CVE-2024-35917

In the Linux kernel, the following vulnerability has been resolved: s390/bpf: Fix bpf_plt pointer arithmetic Kui-Feng Lee reported a crash on s390x triggered by the dummy_st_ops/dummy_init_ptr_arg test [1]: [<0000000000000002>] 0x2 [<00000000009d5cde>] bpf_struct_ops_test_run+0x156/0x250 [<000000000033145a>] __sys_bpf+0xa1a/0xd00 [<00000000003319dc>] __s390x_sys_bpf+0x44/0x50 [<0000000000c4382c>] __do_syscall+0x244/0x300 [<0000000000c59a40>] system_call+0x70/0x98 This is caused by GCC moving memcpy() after assignments in bpf_jit_plt(), resulting in NULL pointers being written instead of the return and the target addresses. Looking at the GCC internals, the reordering is allowed because the alias analysis thinks that the memcpy() destination and the assignments' left-hand-sides are based on different objects: new_plt and bpf_plt_ret/bpf_plt_target respectively, and therefore they cannot alias. This is in turn due to a violation of the C standard: When two pointers are subtracted, both shall point to elements of the same array object, or one past the last element of the array object ... From the C's perspective, bpf_plt_ret and bpf_plt are distinct objects and cannot be subtracted. In the practical terms, doing so confuses the GCC's alias analysis. The code was written this way in order to let the C side know a few offsets defined in the assembly. While nice, this is by no means necessary. Fix the noncompliance by hardcoding these offsets. [1] https://lore.kernel.org/bpf/c9923c1d-971d-4022-8dc8-1364e929d34c@gmail.com/
Configurations

Configuration 1 (hide)

OR cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.9:rc1:*:*:*:*:*:*

History

23 Sep 2025, 15:26

Type Values Removed Values Added
CVSS v2 : unknown
v3 : unknown
v2 : unknown
v3 : 5.5
References () https://git.kernel.org/stable/c/7ded842b356d151ece8ac4985940438e6d3998bb - () https://git.kernel.org/stable/c/7ded842b356d151ece8ac4985940438e6d3998bb - Patch
References () https://git.kernel.org/stable/c/c3062bdb859b6e2567e7f5c8cde20c0250bb130f - () https://git.kernel.org/stable/c/c3062bdb859b6e2567e7f5c8cde20c0250bb130f - Patch
References () https://git.kernel.org/stable/c/d3d74e45a060d218fe4b0c9174f0a77517509d8e - () https://git.kernel.org/stable/c/d3d74e45a060d218fe4b0c9174f0a77517509d8e - Patch
CWE CWE-476
First Time Linux linux Kernel
Linux
CPE cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.9:rc1:*:*:*:*:*:*

21 Nov 2024, 09:21

Type Values Removed Values Added
Summary
  • (es) En el kernel de Linux, se resolvió la siguiente vulnerabilidad: s390/bpf: Corrección de la aritmética del puntero bpf_plt Kui-Feng Lee informó un bloqueo en s390x provocado por la prueba dummy_st_ops/dummy_init_ptr_arg [1]: [&lt;00000000000000002&gt;] 0x2 [&lt;00000000009d5cde&gt; ] bpf_struct_ops_test_run+0x156/0x250 [&lt;000000000033145a&gt;] __sys_bpf+0xa1a/0xd00 [&lt;00000000003319dc&gt;] __s390x_sys_bpf+0x44/0x50 [&lt;0000000000 c4382c&gt;] __do_syscall+0x244/0x300 [&lt;0000000000c59a40&gt;] system_call+0x70/0x98 Esto es causado por GCC mueve memcpy() después de las asignaciones en bpf_jit_plt(), lo que da como resultado que se escriban punteros NULL en lugar de las direcciones de retorno y de destino. Al observar los aspectos internos de GCC, se permite el reordenamiento porque el análisis de alias piensa que el destino memcpy() y los lados izquierdos de las asignaciones se basan en objetos diferentes: new_plt y bpf_plt_ret/bpf_plt_target respectivamente y, por lo tanto, no pueden crear alias. Esto, a su vez, se debe a una violación del estándar C: cuando se restan dos punteros, ambos apuntarán a elementos del mismo objeto de matriz, o uno más allá del último elemento del objeto de matriz... Desde la perspectiva de C, bpf_plt_ret y bpf_plt son objetos distintos y no se pueden restar. En términos prácticos, hacerlo confunde el análisis de alias del CCG. El código se escribió de esta manera para que el lado C conozca algunas compensaciones definidas en el ensamblaje. Si bien es agradable, esto no es necesario. Corrija el incumplimiento codificando estas compensaciones. [1] https://lore.kernel.org/bpf/c9923c1d-971d-4022-8dc8-1364e929d34c@gmail.com/
References () https://git.kernel.org/stable/c/7ded842b356d151ece8ac4985940438e6d3998bb - () https://git.kernel.org/stable/c/7ded842b356d151ece8ac4985940438e6d3998bb -
References () https://git.kernel.org/stable/c/c3062bdb859b6e2567e7f5c8cde20c0250bb130f - () https://git.kernel.org/stable/c/c3062bdb859b6e2567e7f5c8cde20c0250bb130f -
References () https://git.kernel.org/stable/c/d3d74e45a060d218fe4b0c9174f0a77517509d8e - () https://git.kernel.org/stable/c/d3d74e45a060d218fe4b0c9174f0a77517509d8e -

19 May 2024, 09:15

Type Values Removed Values Added
New CVE

Information

Published : 2024-05-19 09:15

Updated : 2025-09-23 15:26


NVD link : CVE-2024-35917

Mitre link : CVE-2024-35917

CVE.ORG link : CVE-2024-35917


JSON object : View

Products Affected

linux

  • linux_kernel
CWE
CWE-476

NULL Pointer Dereference