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([2804:431:c7ca:733:a925:765e:3799:3d34]) by smtp.gmail.com with ESMTPSA id n47sm7695104ota.74.2022.02.10.04.18.11 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 10 Feb 2022 04:18:12 -0800 (PST) To: libc-alpha@sourceware.org Subject: [PATCH v3 3/3] elf: Remove LD_USE_LOAD_BIAS Date: Thu, 10 Feb 2022 09:17:54 -0300 Message-Id: <20220210121754.862331-4-adhemerval.zanella@linaro.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20220210121754.862331-1-adhemerval.zanella@linaro.org> References: <20220210121754.862331-1-adhemerval.zanella@linaro.org> MIME-Version: 1.0 X-Spam-Status: No, score=-13.4 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, GIT_PATCH_0, RCVD_IN_DNSWL_NONE, SPF_HELO_NONE, SPF_PASS, TXREP, T_SCC_BODY_TEXT_LINE autolearn=unavailable autolearn_force=no version=3.4.4 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on server2.sourceware.org X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-Patchwork-Original-From: Adhemerval Zanella via Libc-alpha From: Adhemerval Zanella Netto Reply-To: Adhemerval Zanella Cc: Siddhesh Poyarekar Errors-To: libc-alpha-bounces+patchwork=sourceware.org@sourceware.org Sender: "Libc-alpha" It is solely for prelink with PIE executables [1]. [1] https://sourceware.org/legacy-ml/libc-hacker/2003-11/msg00127.html Reviewed-by: Siddhesh Poyarekar --- NEWS | 3 +++ elf/dl-map-segments.h | 3 +-- elf/dl-support.c | 1 - elf/rtld.c | 13 ------------- sysdeps/generic/ldsodefs.h | 5 ----- sysdeps/generic/unsecvars.h | 1 - 6 files changed, 4 insertions(+), 22 deletions(-) diff --git a/NEWS b/NEWS index 88815bcad1..626eeabf5d 100644 --- a/NEWS +++ b/NEWS @@ -197,6 +197,9 @@ Deprecated and removed features, and other changes affecting compatibility: functionality to obtain the program mapping address can be achieved by using LD_TRACE_LOADED_OBJECTS to value of 2. +* The LD_USE_LOAD_BIAS has been removed. The variable was mainly used to + support prelink PIE binaries. + Changes to build and runtime requirements: * The audit module interface version LAV_CURRENT is increased to enable diff --git a/elf/dl-map-segments.h b/elf/dl-map-segments.h index 172692b120..b3513e7909 100644 --- a/elf/dl-map-segments.h +++ b/elf/dl-map-segments.h @@ -94,8 +94,7 @@ _dl_map_segments (struct link_map *l, int fd, prefer to map such objects at; but this is only a preference, the OS can do whatever it likes. */ ElfW(Addr) mappref - = (ELF_PREFERRED_ADDRESS (loader, maplength, - c->mapstart & GLRO(dl_use_load_bias)) + = (ELF_PREFERRED_ADDRESS (loader, maplength, c->mapstart) - MAP_BASE_ADDR (l)); /* Remember which part of the address space this object uses. */ diff --git a/elf/dl-support.c b/elf/dl-support.c index 0fff62064a..1977a2be76 100644 --- a/elf/dl-support.c +++ b/elf/dl-support.c @@ -54,7 +54,6 @@ size_t _dl_platformlen; int _dl_debug_mask; int _dl_lazy; -ElfW(Addr) _dl_use_load_bias = -2; int _dl_dynamic_weak; /* If nonzero print warnings about problematic situations. */ diff --git a/elf/rtld.c b/elf/rtld.c index aa18256d86..19e328f89e 100644 --- a/elf/rtld.c +++ b/elf/rtld.c @@ -365,7 +365,6 @@ struct rtld_global_ro _rtld_global_ro attribute_relro = ._dl_sysinfo = DL_SYSINFO_DEFAULT, #endif ._dl_debug_fd = STDERR_FILENO, - ._dl_use_load_bias = -2, ._dl_correct_cache_id = _DL_CACHE_DEFAULT_ID, #if !HAVE_TUNABLES ._dl_hwcap_mask = HWCAP_IMPORTANT, @@ -1742,12 +1741,6 @@ dl_main (const ElfW(Phdr) *phdr, ++GL(dl_ns)[LM_ID_BASE]._ns_nloaded; ++GL(dl_load_adds); - /* If LD_USE_LOAD_BIAS env variable has not been seen, default - to not using bias for non-prelinked PIEs and libraries - and using it for executables or prelinked PIEs or libraries. */ - if (GLRO(dl_use_load_bias) == (ElfW(Addr)) -2) - GLRO(dl_use_load_bias) = main_map->l_addr == 0 ? -1 : 0; - /* Starting from binutils-2.23, the linker will define the magic symbol __ehdr_start to point to our own ELF header if it is visible in a segment that also includes the phdrs. If that's not available, we use @@ -2657,12 +2650,6 @@ process_envvars (struct dl_main_state *state) #ifdef EXTRA_LD_ENVVARS_13 EXTRA_LD_ENVVARS_13 #endif - if (!__libc_enable_secure - && memcmp (envline, "USE_LOAD_BIAS", 13) == 0) - { - GLRO(dl_use_load_bias) = envline[14] == '1' ? -1 : 0; - break; - } break; case 14: diff --git a/sysdeps/generic/ldsodefs.h b/sysdeps/generic/ldsodefs.h index d1c6cd902b..9878e7e87e 100644 --- a/sysdeps/generic/ldsodefs.h +++ b/sysdeps/generic/ldsodefs.h @@ -628,11 +628,6 @@ struct rtld_global_ro /* Location of the binary. */ EXTERN const char *_dl_origin_path; - /* -1 if the dynamic linker should honor library load bias, - 0 if not, -2 use the default (honor biases for normal - binaries, don't honor for PIEs). */ - EXTERN ElfW(Addr) _dl_use_load_bias; - /* Size of the static TLS block. */ EXTERN size_t _dl_tls_static_size; diff --git a/sysdeps/generic/unsecvars.h b/sysdeps/generic/unsecvars.h index 5ea8a4a259..b50331b50f 100644 --- a/sysdeps/generic/unsecvars.h +++ b/sysdeps/generic/unsecvars.h @@ -22,7 +22,6 @@ "LD_PRELOAD\0" \ "LD_PROFILE\0" \ "LD_SHOW_AUXV\0" \ - "LD_USE_LOAD_BIAS\0" \ "LOCALDOMAIN\0" \ "LOCPATH\0" \ "MALLOC_TRACE\0" \