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Fix OpenatTest.WithFlag when O_BENEATH is passed after 5eb909a
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The absolute symlink failure to traverse testcases were buggy.

They were trying to verify that openat(2) would fail when opening a path
outside a sandbox, when in reality it was testing using a directory (`TOPDIR`)
fd that was in the sandbox. An easy to implement change was to instead test
the absolute path resolution failure using the subdirectory (`SUBDIR`)
fd.

Reindent the directory hierarchy comment and reorder the elements in the
comments and tests to support the change.

While here, rename `SUBDIR_ABS` to `SUBDIR`, as `SUBDIR` was not an
absolute path.

This fixes the rest of google#28, along with
5eb909a.

Signed-off-by: Enji Cooper <yaneurabeya@gmail.com>
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@ngie-eign
ngie-eign committed Mar 22, 2019
1 parent feb4727 commit 6a33ccb
Showing 1 changed file with 31 additions and 31 deletions.
62 changes: 31 additions & 31 deletions openat.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -148,36 +148,36 @@ FORK_TEST(Openat, Relative) {
}

#define TOPDIR "cap_topdir"
#define SUBDIR_ABS TOPDIR "/subdir"
#define SUBDIR TOPDIR "/subdir"
class OpenatTest : public ::testing::Test {
public:
// Build a collection of files, subdirs and symlinks:
// /tmp/cap_topdir/
// /topfile
// /subdir/
// /subdir/bottomfile
// /symlink.samedir -> topfile
// /dsymlink.samedir -> ./
// /symlink.down -> subdir/bottomfile
// /dsymlink.down -> subdir/
// /symlink.absolute_in -> /tmp/cap_topdir/topfile
// /dsymlink.absolute_in -> /tmp/cap_topdir/
// /symlink.absolute_out -> /etc/passwd
// /dsymlink.absolute_out -> /etc/
// /symlink.relative_in -> ../../tmp/cap_topdir/topfile
// /dsymlink.relative_in -> ../../tmp/cap_topdir/
// /symlink.relative_out -> ../../etc/passwd
// /dsymlink.relative_out -> ../../etc/
// /subdir/symlink.up -> ../topfile
// /subdir/dsymlink.up -> ../
// /symlink.samedir -> topfile
// /dsymlink.samedir -> ./
// /symlink.down -> subdir/bottomfile
// /dsymlink.down -> subdir/
// /symlink.absolute_out -> /etc/passwd
// /dsymlink.absolute_out -> /etc/
// /symlink.relative_in -> ../../tmp/cap_topdir/topfile
// /dsymlink.relative_in -> ../../tmp/cap_topdir/
// /symlink.relative_out -> ../../etc/passwd
// /dsymlink.relative_out -> ../../etc/
// /subdir/dsymlink.absolute_in -> /tmp/cap_topdir/
// /subdir/dsymlink.up -> ../
// /subdir/symlink.absolute_in -> /tmp/cap_topdir/topfile
// /subdir/symlink.up -> ../topfile
// (In practice, this is a little more complicated because tmpdir might
// not be "/tmp".)
OpenatTest() {
// Create a couple of nested directories
int rc = mkdir(TmpFile(TOPDIR), 0755);
EXPECT_OK(rc);
if (rc < 0) EXPECT_EQ(EEXIST, errno);
rc = mkdir(TmpFile(SUBDIR_ABS), 0755);
rc = mkdir(TmpFile(SUBDIR), 0755);
EXPECT_OK(rc);
if (rc < 0) EXPECT_EQ(EEXIST, errno);

Expand All @@ -193,34 +193,34 @@ class OpenatTest : public ::testing::Test {

// Create normal files in each.
CreateFile(TmpFile(TOPDIR "/topfile"), "Top-level file");
CreateFile(TmpFile(SUBDIR_ABS "/bottomfile"), "File in subdirectory");
CreateFile(TmpFile(SUBDIR "/bottomfile"), "File in subdirectory");

