From 43a4525f80534530077683f6472d8971646b0ace Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Tue, 16 Jan 2018 17:16:32 +0100 Subject: objtool: Use existing global variables for options Use the existing global variables instead of passing them around and creating duplicate global variables. Signed-off-by: Peter Zijlstra (Intel) Acked-by: Thomas Gleixner Acked-by: Josh Poimboeuf Cc: Andy Lutomirski Cc: Arjan van de Ven Cc: Borislav Petkov Cc: Dan Williams Cc: Dave Hansen Cc: David Woodhouse Cc: Greg Kroah-Hartman Cc: Linus Torvalds Cc: Peter Zijlstra Signed-off-by: Ingo Molnar --- tools/objtool/check.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) (limited to 'tools/objtool/check.c') diff --git a/tools/objtool/check.c b/tools/objtool/check.c index a8cb69a26576..ab6f0de7f90d 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -18,6 +18,7 @@ #include #include +#include "builtin.h" #include "check.h" #include "elf.h" #include "special.h" @@ -33,7 +34,6 @@ struct alternative { }; const char *objname; -static bool no_fp; struct cfi_state initial_func_cfi; struct instruction *find_insn(struct objtool_file *file, @@ -2022,13 +2022,12 @@ static void cleanup(struct objtool_file *file) elf_close(file->elf); } -int check(const char *_objname, bool _no_fp, bool no_unreachable, bool orc) +int check(const char *_objname, bool orc) { struct objtool_file file; int ret, warnings = 0; objname = _objname; - no_fp = _no_fp; file.elf = elf_open(objname, orc ? O_RDWR : O_RDONLY); if (!file.elf) -- cgit v1.2.1 From b5bc2231b8ad4387c9641f235ca0ad8cd300b6df Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Tue, 16 Jan 2018 10:24:06 +0100 Subject: objtool: Add retpoline validation David requested a objtool validation pass for CONFIG_RETPOLINE=y enabled builds, where it validates no unannotated indirect jumps or calls are left. Add an additional .discard.retpoline_safe section to allow annotating the few indirect sites that are required and safe. Requested-by: David Woodhouse Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: David Woodhouse Acked-by: Thomas Gleixner Acked-by: Josh Poimboeuf Cc: Andy Lutomirski Cc: Arjan van de Ven Cc: Borislav Petkov Cc: Dan Williams Cc: Dave Hansen Cc: Greg Kroah-Hartman Cc: Linus Torvalds Cc: Peter Zijlstra Signed-off-by: Ingo Molnar --- tools/objtool/check.c | 86 ++++++++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 85 insertions(+), 1 deletion(-) (limited to 'tools/objtool/check.c') diff --git a/tools/objtool/check.c b/tools/objtool/check.c index ab6f0de7f90d..5e5db7b4d77b 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -497,6 +497,7 @@ static int add_jump_destinations(struct objtool_file *file) * disguise, so convert them accordingly. */ insn->type = INSN_JUMP_DYNAMIC; + insn->retpoline_safe = true; continue; } else { /* sibling call */ @@ -548,7 +549,8 @@ static int add_call_destinations(struct objtool_file *file) if (!insn->call_dest && !insn->ignore) { WARN_FUNC("unsupported intra-function call", insn->sec, insn->offset); - WARN("If this is a retpoline, please patch it in with alternatives and annotate it with ANNOTATE_NOSPEC_ALTERNATIVE."); + if (retpoline) + WARN("If this is a retpoline, please patch it in with alternatives and annotate it with ANNOTATE_NOSPEC_ALTERNATIVE."); return -1; } @@ -1108,6 +1110,54 @@ static int read_unwind_hints(struct objtool_file *file) return 0; } +static int read_retpoline_hints(struct objtool_file *file) +{ + struct section *sec, *relasec; + struct instruction *insn; + struct rela *rela; + int i; + + sec = find_section_by_name(file->elf, ".discard.retpoline_safe"); + if (!sec) + return 