65 lines
2.1 KiB
C
65 lines
2.1 KiB
C
 
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/* test_dir.c — dir backend: host passthrough + path containment
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* (Section 6.2): a normalized ".." can't reach it (blocked in the
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* virtual namespace, Section 6.1), and an absolute symlink planted
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* inside the mount cannot be used to read outside it. */
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#include <stdio.h>
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#include <stdlib.h>
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#include <sys/stat.h>
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#include <unistd.h>
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#include "packfs.h"
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#include "test_harness.h"
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int main(void) {
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char root[] = "/tmp/packfs_test_dir_XXXXXX";
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CHECK(mkdtemp(root) != NULL);
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char outside_dir[480];
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snprintf(outside_dir, sizeof(outside_dir), "/tmp/packfs_secret_%d", (int)getpid());
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mkdir(outside_dir, 0755);
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char secret_file[512];
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snprintf(secret_file, sizeof(secret_file), "%s/secret.txt", outside_dir);
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FILE *sf = fopen(secret_file, "w");
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CHECK(sf != NULL);
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fputs("top secret", sf);
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fclose(sf);
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/* a symlink INSIDE root pointing OUTSIDE it */
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char link_path[512];
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snprintf(link_path, sizeof(link_path), "%s/escape", root);
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CHECK(symlink(outside_dir, link_path) == 0);
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Vfs *v = vfs_new();
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int derr = 0;
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Backend *dir = backend_dir_new(root, &derr);
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CHECK(dir != NULL);
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CHECK_EQ_INT(vfs_mount(v, "/", dir), VFS_OK);
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int err = 0;
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VfsFile *f = vfs_open(v, "/a.txt", VFS_O_WRONLY | VFS_O_CREAT, &err);
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CHECK(f != NULL);
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CHECK_EQ_INT(vfs_write(f, "abc", 3), 3);
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CHECK_EQ_INT(vfs_close(f), VFS_OK);
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f = vfs_open(v, "/a.txt", VFS_O_RDONLY, &err);
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char buf[8] = {0};
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CHECK_EQ_INT(vfs_read(f, buf, sizeof(buf)), 3);
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CHECK_STR_EQ(buf, "abc");
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CHECK_EQ_INT(vfs_close(f), VFS_OK);
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/* virtual-namespace ".." escape: rejected before any backend is reached */
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f = vfs_open(v, "/../etc/shadow", VFS_O_RDONLY, &err);
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CHECK(f == NULL);
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CHECK_EQ_INT(err, VFS_ERR_INVAL);
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/* symlink escape through the dir backend itself: openat2/O_NOFOLLOW
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* containment (Section 6.2) must refuse to follow it. */
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f = vfs_open(v, "/escape/secret.txt", VFS_O_RDONLY, &err);
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CHECK(f == NULL);
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vfs_unmount(v, "/");
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backend_free(dir);
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vfs_free(v);
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TEST_MAIN_END();
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}
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