@@ -16,58 +16,36 @@
<http://www.gnu.org/licenses/>. */
#include <unistd.h>
+#include <errno.h>
#include <stdarg.h>
-#include <stddef.h>
-#include <stdlib.h>
-#include <string.h>
-
-#include <stackinfo.h>
-
+#include <sys/param.h>
/* Execute PATH with all arguments after PATH until
a NULL pointer and environment from `environ'. */
int
execl (const char *path, const char *arg, ...)
{
-#define INITIAL_ARGV_MAX 1024
- size_t argv_max = INITIAL_ARGV_MAX;
- const char *initial_argv[INITIAL_ARGV_MAX];
- const char **argv = initial_argv;
- va_list args;
-
- argv[0] = arg;
-
- va_start (args, arg);
- unsigned int i = 0;
- while (argv[i++] != NULL)
- {
- if (i == argv_max)
- {
- argv_max *= 2;
- const char **nptr = realloc (argv == initial_argv ? NULL : argv,
- argv_max * sizeof (const char *));
- if (nptr == NULL)
- {
- if (argv != initial_argv)
- free (argv);
- va_end (args);
- return -1;
- }
- if (argv == initial_argv)
- /* We have to copy the already filled-in data ourselves. */
- memcpy (nptr, argv, i * sizeof (const char *));
-
- argv = nptr;
- }
-
- argv[i] = va_arg (args, const char *);
- }
- va_end (args);
-
- int ret = __execve (path, (char *const *) argv, __environ);
- if (argv != initial_argv)
- free (argv);
-
- return ret;
+ int argc;
+ int limit = MIN (NCARGS, __MAX_ALLOCA_CUTOFF / sizeof (char *));
+ va_list ap;
+ va_start (ap, arg);
+ for (argc = 1; va_arg (ap, const char *); argc++)
+ if (argc+1 >= limit)
+ {
+ errno = E2BIG;
+ return -1;
+ }
+ va_end (ap);
+
+ int i;
+ char *argv[argc+1];
+ va_start (ap, arg);
+ argv[0] = (char*) arg;
+ for (i = 1; i < argc; i++)
+ argv[i] = va_arg (ap, char *);
+ argv[i] = NULL;
+ va_end (ap);
+
+ return __execve (path, argv, __environ);
}
libc_hidden_def (execl)
@@ -17,57 +17,36 @@
#include <unistd.h>
#include <stdarg.h>
-#include <stddef.h>
-#include <stdlib.h>
-#include <string.h>
-
-#include <stackinfo.h>
+#include <errno.h>
+#include <sys/param.h>
/* Execute PATH with all arguments after PATH until a NULL pointer,
and the argument after that for environment. */
int
execle (const char *path, const char *arg, ...)
{
-#define INITIAL_ARGV_MAX 1024
- size_t argv_max = INITIAL_ARGV_MAX;
- const char *initial_argv[INITIAL_ARGV_MAX];
- const char **argv = initial_argv;
- va_list args;
- argv[0] = arg;
-
- va_start (args, arg);
- unsigned int i = 0;
- while (argv[i++] != NULL)
- {
- if (i == argv_max)
- {
- argv_max *= 2;
- const char **nptr = realloc (argv == initial_argv ? NULL : argv,
- argv_max * sizeof (const char *));
- if (nptr == NULL)
- {
- if (argv != initial_argv)
- free (argv);
- va_end (args);
- return -1;
- }
- if (argv == initial_argv)
- /* We have to copy the already filled-in data ourselves. */
- memcpy (nptr, argv, i * sizeof (const char *));
-
- argv = nptr;
- }
-
- argv[i] = va_arg (args, const char *);
- }
-
- const char *const *envp = va_arg (args, const char *const *);
- va_end (args);
-
- int ret = __execve (path, (char *const *) argv, (char *const *) envp);
- if (argv != initial_argv)
- free (argv);
-
- return ret;
+ int argc;
+ int limit = MIN (NCARGS, __MAX_ALLOCA_CUTOFF / sizeof (char *));
+ va_list ap;
+ va_start (ap, arg);
+ for (argc = 1; va_arg (ap, const char *); argc++)
+ if (argc+1 >= limit)
+ {
+ errno = E2BIG;
+ return -1;
+ }
+ va_end (ap);
+
+ int i;
+ char *argv[argc+1];
+ char **envp;
+ va_start (ap, arg);
+ argv[0] = (char*) arg;
+ for (i = 1; i < argc; i++)
+ argv[i] = va_arg (ap, char *);
+ envp = va_arg (ap, char **);
+ va_end (ap);
+
+ return __execve (path, argv, envp);
}
libc_hidden_def (execle)
@@ -17,11 +17,8 @@
#include <unistd.h>
#include <stdarg.h>
-#include <stddef.h>
-#include <stdlib.h>
-#include <string.h>
-
-#include <stackinfo.h>
+#include <errno.h>
+#include <sys/param.h>
/* Execute FILE, searching in the `PATH' environment variable if
it contains no slashes, with all arguments after FILE until a
@@ -29,45 +26,27 @@
int
execlp (const char *file, const char *arg, ...)
