Vulnerability CVE-2023-52592
Published: 2024-03-06

Description:
In the Linux kernel, the following vulnerability has been resolved:

libbpf: Fix NULL pointer dereference in bpf_object__collect_prog_relos

An issue occurred while reading an ELF file in libbpf.c during fuzzing:

Program received signal SIGSEGV, Segmentation fault.
0x0000000000958e97 in bpf_object.collect_prog_relos () at libbpf.c:4206
4206 in libbpf.c
(gdb) bt
#0 0x0000000000958e97 in bpf_object.collect_prog_relos () at libbpf.c:4206
#1 0x000000000094f9d6 in bpf_object.collect_relos () at libbpf.c:6706
#2 0x000000000092bef3 in bpf_object_open () at libbpf.c:7437
#3 0x000000000092c046 in bpf_object.open_mem () at libbpf.c:7497
#4 0x0000000000924afa in LLVMFuzzerTestOneInput () at fuzz/bpf-object-fuzzer.c:16
#5 0x000000000060be11 in testblitz_engine::fuzzer::Fuzzer::run_one ()
#6 0x000000000087ad92 in tracing::span::Span::in_scope ()
#7 0x00000000006078aa in testblitz_engine::fuzzer::util::walkdir ()
#8 0x00000000005f3217 in testblitz_engine::entrypoint::main::{{closure}} ()
#9 0x00000000005f2601 in main ()
(gdb)

scn_data was null at this code(tools/lib/bpf/src/libbpf.c):

if (rel->r_offset % BPF_INSN_SZ || rel->r_offset >= scn_data->d_size) {

The scn_data is derived from the code above:

scn = elf_sec_by_idx(obj, sec_idx);
scn_data = elf_sec_data(obj, scn);

relo_sec_name = elf_sec_str(obj, shdr->sh_name);
sec_name = elf_sec_name(obj, scn);
if (!relo_sec_name || !sec_name)// don't check whether scn_data is NULL
return -EINVAL;

In certain special scenarios, such as reading a malformed ELF file,
it is possible that scn_data may be a null pointer

 References:
https://git.kernel.org/stable/c/90dbf4535668042fac0d7201ce9e2c8c770c578a
https://git.kernel.org/stable/c/12473265f50c1e27b0dfd9735738ac418c4bfcce
https://git.kernel.org/stable/c/5f3e436832e86b826a6450eb8d1aaa51205a758e
https://git.kernel.org/stable/c/ab26541270c722eedf8eefd62797c3ce3d18a91b
https://git.kernel.org/stable/c/fc3a5534e2a8855427403113cbeb54af5837bbe0
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