Fix writes past the allocated array bounds in execvpe (BZ#20847)
Commit 6c9e1be87a37bf wrongly fixes BZ#20847 by lefting the else branch
on maybe_script_execute to still being able to invalid write on stack
allocated buffer. It happens if execvp{e} is executed with an empty
arguments list ({ NULL }) and although manual states first argument
should be the script name itself, by convention, old and current
implementation allows it.
This patch fixes the issue by just account for arguments and not the
final 'NULL' (since the 'argv + 1' will indeed ignored the script name).
The empty argument list is handled in a special case with a minimum
allocated size. The patch also adds extra tests for such case in
tst-vfork3.
Tested on x86_64.
[BZ #20847]
* posix/execvpe.c (maybe_script_execute): Remove write past allocated
array bounds for else branch.
(__execvpe): Style fixes.
* posix/tst-vfork3.c (run_script): New function.
(create_script): Likewise.
(do_test): Use run_script internal function.
(do_prepare): Use create_script internal function.
This commit is contained in:
Adhemerval Zanella
parent
657c084cd6
commit
8047e7cf71
12
ChangeLog
12
ChangeLog
@ -1,3 +1,15 @@
|
||||
2016-12-07 Adhemerval Zanella <adhemerval.zanella@linaro.org>
|
||||
Dominik Vogt <vogt@linux.vnet.ibm.com>
|
||||
|
||||
[BZ #20847]
|
||||
* posix/execvpe.c (maybe_script_execute): Remove write past allocated
|
||||
array bounds for else branch.
|
||||
(__execvpe): Style fixes.
|
||||
* posix/tst-vfork3.c (run_script): New function.
|
||||
(create_script): Likewise.
|
||||
(do_test): Use run_script internal function.
|
||||
(do_prepare): Use create_script internal function.
|
||||
|
||||
2016-12-07 Andreas Schwab <schwab@suse.de>
|
||||
|
||||
* sysdeps/unix/sysv/linux/x86/elision-conf.h
|
||||
|
||||
@ -38,8 +38,8 @@
|
||||
static void
|
||||
maybe_script_execute (const char *file, char *const argv[], char *const envp[])
|
||||
{
|
||||
ptrdiff_t argc = 0;
|
||||
while (argv[argc++] != NULL)
|
||||
ptrdiff_t argc;
|
||||
for (argc = 0; argv[argc] != NULL; argc++)
|
||||
{
|
||||
if (argc == INT_MAX - 1)
|
||||
{
|
||||
@ -48,13 +48,18 @@ maybe_script_execute (const char *file, char *const argv[], char *const envp[])
|
||||
}
|
||||
}
|
||||
|
||||
/* Construct an argument list for the shell. It will contain at minimum 3
|
||||
arguments (current shell, script, and an ending NULL. */
|
||||
char *new_argv[argc + 1];
|
||||
/* Construct an argument list for the shell based on original arguments:
|
||||
1. Empty list (argv = { NULL }, argc = 1 }: new argv will contain 3
|
||||
arguments - default shell, script to execute, and ending NULL.
|
||||
2. Non empty argument list (argc = { ..., NULL }, argc > 1}: new argv
|
||||
will contain also the default shell and the script to execute. It
|
||||
will also skip the script name in arguments and only copy script
|
||||
arguments. */
|
||||
char *new_argv[argc > 1 ? 2 + argc : 3];
|
||||
new_argv[0] = (char *) _PATH_BSHELL;
|
||||
new_argv[1] = (char *) file;
|
||||
if (argc > 1)
|
||||
memcpy (new_argv + 2, argv + 1, (argc - 1) * sizeof(char *));
|
||||
memcpy (new_argv + 2, argv + 1, argc * sizeof(char *));
|
||||
else
|
||||
new_argv[2] = NULL;
|
||||
|
||||
@ -96,7 +101,7 @@ __execvpe (const char *file, char *const argv[], char *const envp[])
|
||||
size_t path_len = __strnlen (path, PATH_MAX - 1) + 1;
|
||||
|
||||
/* NAME_MAX does not include the terminating null character. */
|
||||
if (((file_len-1) > NAME_MAX)
|
||||