{
-#define INITIAL_ARGV_MAX 1024
- size_t argv_max = INITIAL_ARGV_MAX;
- const char *initial_argv[INITIAL_ARGV_MAX];
- const char **argv = initial_argv;
- va_list args;
-
- argv[0] = arg;
-
- va_start (args, arg);
- unsigned int i = 0;
- while (argv[i++] != NULL)
- {
- if (i == argv_max)
- {
- argv_max *= 2;
- const char **nptr = realloc (argv == initial_argv ? NULL : argv,
- argv_max * sizeof (const char *));
- if (nptr == NULL)
- {
- if (argv != initial_argv)
- free (argv);
- va_end (args);
- return -1;
- }
- if (argv == initial_argv)
- /* We have to copy the already filled-in data ourselves. */
- memcpy (nptr, argv, i * sizeof (const char *));
-
- argv = nptr;
- }
-
- argv[i] = va_arg (args, const char *);
- }
- va_end (args);
-
- int ret = execvp (file, (char *const *) argv);
- if (argv != initial_argv)
- free (argv);
-
- return ret;
+ int argc;
+ int limit = MIN (NCARGS, __MAX_ALLOCA_CUTOFF / sizeof (char *));
+ va_list ap;
+ va_start (ap, arg);
+ for (argc = 1; va_arg (ap, const char *); argc++)
+ if (argc+1 >= limit)
+ {
+ errno = E2BIG;
+ return -1;
+ }
+ va_end (ap);
+
+ int i;
+ char *argv[argc+1];
+ va_start (ap, arg);
+ argv[0] = (char*) arg;
+ for (i = 1; i < argc; i++)
+ argv[i] = va_arg (ap, char *);
+ argv[i] = NULL;
+ va_end (ap);
+
+ return __execvpe (file, argv, __environ);
}
libc_hidden_def (execlp)
GLIBC execl{e,p} implementation might use malloc if the total number of arguments exceeds initial assumption size (1024). This might lead to issues in two situations: 1. execl/execle is stated to be async-signal-safe by POSIX [1]. However if it is used in a signal handler with a large argument set (that may call malloc internally) and the resulting call fails, it might lead malloc in the program in a bad state. 2. If the functions are used in a vfork/clone(VFORK) situation it also might break internal malloc state from parent. This patch fixes it by using stack allocation instead. It fixes BZ#19534. One caveat is current stack allocation allocation limit the patch is using is based on previous posix_spawn{p}/execvpe comments to use internal __MAX_ALLOCA_CUTOFF definition. It is an arbitrary value that limits total argument handlings to 8192 for 32-bits and 4096 for 64-bits. I think it would be better to increase this value for higher threshold, either by increasing the __MAX_ALLOCA_CUTOFF value or using a different strategy to limit stack allocation on exec functions. Tested on x86_64. [1] http://pubs.opengroup.org/onlinepubs/9699919799/functions/V2_chap02.html [BZ #19534] * posix/execl.c (execl): Remove dynamic memory allocation. * posix/execle.c (execle): Likewise. * posix/execlp.c (execlp): Likewise. --- ChangeLog | 5 +++++ posix/execl.c | 70 ++++++++++++++++++++------------------------------------- posix/execle.c | 71 +++++++++++++++++++++------------------------------------- posix/execlp.c | 69 ++++++++++++++++++++------------------------------------ 4 files changed, 78 insertions(+), 137 deletions(-) -- 1.9.1