CVE-2024-43840

Published: August 22, 2024Last modified: August 22, 2024

Description

In the Linux kernel, the following vulnerability has been resolved: bpf, arm64: Fix trampoline for BPF_TRAMP_F_CALL_ORIG When BPF_TRAMP_F_CALL_ORIG is set, the trampoline calls __bpf_tramp_enter() and __bpf_tramp_exit() functions, passing them the struct bpf_tramp_image *im pointer as an argument in R0. The trampoline generation code uses emit_addr_mov_i64() to emit instructions for moving the bpf_tramp_image address into R0, but emit_addr_mov_i64() assumes the address to be in the vmalloc() space and uses only 48 bits. Because bpf_tramp_image is allocated using kzalloc(), its address can use more than 48-bits, in this case the trampoline will pass an invalid address to __bpf_tramp_enter/exit() causing a kernel crash. Fix this by using emit_a64_mov_i64() in place of emit_addr_mov_i64() as it can work with addresses that are greater than 48-bits.

Severity score breakdown

Status

References

• https://git.kernel.org/stable/c/077149478497b2f00ff4fd9da2c892defa6418d8
• https://git.kernel.org/stable/c/19d3c179a37730caf600a97fed3794feac2b197b
• https://git.kernel.org/stable/c/6d218fcc707d6b2c3616b6cd24b948fd4825cfec
• https://git.kernel.org/stable/c/d9664e6ff040798a46cdc5d401064f55b8676c83