git: 1ee7e4ba70e1 - releng/13.1 - loader: fix elf lookup_symbol type filtering

From: Mark Johnston <markj_at_FreeBSD.org>
Date: Tue, 01 Nov 2022 20:33:46 UTC
The branch releng/13.1 has been updated by markj:

URL: https://cgit.FreeBSD.org/src/commit/?id=1ee7e4ba70e10e0ac0c9c144ad0301ffeca8824d

commit 1ee7e4ba70e10e0ac0c9c144ad0301ffeca8824d
Author:     Kyle Evans <kevans@FreeBSD.org>
AuthorDate: 2022-10-14 03:06:13 +0000
Commit:     Mark Johnston <markj@FreeBSD.org>
CommitDate: 2022-11-01 18:03:25 +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.
    
    Approved by:    so
    Security:       FreeBSD-EN-22:27.loader
    Reported by:    Christian McDonald <cmcdonald netgate com>
    Reviewed by:    imp, kib, tsoome
    
    (cherry picked from commit 0701dbda94f21de8ddab3113f79262a26cc7b96c)
    (cherry picked from commit 2b31059ea701957584e68a75857206d80a230211)
---
 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 c75567b4a560..9e47d3db3828 100644
--- a/stand/common/load_elf.c
+++ b/stand/common/load_elf.c
@@ -1259,9 +1259,8 @@ __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;
 			}