0; + + relasec = sec->rela; + if (!relasec) { + WARN("missing .rela.discard.retpoline_safe section"); + return -1; + } + + if (sec->len % sizeof(unsigned long)) { + WARN("retpoline_safe size mismatch: %d %ld", sec->len, sizeof(unsigned long)); + return -1; + } + + for (i = 0; i < sec->len / sizeof(unsigned long); i++) { + rela = find_rela_by_dest(sec, i * sizeof(unsigned long)); + if (!rela) { + WARN("can't find rela for retpoline_safe[%d]", i); + return -1; + } + + insn = find_insn(file, rela->sym->sec, rela->addend); + if (!insn) { + WARN("can't find insn for retpoline_safe[%d]", i); + return -1; + } + + if (insn->type != INSN_JUMP_DYNAMIC && + insn->type != INSN_CALL_DYNAMIC) { + WARN_FUNC("retpoline_safe hint not a indirect jump/call", + insn->sec, insn->offset); + return -1; + } + + insn->retpoline_safe = true; + } + + return 0; +} + static int decode_sections(struct objtool_file *file) { int ret; @@ -1146,6 +1196,10 @@ static int decode_sections(struct objtool_file *file) if (ret) return ret; + ret = read_retpoline_hints(file); + if (ret) + return ret; + return 0; } @@ -1891,6 +1945,29 @@ static int validate_unwind_hints(struct objtool_file *file) return warnings; } +static int validate_retpoline(struct objtool_file *file) +{ + struct instruction *insn; + int warnings = 0; + + for_each_insn(file, insn) { + if (insn->type != INSN_JUMP_DYNAMIC && + insn->type != INSN_CALL_DYNAMIC) + continue; + + if (insn->retpoline_safe) + continue; + + WARN_FUNC("indirect %s found in RETPOLINE build", + insn->sec, insn->offset, + insn->type == INSN_JUMP_DYNAMIC ? "jump" : "call"); + + warnings++; + } + + return warnings; +} + static bool is_kasan_insn(struct instruction *insn) { return (insn->type == INSN_CALL && @@ -2051,6 +2128,13 @@ int check(const char *_objname, bool orc) if (list_empty(&file.insn_list)) goto out; + if (retpoline) { + ret = validate_retpoline(&file); + if (ret < 0) + return ret; + warnings += ret; + } + ret = validate_functions(&file); if (ret < 0) goto out; -- cgit v1.2.1 From ca41b97ed9124fd62323a162de5852f6e28f94b8 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Wed, 31 Jan 2018 10:18:28 +0100 Subject: objtool: Add module specific retpoline rules David allowed retpolines in .init.text, except for modules, which will trip up objtool retpoline validation, fix that. Requested-by: David Woodhouse Signed-off-by: Peter Zijlstra (Intel) Acked-by: Thomas Gleixner Acked-by: Josh Poimboeuf Cc: Andy Lutomirski Cc: Arjan van de Ven Cc: Borislav Petkov Cc: Dan Williams Cc: Dave Hansen Cc: David Woodhouse Cc: Greg Kroah-Hartman Cc: Linus Torvalds Cc: Peter Zijlstra Signed-off-by: Ingo Molnar --- tools/objtool/check.c | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'tools/objtool/check.c') diff --git a/tools/objtool/check.c b/tools/objtool/check.c index 5e5db7b4d77b..472e64e95891 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -1958,6 +1958,15 @@ static int validate_retpoline(struct objtool_file *file) if (insn->retpoline_safe) continue; + /* + * .init.text code is ran before userspace and thus doesn't + * strictly need retpolines, except for modules which are + * loaded late, they very much do need retpoline in their + * .init.text + */ + if (!strcmp(insn->sec->name, ".init.text") && !module) + continue; + WARN_FUNC("indirect %s found in RETPOLINE build", insn->sec, insn->offset, insn->type == INSN_JUMP_DYNAMIC ? "jump" : "call"); -- cgit v1.2.1 From 1402fd8ed7e5bda1b3e7613b70780b0db392d1e6 Mon Sep 17 00:00:00 2001 From: Josh Poimboeuf Date: Wed, 28 Feb 2018 07:19:21 -0600 Subject: objtool: Fix another switch table detection issue Continue the switch table