From patchwork Sun Jun 7 20:05:37 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jan Kratochvil X-Patchwork-Id: 7065 Received: (qmail 107676 invoked by alias); 7 Jun 2015 20:05:44 -0000 Mailing-List: contact gdb-patches-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Unsubscribe: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sourceware.org Delivered-To: mailing list gdb-patches@sourceware.org Received: (qmail 107649 invoked by uid 89); 7 Jun 2015 20:05:44 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-1.9 required=5.0 tests=AWL, BAYES_50, KAM_LAZY_DOMAIN_SECURITY, SPF_HELO_PASS, T_RP_MATCHES_RCVD autolearn=no version=3.3.2 X-HELO: mx1.redhat.com Received: from mx1.redhat.com (HELO mx1.redhat.com) (209.132.183.28) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with (AES256-GCM-SHA384 encrypted) ESMTPS; Sun, 07 Jun 2015 20:05:41 +0000 Received: from int-mx13.intmail.prod.int.phx2.redhat.com (int-mx13.intmail.prod.int.phx2.redhat.com [10.5.11.26]) by mx1.redhat.com (Postfix) with ESMTPS id 3EE83B7CC0; Sun, 7 Jun 2015 20:05:40 +0000 (UTC) Received: from host1.jankratochvil.net (ovpn-116-44.ams2.redhat.com [10.36.116.44]) by int-mx13.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id t57K5bU1011587; Sun, 7 Jun 2015 16:05:38 -0400 Subject: [PATCH v6 09/10] Validate symbol file using build-id From: Jan Kratochvil To: gdb-patches@sourceware.org Cc: Aleksandar Ristovski Date: Sun, 07 Jun 2015 22:05:37 +0200 Message-ID: <20150607200537.8918.71354.stgit@host1.jankratochvil.net> In-Reply-To: <20150607200422.8918.48900.stgit@host1.jankratochvil.net> References: <20150607200422.8918.48900.stgit@host1.jankratochvil.net> User-Agent: StGit/0.17.1-dirty MIME-Version: 1.0 X-IsSubscribed: yes Hi, consumer part of the "build-id" attribute. Approved by: https://sourceware.org/ml/gdb-patches/2014-05/msg00424.html Jan gdb/ChangeLog 2014-02-26 Aleksandar Ristovski Validate symbol file using build-id. * NEWS (Changes since GDB 7.9): Add 'set solib-build-id-force' and 'show solib-build-id-force'. Add build-id attribute. * solib-darwin.c (_initialize_darwin_solib): Assign validate value. * solib-dsbt.c (_initialize_dsbt_solib): Ditto. * solib-frv.c (_initialize_frv_solib): Ditto. * solib-spu.c (set_spu_solib_ops): Ditto. * solib-svr4.c: Include rsp-low.h. (NOTE_GNU_BUILD_ID_NAME): New define. (svr4_validate): New function. (svr4_copy_library_list): Duplicate field build_id. (library_list_start_library): Parse 'build-id' attribute. (svr4_library_attributes): Add 'build-id' attribute. (_initialize_svr4_solib): Assign validate value. * solib-target.c (solib.h): Include. (_initialize_solib_target): Assign validate value. * solib.c (solib_build_id_force, show_solib_build_id_force): New. (solib_map_sections): Use ops->validate. (clear_so): Free build_id. (default_solib_validate): New function. (_initialize_solib): Add "solib-build-id-force". * solib.h (default_solib_validate): New declaration. * solist.h (struct so_list): New fields 'build_idsz' and 'build_id'. (target_so_ops): New field 'validate'. gdb/doc/ChangeLog 2014-03-02 Jan Kratochvil * gdb.texinfo (Files): Add 'set solib-build-id-force' and 'show solib-build-id-force'. --- gdb/NEWS | 12 +++++++ gdb/doc/gdb.texinfo | 38 +++++++++++++++++++++ gdb/solib-darwin.c | 1 + gdb/solib-dsbt.c | 1 + gdb/solib-frv.c | 1 + gdb/solib-spu.c | 1 + gdb/solib-svr4.c | 91 +++++++++++++++++++++++++++++++++++++++++++++++++++ gdb/solib-target.c | 2 + gdb/solib.c | 62 ++++++++++++++++++++++++++++++++++- gdb/solib.h | 4 ++ gdb/solist.h | 21 ++++++++++++ 11 files changed, 233 insertions(+), 1 deletion(-) diff --git a/gdb/NEWS b/gdb/NEWS index bbfb55d..4942efa 100644 --- a/gdb/NEWS +++ b/gdb/NEWS @@ -133,6 +133,12 @@ set|show record btrace bts buffer-size The obtained