CVE-2022-50450 Detail
Received
This CVE record has recently been published to the CVE List and has been included within the NVD dataset. DescriptionIn the Linux kernel, the following vulnerability has been resolved: libbpf: Use elf_getshdrnum() instead of e_shnum This commit replace e_shnum with the elf_getshdrnum() helper to fix two oss-fuzz-reported heap-buffer overflow in __bpf_object__open. Both reports are incorrectly marked as fixed and while still being reproducible in the latest libbpf. # clusterfuzz-testcase-minimized-bpf-object-fuzzer-5747922482888704 libbpf: loading object 'fuzz-object' from buffer libbpf: sec_cnt is 0 libbpf: elf: section(1) .data, size 0, link 538976288, flags 2020202020202020, type=2 libbpf: elf: section(2) .data, size 32, link 538976288, flags 202020202020ff20, type=1 ================================================================= ==13==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x6020000000c0 at pc 0x0000005a7b46 bp 0x7ffd12214af0 sp 0x7ffd12214ae8 WRITE of size 4 at 0x6020000000c0 thread T0 SCARINESS: 46 (4-byte-write-heap-buffer-overflow-far-from-bounds) #0 0x5a7b45 in bpf_object__elf_collect /src/libbpf/src/libbpf.c:3414:24 #1 0x5733c0 in bpf_object_open /src/libbpf/src/libbpf.c:7223:16 #2 0x5739fd in bpf_object__open_mem /src/libbpf/src/libbpf.c:7263:20 ... The issue lie in libbpf's direct use of e_shnum field in ELF header as the section header count. Where as libelf implemented an extra logic that, when e_shnum == 0 && e_shoff != 0, will use sh_size member of the initial section header as the real section header count (part of ELF spec to accommodate situation where section header counter is larger than SHN_LORESERVE). The above inconsistency lead to libbpf writing into a zero-entry calloc area. So intead of using e_shnum directly, use the elf_getshdrnum() helper provided by libelf to retrieve the section header counter into sec_cnt. Metrics
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CVSS 4.0 Severity and Vector Strings:
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Weakness Enumeration
Quick InfoCVE Dictionary Entry:CVE-2022-50450 NVD Published Date: 10/01/2025 NVD Last Modified: 10/01/2025 Source: kernel.org |