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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180#!/usr/bin/env python3# SPDX-License-Identifier: GPL-2.0## Test that truncation of bprm->buf doesn't cause unexpected execs paths, along# with various other pathological cases.import os, subprocess
# Relevant commits## b5372fe5dc84 ("exec: load_script: Do not exec truncated interpreter path")# 6eb3c3d0a52d ("exec: increase BINPRM_BUF_SIZE to 256")
# BINPRM_BUF_SIZESIZE=256
NAME_MAX=int(subprocess.check_output(["getconf", "NAME_MAX", "."]))
test_num=0pass_num=0fail_num=0
code='''#!/usr/bin/perlprint "Executed interpreter! Args:\n";print "0 : '$0'\n";$counter = 1;foreach my $a (@ARGV) { print "$counter : '$a'\n"; $counter++;}'''
### test - produce a binfmt_script hashbang line for testing## @size: bytes for bprm->buf line, including hashbang but not newline# @good: whether this script is expected to execute correctly# @hashbang: the special 2 bytes for running binfmt_script# @leading: any leading whitespace before the executable path# @root: start of executable pathname# @target: end of executable pathname# @arg: bytes following the executable pathname# @fill: character to fill between @root and @target to reach @size bytes# @newline: character to use as newline, not counted towards @size# ...def test(name, size, good=True, leading="", root="./", target="/perl", fill="A", arg="", newline="\n", hashbang="#!"): global test_num, pass_num, fail_num, tests, NAME_MAX test_num += 1 if test_num > tests: raise ValueError("more binfmt_script tests than expected! (want %d, expected %d)" % (test_num, tests))
middle = "" remaining = size - len(hashbang) - len(leading) - len(root) - len(target) - len(arg) # The middle of the pathname must not exceed NAME_MAX while remaining >= NAME_MAX: middle += fill * (NAME_MAX - 1) middle += '/' remaining -= NAME_MAX middle += fill * remaining
dirpath = root + middle binary = dirpath + target if len(target): os.makedirs(dirpath, mode=0o755, exist_ok=True) open(binary, "w").write(code) os.chmod(binary, 0o755)
buf=hashbang + leading + root + middle + target + arg + newline if len(newline) > 0: buf += 'echo this is not really perl\n'
script = "binfmt_script-%s" % (name) open(script, "w").write(buf) os.chmod(script, 0o755)
proc = subprocess.Popen(["./%s" % (script)], shell=True, stdout=subprocess.PIPE, stderr=subprocess.STDOUT) stdout = proc.communicate()[0]
if proc.returncode == 0 and b'Executed interpreter' in stdout: if good: print("ok %d - binfmt_script %s (successful good exec)" % (test_num, name)) pass_num += 1 else: print("not ok %d - binfmt_script %s succeeded when it should have failed" % (test_num, name)) fail_num = 1 else: if good: print("not ok %d - binfmt_script %s failed when it should have succeeded (rc:%d)" % (test_num, name, proc.returncode)) fail_num = 1 else: print("ok %d - binfmt_script %s (correctly failed bad exec)" % (test_num, name)) pass_num += 1
# Clean up crazy binaries os.unlink(script) if len(target): elements = binary.split('/') os.unlink(binary) elements.pop() while len(elements) > 1: os.rmdir("/".join(elements)) elements.pop()
tests=27print("TAP version 1.3")print("1..%d" % (tests))
### FAIL (8 tests)
# Entire path is well past the BINFMT_BUF_SIZE.test(name="too-big", size=SIZE+80, good=False)# Path is right at max size, making it impossible to tell if it was truncated.test(name="exact", size=SIZE, good=False)# Same as above, but with leading whitespace.test(name="exact-space", size=SIZE, good=False, leading=" ")# Huge buffer of only whitespace.test(name="whitespace-too-big", size=SIZE+71, good=False, root="", fill=" ", target="")# A good path, but it gets truncated due to leading whitespace.test(name="truncated", size=SIZE+17, good=False, leading=" " * 19)# Entirely empty except for #!test(name="empty", size=2, good=False, root="", fill="", target="", newline="")# Within size, but entirely spacestest(name="spaces", size=SIZE-1, good=False, root="", fill=" ", target="", newline="")# Newline before binary.test(name="newline-prefix", size=SIZE-1, good=False, leading="\n", root="", fill=" ", target="")
### ok (19 tests)
# The original test case that was broken by commit:# 8099b047ecc4 ("exec: load_script: don't blindly truncate shebang string")test(name="test.pl", size=439, leading=" ", root="./nix/store/bwav8kz8b3y471wjsybgzw84mrh4js9-perl-5.28.1/bin", arg=" -I/nix/store/x6yyav38jgr924nkna62q3pkp0dgmzlx-perl5.28.1-File-Slurp-9999.25/lib/perl5/site_perl -I/nix/store/ha8v67sl8dac92r9z07vzr4gv1y9nwqz-perl5.28.1-Net-DBus-1.1.0/lib/perl5/site_perl -I/nix/store/dcrkvnjmwh69ljsvpbdjjdnqgwx90a9d-perl5.28.1-XML-Parser-2.44/lib/perl5/site_perl -I/nix/store/rmji88k2zz7h4zg97385bygcydrf2q8h-perl5.28.1-XML-Twig-3.52/lib/perl5/site_perl")# One byte under size, leaving newline visible.test(name="one-under", size=SIZE-1)# Two bytes under size, leaving newline visible.test(name="two-under", size=SIZE-2)# Exact size, but trailing whitespace visible instead of newlinetest(name="exact-trunc-whitespace", size=SIZE, arg=" ")# Exact size, but trailing space and first arg char visible instead of newline.test(name="exact-trunc-arg", size=SIZE, arg=" f")# One bute under, with confirmed non-truncated arg since newline now visible.test(name="one-under-full-arg", size=SIZE-1, arg=" f")# Short read buffer by one byte.test(name="one-under-no-nl", size=SIZE-1, newline="")# Short read buffer by half buffer size.test(name="half-under-no-nl", size=int(SIZE/2), newline="")# One byte under with whitespace arg. leaving wenline visible.test(name="one-under-trunc-arg", size=SIZE-1, arg=" ")# One byte under with whitespace leading. leaving wenline visible.test(name="one-under-leading", size=SIZE-1, leading=" ")# One byte under with whitespace leading and as arg. leaving newline visible.test(name="one-under-leading-trunc-arg", size=SIZE-1, leading=" ", arg=" ")# Same as above, but with 2 bytes undertest(name="two-under-no-nl", size=SIZE-2, newline="")test(name="two-under-trunc-arg", size=SIZE-2, arg=" ")test(name="two-under-leading", size=SIZE-2, leading=" ")test(name="two-under-leading-trunc-arg", size=SIZE-2, leading=" ", arg=" ")# Same as above, but with buffer half filledtest(name="two-under-no-nl", size=int(SIZE/2), newline="")test(name="two-under-trunc-arg", size=int(SIZE/2), arg=" ")test(name="two-under-leading", size=int(SIZE/2), leading=" ")test(name="two-under-lead-trunc-arg", size=int(SIZE/2), leading=" ", arg=" ")
print("# Totals: pass:%d fail:%d xfail:0 xpass:0 skip:0 error:0" % (pass_num, fail_num))
if test_num != tests: raise ValueError("fewer binfmt_script tests than expected! (ran %d, expected %d" % (test_num, tests))