netfilter: use get_random_u32 instead of prandom
3Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackepss 0.3%
exploitation probability
0.3%top 78% of all CVEs
observed exploitation
nono source reports it
In the Linux kernel, the following vulnerability has been resolved:
netfilter: use get_random_u32 instead of prandom
bh might occur while updating per-cpu rnd_state from user context,
ie. local_out path.
BUG: using smp_processor_id() in preemptible [00000000] code: nginx/2725
caller is nft_ng_random_eval+0x24/0x54 [nft_numgen]
Call Trace:
check_preemption_disabled+0xde/0xe0
nft_ng_random_eval+0x24/0x54 [nft_numgen]
Use the random driver instead, this also avoids need for local prandom
state. Moreover, prandom now uses the random driver since d4150779e60f
("random32: use real rng for non-deterministic randomness").
Based on earlier patch from Pablo Neira.
Affected products
Linux · Linux