if ((file_len - 1 > NAME_MAX)
|
||||
|| !__libc_alloca_cutoff (path_len + file_len + 1))
|
||||
{
|
||||
errno = ENAMETOOLONG;
|
||||
|
||||
@ -33,6 +33,35 @@ char *tmpdirname;
|
||||
#define PREPARE(argc, argv) do_prepare ()
|
||||
#include "../test-skeleton.c"
|
||||
|
||||
static void
|
||||
run_script (const char *script, char *const argv[])
|
||||
{
|
||||
for (size_t i = 0; i < 5; i++)
|
||||
{
|
||||
pid_t pid = vfork ();
|
||||
if (pid < 0)
|
||||
FAIL_EXIT1 ("vfork failed: %m");
|
||||
else if (pid == 0)
|
||||
{
|
||||
execvp (script, argv);
|
||||
_exit (errno);
|
||||
}
|
||||
|
||||
int status;
|
||||
if (TEMP_FAILURE_RETRY (waitpid (pid, &status, 0)) != pid)
|
||||
FAIL_EXIT1 ("waitpid failed");
|
||||
else if (status != 0)
|
||||
{
|
||||
if (WIFEXITED (status))
|
||||
FAIL_EXIT1 ("%s failed with status %d\n", script,
|
||||
WEXITSTATUS (status));
|
||||
else
|
||||
FAIL_EXIT1 ("%s killed by signal %d\n", script,
|
||||
WTERMSIG (status));
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
static int
|
||||
do_test (void)
|
||||
{
|
||||
@ -49,68 +78,22 @@ do_test (void)
|
||||
return 1;
|
||||
}
|
||||
|
||||
size_t i;
|
||||
char *argv[3] = { (char *) "script1.sh", (char *) "1", NULL };
|
||||
for (i = 0; i < 5; i++)
|
||||
{
|
||||
pid_t pid = vfork ();
|
||||
if (pid < 0)
|
||||
{
|
||||
printf ("vfork failed: %m\n");
|
||||
return 1;
|
||||
}
|
||||
else if (pid == 0)
|
||||
{
|
||||
execvp ("script1.sh", argv);
|
||||
_exit (errno);
|
||||
}
|
||||
int status;
|
||||
if (TEMP_FAILURE_RETRY (waitpid (pid, &status, 0)) != pid)
|
||||
{
|
||||
puts ("waitpid failed");
|
||||
return 1;
|
||||
}
|
||||
else if (status != 0)
|
||||
{
|
||||
if (WIFEXITED (status))
|
||||
printf ("script1.sh failed with status %d\n",
|
||||
WEXITSTATUS (status));
|
||||
else
|
||||
printf ("script1.sh kill by signal %d\n",
|
||||
WTERMSIG (status));
|
||||
return 1;
|
||||
}
|
||||
}
|
||||
/* Although manual states first argument should be the script name itself,
|
||||
current execv{p,e} implementation allows it. */
|
||||
char *argv00[] = { NULL };
|
||||
run_script ("script0.sh", argv00);
|
||||
|
||||
argv[0] = (char *) "script2.sh";
|
||||
argv[1] = (char *) "2";
|
||||
for (i = 0; i < 5; i++)
|
||||
{
|
||||
pid_t pid = vfork ();
|
||||
if (pid < 0)
|
||||
{
|
||||
printf ("vfork failed: %m\n");
|
||||
return 1;
|
||||
}
|
||||
else if (pid == 0)
|
||||
{
|
||||
execvp ("script2.sh", argv);
|
||||
_exit (errno);
|
||||
}
|
||||
int status;
|
||||
if (TEMP_FAILURE_RETRY (waitpid (pid, &status, 0)) != pid)
|
||||
{
|
||||
puts ("waitpid failed");
|
||||
return 1;
|
||||
}
|
||||
else if (status != 0)
|
||||
{
|
||||
printf ("script2.sh failed with status %d\n", status);
|
||||
return 1;
|
||||
}
|
||||
}
|
||||
char *argv01[] = { (char*) "script0.sh", NULL };
|
||||
run_script ("script0.sh", argv01);
|
||||
|
||||
for (i = 0; i < 5; i++)
|
||||
char *argv1[] = { (char *) "script1.sh", (char *) "1", NULL };
|
||||
run_script ("script1.sh", argv1);
|
||||
|
||||
char *argv2[] = { (char *) "script2.sh", (char *) "2", NULL };
|
||||
run_script ("script2.sh", argv2);
|
||||
|
||||
/* Same as before but with execlp. */
|
||||
for (size_t i = 0; i < 5; i++)
|
||||
{
|
||||
pid_t pid = vfork ();
|
||||
if (pid < 0)
|
||||
@ -137,87 +120,56 @@ do_test (void)
|
||||
}
|
||||
|
||||
unsetenv ("PATH");
|
||||
argv[0] = (char *) "echo";
|
||||
argv[1] = (char *) "script 4";
|
||||
for (i = 0; i < 5; i++)
|
||||
{
|
||||
pid_t pid = vfork ();
|
||||
if (pid < 0)
