diff options
author | Adhemerval Zanella <adhemerval.zanella@linaro.org> | 2019-04-11 18:12:00 -0300 |
---|---|---|
committer | Adhemerval Zanella <adhemerval.zanella@linaro.org> | 2019-04-23 18:13:08 -0300 |
commit | 1a4c27355e146b6d8cc6487b998462c7fdd1048f (patch) | |
tree | f4e0729fa653ce0724858156b63e53ab7a1b87e6 /elf/pldd.c | |
parent | 2d398aa272648a6078b56899db84f86f7b3bdf39 (diff) | |
download | glibc-1a4c27355e146b6d8cc6487b998462c7fdd1048f.zip glibc-1a4c27355e146b6d8cc6487b998462c7fdd1048f.tar.gz glibc-1a4c27355e146b6d8cc6487b998462c7fdd1048f.tar.bz2 |
elf: Fix pldd (BZ#18035)
Since 9182aa67994 (Fix vDSO l_name for GDB's, BZ#387) the initial link_map
for executable itself and loader will have both l_name and l_libname->name
holding the same value due:
elf/dl-object.c
95 new->l_name = *realname ? realname : (char *) newname->name + libname_len - 1;
Since newname->name points to new->l_libname->name.
This leads to pldd to an infinite call at:
elf/pldd-xx.c
203 again:
204 while (1)
205 {
206 ssize_t n = pread64 (memfd, tmpbuf.data, tmpbuf.length, name_offset);
228 /* Try the l_libname element. */
229 struct E(libname_list) ln;
230 if (pread64 (memfd, &ln, sizeof (ln), m.l_libname) == sizeof (ln))
231 {
232 name_offset = ln.name;
233 goto again;
234 }
Since the value at ln.name (l_libname->name) will be the same as previously
read. The straightforward fix is just avoid the check and read the new list
entry.
I checked also against binaries issues with old loaders with fix for BZ#387,
and pldd could dump the shared objects.
Checked on x86_64-linux-gnu, i686-linux-gnu, aarch64-linux-gnu, and
powerpc64le-linux-gnu.
[BZ #18035]
* elf/Makefile (tests-container): Add tst-pldd.
* elf/pldd-xx.c: Use _Static_assert in of pldd_assert.
(E(find_maps)): Avoid use alloca, use default read file operations
instead of explicit LFS names, and fix infinite loop.
* elf/pldd.c: Explicit set _FILE_OFFSET_BITS, cleanup headers.
(get_process_info): Use _Static_assert instead of assert, use default
directory operations instead of explicit LFS names, and free some
leadek pointers.
* elf/tst-pldd.c: New file.
Diffstat (limited to 'elf/pldd.c')
-rw-r--r-- | elf/pldd.c | 64 |
1 files changed, 30 insertions, 34 deletions
@@ -17,23 +17,17 @@ License along with the GNU C Library; if not, see <http://www.gnu.org/licenses/>. */ -#include <alloca.h> +#define _FILE_OFFSET_BITS 64 + #include <argp.h> -#include <assert.h> #include <dirent.h> -#include <elf.h> -#include <errno.h> #include <error.h> #include <fcntl.h> #include <libintl.h> -#include <link.h> -#include <stddef.h> #include <stdio.h> #include <stdlib.h> -#include <string.h> #include <unistd.h> #include <sys/ptrace.h> -#include <sys/stat.h> #include <sys/wait.h> #include <scratch_buffer.h> @@ -76,14 +70,9 @@ static struct argp argp = options, parse_opt, args_doc, doc, NULL, more_help, NULL }; -// File descriptor of /proc/*/mem file. -static int memfd; - -/* Name of the executable */ -static char *exe; /* Local functions. */ -static int get_process_info (int dfd, long int pid); +static int get_process_info (const char *exe, int dfd, long int pid); static void wait_for_ptrace_stop (long int pid); @@ -102,8 +91,10 @@ main (int argc, char *argv[]) return 1; } - assert (sizeof (pid_t) == sizeof (int) - || sizeof (pid_t) == sizeof (long int)); + _Static_assert (sizeof (pid_t) == sizeof (int) + || sizeof (pid_t) == sizeof (long int), + "sizeof (pid_t) != sizeof (int) or sizeof (long int)"); + char *endp; errno = 0; long int pid = strtol (argv[remaining], &endp, 10); @@ -119,25 +110,24 @@ main (int argc, char *argv[]) if (dfd == -1) error (EXIT_FAILURE, errno, gettext ("cannot open %s"), buf); - struct scratch_buffer exebuf; - scratch_buffer_init (&exebuf); + /* Name of the executable */ + struct scratch_buffer exe; + scratch_buffer_init (&exe); ssize_t nexe; while ((nexe = readlinkat (dfd, "exe", - exebuf.data, exebuf.length)) == exebuf.length) + exe.data, exe.length)) == exe.length) { - if (!scratch_buffer_grow (&exebuf)) + if (!scratch_buffer_grow (&exe)) { nexe = -1; break; } } if (nexe == -1) - exe = (char *) "<program name undetermined>"; + /* Default stack allocation is at least 1024. */ + snprintf (exe.data, exe.length, "<program name undetermined>"); else - { - exe = exebuf.data; - exe[nexe] = '\0'; - } + ((char*)exe.data)[nexe] = '\0'; /* Stop all threads since otherwise the list of loaded modules might change while we are reading it. */ @@ -155,8 +145,8 @@ main (int argc, char *argv[]) error (EXIT_FAILURE, errno, gettext ("cannot prepare reading %s/task"), buf); - struct dirent64 *d; - while ((d = readdir64 (dir)) != NULL) + struct dirent *d; + while ((d = readdir (dir)) != NULL) { if (! isdigit (d->d_name[0])) continue; @@ -182,7 +172,7 @@ main (int argc, char *argv[]) wait_for_ptrace_stop (tid); - struct thread_list *newp = alloca (sizeof (*newp)); + struct thread_list *newp = xmalloc (sizeof (*newp)); newp->tid = tid; newp->next = thread_list; thread_list = newp; @@ -190,17 +180,22 @@ main (int argc, char *argv[]) closedir (dir); - int status = get_process_info (dfd, pid); + if (thread_list == NULL) + error (EXIT_FAILURE, 0, gettext ("no valid %s/task entries"), buf); + + int status = get_process_info (exe.data, dfd, pid); - assert (thread_list != NULL); do { ptrace (PTRACE_DETACH, thread_list->tid, NULL, NULL); + struct thread_list *prev = thread_list; thread_list = thread_list->next; + free (prev); } while (thread_list != NULL); close (dfd); + scratch_buffer_free (&exe); return status; } @@ -281,9 +276,10 @@ warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.\n\ static int -get_process_info (int dfd, long int pid) +get_process_info (const char *exe, int dfd, long int pid) { - memfd = openat (dfd, "mem", O_RDONLY); + /* File descriptor of /proc/<pid>/mem file. */ + int memfd = openat (dfd, "mem", O_RDONLY); if (memfd == -1) goto no_info; @@ -333,9 +329,9 @@ get_process_info (int dfd, long int pid) int retval; if (e_ident[EI_CLASS] == ELFCLASS32) - retval = find_maps32 (pid, auxv, auxv_size); + retval = find_maps32 (exe, memfd, pid, auxv, auxv_size); else - retval = find_maps64 (pid, auxv, auxv_size); + retval = find_maps64 (exe, memfd, pid, auxv, auxv_size); free (auxv); close (memfd); |