diff options
| -rw-r--r-- | src/linux/setgroups.c | 30 |
1 files changed, 29 insertions, 1 deletions
diff --git a/src/linux/setgroups.c b/src/linux/setgroups.c index 1248fdbf..47142f14 100644 --- a/src/linux/setgroups.c +++ b/src/linux/setgroups.c @@ -1,8 +1,36 @@ #define _GNU_SOURCE #include <unistd.h> +#include <signal.h> #include "syscall.h" +#include "libc.h" + +struct ctx { + size_t count; + const gid_t *list; + int ret; +}; + +static void do_setgroups(void *p) +{ + struct ctx *c = p; + if (c->ret<0) return; + int ret = __syscall(SYS_setgroups, c->count, c->list); + if (ret && !c->ret) { + /* If one thread fails to set groups after another has already + * succeeded, forcibly killing the process is the only safe + * thing to do. State is inconsistent and dangerous. Use + * SIGKILL because it is uncatchable. */ + __block_all_sigs(0); + __syscall(SYS_kill, __syscall(SYS_getpid), SIGKILL); + } + c->ret = ret; +} int setgroups(size_t count, const gid_t list[]) { - return syscall(SYS_setgroups, count, list); + /* ret is initially nonzero so that failure of the first thread does not + * trigger the safety kill above. */ + struct ctx c = { .count = count, .list = list, .ret = 1 }; + __synccall(do_setgroups, &c); + return __syscall_ret(c.ret); } |