From 480b6fa3662ba8ffeee274bf0d37423413c01e55 Mon Sep 17 00:00:00 2001 From: Mark Wielaard Date: Wed, 3 Mar 2021 21:40:53 +0100 Subject: [PATCH] readelf: Sanity check verneed and verdef offsets in handle_symtab. We are going through vna_next, vn_next and vd_next in a while loop. Make sure that all offsets are sane. We don't want things to wrap around so we go in cycles. https://sourceware.org/bugzilla/show_bug.cgi?id=27501 Signed-off-by: Mark Wielaard --- src/readelf.c | 10 +++++++++- 1 files changed, 9 insertions(+), 1 deletion(-) diff --git a/src/readelf.c b/src/readelf.c index 715af3b3..b9740455 100644 --- a/src/readelf.c +++ b/src/readelf.c @@ -2554,7 +2554,9 @@ handle_symtab (Ebl *ebl, Elf_Scn *scn, GElf_Shdr *shdr) &vernaux_mem); while (vernaux != NULL && vernaux->vna_other != *versym - && vernaux->vna_next != 0) + && vernaux->vna_next != 0 + && (verneed_data->d_size - vna_offset + >= vernaux->vna_next)) { /* Update the offset. */ vna_offset += vernaux->vna_next; @@ -2571,6 +2573,9 @@ handle_symtab (Ebl *ebl, Elf_Scn *scn, GElf_Shdr *shdr) /* Found it. */ break; + if (verneed_data->d_size - vn_offset < verneed->vn_next) + break; + vn_offset += verneed->vn_next; verneed = (verneed->vn_next == 0 ? NULL @@ -2606,6 +2611,9 @@ handle_symtab (Ebl *ebl, Elf_Scn *scn, GElf_Shdr *shdr) /* Found the definition. */ break; + if (verdef_data->d_size - vd_offset < verdef->vd_next) + break; + vd_offset += verdef->vd_next; verdef = (verdef->vd_next == 0 ? NULL -- 2.27.0