bug#35662: Really relocatable binaries crash with Permission denied

[pelzflorian (Florian Pelz)]

On Fri, May 10, 2019 at 11:50:19PM +0200, Ludovic Courtès wrote:
> That suggests the wrapper chose the user namespace method (not PRoot),
> but that didn’t quite work.
> 
> Could you post the output of:
> 
>   strace ./mybin/sh
> 
> ?
> 

address@hidden ~]$ strace ./mybin/sh 
execve("./mybin/sh", ["./mybin/sh"], 0x7fffcdf87290 /* 39 vars */) = 0
brk(NULL)                               = 0x2301000
brk(0x23021c0)                          = 0x23021c0
arch_prctl(ARCH_SET_FS, 0x2301880)      = 0
uname({sysname="Linux", nodename="tux6", ...}) = 0
readlink("/proc/self/exe", "/home/f_pelz12/gnu/store/wl2l59l"..., 4096) = 77
brk(0x23231c0)                          = 0x23231c0
brk(0x2324000)                          = 0x2324000
readlink("/proc/self/exe", "/home/f_pelz12/gnu/store/wl2l59l"..., 4095) = 77
lstat("/gnu/store/qn1ax1fkj16x280m1rv7mcimfmn9l2pf-bash-4.4.23/bin/sh", 
0x7ffd9741c980) = -1 ENOENT (No such file or directory)
gettimeofday({tv_sec=1557550876, tv_usec=116037}, NULL) = 0
getpid()                                = 28923
mkdir("/tmp/guix-exec-ABt7cT", 0700)    = 0
stat(".", {st_mode=S_IFDIR|0700, st_size=113, ...}) = 0
stat("/home/f_pelz12", {st_mode=S_IFDIR|0700, st_size=113, ...}) = 0
clone(child_stack=NULL, flags=CLONE_NEWNS|CLONE_NEWUSER|SIGCHLD) = 28924
openat(AT_FDCWD, "/proc/28924/setgroups", O_WRONLY) = 3
write(3, "deny\0", 5)                   = 5
close(3)                                = 0
getuid()                                = 24038
openat(AT_FDCWD, "/proc/28924/uid_map", O_WRONLY) = 3
write(3, "24038 24038 1\n", 14)         = 14
close(3)                                = 0
getgid()                                = 10004
openat(AT_FDCWD, "/proc/28924/gid_map", O_WRONLY) = 3
write(3, "10004 10004 1\n", 14)         = 14
close(3)                                = 0
wait4(28924, sh: run.c:162: bind_mount: Unexpected error: Permission denied.
[{WIFSIGNALED(s) && WTERMSIG(s) == SIGABRT}], 0, NULL) = 28924
--- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_KILLED, si_pid=28924, si_uid=24038, 
si_status=SIGABRT, si_utime=0, si_stime=0} ---
chdir("/")                              = 0
openat(AT_FDCWD, "/tmp/guix-exec-ABt7cT", 
O_RDONLY|O_NONBLOCK|O_CLOEXEC|O_DIRECTORY) = 3
fstat(3, {st_mode=S_IFDIR|0700, st_size=25, ...}) = 0
getdents64(3, /* 25 entries */, 131072) = 632
unlink("/tmp/guix-exec-ABt7cT/home")    = -1 EISDIR (Is a directory)
openat(AT_FDCWD, "/tmp/guix-exec-ABt7cT/home", 
O_RDONLY|O_NONBLOCK|O_CLOEXEC|O_DIRECTORY) = 4
fstat(4, {st_mode=S_IFDIR|0700, st_size=2, ...}) = 0
mmap(NULL, 135168, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 
0x7f4e71c68000
getdents64(4, /* 2 entries */, 131072)  = 48
getdents64(4, /* 0 entries */, 131072)  = 0
munmap(0x7f4e71c68000, 135168)          = 0
close(4)                                = 0
