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| author | Andrii Nakryiko <andrii@kernel.org> | 2023-10-16 11:28:40 -0700 |
|---|---|---|
| committer | Daniel Borkmann <daniel@iogearbox.net> | 2023-10-17 11:43:20 +0200 |
| commit | 137df1189d128a6b5dee2f653e054b40ef36b94c (patch) | |
| tree | 63414cb538d83336a18287774f062f2f0df1eb2e | |
| parent | a3c2dd96487f1dd734c9443a3472c8dafa689813 (diff) | |
| download | linux-137df1189d128a6b5dee2f653e054b40ef36b94c.tar.gz linux-137df1189d128a6b5dee2f653e054b40ef36b94c.tar.bz2 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
| -rw-r--r-- | tools/lib/bpf/elf.c | 16 |
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) { |