size may differ from the requested size. Use "info record" to see the obtained buffer size. +set solib-build-id-force (on|off) +show solib-build-id-force + Inferior shared library and symbol file may contain unique build-id. + If both build-ids are present but they do not match then this setting + enables (on) or disables (off) loading of such symbol file. + * The command 'thread apply all' can now support new option '-ascending' to call its specified command for all threads in ascending order. @@ -201,6 +207,12 @@ fork-events and vfork-events features in qSupported * GDB now supports access to vector registers on S/390 GNU/Linux targets. +* New features in the GDB remote stub, GDBserver + + ** library-list-svr4 contains also optional attribute 'build-id' for + each library. GDB does not load library with build-id that + does not match such attribute. + * Removed command line options -xdb HP-UX XDB compatibility mode. diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo index 2adf5f5..9ab40c9 100644 --- a/gdb/doc/gdb.texinfo +++ b/gdb/doc/gdb.texinfo @@ -17900,6 +17900,44 @@ libraries that were loaded by explicit user requests are not discarded. @end table +@table @code +@kindex set solib-build-id-force +@cindex override @value{GDBN} build-id check +@item set solib-build-id-force @var{mode} +Setting to override @value{GDBN} build-id check. + +Inferior shared libraries and symbol files may contain unique build-id. +By default @value{GDBN} will ignore symbol files with non-matching build-id +while printing: + +@smallexample + warning: Shared object "libfoo.so.1" could not be validated (remote + build ID 2bc1745e does not match local build ID a08f8767) and will be + ignored; or use 'set solib-build-id-force'. +@end smallexample + +Turning on this setting would load such symbol file while still printing: + +@smallexample + warning: Shared object "libfoo.so.1" could not be validated (remote + build ID 2bc1745e does not match local build ID a08f8767) but it is + being loaded due to 'set solib-build-id-force'. +@end smallexample + +If remote build-id is present but it does not match local build-id (or local +build-id is not present) then this setting enables (@var{mode} is @code{on}) or +disables (@var{mode} is @code{off}) loading of such symbol file. On systems +where build-id is not present in the remote system this setting has no effect. +The default value is @code{off}. + +Loading non-matching symbol file may confuse debugging including breakage +of backtrace output. + +@kindex show solib-build-id-force +@item show solib-build-id-force +Display the current mode of build-id check override. +@end table + Sometimes you may wish that @value{GDBN} stops and gives you control when any of shared library events happen. The best way to do this is to use @code{catch load} and @code{catch unload} (@pxref{Set diff --git a/gdb/solib-darwin.c b/gdb/solib-darwin.c index f96841f..9309c35 100644 --- a/gdb/solib-darwin.c +++ b/gdb/solib-darwin.c @@ -634,4 +634,5 @@ _initialize_darwin_solib (void) darwin_so_ops.in_dynsym_resolve_code = darwin_in_dynsym_resolve_code; darwin_so_ops.lookup_lib_global_symbol = darwin_lookup_lib_symbol; darwin_so_ops.bfd_open = darwin_bfd_open; + darwin_so_ops.validate = default_solib_validate; } diff --git a/gdb/solib-dsbt.c b/gdb/solib-dsbt.c index 7da5833..9fe6533 100644 --- a/gdb/solib-dsbt.c +++ b/gdb/solib-dsbt.c @@ -1080,6 +1080,7 @@ _initialize_dsbt_solib (void) dsbt_so_ops.open_symbol_file_object = open_symbol_file_object; dsbt_so_ops.in_dynsym_resolve_code = dsbt_in_dynsym_resolve_code; dsbt_so_ops.bfd_open = solib_bfd_open; + dsbt_so_ops.validate = default_solib_validate; /* Debug this file's internals. */ add_setshow_zuinteger_cmd ("solib-dsbt", class_maintenance, diff --git