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authorAndrii Nakryiko <andrii@kernel.org>2023-10-16 20:28:40 +0200
committerDaniel Borkmann <daniel@iogearbox.net>2023-10-17 11:43:20 +0200
commit137df1189d128a6b5dee2f653e054b40ef36b94c (patch)
tree63414cb538d83336a18287774f062f2f0df1eb2e /tools/lib
parentMerge tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf... (diff)
downloadlinux-137df1189d128a6b5dee2f653e054b40ef36b94c.tar.xz
linux-137df1189d128a6b5dee2f653e054b40ef36b94c.zip
libbpf: Don't assume SHT_GNU_verdef presence for SHT_GNU_versym section
Fix too eager assumption that SHT_GNU_verdef ELF section is going to be present whenever binary has SHT_GNU_versym section. It seems like either SHT_GNU_verdef or SHT_GNU_verneed can be used, so failing on missing SHT_GNU_verdef actually breaks use cases in production. One specific reported issue, which was used to manually test this fix, was trying to attach to `readline` function in BASH binary. Fixes: bb7fa09399b9 ("libbpf: Support symbol versioning for uprobe") Reported-by: Liam Wisehart <liamwisehart@meta.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Tested-by: Manu Bretelle <chantr4@gmail.com> Reviewed-by: Fangrui Song <maskray@google.com> Acked-by: Hengqi Chen <hengqi.chen@gmail.com> Link: https://lore.kernel.org/bpf/20231016182840.4033346-1-andrii@kernel.org
Diffstat (limited to 'tools/lib')
-rw-r--r--tools/lib/bpf/elf.c16
1 files changed, 10 insertions, 6 deletions
diff --git a/tools/lib/bpf/elf.c b/tools/lib/bpf/elf.c
index 2a158e8a8b7c..2a62bf411bb3 100644
--- a/tools/lib/bpf/elf.c
+++ b/tools/lib/bpf/elf.c
@@ -141,14 +141,15 @@ static int elf_sym_iter_new(struct elf_sym_iter *iter,
iter->versyms = elf_getdata(scn, 0);
scn = elf_find_next_scn_by_type(elf, SHT_GNU_verdef, NULL);
- if (!scn) {
- pr_debug("elf: failed to find verdef ELF sections in '%s'\n", binary_path);
- return -ENOENT;
- }
- if (!gelf_getshdr(scn, &sh))
+ if (!scn)
+ return 0;
+
+ iter->verdefs = elf_getdata(scn, 0);
+ if (!iter->verdefs || !gelf_getshdr(scn, &sh)) {
+ pr_warn("elf: failed to get verdef ELF section in '%s'\n", binary_path);
return -EINVAL;
+ }
iter->verdef_strtabidx = sh.sh_link;
- iter->verdefs = elf_getdata(scn, 0);
return 0;
}
@@ -199,6 +200,9 @@ static const char *elf_get_vername(struct elf_sym_iter *iter, int ver)
GElf_Verdef verdef;
int offset;
+ if (!iter->verdefs)
+ return NULL;
+
offset = 0;
while (gelf_getverdef(iter->verdefs, offset, &verdef)) {
if (verdef.vd_ndx != ver) {