diff mbox

[iproute2,-next,1/2] tc, bpf: check section names and type everywhere

Message ID 3947559fab4ac91c5b017170b80b2288a4c086c7.1452559602.git.daniel@iogearbox.net
State Accepted, archived
Delegated to: stephen hemminger
Headers show

Commit Message

Daniel Borkmann Jan. 12, 2016, 1:03 a.m. UTC 
When extracting sections, we better check for name and type. Noticed
that some llvm versions emit .strtab and .shstrtab (e.g. saw it on pre
3.7), while more recent ones only seem to emit .strtab. Thus, make sure
we get the right sections.

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
---
 tc/tc_bpf.c | 21 +++++++++++++++------
 1 file changed, 15 insertions(+), 6 deletions(-)
diff mbox

Patch

diff --git a/tc/tc_bpf.c b/tc/tc_bpf.c
index f9b2b00..677dd62 100644
--- a/tc/tc_bpf.c
+++ b/tc/tc_bpf.c
@@ -1237,14 +1237,17 @@  static int bpf_fetch_ancillary(struct bpf_elf_ctx *ctx)
 		if (ret < 0)
 			continue;
 
-		if (!strcmp(data.sec_name, ELF_SECTION_MAPS))
+		if (data.sec_hdr.sh_type == SHT_PROGBITS &&
+		    !strcmp(data.sec_name, ELF_SECTION_MAPS))
 			ret = bpf_fetch_maps(ctx, i, &data);
-		else if (!strcmp(data.sec_name, ELF_SECTION_LICENSE))
+		else if (data.sec_hdr.sh_type == SHT_PROGBITS &&
+			 !strcmp(data.sec_name, ELF_SECTION_LICENSE))
 			ret = bpf_fetch_license(ctx, i, &data);
-		else if (data.sec_hdr.sh_type == SHT_SYMTAB)
+		else if (data.sec_hdr.sh_type == SHT_SYMTAB &&
+			 !strcmp(data.sec_name, ".symtab"))
 			ret = bpf_fetch_symtab(ctx, i, &data);
 		else if (data.sec_hdr.sh_type == SHT_STRTAB &&
-			 i != ctx->elf_hdr.e_shstrndx)
+			 !strcmp(data.sec_name, ".strtab"))
 			ret = bpf_fetch_strtab(ctx, i, &data);
 		if (ret < 0) {
 			fprintf(stderr, "Error parsing section %d! Perhaps"
@@ -1275,7 +1278,10 @@  static int bpf_fetch_prog(struct bpf_elf_ctx *ctx, const char *section)
 			continue;
 
 		ret = bpf_fill_section_data(ctx, i, &data);
-		if (ret < 0 || strcmp(data.sec_name, section))
+		if (ret < 0 ||
+		    !(data.sec_hdr.sh_type == SHT_PROGBITS &&
+		      data.sec_hdr.sh_flags & SHF_EXECINSTR &&
+		      !strcmp(data.sec_name, section)))
 			continue;
 
 		memset(&prog, 0, sizeof(prog));
@@ -1353,7 +1359,10 @@  static int bpf_fetch_prog_relo(struct bpf_elf_ctx *ctx, const char *section)
 
 		idx = data_relo.sec_hdr.sh_info;
 		ret = bpf_fill_section_data(ctx, idx, &data_insn);
-		if (ret < 0 || strcmp(data_insn.sec_name, section))
+		if (ret < 0 ||
+		    !(data_insn.sec_hdr.sh_type == SHT_PROGBITS &&
+		      data_insn.sec_hdr.sh_flags & SHF_EXECINSTR &&
+		      !strcmp(data_insn.sec_name, section)))
 			continue;
 
 		ret = bpf_apply_relo_data(ctx, &data_relo, &data_insn);