diff options
| -rw-r--r-- | src/unistd/faccessat.c | 47 |
1 files changed, 46 insertions, 1 deletions
diff --git a/src/unistd/faccessat.c b/src/unistd/faccessat.c index 1efbb778..0256d60f 100644 --- a/src/unistd/faccessat.c +++ b/src/unistd/faccessat.c @@ -1,7 +1,52 @@ #include <unistd.h> +#include <fcntl.h> #include "syscall.h" +#include "pthread_impl.h" + +struct ctx { + int fd; + const char *filename; + int amode; + int p; +}; + +static int checker(void *p) +{ + struct ctx *c = p; + int ret; + if (__syscall(SYS_setgid, __syscall(SYS_getegid)) + || __syscall(SYS_setuid, __syscall(SYS_geteuid))) + __syscall(SYS_exit, 1); + ret = __syscall(SYS_faccessat, c->fd, c->filename, c->amode, 0); + __syscall(SYS_write, c->p, &ret, sizeof ret); + __syscall(SYS_exit, 0); +} int faccessat(int fd, const char *filename, int amode, int flag) { - return syscall(SYS_faccessat, fd, filename, amode, flag); + if (!flag || (flag==AT_EACCESS && getuid()==geteuid() && getgid()==getegid())) + return syscall(SYS_faccessat, fd, filename, amode, flag); + + if (flag != AT_EACCESS) + return __syscall_ret(-EINVAL); + + char stack[1024]; + sigset_t set; + int ret, p[2]; + + if (pipe(p)) return __syscall_ret(-EBUSY); + struct ctx c = { .fd = fd, .filename = filename, .amode = amode, .p = p[1] }; + + __block_app_sigs(&set); + + ret = __clone(checker, stack+sizeof stack, 0, &c); + __syscall(SYS_close, p[1]); + + if (ret<0 || __syscall(SYS_read, p[0], &ret, sizeof ret) != sizeof(ret)) + ret = -EBUSY; + __syscall(SYS_close, p[0]); + + __restore_sigs(&set); + + return __syscall_ret(ret); } |