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authorAdhemerval Zanella <adhemerval.zanella@linaro.org>2019-04-11 18:12:00 -0300
committerAdhemerval Zanella <adhemerval.zanella@linaro.org>2019-04-23 18:13:08 -0300
commit1a4c27355e146b6d8cc6487b998462c7fdd1048f (patch)
treef4e0729fa653ce0724858156b63e53ab7a1b87e6 /elf/pldd.c
parent2d398aa272648a6078b56899db84f86f7b3bdf39 (diff)
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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.c64
1 files changed, 30 insertions, 34 deletions
diff --git a/elf/pldd.c b/elf/pldd.c
index f3fac4e487..69629bd5d2 100644
--- a/elf/pldd.c
+++ b/elf/pldd.c
@@ -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);