From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pl1-x641.google.com (mail-pl1-x641.google.com [IPv6:2607:f8b0:4864:20::641]) by sourceware.org (Postfix) with ESMTPS id 630E93851C0A; Tue, 19 May 2020 23:40:20 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org 630E93851C0A Received: by mail-pl1-x641.google.com with SMTP id f15so567697plr.3; Tue, 19 May 2020 16:40:20 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=ahvMH+/4D/ovTPDz/NDDuK8dx8bvCSBnlUZeWNI2UlI=; b=cuZSSQcZ/M7Q5ldu5dRmpBgix/13B/+nbP3nOgXK01Bi4sK7NCaUyUfRfPw3dKqFew 0N9pAwiUZMN3JH6aqe6kS9zfUiDXCqzW+ZCxs30IRivhtgHkwrIMpbiW1iJR0RCMZl60 EdbYlW3BFchb0a5csOqdM9guL2wNtY6fkSUUbx2JW5YgGbuK7TqRHGLnFolO2uK6mWm9 MTGdq1LlLYfPGgeyPn0NnFwC1+G8PjToBqv7fIBzuNJvmfMoxFnKyAd95QPaZOnQbYgH j1s6bK7CJ2BzLqkcaiA6Y0zg4O+rxSqRnyEl87mcURT9Om8C5HTeZepmIy49lLvLP6fD NXhA== X-Gm-Message-State: AOAM532JE97ARB2eY+Ily4axe9xS/4o0POtmUjkjXlpOiCtJKmpUCJ0i mq22TRqPTMaXNlhz/8T+gaU= X-Google-Smtp-Source: ABdhPJzs/jvCBKZpPwh3HQ6iQl6xv0PO557h23mOD6TqR9EXFzs3QUBcwg9bDvFs8UzKio9dBjd5tA== X-Received: by 2002:a17:90a:23ef:: with SMTP id g102mr2043506pje.144.1589931619173; Tue, 19 May 2020 16:40:19 -0700 (PDT) Received: from bubble.grove.modra.org (158.106.96.58.static.exetel.com.au. [58.96.106.158]) by smtp.gmail.com with ESMTPSA id w186sm478620pff.83.2020.05.19.16.40.17 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 19 May 2020 16:40:18 -0700 (PDT) Received: by bubble.grove.modra.org (Postfix, from userid 1000) id A2DB088A38; Wed, 20 May 2020 09:10:14 +0930 (ACST) Date: Wed, 20 May 2020 09:10:14 +0930 From: Alan Modra To: Simon Marchi Cc: binutils@sourceware.org, gdb-patches@sourceware.org Subject: Re: PR25993, read of freed memory Message-ID: <20200519234014.GA16809@bubble.grove.modra.org> References: <20200519043205.GT1088@bubble.grove.modra.org> <111d8c5d-d615-e0ae-36de-519c43a51139@simark.ca> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <111d8c5d-d615-e0ae-36de-519c43a51139@simark.ca> User-Agent: Mutt/1.9.4 (2018-02-28) X-Spam-Status: No, score=-13.5 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, FREEMAIL_FROM, GIT_PATCH_0, RCVD_IN_DNSWL_NONE, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org X-BeenThere: gdb-patches@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Gdb-patches mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 19 May 2020 23:40:22 -0000 On Tue, May 19, 2020 at 09:27:15AM -0400, Simon Marchi wrote: > On 2020-05-19 12:32 a.m., Alan Modra via Gdb-patches wrote: > > -void bfd_set_filename (bfd *abfd, char *filename); > > +char *bfd_set_filename (bfd *abfd, const char *filename); > > Should this return a `const char *`, just like bfd_get_filename? > > I haven't inspected all call sites, but it sounds like the caller > shouldn't be able to modify the filename contents. Yes, I've updated the return type. One minor change needed to mach-o.c. > Since the string gets copied by bfd_set_filename, let's use std::string > to avoid having to free: Done, and symfile-mem.c updated as per down-thread suggestion to make name a const char*. I've left the return status from bfd_set_filename in gdb unchecked, ie. the out-of-memory NULL return, since it seems to me that not getting the expected name change is a minor detail very likely to be lost in some later OOM. PR 25993 bfd/ * archive.c (_bfd_get_elt_at_filepos): Don't strdup filename, use bfd_set_filename. * elfcode.h (_bfd_elf_bfd_from_remote_memory): Likewise. * mach-o.c (bfd_mach_o_fat_member_init): Likewise. * opncls.c (bfd_fopen, bfd_openstreamr, bfd_openr_iovec, bfd_openw), (bfd_create): Likewise. (_bfd_delete_bfd): Don't free filename. (bfd_set_filename): Copy filename param to bfd_alloc'd memory, return pointer to the copy or NULL on alloc fail. * vms-lib.c (_bfd_vms_lib_get_module): Free newname and test result of bfd_set_filename. * bfd-in2.h: Regenerate. gdb/ * solib-darwin.c (darwin_bfd_open): Don't strdup pathname for bfd_set_filename. * solib-aix.c (solib_aix_bfd_open): Free name after calling bfd_set_filename. * symfile-mem.c (symbol_file_add_from_memory): Likewise. ld/ * emultempl/pe.em (gld_${EMULATION_NAME}_after_open): Don't copy other_bfd_filename for bfd_set_filename, and test result of bfd_set_filename call. Don't create a new is->filename, simply copy from bfd filename. Free new_name after bfd_set_filename. * emultempl/pep.em (gld_${EMULATION_NAME}_after_open): Likewise. diff --git a/bfd/archive.c b/bfd/archive.c index ff64727c44..1322977744 100644 --- a/bfd/archive.c +++ b/bfd/archive.c @@ -737,8 +737,7 @@ _bfd_get_elt_at_filepos (bfd *archive, file_ptr filepos) else { n_bfd->origin = n_bfd->proxy_origin; - n_bfd->filename = bfd_strdup (filename); - if (n_bfd->filename == NULL) + if (!bfd_set_filename (n_bfd, filename)) goto out; } diff --git a/bfd/elfcode.h b/bfd/elfcode.h index 68db3e9ee3..5e6b2a430f 100644 --- a/bfd/elfcode.h +++ b/bfd/elfcode.h @@ -1680,7 +1680,6 @@ NAME(_bfd_elf,bfd_from_remote_memory) bfd_vma high_offset; bfd_vma shdr_end; bfd_vma loadbase; /* Bytes. */ - char *filename; size_t amt; unsigned int opb = bfd_octets_per_byte (templ, NULL); @@ -1894,22 +1893,14 @@ NAME(_bfd_elf,bfd_from_remote_memory) free (contents); return NULL; } - filename = bfd_strdup (""); - if (filename == NULL) - { - free (bim); - free (contents); - return NULL; - } nbfd = _bfd_new_bfd (); - if (nbfd == NULL) + if (nbfd == NULL + || !bfd_set_filename (nbfd, "")) { - free (filename); free (bim); free (contents); return NULL; } - nbfd->filename = filename; nbfd->xvec = templ->xvec; bim->size = high_offset; bim->buffer = contents; diff --git a/bfd/mach-o.c b/bfd/mach-o.c index 33bd81e121..43fa56cb58 100644 --- a/bfd/mach-o.c +++ b/bfd/mach-o.c @@ -5573,26 +5573,23 @@ bfd_mach_o_fat_member_init (bfd *abfd, struct areltdata *areltdata; /* Create the member filename. Use ARCH_NAME. */ const bfd_arch_info_type *ap = bfd_lookup_arch (arch_type, arch_subtype); - char *filename; + const char *filename; if (ap) { /* Use the architecture name if known. */ - filename = bfd_strdup (ap->printable_name); - if (filename == NULL) - return FALSE; + filename = bfd_set_filename (abfd, ap->printable_name); } else { /* Forge a uniq id. */ - const size_t namelen = 2 + 8 + 1 + 2 + 8 + 1; - filename = bfd_malloc (namelen); - if (filename == NULL) - return FALSE; - snprintf (filename, namelen, "0x%lx-0x%lx", + char buf[2 + 8 + 1 + 2 + 8 + 1]; + snprintf (buf, sizeof (buf), "0x%lx-0x%lx", entry->cputype, entry->cpusubtype); + filename = bfd_set_filename (abfd, buf); } - bfd_set_filename (abfd, filename); + if (!filename) + return FALSE; areltdata = bfd_zmalloc (sizeof (struct areltdata)); if (areltdata == NULL) diff --git a/bfd/opncls.c b/bfd/opncls.c index 5d3437d382..78b2ad7dd7 100644 --- a/bfd/opncls.c +++ b/bfd/opncls.c @@ -126,7 +126,6 @@ _bfd_delete_bfd (bfd *abfd) objalloc_free ((struct objalloc *) abfd->memory); } - free ((char *) bfd_get_filename (abfd)); free (abfd->arelt_data); free (abfd); } @@ -232,8 +231,7 @@ bfd_fopen (const char *filename, const char *target, const char *mode, int fd) /* PR 11983: Do not cache the original filename, but rather make a copy - the original might go away. */ - nbfd->filename = bfd_strdup (filename); - if (nbfd->filename == NULL) + if (!bfd_set_filename (nbfd, filename)) { fclose (nbfd->iostream); _bfd_delete_bfd (nbfd); @@ -406,8 +404,7 @@ bfd_openstreamr (const char *filename, const char *target, void *streamarg) nbfd->iostream = stream; /* PR 11983: Do not cache the original filename, but rather make a copy - the original might go away. */ - nbfd->filename = bfd_strdup (filename); - if (nbfd->filename == NULL) + if (!bfd_set_filename (nbfd, filename)) { _bfd_delete_bfd (nbfd); return NULL; @@ -607,8 +604,7 @@ bfd_openr_iovec (const char *filename, const char *target, /* PR 11983: Do not cache the original filename, but rather make a copy - the original might go away. */ - nbfd->filename = bfd_strdup (filename); - if (nbfd->filename == NULL) + if (!bfd_set_filename (nbfd, filename)) { _bfd_delete_bfd (nbfd); return NULL; @@ -679,8 +675,7 @@ bfd_openw (const char *filename, const char *target) /* PR 11983: Do not cache the original filename, but rather make a copy - the original might go away. */ - nbfd->filename = bfd_strdup (filename); - if (nbfd->filename == NULL) + if (!bfd_set_filename (nbfd, filename)) { _bfd_delete_bfd (nbfd); return NULL; @@ -824,8 +819,7 @@ bfd_create (const char *filename, bfd *templ) return NULL; /* PR 11983: Do not cache the original filename, but rather make a copy - the original might go away. */ - nbfd->filename = bfd_strdup (filename); - if (nbfd->filename == NULL) + if (!bfd_set_filename (nbfd, filename)) { _bfd_delete_bfd (nbfd); return NULL; @@ -2040,17 +2034,23 @@ FUNCTION bfd_set_filename SYNOPSIS - void bfd_set_filename (bfd *abfd, char *filename); + const char *bfd_set_filename (bfd *abfd, const char *filename); DESCRIPTION - Set the filename of @var{abfd}. The old filename, if any, is freed. - @var{filename} must be allocated using @code{xmalloc}. After - this call, it is owned @var{abfd}. + Set the filename of @var{abfd}, copying the FILENAME parameter to + bfd_alloc'd memory owned by @var{abfd}. Returns a pointer the + newly allocated name, or NULL if the allocation failed. */ -void -bfd_set_filename (bfd *abfd, char *filename) +const char * +bfd_set_filename (bfd *abfd, const char *filename) { - free ((char *) abfd->filename); - abfd->filename = filename; + size_t len = strlen (filename) + 1; + char *n = bfd_alloc (abfd, len); + if (n) + { + memcpy (n, filename, len); + abfd->filename = n; + } + return n; } diff --git a/bfd/vms-lib.c b/bfd/vms-lib.c index 9504cf4976..6a8a76ecb0 100644 --- a/bfd/vms-lib.c +++ b/bfd/vms-lib.c @@ -1452,6 +1452,12 @@ _bfd_vms_lib_get_module (bfd *abfd, unsigned int modidx) break; } bfd_set_filename (res, newname); + free (newname); + if (bfd_get_filename (res) == NULL) + { + bfd_close (res); + return NULL; + } tdata->cache[modidx] = res; diff --git a/gdb/solib-aix.c b/gdb/solib-aix.c index 5da1214a25..344c1f5760 100644 --- a/gdb/solib-aix.c +++ b/gdb/solib-aix.c @@ -637,10 +637,10 @@ solib_aix_bfd_open (const char *pathname) along with appended parenthesized member name in order to allow commands listing all shared libraries to display. Otherwise, we would only be displaying the name of the archive member object. */ - bfd_set_filename (object_bfd.get (), - xstrprintf ("%s%s", - bfd_get_filename (archive_bfd.get ()), - sep)); + std::string fname = string_printf ("%s%s", + bfd_get_filename (archive_bfd.get ()), + sep); + bfd_set_filename (object_bfd.get (), fname.c_str ()); return object_bfd; } diff --git a/gdb/solib-darwin.c b/gdb/solib-darwin.c index e740a41fa4..ee0483d2c8 100644 --- a/gdb/solib-darwin.c +++ b/gdb/solib-darwin.c @@ -662,7 +662,7 @@ darwin_bfd_open (const char *pathname) /* The current filename for fat-binary BFDs is a name generated by BFD, usually a string containing the name of the architecture. Reset its value to the actual filename. */ - bfd_set_filename (res.get (), xstrdup (pathname)); + bfd_set_filename (res.get (), pathname); return res; } diff --git a/gdb/symfile-mem.c b/gdb/symfile-mem.c index e2d2e43d7f..78096fcbae 100644 --- a/gdb/symfile-mem.c +++ b/gdb/symfile-mem.c @@ -78,11 +78,10 @@ target_read_memory_bfd (bfd_vma memaddr, bfd_byte *myaddr, bfd_size_type len) and read its in-core symbols out of inferior memory. SIZE, if non-zero, is the known size of the object. TEMPL is a bfd representing the target's format. NAME is the name to use for this - symbol file in messages; it can be NULL or a malloc-allocated string - which will be attached to the BFD. */ + symbol file in messages; it can be NULL. */ static struct objfile * symbol_file_add_from_memory (struct bfd *templ, CORE_ADDR addr, - size_t size, char *name, int from_tty) + size_t size, const char *name, int from_tty) { struct objfile *objf; struct bfd *nbfd; @@ -102,7 +101,7 @@ symbol_file_add_from_memory (struct bfd *templ, CORE_ADDR addr, gdb_bfd_ref_ptr nbfd_holder = gdb_bfd_ref_ptr::new_reference (nbfd); if (name == NULL) - name = xstrdup ("shared object read from target memory"); + name = "shared object read from target memory"; bfd_set_filename (nbfd, name); if (!bfd_check_format (nbfd, bfd_object)) @@ -183,8 +182,9 @@ add_vsyscall_page (struct target_ops *target, int from_tty) return; } - char *name = xstrprintf ("system-supplied DSO at %s", - paddress (target_gdbarch (), vsyscall_range.start)); + std::string name = string_printf ("system-supplied DSO at %s", + paddress (target_gdbarch (), + vsyscall_range.start)); try { /* Pass zero for FROM_TTY, because the action of loading the @@ -193,7 +193,7 @@ add_vsyscall_page (struct target_ops *target, int from_tty) symbol_file_add_from_memory (bfd, vsyscall_range.start, vsyscall_range.length, - name, + name.c_str (), 0 /* from_tty */); } catch (const gdb_exception &ex) diff --git a/ld/emultempl/pe.em b/ld/emultempl/pe.em index fe65d2b266..8c5ee76233 100644 --- a/ld/emultempl/pe.em +++ b/ld/emultempl/pe.em @@ -1523,7 +1523,6 @@ gld_${EMULATION_NAME}_after_open (void) struct bfd_symbol *s; struct bfd_link_hash_entry * blhe; const char *other_bfd_filename; - char *n; s = (relocs[i]->sym_ptr_ptr)[0]; @@ -1550,9 +1549,9 @@ gld_${EMULATION_NAME}_after_open (void) continue; /* Rename this implib to match the other one. */ - n = xmalloc (strlen (other_bfd_filename) + 1); - strcpy (n, other_bfd_filename); - bfd_set_filename (is->the_bfd->my_archive, n); + if (!bfd_set_filename (is->the_bfd->my_archive, + other_bfd_filename)) + einfo ("%F%P: %pB: %E\n", is->the_bfd); } free (relocs); @@ -1655,28 +1654,14 @@ gld_${EMULATION_NAME}_after_open (void) else /* sentinel */ seq = 'c'; - /* PR 25993: It is possible that is->the_bfd-filename == is->filename. - In which case calling bfd_set_filename on one will free the memory - pointed to by the other. */ - if (is->filename == bfd_get_filename (is->the_bfd)) - { - new_name = xmalloc (strlen (is->filename) + 3); - sprintf (new_name, "%s.%c", is->filename, seq); - bfd_set_filename (is->the_bfd, new_name); - is->filename = new_name; - } - else - { - new_name - = xmalloc (strlen (bfd_get_filename (is->the_bfd)) + 3); - sprintf (new_name, "%s.%c", - bfd_get_filename (is->the_bfd), seq); - bfd_set_filename (is->the_bfd, new_name); - - new_name = xmalloc (strlen (is->filename) + 3); - sprintf (new_name, "%s.%c", is->filename, seq); - is->filename = new_name; - } + new_name + = xmalloc (strlen (bfd_get_filename (is->the_bfd)) + 3); + sprintf (new_name, "%s.%c", + bfd_get_filename (is->the_bfd), seq); + is->filename = bfd_set_filename (is->the_bfd, new_name); + free (new_name); + if (!is->filename) + einfo ("%F%P: %pB: %E\n", is->the_bfd); } } } diff --git a/ld/emultempl/pep.em b/ld/emultempl/pep.em index 699b86501c..ea8e768ea9 100644 --- a/ld/emultempl/pep.em +++ b/ld/emultempl/pep.em @@ -1491,7 +1491,6 @@ gld_${EMULATION_NAME}_after_open (void) struct bfd_symbol *s; struct bfd_link_hash_entry * blhe; const char *other_bfd_filename; - char *n; s = (relocs[i]->sym_ptr_ptr)[0]; @@ -1518,9 +1517,9 @@ gld_${EMULATION_NAME}_after_open (void) continue; /* Rename this implib to match the other one. */ - n = xmalloc (strlen (other_bfd_filename) + 1); - strcpy (n, other_bfd_filename); - bfd_set_filename (is->the_bfd->my_archive, n); + if (!bfd_set_filename (is->the_bfd->my_archive, + other_bfd_filename)) + einfo ("%F%P: %pB: %E\n", is->the_bfd); } free (relocs); @@ -1623,28 +1622,14 @@ gld_${EMULATION_NAME}_after_open (void) else /* sentinel */ seq = 'c'; - /* PR 25993: It is possible that is->the_bfd-filename == is->filename. - In which case calling bfd_set_filename on one will free the memory - pointed to by the other. */ - if (is->filename == bfd_get_filename (is->the_bfd)) - { - new_name = xmalloc (strlen (is->filename) + 3); - sprintf (new_name, "%s.%c", is->filename, seq); - bfd_set_filename (is->the_bfd, new_name); - is->filename = new_name; - } - else - { - new_name - = xmalloc (strlen (bfd_get_filename (is->the_bfd)) + 3); - sprintf (new_name, "%s.%c", - bfd_get_filename (is->the_bfd), seq); - bfd_set_filename (is->the_bfd, new_name); - - new_name = xmalloc (strlen (is->filename) + 3); - sprintf (new_name, "%s.%c", is->filename, seq); - is->filename = new_name; - } + new_name + = xmalloc (strlen (bfd_get_filename (is->the_bfd)) + 3); + sprintf (new_name, "%s.%c", + bfd_get_filename (is->the_bfd), seq); + is->filename = bfd_set_filename (is->the_bfd, new_name); + free (new_name); + if (!is->filename) + einfo ("%F%P: %pB: %E\n", is->the_bfd); } } } -- Alan Modra Australia Development Lab, IBM