CVE - CVE-2024-26589

CVE-ID
CVE-2024-26589	Learn more at National Vulnerability Database (NVD) • CVSS Severity Rating • Fix Information • Vulnerable Software Versions • SCAP Mappings • CPE Information
Description
In the Linux kernel, the following vulnerability has been resolved: bpf: Reject variable offset alu on PTR_TO_FLOW_KEYS For PTR_TO_FLOW_KEYS, check_flow_keys_access() only uses fixed off for validation. However, variable offset ptr alu is not prohibited for this ptr kind. So the variable offset is not checked. The following prog is accepted: func#0 @0 0: R1=ctx() R10=fp0 0: (bf) r6 = r1 ; R1=ctx() R6_w=ctx() 1: (79) r7 = (u64 )(r6 +144) ; R6_w=ctx() R7_w=flow_keys() 2: (b7) r8 = 1024 ; R8_w=1024 3: (37) r8 /= 1 ; R8_w=scalar() 4: (57) r8 &= 1024 ; R8_w=scalar(smin=smin32=0, smax=umax=smax32=umax32=1024,var_off=(0x0; 0x400)) 5: (0f) r7 += r8 mark_precise: frame0: last_idx 5 first_idx 0 subseq_idx -1 mark_precise: frame0: regs=r8 stack= before 4: (57) r8 &= 1024 mark_precise: frame0: regs=r8 stack= before 3: (37) r8 /= 1 mark_precise: frame0: regs=r8 stack= before 2: (b7) r8 = 1024 6: R7_w=flow_keys(smin=smin32=0,smax=umax=smax32=umax32=1024,var_off =(0x0; 0x400)) R8_w=scalar(smin=smin32=0,smax=umax=smax32=umax32=1024, var_off=(0x0; 0x400)) 6: (79) r0 = (u64 )(r7 +0) ; R0_w=scalar() 7: (95) exit This prog loads flow_keys to r7, and adds the variable offset r8 to r7, and finally causes out-of-bounds access: BUG: unable to handle page fault for address: ffffc90014c80038 [...] Call Trace: <TASK> bpf_dispatcher_nop_func include/linux/bpf.h:1231 [inline] __bpf_prog_run include/linux/filter.h:651 [inline] bpf_prog_run include/linux/filter.h:658 [inline] bpf_prog_run_pin_on_cpu include/linux/filter.h:675 [inline] bpf_flow_dissect+0x15f/0x350 net/core/flow_dissector.c:991 bpf_prog_test_run_flow_dissector+0x39d/0x620 net/bpf/test_run.c:1359 bpf_prog_test_run kernel/bpf/syscall.c:4107 [inline] __sys_bpf+0xf8f/0x4560 kernel/bpf/syscall.c:5475 __do_sys_bpf kernel/bpf/syscall.c:5561 [inline] __se_sys_bpf kernel/bpf/syscall.c:5559 [inline] __x64_sys_bpf+0x73/0xb0 kernel/bpf/syscall.c:5559 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0x3f/0x110 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x63/0x6b Fix this by rejecting ptr alu with variable offset on flow_keys. Applying the patch rejects the program with "R7 pointer arithmetic on flow_keys prohibited".
References
Note: References are provided for the convenience of the reader to help distinguish between vulnerabilities. The list is not intended to be complete.
MISC:https://git.kernel.org/stable/c/1b500d5d6cecf98dd6ca88bc9e7ae1783c83e6d3 URL:https://git.kernel.org/stable/c/1b500d5d6cecf98dd6ca88bc9e7ae1783c83e6d3 MISC:https://git.kernel.org/stable/c/22c7fa171a02d310e3a3f6ed46a698ca8a0060ed URL:https://git.kernel.org/stable/c/22c7fa171a02d310e3a3f6ed46a698ca8a0060ed MISC:https://git.kernel.org/stable/c/29ffa63f21bcdcef3e36b03cccf9d0cd031f6ab0 URL:https://git.kernel.org/stable/c/29ffa63f21bcdcef3e36b03cccf9d0cd031f6ab0 MISC:https://git.kernel.org/stable/c/4108b86e324da42f7ed425bd71632fd844300dc8 URL:https://git.kernel.org/stable/c/4108b86e324da42f7ed425bd71632fd844300dc8 MISC:https://git.kernel.org/stable/c/e8d3872b617c21100c5ee4f64e513997a68c2e3d URL:https://git.kernel.org/stable/c/e8d3872b617c21100c5ee4f64e513997a68c2e3d
Assigning CNA
kernel.org
Date Record Created
20240219	Disclaimer: The record creation date may reflect when the CVE ID was allocated or reserved, and does not necessarily indicate when this vulnerability was discovered, shared with the affected vendor, publicly disclosed, or updated in CVE.
Phase (Legacy)
Assigned (20240219)
Votes (Legacy)

Comments (Legacy)

Proposed (Legacy)
N/A
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