From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-yw1-f202.google.com (mail-yw1-f202.google.com [209.85.128.202]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id CA2921C4610 for ; Thu, 10 Oct 2024 12:28:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.202 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728563301; cv=none; b=Z1aE6NzTzMLfVMWTeOC3o+Vwm/AA0HK/MRQhDn/hdQ3z9WPGe8P66ZXJtCbGMAxZucbOY5w0OLYV4CGVQUEr/rx0z1OuInRRZbYsCauTYChuj+yOsU5xhoEDjVRjsDxweP/nwvW1UL0KmqJRFg2nZfbIfEPPznSn+JBYEe0EiPE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728563301; c=relaxed/simple; bh=XueFKKJfNv5S62FTI6Nn6miZHSnizhT2/a1kRTz+4zc=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=EXspukqJB2vno4RsDWrnYgTk9RUXVF5x0oLd2ew/aloq6GFISJhyEBtADvslVkPkqvN018vKQlOdeYk4aaBRO773JIi4q7ziKwX/UJgpoW6Z9SzQSWuu7CSXeAzPHdDq5Cvl6O1fp3N37TGCztpWERxiMx29sSejxiahKMnVoSg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--ardb.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=W6wlejm+; arc=none smtp.client-ip=209.85.128.202 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--ardb.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="W6wlejm+" Received: by mail-yw1-f202.google.com with SMTP id 00721157ae682-6e000d68bb1so22697697b3.1 for ; Thu, 10 Oct 2024 05:28:19 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1728563298; x=1729168098; darn=lists.linux.dev; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=1h9fFvgBUeRFx9Aotl4DWJObQ4kxzCBME+ifVsDcAJM=; b=W6wlejm+bGgE8jjaaEIbMR5qg3UWF+zzPFVpKIq/wYxl39rFQisRv0zAnPdF//ZTNs GCS/3M88c/Wp890gLJNaev3YZUz1RO4Iq03GEVDtmOsGPRF5/j7ELMoMorJw5ULvMzGz pU4rvxIRsr2hGCDgcwRhzvVM4OODW2aLNLcTZlcqNP6FiIcjnmUUNOrLmhfuWbL8JC4Q 7JDk9xMXZ26rxmwpPPoC3+wU6tDUl8XH7GDfvRJEHUjIWBjP1ofCH1cp0uiNgzNZyzZc 5BMM7ttuBpt3tHet7wmSnMYqah6wOl0djsyYjJW+bxKv8g9heSYGAa1vzDtf9OD4KI73 1tNA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1728563298; x=1729168098; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=1h9fFvgBUeRFx9Aotl4DWJObQ4kxzCBME+ifVsDcAJM=; b=Z/fmY9a8gngDnVyPmBgaowpQLx8tVvlb3NhgLlMBp1DFBOn4byQaPE+TJQheP7Xtqm aofKrnTH9vlw0pwX0Q4MoEjt1Z846+51PxNQiwTJhBaFjNFRgdVZ51sBa0minpDjh7IM 7+pCft7nNJfNnuvJ2L57rnrGPywuMvIaBohTzTEFsrMSFw3oFyJ9fepJmndbQJc2yj/7 uZfZkfTNeuAmPcrAmUm3AWFsAyY462ZReuu7VL6SlhMiT+r1Cx3tsPnn1aK3ZeTFnZ/N UGnXdqqxeFjhITWnCFluvYNsGlWrFWT37ZUb1s9wJGdwcCq5t2+gweEW3Iu6lbPi/4mx Gbag== X-Gm-Message-State: AOJu0YyvzlCK/fCMDubUIttCtCV3RgUrD3Q637L/E4Jnl3eYqWULqjeh aH4G3g7zgG7xNeio9OtG66g20zkLw4tH3jqIWOvuDbTXS+mC4mGH9XtVhyfqZC0ZtUJzuA== X-Google-Smtp-Source: AGHT+IE9TBQHDn81ejkh1rw2v+XDC+2cpXnc7DsPnWjm4u6sifCrO6OF2c5NoEQ7evGC5PCEb3uoSlO6 X-Received: from palermo.c.googlers.com ([fda3:e722:ac3:cc00:7b:198d:ac11:8138]) (user=ardb job=sendgmr) by 2002:a05:6902:2d02:b0:e29:2a3:ad7f with SMTP id 3f1490d57ef6-e290b5afe99mr42880276.1.1728563298554; Thu, 10 Oct 2024 05:28:18 -0700 (PDT) Date: Thu, 10 Oct 2024 14:28:04 +0200 In-Reply-To: <20241010122801.1321976-7-ardb+git@google.com> Precedence: bulk X-Mailing-List: llvm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20241010122801.1321976-7-ardb+git@google.com> X-Developer-Key: i=ardb@kernel.org; a=openpgp; fpr=F43D03328115A198C90016883D200E9CA6329909 X-Developer-Signature: v=1; a=openpgp-sha256; l=6898; i=ardb@kernel.org; h=from:subject; bh=jlstyuRGCsVkoeHTvHTTSvfyzwb2vzkKg7m++dSyEtY=; b=owGbwMvMwCFmkMcZplerG8N4Wi2JIZ39RKg1x/mChKdFy6Q2BvjdbTARsDHbn87dG1siXWud8 plB9H1HKQuDGAeDrJgii8Dsv+92np4oVes8SxZmDisTyBAGLk4BmEiRACPDapENBTc1fXP4/bbW