git: 2b31059ea701 - stable/13 - loader: fix elf lookup_symbol type filtering

From: Kyle Evans <kevans_at_FreeBSD.org>
Date: Mon, 17 Oct 2022 15:40:54 UTC
The branch stable/13 has been updated by kevans:

URL: https://cgit.FreeBSD.org/src/commit/?id=2b31059ea701957584e68a75857206d80a230211

commit 2b31059ea701957584e68a75857206d80a230211
Author:     Kyle Evans <kevans@FreeBSD.org>
AuthorDate: 2022-10-14 03:06:13 +0000
Commit:     Kyle Evans <kevans@FreeBSD.org>
CommitDate: 2022-10-17 15:40:41 +0000

    loader: fix elf lookup_symbol type filtering
    
    The existing logic doesn't seem to make much sense, as we won't filter
    on the type if st_shndx != SHN_UNDEF.  In practice, this breaks booting
    12.3 kernels on newer loaders, as they do have a `kernphys` symbol of
    the wrong type (NOTYPE, rather than OBJECT) -- we end up deriving the
    wrong value for copy_staging.
    
    It's unclear if this version makes any more sense, but it seems to match
    what rtld's matched_symbol() does.  Loader doesn't need to care about
    STT_FUNC w/ UND shndx, because we won't encounter those; in kmods,
    undefined (kernel) functions are NOTYPE.
    
    Reported by:    Christian McDonald <cmcdonald netgate com>
    Reviewed by:    imp, kib, tsoome
    
    (cherry picked from commit 0701dbda94f21de8ddab3113f79262a26cc7b96c)
---
 stand/common/load_elf.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/stand/common/load_elf.c b/stand/common/load_elf.c
index d8fad9df994b..7454c550c7f2 100644
--- a/stand/common/load_elf.c
+++ b/stand/common/load_elf.c
@@ -1258,9 +1258,8 @@ __elfN(lookup_symbol)(elf_file_t ef, const char* name, Elf_Sym *symp,
 		strp = strdupout((vm_offset_t)(ef->strtab + sym.st_name));
 		if (strcmp(name, strp) == 0) {
 			free(strp);
-			if (sym.st_shndx != SHN_UNDEF ||
-			    (sym.st_value != 0 &&
-			    ELF_ST_TYPE(sym.st_info) == type)) {
+			if (sym.st_shndx != SHN_UNDEF && sym.st_value != 0 &&
+			    ELF_ST_TYPE(sym.st_info) == type) {
 				*symp = sym;
 				return 0;
 			}