT_MAX.
Your right, it's only cleanup, I'll push patch 3 separately only on
netdev, with extended impact analyses, sorry for that.
I am asking because if this is cleanup then it would be "net-next"
material instead of "net" and would need to be resubmit when then
merge window has passed [1].
FWIW, I submit a similar change some time ago and it was submit to
net-next as cleanup [2].
[1]: https://lore.kernel.org/netdev/20250117182059.7ce1196f@xxxxxxxxxx/
[2]: https://lore.kernel.org/netdev/CANn89i+=HiffVo9iv2NKMC2LFT15xFLG16h7wN3MCrTiKT3zQQ@xxxxxxxxxxxxxx/T/