rmdir("/tmp/guix-exec-ABt7cT/home")     = 0
unlink("/tmp/guix-exec-ABt7cT/tmp")     = -1 EISDIR (Is a directory)
openat(AT_FDCWD, "/tmp/guix-exec-ABt7cT/tmp", 
O_RDONLY|O_NONBLOCK|O_CLOEXEC|O_DIRECTORY) = 4
fstat(4, {st_mode=S_IFDIR|0700, st_size=2, ...}) = 0
brk(0x2363000)                          = 0x2363000
getdents64(4, /* 2 entries */, 131072)  = 48
getdents64(4, /* 0 entries */, 131072)  = 0
close(4)                                = 0
rmdir("/tmp/guix-exec-ABt7cT/tmp")      = 0
unlink("/tmp/guix-exec-ABt7cT/mnt")     = -1 EISDIR (Is a directory)
openat(AT_FDCWD, "/tmp/guix-exec-ABt7cT/mnt", 
O_RDONLY|O_NONBLOCK|O_CLOEXEC|O_DIRECTORY) = 4
fstat(4, {st_mode=S_IFDIR|0700, st_size=2, ...}) = 0
getdents64(4, /* 2 entries */, 131072)  = 48
getdents64(4, /* 0 entries */, 131072)  = 0
close(4)                                = 0
rmdir("/tmp/guix-exec-ABt7cT/mnt")      = 0
unlink("/tmp/guix-exec-ABt7cT/sys")     = -1 EISDIR (Is a directory)
openat(AT_FDCWD, "/tmp/guix-exec-ABt7cT/sys", 
O_RDONLY|O_NONBLOCK|O_CLOEXEC|O_DIRECTORY) = 4
fstat(4, {st_mode=S_IFDIR|0700, st_size=2, ...}) = 0
getdents64(4, /* 2 entries */, 131072)  = 48
getdents64(4, /* 0 entries */, 131072)  = 0
close(4)                                = 0
rmdir("/tmp/guix-exec-ABt7cT/sys")      = 0
unlink("/tmp/guix-exec-ABt7cT/libx32")  = -1 EISDIR (Is a directory)
openat(AT_FDCWD, "/tmp/guix-exec-ABt7cT/libx32", 
O_RDONLY|O_NONBLOCK|O_CLOEXEC|O_DIRECTORY) = 4
fstat(4, {st_mode=S_IFDIR|0700, st_size=2, ...}) = 0
getdents64(4, /* 2 entries */, 131072)  = 48
getdents64(4, /* 0 entries */, 131072)  = 0
close(4)                                = 0
rmdir("/tmp/guix-exec-ABt7cT/libx32")   = 0
unlink("/tmp/guix-exec-ABt7cT/opt")     = -1 EISDIR (Is a directory)
openat(AT_FDCWD, "/tmp/guix-exec-ABt7cT/opt", 
O_RDONLY|O_NONBLOCK|O_CLOEXEC|O_DIRECTORY) = 4
fstat(4, {st_mode=S_IFDIR|0700, st_size=2, ...}) = 0
getdents64(4, /* 2 entries */, 131072)  = 48
getdents64(4, /* 0 entries */, 131072)  = 0
close(4)                                = 0
rmdir("/tmp/guix-exec-ABt7cT/opt")      = 0
unlink("/tmp/guix-exec-ABt7cT/srv")     = -1 EISDIR (Is a directory)
openat(AT_FDCWD, "/tmp/guix-exec-ABt7cT/srv", 
O_RDONLY|O_NONBLOCK|O_CLOEXEC|O_DIRECTORY) = 4
fstat(4, {st_mode=S_IFDIR|0700, st_size=2, ...}) = 0
getdents64(4, /* 2 entries */, 131072)  = 48
getdents64(4, /* 0 entries */, 131072)  = 0
close(4)                                = 0
rmdir("/tmp/guix-exec-ABt7cT/srv")      = 0
unlink("/tmp/guix-exec-ABt7cT/dev")     = -1 EISDIR (Is a directory)
openat(AT_FDCWD, "/tmp/guix-exec-ABt7cT/dev", 
O_RDONLY|O_NONBLOCK|O_CLOEXEC|O_DIRECTORY) = 4
fstat(4, {st_mode=S_IFDIR|0700, st_size=2, ...}) = 0
getdents64(4, /* 2 entries */, 131072)  = 48
getdents64(4, /* 0 entries */, 131072)  = 0
close(4)                                = 0
rmdir("/tmp/guix-exec-ABt7cT/dev")      = 0
