Overview
About vulnerability
In the Linux kernel, the following vulnerability has been resolved:
bpf: fix check for attempt to corrupt spilled pointer
When register is spilled onto a stack as a 1/2/4-byte register, we set slot_type[BPF_REG_SIZE - 1] (plus potentially few more below it, depending on actual spill size). So to check if some stack slot has spilled register we need to consult slot_type[7], not slot_type[0].
To avoid the need to remember and double-check this in the future, just use is_spilled_reg() helper.
Details
- Affected product:
- AlmaLinux 9.2 ESU , CentOS 6 ELS , CentOS 7 ELS , CentOS 8.4 ELS , CentOS 8.5 ELS , CloudLinux 6 ELS , Oracle Linux 6 ELS , Ubuntu 16.04 ELS , Ubuntu 18.04 ELS
- Affected packages:
- kernel @ 4.18.0 (+10 more)
In the Linux kernel, the following vulnerability has been resolved:
bpf: fix check for attempt to corrupt spilled pointer
When register is spilled onto a stack as a 1/2/4-byte register, we set slot_type[BPF_REG_SIZE - 1] (plus potentially few more below it, depending on actual spill size). So to check if some stack slot has spilled register we need to consult slot_type[7], not slot_type[0].
To avoid the need to remember and double-check this in the future, just use is_spilled_reg() helper.