// Create various symlinks to files.
EXPECT_OK(symlink("topfile", TmpFile(TOPDIR "/symlink.samedir")));
EXPECT_OK(symlink("subdir/bottomfile", TmpFile(TOPDIR "/symlink.down")));
EXPECT_OK(symlink(TmpFile(TOPDIR "/topfile"), TmpFile(TOPDIR "/symlink.absolute_in")));
EXPECT_OK(symlink(TmpFile(TOPDIR "/topfile"), TmpFile(SUBDIR "/symlink.absolute_in")));
EXPECT_OK(symlink("/etc/passwd", TmpFile(TOPDIR "/symlink.absolute_out")));
std::string dots2top = dots2root + TmpFile(TOPDIR "/topfile");
EXPECT_OK(symlink(dots2top.c_str(), TmpFile(TOPDIR "/symlink.relative_in")));
std::string dots2passwd = dots2root + "/etc/passwd";
EXPECT_OK(symlink(dots2passwd.c_str(), TmpFile(TOPDIR "/symlink.relative_out")));
EXPECT_OK(symlink("../topfile", TmpFile(SUBDIR_ABS "/symlink.up")));
EXPECT_OK(symlink("../topfile", TmpFile(SUBDIR "/symlink.up")));

// Create various symlinks to directories.
EXPECT_OK(symlink("./", TmpFile(TOPDIR "/dsymlink.samedir")));
EXPECT_OK(symlink("subdir/", TmpFile(TOPDIR "/dsymlink.down")));
EXPECT_OK(symlink(TmpFile(TOPDIR "/"), TmpFile(TOPDIR "/dsymlink.absolute_in")));
EXPECT_OK(symlink(TmpFile(TOPDIR "/"), TmpFile(SUBDIR "/dsymlink.absolute_in")));
EXPECT_OK(symlink("/etc/", TmpFile(TOPDIR "/dsymlink.absolute_out")));
std::string dots2cwd = dots2root + tmpdir + "/";
EXPECT_OK(symlink(dots2cwd.c_str(), TmpFile(TOPDIR "/dsymlink.relative_in")));
std::string dots2etc = dots2root + "/etc/";
EXPECT_OK(symlink(dots2etc.c_str(), TmpFile(TOPDIR "/dsymlink.relative_out")));
EXPECT_OK(symlink("../", TmpFile(SUBDIR_ABS "/dsymlink.up")));
EXPECT_OK(symlink("../", TmpFile(SUBDIR "/dsymlink.up")));

// Open directory FDs for those directories and for cwd.
dir_fd_ = open(TmpFile(TOPDIR), O_RDONLY);
EXPECT_OK(dir_fd_);
sub_fd_ = open(TmpFile(SUBDIR_ABS), O_RDONLY);
sub_fd_ = open(TmpFile(SUBDIR), O_RDONLY);
EXPECT_OK(sub_fd_);
cwd_ = openat(AT_FDCWD, ".", O_RDONLY);
EXPECT_OK(cwd_);
Expand All @@ -232,23 +232,23 @@ class OpenatTest : public ::testing::Test {
close(cwd_);
close(sub_fd_);
close(dir_fd_);
unlink(TmpFile(SUBDIR_ABS "/symlink.up"));
unlink(TmpFile(TOPDIR "/symlink.absolute_in"));
unlink(TmpFile(SUBDIR "/symlink.up"));
unlink(TmpFile(SUBDIR "/symlink.absolute_in"));
unlink(TmpFile(TOPDIR "/symlink.absolute_out"));
unlink(TmpFile(TOPDIR "/symlink.relative_in"));
unlink(TmpFile(TOPDIR "/symlink.relative_out"));
unlink(TmpFile(TOPDIR "/symlink.down"));
unlink(TmpFile(TOPDIR "/symlink.samedir"));
unlink(TmpFile(SUBDIR_ABS "/dsymlink.up"));
unlink(TmpFile(TOPDIR "/dsymlink.absolute_in"));
unlink(TmpFile(SUBDIR "/dsymlink.up"));
unlink(TmpFile(SUBDIR "/dsymlink.absolute_in"));
unlink(TmpFile(TOPDIR "/dsymlink.absolute_out"));
unlink(TmpFile(TOPDIR "/dsymlink.relative_in"));
unlink(TmpFile(TOPDIR "/dsymlink.relative_out"));
unlink(TmpFile(TOPDIR "/dsymlink.down"));
unlink(TmpFile(TOPDIR "/dsymlink.samedir"));
unlink(TmpFile(SUBDIR_ABS "/bottomfile"));
unlink(TmpFile(SUBDIR "/bottomfile"));
unlink(TmpFile(TOPDIR "/topfile"));
rmdir(TmpFile(SUBDIR_ABS));
rmdir(TmpFile(SUBDIR));
rmdir(TmpFile(TOPDIR));
}