unlink("/tmp/guix-exec-ABt7cT/var")     = -1 EISDIR (Is a directory)
openat(AT_FDCWD, "/tmp/guix-exec-ABt7cT/var", 
O_RDONLY|O_NONBLOCK|O_CLOEXEC|O_DIRECTORY) = 4
fstat(4, {st_mode=S_IFDIR|0700, st_size=2, ...}) = 0
getdents64(4, /* 2 entries */, 131072)  = 48
getdents64(4, /* 0 entries */, 131072)  = 0
close(4)                                = 0
rmdir("/tmp/guix-exec-ABt7cT/var")      = 0
unlink("/tmp/guix-exec-ABt7cT/sbin")    = -1 EISDIR (Is a directory)
openat(AT_FDCWD, "/tmp/guix-exec-ABt7cT/sbin", 
O_RDONLY|O_NONBLOCK|O_CLOEXEC|O_DIRECTORY) = 4
fstat(4, {st_mode=S_IFDIR|0700, st_size=2, ...}) = 0
getdents64(4, /* 2 entries */, 131072)  = 48
getdents64(4, /* 0 entries */, 131072)  = 0
close(4)                                = 0
rmdir("/tmp/guix-exec-ABt7cT/sbin")     = 0
unlink("/tmp/guix-exec-ABt7cT/lib64")   = -1 EISDIR (Is a directory)
openat(AT_FDCWD, "/tmp/guix-exec-ABt7cT/lib64", 
O_RDONLY|O_NONBLOCK|O_CLOEXEC|O_DIRECTORY) = 4
fstat(4, {st_mode=S_IFDIR|0700, st_size=2, ...}) = 0
getdents64(4, /* 2 entries */, 131072)  = 48
getdents64(4, /* 0 entries */, 131072)  = 0
close(4)                                = 0
rmdir("/tmp/guix-exec-ABt7cT/lib64")    = 0
unlink("/tmp/guix-exec-ABt7cT/lib32")   = -1 EISDIR (Is a directory)
openat(AT_FDCWD, "/tmp/guix-exec-ABt7cT/lib32", 
O_RDONLY|O_NONBLOCK|O_CLOEXEC|O_DIRECTORY) = 4
fstat(4, {st_mode=S_IFDIR|0700, st_size=2, ...}) = 0
getdents64(4, /* 2 entries */, 131072)  = 48
getdents64(4, /* 0 entries */, 131072)  = 0
close(4)                                = 0
rmdir("/tmp/guix-exec-ABt7cT/lib32")    = 0
unlink("/tmp/guix-exec-ABt7cT/media")   = -1 EISDIR (Is a directory)
openat(AT_FDCWD, "/tmp/guix-exec-ABt7cT/media", 
O_RDONLY|O_NONBLOCK|O_CLOEXEC|O_DIRECTORY) = 4
fstat(4, {st_mode=S_IFDIR|0700, st_size=2, ...}) = 0
getdents64(4, /* 2 entries */, 131072)  = 48
getdents64(4, /* 0 entries */, 131072)  = 0
close(4)                                = 0
rmdir("/tmp/guix-exec-ABt7cT/media")    = 0
unlink("/tmp/guix-exec-ABt7cT/usr")     = -1 EISDIR (Is a directory)
openat(AT_FDCWD, "/tmp/guix-exec-ABt7cT/usr", 
O_RDONLY|O_NONBLOCK|O_CLOEXEC|O_DIRECTORY) = 4
fstat(4, {st_mode=S_IFDIR|0700, st_size=2, ...}) = 0
getdents64(4, /* 2 entries */, 131072)  = 48
getdents64(4, /* 0 entries */, 131072)  = 0
close(4)                                = 0
rmdir("/tmp/guix-exec-ABt7cT/usr")      = 0
unlink("/tmp/guix-exec-ABt7cT/bin")     = -1 EISDIR (Is a directory)
openat(AT_FDCWD, "/tmp/guix-exec-ABt7cT/bin", 
O_RDONLY|O_NONBLOCK|O_CLOEXEC|O_DIRECTORY) = 4
fstat(4, {st_mode=S_IFDIR|0700, st_size=2, ...}) = 0
getdents64(4, /* 2 entries */, 131072)  = 48
getdents64(4, /* 0 entries */, 131072)  = 0
close(4)                                = 0
rmdir("/tmp/guix-exec-ABt7cT/bin")      = 0
unlink("/tmp/guix-exec-ABt7cT/boot")    = -1 EISDIR (Is a directory)
openat(AT_FDCWD, "/tmp/guix-exec-ABt7cT/boot", 
O_RDONLY|O_NONBLOCK|O_CLOEXEC|O_DIRECTORY) = 4
