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ext/pcntl: pcntl_exec() using execveat whenever possible instead. #17834

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ext/pcntl: pcntl_exec() using execveat whenever possible instead. #17834

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2 changes: 1 addition & 1 deletion ext/pcntl/config.m4
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Original file line number Diff line number Diff line change
Expand Up @@ -10,7 +10,7 @@ if test "$PHP_PCNTL" != "no"; then
done

AC_CHECK_FUNCS(m4_normalize([
forkx
execveat
getcpuid
getpriority
pidfd_open
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43 changes: 41 additions & 2 deletions ext/pcntl/pcntl.c
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Original file line number Diff line number Diff line change
Expand Up @@ -39,6 +39,11 @@
#include <sys/resource.h>
#endif

#if defined(HAVE_EXECVEAT)
#include <fcntl.h>
#include <unistd.h>
#endif

#ifdef HAVE_WAITID
#if defined (HAVE_DECL_P_ALL) && HAVE_DECL_P_ALL == 1
#define HAVE_POSIX_IDTYPES 1
Expand Down Expand Up @@ -617,6 +622,40 @@ PHP_FUNCTION(pcntl_wstopsig)
}
/* }}} */

#ifdef HAVE_EXECVEAT
static zend_always_inline zend_result php_execve(const char *path, char **argv, char **envp) {
int fd = open(path, O_RDONLY | O_CLOEXEC);
if (fd < 0) {
return FAILURE;
}
#ifdef AT_EXECVE_CHECK
// Linux >= 6.14 allows to check if `path` is allowed
// for execution per kernel security policy (w/o actually running it)
if (execveat(fd, "", argv, envp, AT_EMPTY_PATH | AT_EXECVE_CHECK) < 0) {
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If we consider that the check is successful most of the time, does this really makes much sense?

close(fd);
return FAILURE;
}
#endif
if (execveat(fd, "", argv, envp, AT_EMPTY_PATH) < 0) {
close(fd);
return FAILURE;
}
return SUCCESS;
}

static zend_always_inline zend_result php_execv(const char *path, char **argv) {
return php_execve(path, argv, 0);
}
#else
static zend_always_inline zend_result php_execve(const char *path, char **argv, char **envp) {
return execve(path, argv, envp) == 0 ? SUCCESS : FAILURE;
}

static zend_always_inline zend_result php_execv(const char *path, char **argv) {
return execv(path, argv) == 0 ? SUCCESS : FAILURE;
}
#endif

/* {{{ Executes specified program in current process space as defined by exec(2) */
PHP_FUNCTION(pcntl_exec)
{
Expand Down Expand Up @@ -716,7 +755,7 @@ PHP_FUNCTION(pcntl_exec)
} ZEND_HASH_FOREACH_END();
*(pair) = NULL;

if (execve(path, argv, envp) == -1) {
if (php_execve(path, argv, envp) == FAILURE) {
PCNTL_G(last_error) = errno;
php_error_docref(NULL, E_WARNING, "Error has occurred: (errno %d) %s", errno, strerror(errno));
}
Expand All @@ -727,7 +766,7 @@ PHP_FUNCTION(pcntl_exec)
efree(envp);
} else {

if (execv(path, argv) == -1) {
if (php_execv(path, argv) == FAILURE) {
PCNTL_G(last_error) = errno;
php_error_docref(NULL, E_WARNING, "Error has occurred: (errno %d) %s", errno, strerror(errno));
}
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