From patchwork Thu Sep 9 11:31:28 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Dmitry V. Levin" X-Patchwork-Id: 45871 From: ldv@altlinux.org (Dmitry V. Levin) Date: Thu, 9 Sep 2021 14:31:28 +0300 Subject: [PATCH v2] findtextrel: do not use unbound alloca In-Reply-To: <20210906180000.GA19040@altlinux.org> References: <20210906180000.GA19040@altlinux.org> Message-ID: <20210909113127.GA29171@altlinux.org> This fixes the following compilation warning: findtextrel.c:184:1: warning: stack usage might be unbounded [-Wstack-usage=] Signed-off-by: Dmitry V. Levin --- v1 introduced a memory leak, so in v2 I rearranged the code a bit to make clear the new code does not introduce any memory leaks. src/ChangeLog | 7 +++++++ src/Makefile.am | 1 - src/findtextrel.c | 52 +++++++++++++++++++++-------------------------- 3 files changed, 30 insertions(+), 30 deletions(-) diff --git a/src/ChangeLog b/src/ChangeLog index 297627df..449ca17b 100644 --- a/src/ChangeLog +++ b/src/ChangeLog @@ -1,3 +1,10 @@ +2021-09-09 Dmitry V. Levin + + * findtextrel.c: Include "libeu.h". + (open_rootdir_file): New function. + (process_file): Use it to open file inside rootdir. + * Makefile.am (findtextrel_no_Wstack_usage): Remove. + 2021-09-06 Dmitry V. Levin * objdump.c (show_disasm): Replace asprintf followed by diff --git a/src/Makefile.am b/src/Makefile.am index 88d0ac8f..ee695d5d 100644 --- a/src/Makefile.am +++ b/src/Makefile.am @@ -61,7 +61,6 @@ nm_no_Wstack_usage = yes size_no_Wstack_usage = yes strip_no_Wstack_usage = yes elflint_no_Wstack_usage = yes -findtextrel_no_Wstack_usage = yes elfcmp_no_Wstack_usage = yes objdump_no_Wstack_usage = yes ranlib_no_Wstack_usage = yes diff --git a/src/findtextrel.c b/src/findtextrel.c index 220ee909..fd7baddb 100644 --- a/src/findtextrel.c +++ b/src/findtextrel.c @@ -36,6 +36,7 @@ #include #include +#include "libeu.h" #include "system.h" struct segments @@ -181,30 +182,31 @@ noop (void *arg __attribute__ ((unused))) static int -process_file (const char *fname, bool more_than_one) +open_rootdir_file (const char *fname) { - int result = 0; - void *knownsrcs = NULL; - - size_t fname_len = strlen (fname); - size_t rootdir_len = strlen (rootdir); + char *new_fname = NULL; const char *real_fname = fname; + if (fname[0] == '/' && (rootdir[0] != '/' || rootdir[1] != '\0')) - { - /* Prepend the user-provided root directory. */ - char *new_fname = alloca (rootdir_len + fname_len + 2); - *((char *) mempcpy (stpcpy (mempcpy (new_fname, rootdir, rootdir_len), - "/"), - fname, fname_len)) = '\0'; - real_fname = new_fname; - } + real_fname = new_fname = xasprintf ("%s/%s", rootdir, fname); int fd = open (real_fname, O_RDONLY); if (fd == -1) - { - error (0, errno, _("cannot open '%s'"), fname); - return 1; - } + error (0, errno, _("cannot open '%s'"), fname); + + free (new_fname); + return fd; +} + + +static int +process_file (const char *fname, bool more_than_one) +{ + int result = 0; + void *knownsrcs = NULL; + int fd = open_rootdir_file (fname); + if (fd == -1) + return 1; Elf *elf = elf_begin (fd, ELF_C_READ_MMAP, NULL); if (elf == NULL) @@ -362,18 +364,10 @@ cannot get program header index at offset %zd: %s"), is specified with an absolute path. */ if (dw == NULL && fname[0] == '/') { - size_t debuginfo_rootlen = strlen (debuginfo_root); - char *difname = (char *) alloca (rootdir_len + debuginfo_rootlen - + fname_len + 8); - strcpy (mempcpy (stpcpy (mempcpy (mempcpy (difname, rootdir, - rootdir_len), - debuginfo_root, - debuginfo_rootlen), - "/"), - fname, fname_len), - ".debug"); - + char *difname = + xasprintf("%s%s/%s.debug", rootdir, debuginfo_root, fname); fd2 = open (difname, O_RDONLY); + free (difname); if (fd2 != -1 && (elf2 = elf_begin (fd2, ELF_C_READ_MMAP, NULL)) != NULL) dw = dwarf_begin_elf (elf2, DWARF_C_READ, NULL);