fstat(4, {st_mode=S_IFDIR|0700, st_size=2, ...}) = 0
getdents64(4, /* 2 entries */, 131072)  = 48
getdents64(4, /* 0 entries */, 131072)  = 0
close(4)                                = 0
rmdir("/tmp/guix-exec-ABt7cT/boot")     = 0
unlink("/tmp/guix-exec-ABt7cT/etc")     = -1 EISDIR (Is a directory)
openat(AT_FDCWD, "/tmp/guix-exec-ABt7cT/etc", 
O_RDONLY|O_NONBLOCK|O_CLOEXEC|O_DIRECTORY) = 4
fstat(4, {st_mode=S_IFDIR|0700, st_size=2, ...}) = 0
getdents64(4, /* 2 entries */, 131072)  = 48
getdents64(4, /* 0 entries */, 131072)  = 0
close(4)                                = 0
rmdir("/tmp/guix-exec-ABt7cT/etc")      = 0
unlink("/tmp/guix-exec-ABt7cT/run")     = -1 EISDIR (Is a directory)
openat(AT_FDCWD, "/tmp/guix-exec-ABt7cT/run", 
O_RDONLY|O_NONBLOCK|O_CLOEXEC|O_DIRECTORY) = 4
fstat(4, {st_mode=S_IFDIR|0700, st_size=2, ...}) = 0
getdents64(4, /* 2 entries */, 131072)  = 48
getdents64(4, /* 0 entries */, 131072)  = 0
close(4)                                = 0
rmdir("/tmp/guix-exec-ABt7cT/run")      = 0
unlink("/tmp/guix-exec-ABt7cT/core")    = 0
unlink("/tmp/guix-exec-ABt7cT/snap")    = -1 EISDIR (Is a directory)
openat(AT_FDCWD, "/tmp/guix-exec-ABt7cT/snap", 
O_RDONLY|O_NONBLOCK|O_CLOEXEC|O_DIRECTORY) = 4
fstat(4, {st_mode=S_IFDIR|0700, st_size=2, ...}) = 0
getdents64(4, /* 2 entries */, 131072)  = 48
getdents64(4, /* 0 entries */, 131072)  = 0
close(4)                                = 0
rmdir("/tmp/guix-exec-ABt7cT/snap")     = 0
unlink("/tmp/guix-exec-ABt7cT/lib")     = -1 EISDIR (Is a directory)
openat(AT_FDCWD, "/tmp/guix-exec-ABt7cT/lib", 
O_RDONLY|O_NONBLOCK|O_CLOEXEC|O_DIRECTORY) = 4
fstat(4, {st_mode=S_IFDIR|0700, st_size=2, ...}) = 0
getdents64(4, /* 2 entries */, 131072)  = 48
getdents64(4, /* 0 entries */, 131072)  = 0
close(4)                                = 0
rmdir("/tmp/guix-exec-ABt7cT/lib")      = 0
unlink("/tmp/guix-exec-ABt7cT/proc")    = -1 EISDIR (Is a directory)
openat(AT_FDCWD, "/tmp/guix-exec-ABt7cT/proc", 
O_RDONLY|O_NONBLOCK|O_CLOEXEC|O_DIRECTORY) = 4
fstat(4, {st_mode=S_IFDIR|0700, st_size=2, ...}) = 0
getdents64(4, /* 2 entries */, 131072)  = 48
getdents64(4, /* 0 entries */, 131072)  = 0
close(4)                                = 0
rmdir("/tmp/guix-exec-ABt7cT/proc")     = 0
unlink("/tmp/guix-exec-ABt7cT/root")    = -1 EISDIR (Is a directory)
openat(AT_FDCWD, "/tmp/guix-exec-ABt7cT/root", 
O_RDONLY|O_NONBLOCK|O_CLOEXEC|O_DIRECTORY) = 4
fstat(4, {st_mode=S_IFDIR|0700, st_size=2, ...}) = 0
getdents64(4, /* 2 entries */, 131072)  = 48
getdents64(4, /* 0 entries */, 131072)  = 0
close(4)                                = 0
rmdir("/tmp/guix-exec-ABt7cT/root")     = 0
getdents64(3, /* 0 entries */, 131072)  = 0
close(3)                                = 0
rmdir("/tmp/guix-exec-ABt7cT")          = 0
exit_group(6)                           = ?
+++ exited with 6 +++

Thank you for looking into it!

Regards,
Florian