detection whack-a-mole. Add a check to distinguish KASAN data reads from switch data reads. The switch jump tables in .rodata have relocations associated with them. This fixes the following warning: crypto/asymmetric_keys/x509_cert_parser.o: warning: objtool: x509_note_pkey_algo()+0xa4: sibling call from callable instruction with modified stack frame Reported-by: Arnd Bergmann Signed-off-by: Josh Poimboeuf Signed-off-by: Thomas Gleixner Tested-by: Arnd Bergmann Cc: Peter Zijlstra Link: https://lkml.kernel.org/r/d7c8853022ad47d158cb81e953a40469fc08a95e.1519784382.git.jpoimboe@redhat.com --- tools/objtool/check.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) (limited to 'tools/objtool/check.c') diff --git a/tools/objtool/check.c b/tools/objtool/check.c index 472e64e95891..46c1d239cc1b 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -925,7 +925,11 @@ static struct rela *find_switch_table(struct objtool_file *file, if (find_symbol_containing(file->rodata, text_rela->addend)) continue; - return find_rela_by_dest(file->rodata, text_rela->addend); + rodata_rela = find_rela_by_dest(file->rodata, text_rela->addend); + if (!rodata_rela) + continue; + + return rodata_rela; } return NULL; -- cgit v1.2.1 From 63474dc4ac7ed3848a4786b9592dd061901f606d Mon Sep 17 00:00:00 2001 From: Josh Poimboeuf Date: Tue, 6 Mar 2018 17:58:15 -0600 Subject: objtool: Fix 32-bit build Fix the objtool build when cross-compiling a 64-bit kernel on a 32-bit host. This also simplifies read_retpoline_hints() a bit and makes its implementation similar to most of the other annotation reading functions. Reported-by: Sven Joachim Signed-off-by: Josh Poimboeuf Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Fixes: b5bc2231b8ad ("objtool: Add retpoline validation") Link: http://lkml.kernel.org/r/2ca46c636c23aa9c9d57d53c75de4ee3ddf7a7df.1520380691.git.jpoimboe@redhat.com Signed-off-by: Ingo Molnar --- tools/objtool/check.c | 27 +++++++-------------------- 1 file changed, 7 insertions(+), 20 deletions(-) (limited to 'tools/objtool/check.c') diff --git a/tools/objtool/check.c b/tools/objtool/check.c index 46c1d239cc1b..92b6a2c21631 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -1116,42 +1116,29 @@ static int read_unwind_hints(struct objtool_file *file) static int read_retpoline_hints(struct objtool_file *file) { - struct section *sec, *relasec; + struct section *sec; struct instruction *insn; struct rela *rela; - int i; - sec = find_section_by_name(file->elf, ".discard.retpoline_safe"); + sec = find_section_by_name(file->elf, ".rela.discard.retpoline_safe"); if (!sec) return 0; - relasec = sec->rela; - if (!relasec) { - WARN("missing .rela.discard.retpoline_safe section"); - return -1; - } - - if (sec->len % sizeof(unsigned long)) { - WARN("retpoline_safe size mismatch: %d %ld", sec->len, sizeof(unsigned long)); - return -1; - } - - for (i = 0; i < sec->len / sizeof(unsigned long); i++) { - rela = find_rela_by_dest(sec, i * sizeof(unsigned long)); - if (!rela) { - WARN("can't find rela for retpoline_safe[%d]", i); + list_for_each_entry(rela, &sec->rela_list, list) { + if (rela->sym->type != STT_SECTION) { + WARN("unexpected relocation symbol type in %s", sec->name); return -1; } insn = find_insn(file, rela->sym->sec, rela->addend); if (!insn) { - WARN("can't find insn for retpoline_safe[%d]", i); + WARN("bad .discard.retpoline_safe entry"); return -1; } if (insn->type != INSN_JUMP_DYNAMIC && insn->type != INSN_CALL_DYNAMIC) { - WARN_FUNC("retpoline_safe hint not a indirect jump/call", + WARN_FUNC("retpoline_safe hint not an indirect jump/call", insn->sec, insn->offset); return -1; } -- cgit v1.2.1