kern/dl: Check for the SHF_INFO_LINK flag in grub_dl_relocate_symbols()

The grub_dl_relocate_symbols() iterates through the sections in
an ELF looking for relocation sections. According to the spec [1]
the SHF_INFO_LINK flag should be set if the sh_info field is meant
to be a section index.

[1] https://refspecs.linuxbase.org/elf/gabi4+/ch4.sheader.html

Reported-by: B Horn <b@horn.uk>
Signed-off-by: B Horn <b@horn.uk>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Conflicts:
	grub-core/kern/dl.c

Conflicts:
	grub-core/kern/dl.c

Gbp-Pq: Topic cve-2025-jan
Gbp-Pq: Name kern-dl-Check-for-the-SHF_INFO_LINK-flag-in-grub_dl_reloc.patch

diff --git a/grub-core/kern/dl.c b/grub-core/kern/dl.c
index 1a38742e6ac42932d18edf75b960590b700a58d0..958de3bf172c6fc7fb0689d6c2f99f6925c35ce7 100644 (file)
--- a/grub-core/kern/dl.c
+++ b/grub-core/kern/dl.c
@@ -599,6 +599,9 @@ grub_dl_relocate_symbols (grub_dl_t mod, void *ehdr)
        grub_dl_segment_t seg;
        grub_err_t err;
 
+        if (!(s->sh_flags & SHF_INFO_LINK))
+          continue;
+
        /* Find the target segment.  */
        for (seg = mod->segment; seg; seg = seg->next)
          if (seg->section == s->sh_info)