[PATCH bpf-next] libbpf: Validate ELF symbol table entry size

[Luis Vieira]

elf_sym_iter_new() calculates the number of symbols by dividing the
symbol table data size by sh_entsize. A malformed ELF file with a zero
sh_entsize causes a division by zero.

Reject symbol table sections with a zero entry size before calculating
the number of symbols.

Signed-off-by: Luis Vieira <luisflavieira@xxxxxxxxx>
---
 tools/lib/bpf/elf.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/tools/lib/bpf/elf.c b/tools/lib/bpf/elf.c
index fe136d025967..ba0b3df37a59 100644
--- a/tools/lib/bpf/elf.c
+++ b/tools/lib/bpf/elf.c
@@ -118,6 +118,11 @@ static int elf_sym_iter_new(struct elf_sym_iter *iter,
 	if (!gelf_getshdr(scn, &sh))
 		return -EINVAL;
 
+	if (!sh.sh_entsize) {
+		pr_warn("elf: symbol table section has zero entry size in '%s'\n", binary_path);
+		return -EINVAL;
+	}
+
 	iter->strtabidx = sh.sh_link;
 	iter->syms = elf_getdata(scn, 0);
 	if (!iter->syms) {

---
base-commit: 10c4f610b215bf961235141161992f010cf7e451
change-id: 20260916-libbpf-elf-entsize-fix-a0f9440e79c7

Best regards,
--  
Luis Vieira <luisflavieira@xxxxxxxxx>