cf7M+7RlVUPXE2vNrrSTr69mzAveysjQ4b4s0PydpdP075/X7/ffkfNyRsnsezZLI9o/pc6pvOP ICAA= X-Mailer: git-send-email 2.47.0.rc0.187.ge670bccf7e-goog Message-ID: <20241010122801.1321976-9-ardb+git@google.com> Subject: [PATCH v2 2/5] objtool: Allow arch code to discover jump table size From: Ard Biesheuvel To: linux-kernel@vger.kernel.org Cc: llvm@lists.linux.dev, keescook@chromium.org, linux-hardening@vger.kernel.org, nathan@kernel.org, Ard Biesheuvel , Josh Poimboeuf , Peter Zijlstra , Jan Beulich , "Jose E. Marchesi" , Kees Cook Content-Type: text/plain; charset="UTF-8" From: Ard Biesheuvel In preparation for adding support for annotated jump tables, where ELF relocations and symbols are used to describe the locations of jump tables in the executable, refactor the jump table discovery logic so the table size can be returned from arch_find_switch_table(). Signed-off-by: Ard Biesheuvel --- tools/objtool/arch/loongarch/special.c | 3 +- tools/objtool/arch/powerpc/special.c | 3 +- tools/objtool/arch/x86/special.c | 4 ++- tools/objtool/check.c | 31 +++++++++++++------- tools/objtool/include/objtool/check.h | 5 +++- tools/objtool/include/objtool/special.h | 3 +- 6 files changed, 33 insertions(+), 16 deletions(-) diff --git a/tools/objtool/arch/loongarch/special.c b/tools/objtool/arch/loongarch/special.c index 9bba1e9318e0..87230ed570fd 100644 --- a/tools/objtool/arch/loongarch/special.c +++ b/tools/objtool/arch/loongarch/special.c @@ -9,7 +9,8 @@ bool arch_support_alt_relocation(struct special_alt *special_alt, } struct reloc *arch_find_switch_table(struct objtool_file *file, - struct instruction *insn) + struct instruction *insn, + unsigned long *table_size) { return NULL; } diff --git a/tools/objtool/arch/powerpc/special.c b/tools/objtool/arch/powerpc/special.c index d33868147196..51610689abf7 100644 --- a/tools/objtool/arch/powerpc/special.c +++ b/tools/objtool/arch/powerpc/special.c @@ -13,7 +13,8 @@ bool arch_support_alt_relocation(struct special_alt *special_alt, } struct reloc *arch_find_switch_table(struct objtool_file *file, - struct instruction *insn) + struct instruction *insn, + unsigned long *table_size) { exit(-1); } diff --git a/tools/objtool/arch/x86/special.c b/tools/objtool/arch/x86/special.c index 415e4d035e53..f8fb67636384 100644 --- a/tools/objtool/arch/x86/special.c +++ b/tools/objtool/arch/x86/special.c @@ -109,7 +109,8 @@ bool arch_support_alt_relocation(struct special_alt *special_alt, * NOTE: MITIGATION_RETPOLINE made it harder still to decode dynamic jumps. */ struct reloc *arch_find_switch_table(struct objtool_file *file, - struct instruction *insn) + struct instruction *insn, + unsigned long *table_size) { struct reloc *text_reloc, *rodata_reloc; struct section *table_sec; @@ -150,5 +151,6 @@ struct reloc *arch_find_switch_table(struct objtool_file *file, if (!rodata_reloc) return NULL; + *table_size = 0; return rodata_reloc; } diff --git a/tools/objtool/check.c b/tools/objtool/check.c index 7f7981a93535..5f711ac5b43d 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -150,6 +150,15 @@ static inline struct reloc *insn_jump_table(struct instruction *insn) return NULL; } +static inline unsigned long insn_jump_table_size(struct instruction *insn) +{ + if (insn->type == INSN_JUMP_DYNAMIC || + insn->type == INSN_CALL_DYNAMIC) + return insn->_jump_table_size; + + return 0; +} + static bool is_jump_table_jump(struct instruction *insn) { struct alt_group *alt_group = insn->alt_group; @@ -2099,6 +2108,7 @@ static int add_special_section_alts(struct objtool_file *file) static int add_jump_table(struct objtool_file *file, struct instruction *insn, struct reloc *next_table) { + unsigned long table_size = insn_jump_table_size(insn); struct symbol *pfunc = insn_func(insn)->pfunc; struct reloc *table = insn_jump_table(insn); unsigned int rtype = reloc_type(table); @@ -2116,6 +2126,8 @@ static int add_jump_table(struct objtool_file *file, struct instruction *insn, unsigned long addend = reloc_addend(reloc); /* Check for the end of the table: */ + if (table_size && reloc_offset(reloc) - reloc_offset(table) >= table_size) + break; if (reloc != table && reloc == next_table) break; @@ -2175,12 +2187,12 @@ static int add_jump_table(struct objtool_file *file, struct instruction *insn, * find_jump_table() - Given a dynamic jump, find the switch jump table * associated with it. */ -static struct reloc *find_jump_table(struct objtool_file *file, - struct symbol *func, - struct instruction *insn) +static void find_jump_table(struct objtool_file *file, struct symbol *func, + struct instruction *insn) { struct reloc *table_reloc; struct instruction *dest_insn, *orig_insn = insn; + unsigned long table_size; /* * Backward search using the @first_jump_src links, these help avoid @@ -2201,17 +2213,17 @@ static struct reloc *find_jump_table(struct objtool_file *file, insn->jump_dest->offset > orig_insn->offset)) break; - table_reloc = arch_find_switch_table(file, insn); + table_reloc = arch_find_switch_table(file, insn, &table_size); if (!table_reloc) continue; dest_insn = find_insn(file, table_reloc->sym->sec, reloc_addend(table_reloc)); if (!dest_insn || !insn_func(dest_insn) || insn_func(dest_insn)->pfunc != func) continue; - return table_reloc; + orig_insn->_jump_table = table_reloc; + orig_insn->_jump_table_size = table_size; + break; } - - return NULL; } /* @@ -2222,7 +2234,6 @@ static void mark_func_jump_tables(struct objtool_file *file, struct symbol *func) { struct instruction *insn, *last = NULL; - struct reloc *reloc; func_for_each_insn(file, func, insn) { if (!last) @@ -2245,9 +2256,7 @@ static void mark_func_jump_tables(struct objtool_file *file, if (insn->type != INSN_JUMP_DYNAMIC) continue; - reloc = find_jump_table(file, func, insn); - if (reloc) - insn->_jump_table = reloc; + find_jump_table(file, func, insn); } } diff --git a/tools/objtool/include/objtool/check.h b/tools/objtool/include/objtool/check.h index daa46f1f0965..e1cd13cd28a3 100644 --- a/tools/objtool/include/objtool/check.h +++ b/tools/objtool/include/objtool/check.h @@ -71,7 +71,10 @@ struct instruction { struct instruction *first_jump_src; union { struct symbol *_call_dest; - struct reloc *_jump_table; + struct { + struct reloc *_jump_table; + unsigned long _jump_table_size; + }; }; struct alternative *alts; struct symbol *sym; diff --git a/tools/objtool/include/objtool/special.h b/tools/objtool/include/objtool/special.h index 89ee12b1a138..e049679bb17b 100644 --- a/tools/objtool/include/objtool/special.h +++ b/tools/objtool/include/objtool/special.h @@ -38,5 +38,6 @@ bool arch_support_alt_relocation(struct special_alt *special_alt, struct instruction *insn, struct reloc *reloc); struct reloc *arch_find_switch_table(struct objtool_file *file, - struct instruction *insn); + struct instruction *insn, + unsigned long *table_size); #endif /* _SPECIAL_H */ -- 2.47.0.rc0.187.ge670bccf7e-goog