From: Sami Tolvanen samitolvanen@google.com
[ Upstream commit 5141d3a06b2da1731ac82091298b766a1f95d3d8 ]
elf_update_symbol fails to preserve the special st_shndx values between [SHN_LORESERVE, SHN_HIRESERVE], which results in it converting SHN_ABS entries into SHN_UNDEF, for example. Explicitly check for the special indexes and ensure these symbols are not marked undefined.
Fixes: ead165fa1042 ("objtool: Fix symbol creation") Signed-off-by: Sami Tolvanen samitolvanen@google.com Acked-by: Peter Zijlstra (Intel) peterz@infradead.org Tested-by: Peter Zijlstra (Intel) peterz@infradead.org Signed-off-by: Kees Cook keescook@chromium.org Link: https://lore.kernel.org/r/20220908215504.3686827-17-samitolvanen@google.com Signed-off-by: Sasha Levin sashal@kernel.org --- tools/objtool/elf.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/tools/objtool/elf.c b/tools/objtool/elf.c index c25e957c1e52..7e24b09b1163 100644 --- a/tools/objtool/elf.c +++ b/tools/objtool/elf.c @@ -619,6 +619,11 @@ static int elf_update_symbol(struct elf *elf, struct section *symtab, Elf64_Xword entsize = symtab->sh.sh_entsize; int max_idx, idx = sym->idx; Elf_Scn *s, *t = NULL; + bool is_special_shndx = sym->sym.st_shndx >= SHN_LORESERVE && + sym->sym.st_shndx != SHN_XINDEX; + + if (is_special_shndx) + shndx = sym->sym.st_shndx;
s = elf_getscn(elf->elf, symtab->idx); if (!s) { @@ -704,7 +709,7 @@ static int elf_update_symbol(struct elf *elf, struct section *symtab, }
/* setup extended section index magic and write the symbol */ - if (shndx >= SHN_UNDEF && shndx < SHN_LORESERVE) { + if ((shndx >= SHN_UNDEF && shndx < SHN_LORESERVE) || is_special_shndx) { sym->sym.st_shndx = shndx; if (!shndx_data) shndx = 0;