Expand Down Expand Up @@ -277,18 +277,18 @@ class OpenatTest : public ::testing::Test {
// Should only be able to open symlinks that stay within the directory.
EXPECT_OPEN_OK(openat(dir_fd_, "symlink.samedir", O_RDONLY|oflag));
EXPECT_OPEN_OK(openat(dir_fd_, "symlink.down", O_RDONLY|oflag));
EXPECT_OPENAT_FAIL_TRAVERSAL(dir_fd_, "symlink.absolute_in", O_RDONLY|oflag);
EXPECT_OPENAT_FAIL_TRAVERSAL(dir_fd_, "symlink.absolute_out", O_RDONLY|oflag);
EXPECT_OPENAT_FAIL_TRAVERSAL(dir_fd_, "symlink.relative_in", O_RDONLY|oflag);
EXPECT_OPENAT_FAIL_TRAVERSAL(dir_fd_, "symlink.relative_out", O_RDONLY|oflag);
EXPECT_OPENAT_FAIL_TRAVERSAL(sub_fd_, "symlink.absolute_in", O_RDONLY|oflag);
EXPECT_OPENAT_FAIL_TRAVERSAL(sub_fd_, "symlink.up", O_RDONLY|oflag);

EXPECT_OPEN_OK(openat(dir_fd_, "dsymlink.samedir/topfile", O_RDONLY|oflag));
EXPECT_OPEN_OK(openat(dir_fd_, "dsymlink.down/bottomfile", O_RDONLY|oflag));
EXPECT_OPENAT_FAIL_TRAVERSAL(dir_fd_, "dsymlink.absolute_in/topfile", O_RDONLY|oflag);
EXPECT_OPENAT_FAIL_TRAVERSAL(dir_fd_, "dsymlink.absolute_out/passwd", O_RDONLY|oflag);
EXPECT_OPENAT_FAIL_TRAVERSAL(dir_fd_, "dsymlink.relative_in/topfile", O_RDONLY|oflag);
EXPECT_OPENAT_FAIL_TRAVERSAL(dir_fd_, "dsymlink.relative_out/passwd", O_RDONLY|oflag);
EXPECT_OPENAT_FAIL_TRAVERSAL(sub_fd_, "dsymlink.absolute_in/topfile", O_RDONLY|oflag);
EXPECT_OPENAT_FAIL_TRAVERSAL(sub_fd_, "dsymlink.up/topfile", O_RDONLY|oflag);

// Although recall that O_NOFOLLOW prevents symlink following in final component.
Expand All @@ -306,10 +306,10 @@ TEST_F(OpenatTest, WithCapability) {
// Any kind of symlink can be opened relative to an ordinary directory FD.
EXPECT_OPEN_OK(openat(dir_fd_, "symlink.samedir", O_RDONLY));
EXPECT_OPEN_OK(openat(dir_fd_, "symlink.down", O_RDONLY));
EXPECT_OPEN_OK(openat(dir_fd_, "symlink.absolute_in", O_RDONLY));
EXPECT_OPEN_OK(openat(dir_fd_, "symlink.absolute_out", O_RDONLY));
EXPECT_OPEN_OK(openat(dir_fd_, "symlink.relative_in", O_RDONLY));
EXPECT_OPEN_OK(openat(dir_fd_, "symlink.relative_out", O_RDONLY));
EXPECT_OPEN_OK(openat(sub_fd_, "symlink.absolute_in", O_RDONLY));
EXPECT_OPEN_OK(openat(sub_fd_, "symlink.up", O_RDONLY));

// Now make both DFDs into Capsicum capabilities.
Expand Down

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