a/gdb/solib-frv.c b/gdb/solib-frv.c index f7ef38b..b768146 100644 --- a/gdb/solib-frv.c +++ b/gdb/solib-frv.c @@ -1183,6 +1183,7 @@ _initialize_frv_solib (void) frv_so_ops.open_symbol_file_object = open_symbol_file_object; frv_so_ops.in_dynsym_resolve_code = frv_in_dynsym_resolve_code; frv_so_ops.bfd_open = solib_bfd_open; + frv_so_ops.validate = default_solib_validate; /* Debug this file's internals. */ add_setshow_zuinteger_cmd ("solib-frv", class_maintenance, diff --git a/gdb/solib-spu.c b/gdb/solib-spu.c index 44fbf91..d162884 100644 --- a/gdb/solib-spu.c +++ b/gdb/solib-spu.c @@ -519,6 +519,7 @@ set_spu_solib_ops (struct gdbarch *gdbarch) spu_so_ops.current_sos = spu_current_sos; spu_so_ops.bfd_open = spu_bfd_open; spu_so_ops.lookup_lib_global_symbol = spu_lookup_lib_symbol; + spu_so_ops.validate = default_solib_validate; } set_solib_ops (gdbarch, &spu_so_ops); diff --git a/gdb/solib-svr4.c b/gdb/solib-svr4.c index 909dfb7..881b8f3 100644 --- a/gdb/solib-svr4.c +++ b/gdb/solib-svr4.c @@ -45,6 +45,9 @@ #include "auxv.h" #include "gdb_bfd.h" #include "probe.h" +#include "rsp-low.h" + +#define NOTE_GNU_BUILD_ID_NAME ".note.gnu.build-id" static struct link_map_offsets *svr4_fetch_link_map_offsets (void); static int svr4_have_link_map_offsets (void); @@ -970,6 +973,64 @@ svr4_keep_data_in_core (CORE_ADDR vaddr, unsigned long size) return (name_lm >= vaddr && name_lm < vaddr + size); } +/* Validate SO by comparing build-id from the associated bfd and + corresponding build-id from target memory. */ + +static char * +svr4_validate (const struct so_list *const so) +{ + bfd_byte *local_id; + size_t local_idsz; + + gdb_assert (so != NULL); + + /* Target doesn't support reporting the build ID or the remote shared library + does not have build ID. */ + if (so->build_id == NULL) + return NULL; + + /* Build ID may be present in the local file, just GDB is unable to retrieve + it. As it has been reported by gdbserver it is not FSF gdbserver. */ + if (so->abfd == NULL + || !bfd_check_format (so->abfd, bfd_object) + || bfd_get_flavour (so->abfd) != bfd_target_elf_flavour) + return NULL; + + /* GDB has verified the local file really does not contain the build ID. */ + if (elf_tdata (so->abfd)->build_id == NULL) + { + char *remote_hex; + + remote_hex = alloca (so->build_idsz * 2 + 1); + bin2hex (so->build_id, remote_hex, so->build_idsz); + + return xstrprintf (_("remote build ID is %s " + "but local file does not have build ID"), + remote_hex); + } + + local_id = elf_tdata (so->abfd)->build_id->data; + local_idsz = elf_tdata (so->abfd)->build_id->size; + + if (so->build_idsz != local_idsz + || memcmp (so->build_id, local_id, so->build_idsz) != 0) + { + char *remote_hex, *local_hex; + + remote_hex = alloca (so->build_idsz * 2 + 1); + bin2hex (so->build_id, remote_hex, so->build_idsz); + local_hex = alloca (local_idsz * 2 + 1); + bin2hex (local_id, local_hex, local_idsz); + + return xstrprintf (_("remote build ID %s " + "does not match local build ID %s"), + remote_hex, local_hex); + } + + /* Both build IDs are present and they match. */ + return NULL; +} + /* Implement the "open_symbol_file_object" target_so_ops method. If no open symbol file, attempt to locate and open the main symbol @@ -1108,6 +1169,12 @@ svr4_copy_library_list (struct so_list *src) newobj->lm_info = xmalloc (sizeof (struct lm_info)); memcpy (newobj->lm_info, src->lm_info, sizeof (struct lm_info)); + if (newobj->build_id != NULL) + { + newobj->build_id = xmalloc (src->build_idsz); + memcpy (newobj->build_id, src->build_id, src->build_idsz); + } + newobj->next = NULL; *link = newobj; link = &newobj->next; @@ -1135,6 +1202,9 @@ library_list_start_library (struct gdb_xml_parser *parser, ULONGEST *lmp = xml_find_attribute (attributes, "lm")->value; ULONGEST *l_addrp = xml_find_attribute (attributes, "l_addr")->value; ULONGEST *l_ldp = xml_find_attribute (attributes, "l_ld")->value; + const struct gdb_xml_value *const att_build_id + = xml_find_attribute (attributes, "build-id"); + const char *const hex_build_id = att_build_id ? att_build_id->value : NULL; struct so_list *new_elem; new_elem = XCNEW (struct so_list); @@ -1146,6 +1216,25 @@ library_list_start_library (struct gdb_xml_parser *parser, strncpy (new_elem->so_name, name, sizeof (new_elem->so_name) - 1); new_elem->so_name[sizeof (new_elem->so_name) - 1] = 0; strcpy (new_elem->so_original_name, new_elem->so_name); + if (hex_build_id != NULL) + { + const size_t hex_build_id_len = strlen (hex_build_id); + + if (hex_build_id_len > 0 && (hex_build_id_len & 1U) == 0) + { + const size_t build_idsz = hex_build_id_len / 2; + + new_elem->build_id = xmalloc (build_idsz); + new_elem->build_idsz = hex2bin (hex_build_id, new_elem->build_id, + build_idsz); + if (new_elem->build_idsz != build_idsz) + { + xfree (new_elem->build_id); + new_elem->build_id = NULL; + new_elem->build_idsz = 0; + } + } + } *list->tailp = new_elem; list->tailp = &new_elem->next; @@ -1180,6 +1269,7 @@ static const struct gdb_xml_attribute svr4_library_attributes[] = { "lm", GDB_XML_AF_NONE, gdb_xml_parse_attr_ulongest, NULL }, { "l_addr", GDB_XML_AF_NONE, gdb_xml_parse_attr_ulongest, NULL }, { "l_ld", GDB_XML_AF_NONE, gdb_xml_parse_attr_ulongest, NULL }, + { "build-id", GDB_XML_AF_OPTIONAL, NULL, NULL }, { NULL, GDB_XML_AF_NONE, NULL, NULL } }; @@ -3258,4 +3348,5 @@ _initialize_svr4_solib (void) svr4_so_ops.keep_data_in_core = svr4_keep_data_in_core; svr4_so_ops.update_breakpoints = svr4_update_solib_event_breakpoints; svr4_so_ops.handle_event = svr4_handle_solib_event; + svr4_so_ops.validate = svr4_validate; } diff --git a/gdb/solib-target.c b/gdb/solib-target.c index bd8f58a..689bc74 100644 --- a/gdb/solib-target.c +++ b/gdb/solib-target.c @@ -25,6 +25,7 @@ #include "target.h" #include "vec.h" #include "solib-target.h" +#include "solib.h" /* Private data for each loaded library. */ struct lm_info @@ -500,6 +501,7 @@ _initialize_solib_target (void) solib_target_so_ops.in_dynsym_resolve_code = solib_target_in_dynsym_resolve_code; solib_target_so_ops.bfd_open = solib_bfd_open; + solib_target_so_ops.validate = default_solib_validate; /* Set current_target_so_ops to solib_target_so_ops if not already set. */ diff --git a/gdb/solib.c b/gdb/solib.c index 0010c2f..4bd47d0 100644 --- a/gdb/solib.c +++ b/gdb/solib.c @@ -523,6 +523,20 @@ solib_bfd_open (char *pathname) return abfd; } +/* Boolean for command 'set solib-build-id-force'. */ +static int solib_build_id_force = 0; + +/* Implement 'show solib-build-id-force'. */ + +static void +show_solib_build_id_force (struct ui_file *file, int from_tty, + struct cmd_list_element *c, const char *value) +{ + fprintf_filtered (file, _("Loading of shared libraries " + "with non-matching build-id is %s.\n"), + value); +} + /* Given a pointer to one of the shared objects in our list of mapped objects, use the recorded name to open a bfd descriptor for the object, build a section table, relocate all the section addresses @@ -539,7 +553,7 @@ static int solib_map_sections (struct so_list *so) { const struct target_so_ops *ops = solib_ops (target_gdbarch ()); - char *filename; + char *filename, *validate_error; struct target_section *p; struct cleanup *old_chain; bfd *abfd; @@ -555,6 +569,27 @@ solib_map_sections (struct so_list *so) /* Leave bfd open, core_xfer_memory and "info files" need it. */ so->abfd = abfd; + gdb_assert (ops->validate != NULL); + + validate_error = ops->validate (so); + if (validate_error != NULL) + { + if (!solib_build_id_force) + { + warning (_("Shared object \"%s\" could not be validated (%s) and " + "will be ignored; or use 'set solib-build-id-force'."), + so->so_name, validate_error); + xfree (validate_error); + gdb_bfd_unref (so->abfd); + so->abfd = NULL; + return 0; + } + warning (_("Shared object \"%s\" could not be validated (%s) " + "but it is being loaded due to 'set solib-build-id-force'."), + so->so_name, validate_error); + xfree (validate_error); + } + /* Copy the full path name into so_name, allowing symbol_file_add to find it later. This also affects the =library-loaded GDB/MI event, and in particular the part of that notification providing @@ -631,6 +666,9 @@ clear_so (struct so_list *so) of the symbol file. */ strcpy (so->so_name, so->so_original_name); + xfree (so->build_id); + so->build_id = NULL; + /* Do the same for target-specific data. */ if (ops->clear_so != NULL) ops->clear_so (so); @@ -1662,6 +1700,14 @@ remove_user_added_objfile (struct objfile *objfile) } } +/* Default implementation does not perform any validation. */ + +char * +default_solib_validate (const struct so_list *const so) +{ + return NULL; /* No validation. */ +} + extern initialize_file_ftype _initialize_solib; /* -Wmissing-prototypes */ void @@ -1719,4 +1765,18 @@ PATH and LD_LIBRARY_PATH."), reload_shared_libraries, show_solib_search_path, &setlist, &showlist); + + add_setshow_boolean_cmd ("solib-build-id-force", class_support, + &solib_build_id_force, _("\ +Set loading of shared libraries with non-matching build-id."), _("\ +Show loading of shared libraries with non-matching build-id."), _("\ +Inferior shared library and symbol file may contain unique build-id.\n\ +If both build-ids are present but they do not match then this setting\n\ +enables (on) or disables (off) loading of such symbol file.\n\ +Loading non-matching symbol file may confuse debugging including breakage\n\ +of backtrace output."), + NULL, + show_solib_build_id_force, + &setlist, &showlist); + } diff --git a/gdb/solib.h b/gdb/solib.h index 336971d..c3bf529 100644 --- a/gdb/solib.h +++ b/gdb/solib.h @@ -98,4 +98,8 @@ extern void update_solib_breakpoints (void); extern void handle_solib_event (void); +/* Default validation always returns 1. */ + +extern char *default_solib_validate (const struct so_list *so); + #endif /* SOLIB_H */ diff --git a/gdb/solist.h b/gdb/solist.h index 7021f5c..f0d8653 100644 --- a/gdb/solist.h +++ b/gdb/solist.h @@ -75,6 +75,22 @@ struct so_list There may not be just one (e.g. if two segments are relocated differently); but this is only used for "info sharedlibrary". */ CORE_ADDR addr_low, addr_high; + + /* Build id in raw format, contains verbatim contents of + .note.gnu.build-id including note header. This is actual + BUILD_ID which comes either from the remote target via qXfer + packet or via reading target memory. Therefore, it may differ + from the build-id of the associated bfd. In a normal + scenario, this so would soon lose its abfd due to failed + validation. + Reading target memory should be done by following execution view + of the binary (following program headers in the case of ELF). + Computing address from the linking view (following ELF section + headers) may give incorrect build-id memory address despite the + symbols still match. + Such an example is a prelinked vs. unprelinked i386 ELF file. */ + size_t build_idsz; + gdb_byte *build_id; }; struct target_so_ops @@ -168,6 +184,11 @@ struct target_so_ops NULL, in which case no specific preprocessing is necessary for this target. */ void (*handle_event) (void); + + /* Return NULL if SO does match target SO it is supposed to + represent. Otherwise return string describing why it does not match. + Caller has to free the string. */ + char *(*validate) (const struct so_list *so); }; /* Free the memory associated with a (so_list *). */