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[bpf-next,v2] libbpf: verify section type in btf_find_elf_sections

Message ID 20250410182823.1591681-1-ihor.solodrai@linux.dev (mailing list archive)
State Accepted
Commit 8582d9ab3efdebb88e0cd8beed8e0b9de76443e7
Delegated to: BPF
Headers show
Series [bpf-next,v2] libbpf: verify section type in btf_find_elf_sections | expand

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Commit Message

Ihor Solodrai April 10, 2025, 6:28 p.m. UTC 
A valid ELF file may contain a SHT_NOBITS .BTF section. This case is
not handled correctly in btf_parse_elf, which leads to a segfault.

Before attempting to load BTF section data, check that the section
type is SHT_PROGBITS, which is the expected type for BTF data.  Fail
with an error if the type is different.

Bug report: https://github.com/libbpf/libbpf/issues/894
v1: https://lore.kernel.org/bpf/20250408184104.3962949-1-ihor.solodrai@linux.dev/

Signed-off-by: Ihor Solodrai <ihor.solodrai@linux.dev>
---
 tools/lib/bpf/btf.c | 6 ++++++
 1 file changed, 6 insertions(+)

Comments

patchwork-bot+netdevbpf@kernel.org April 15, 2025, 10:31 p.m. UTC | #1 
Hello:

This patch was applied to bpf/bpf-next.git (master)
by Andrii Nakryiko <andrii@kernel.org>:

On Thu, 10 Apr 2025 11:28:23 -0700 you wrote:
> A valid ELF file may contain a SHT_NOBITS .BTF section. This case is
> not handled correctly in btf_parse_elf, which leads to a segfault.
> 
> Before attempting to load BTF section data, check that the section
> type is SHT_PROGBITS, which is the expected type for BTF data.  Fail
> with an error if the type is different.
> 
> [...]

Here is the summary with links:
  - [bpf-next,v2] libbpf: verify section type in btf_find_elf_sections
    https://git.kernel.org/bpf/bpf-next/c/8582d9ab3efd

You are awesome, thank you!
diff mbox series

Patch

diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c
index 38bc6b14b066..24fc71ce5631 100644
--- a/tools/lib/bpf/btf.c
+++ b/tools/lib/bpf/btf.c
@@ -1148,6 +1148,12 @@  static int btf_find_elf_sections(Elf *elf, const char *path, struct btf_elf_secs
 		else
 			continue;
 
+		if (sh.sh_type != SHT_PROGBITS) {
+			pr_warn("unexpected section type (%d) of section(%d, %s) from %s\n",
+				sh.sh_type, idx, name, path);
+			goto err;
+		}
+
 		data = elf_getdata(scn, 0);
 		if (!data) {
 			pr_warn("failed to get section(%d, %s) data from %s\n",