|
||||
{
|
||||
printf ("vfork failed: %m\n");
|
||||
return 1;
|
||||
}
|
||||
else if (pid == 0)
|
||||
{
|
||||
execvp ("echo", argv);
|
||||
_exit (errno);
|
||||
}
|
||||
int status;
|
||||
if (TEMP_FAILURE_RETRY (waitpid (pid, &status, 0)) != pid)
|
||||
{
|
||||
puts ("waitpid failed");
|
||||
return 1;
|
||||
}
|
||||
else if (status != 0)
|
||||
{
|
||||
printf ("echo failed with status %d\n", status);
|
||||
return 1;
|
||||
}
|
||||
}
|
||||
char *argv4[] = { (char *) "echo", (char *) "script 4", NULL };
|
||||
run_script ("echo", argv4);
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
static void
|
||||
create_script (const char *script, const char *contents, size_t size)
|
||||
{
|
||||
int fd = open (script, O_WRONLY | O_CREAT, 0700);
|
||||
if (fd < 0
|
||||
|| TEMP_FAILURE_RETRY (write (fd, contents, size)) != size
|
||||
|| fchmod (fd, S_IRUSR | S_IXUSR) < 0)
|
||||
FAIL_EXIT1 ("could not write %s\n", script);
|
||||
close (fd);
|
||||
}
|
||||
|
||||
static void
|
||||
do_prepare (void)
|
||||
{
|
||||
size_t len = strlen (test_dir) + sizeof ("/tst-vfork3.XXXXXX");
|
||||
tmpdirname = malloc (len);
|
||||
char *script1 = malloc (len + sizeof "/script1.sh");
|
||||
char *script2 = malloc (len + sizeof "/script2.sh");
|
||||
if (tmpdirname == NULL || script1 == NULL || script2 == NULL)
|
||||
{
|
||||
puts ("out of memory");
|
||||
exit (1);
|
||||
}
|
||||
if (tmpdirname == NULL)
|
||||
FAIL_EXIT1 ("out of memory");
|
||||
strcpy (stpcpy (tmpdirname, test_dir), "/tst-vfork3.XXXXXX");
|
||||
|
||||
tmpdirname = mkdtemp (tmpdirname);
|
||||
if (tmpdirname == NULL)
|
||||
{
|
||||
puts ("could not create temporary directory");
|
||||
exit (1);
|
||||
}
|
||||
FAIL_EXIT1 ("could not create temporary directory");
|
||||
|
||||
char script0[len + sizeof "/script0.sh"];
|
||||
char script1[len + sizeof "/script1.sh"];
|
||||
char script2[len + sizeof "/script2.sh"];
|
||||
|
||||
strcpy (stpcpy (script0, tmpdirname), "/script0.sh");
|
||||
strcpy (stpcpy (script1, tmpdirname), "/script1.sh");
|
||||
strcpy (stpcpy (script2, tmpdirname), "/script2.sh");
|
||||
|
||||
/* Need to make sure tmpdirname is at the end of the linked list. */
|
||||
add_temp_file (script0);
|
||||
add_temp_file (script1);
|
||||
add_temp_file (tmpdirname);
|
||||
add_temp_file (script2);
|
||||
/* Need to make sure tmpdirname is at the end of the linked list. */
|
||||
add_temp_file (tmpdirname);
|
||||
|
||||
const char content0[] = "#!/bin/sh\necho empty\n";
|
||||
create_script (script0, content0, sizeof content0);
|
||||
|
||||
const char content1[] = "#!/bin/sh\necho script $1\n";
|
||||
int fd = open (script1, O_WRONLY | O_CREAT, 0700);
|
||||
if (fd < 0
|
||||
|| TEMP_FAILURE_RETRY (write (fd, content1, sizeof content1))
|
||||
!= sizeof content1
|
||||
|| fchmod (fd, S_IRUSR | S_IXUSR) < 0)
|
||||
{
|
||||
printf ("Could not write %s\n", script1);
|
||||
exit (1);
|
||||
}
|
||||
close (fd);
|
||||
create_script (script1, content1, sizeof content1);
|
||||
|
||||
const char content2[] = "echo script $1\n";
|
||||
fd = open (script2, O_WRONLY | O_CREAT, 0700);
|
||||
if (fd < 0
|
||||
|| TEMP_FAILURE_RETRY (write (fd, content2, sizeof content2))
|
||||
!= sizeof content2
|
||||
|| fchmod (fd, S_IRUSR | S_IXUSR) < 0)
|
||||
{
|
||||
printf ("Could not write %s\n", script2);
|
||||
exit (1);
|
||||
}
|
||||
close (fd);
|
||||
create_script (script2, content2, sizeof content2);
|
||||
}
|
||||
|
||||
Loading…
x
Reference in New Issue
Block a user