Michael Chang
5121551e07
- Fix "no symbol table" error on new binutil, backport patches (bsc#1100984) * 0001-Verify-modules-on-build-time-rather-than-failing-in-.patch * 0002-module-verifier-Check-range-limited-relative-relocat.patch * 0003-support-modules-without-symbol-table.patch OBS-URL: https://build.opensuse.org/request/show/624214 OBS-URL: https://build.opensuse.org/package/show/Base:System/trustedgrub2?expand=0&rev=16
107 lines
3.9 KiB
Diff
107 lines
3.9 KiB
Diff
From 67dba97e4598eaf2deb14da044fbfb1c119cf76f Mon Sep 17 00:00:00 2001
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From: Andrei Borzenkov <arvidjaar@gmail.com>
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Date: Wed, 3 Feb 2016 20:34:55 +0300
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Subject: [PATCH] support modules without symbol table
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all_video module does not have any code or data and exists solely for
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.moddeps section to pull in dependencies. This makes all symbols unneeded.
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While in current binutils (last released version as of this commit is 2.26)
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``strip --strip-unneeded'' unintentionally adds section symbols for each
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existing section, this behavior was considered a bug and changed in commit
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14f2c699ddca1e2f706342dffc59a6c7e23e844c to completely strip symbol table
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in this case.
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Older binutils (verified with 2.17) and some other toolchains (at least
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elftoolchain r3223M), both used in FreeBSD, remove symbol table in all_video
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as well.
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Relax run-time check and do not return error for modules without symbol table.
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Add additional checks to module verifier to make sure such modules
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a) have non-empty .moddeps section. Without either externally visible symbols
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or .moddeps modules are completely useless and should not be built.
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b) do not have any relocations.
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Closes: 46986
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v2: add run-time check for empty symbol table if relocations are present as
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suggested by Vladimir.
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---
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grub-core/kern/dl.c | 8 +++++++-
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util/grub-module-verifierXX.c | 18 +++++++++++++++++-
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2 files changed, 24 insertions(+), 2 deletions(-)
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Index: trustedgrub2-1.4.0/grub-core/kern/dl.c
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===================================================================
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--- trustedgrub2-1.4.0.orig/grub-core/kern/dl.c
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+++ trustedgrub2-1.4.0/grub-core/kern/dl.c
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@@ -337,8 +337,11 @@ grub_dl_resolve_symbols (grub_dl_t mod,
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if (s->sh_type == SHT_SYMTAB)
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break;
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+ /* Module without symbol table may still be used to pull in dependencies.
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+ We verify at build time that such modules do not contain any relocations
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+ that may reference symbol table. */
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if (i == e->e_shnum)
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- return grub_error (GRUB_ERR_BAD_MODULE, N_("no symbol table"));
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+ return GRUB_ERR_NONE;
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#ifdef GRUB_MODULES_MACHINE_READONLY
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mod->symtab = grub_malloc (s->sh_size);
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@@ -580,6 +583,9 @@ grub_dl_relocate_symbols (grub_dl_t mod,
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if (seg)
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{
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+ if (!mod->symtab)
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+ return grub_error (GRUB_ERR_BAD_MODULE, "relocation without symbol table");
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+
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err = grub_arch_dl_relocate_symbols (mod, ehdr, s, seg);
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if (err)
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return err;
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Index: trustedgrub2-1.4.0/util/grub-module-verifierXX.c
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===================================================================
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--- trustedgrub2-1.4.0.orig/util/grub-module-verifierXX.c
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+++ trustedgrub2-1.4.0/util/grub-module-verifierXX.c
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@@ -176,7 +176,7 @@ get_symtab (const struct grub_module_ver
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break;
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if (i == grub_target_to_host16 (e->e_shnum))
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- grub_util_error ("no symbol table");
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+ return NULL;
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sym = (Elf_Sym *) ((char *) e + grub_target_to_host (s->sh_offset));
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*size = grub_target_to_host (s->sh_size);
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@@ -191,7 +191,21 @@ check_symbols (const struct grub_module_
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Elf_Word size, entsize;
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unsigned i;
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+ /* Module without symbol table and without .moddeps section is useless
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+ at boot time, so catch it early to prevent build errors */
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sym = get_symtab (arch, e, &size, &entsize);
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+ if (!sym)
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+ {
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+ Elf_Shdr *s = find_section (arch, e, ".moddeps");
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+
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+ if (!s)
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+ grub_util_error ("no symbol table and no .moddeps section");
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+
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+ if (!s->sh_size)
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+ grub_util_error ("no symbol table and empty .moddeps section");
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+
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+ return;
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+ }
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for (i = 0;
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i < size / entsize;
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@@ -243,6 +257,8 @@ section_check_relocations (const struct
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Elf_Word symtabsize, symtabentsize;
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symtab = get_symtab (arch, ehdr, &symtabsize, &symtabentsize);
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+ if (!symtab)
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+ grub_util_error ("relocation without symbol table");
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for (rel = (Elf_Rel *) ((char *) ehdr + grub_target_to_host (s->sh_offset)),
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max = (Elf_Rel *) ((char *) rel + grub_target_to_host (s->sh_size));
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