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ANDROID: Incremental fs: Fix mlock to fail gracefully on corrupt files

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Test: incfs_test passes
Bug: 174875107
Signed-off-by: Paul Lawrence <paullawrence@google.com>
Change-Id: I93ce3600e88ddd89cf69f032ea858d169b0a7bec
This commit is contained in:
Paul Lawrence
2021-03-10 08:40:53 -08:00
parent 2a8c6b0f30
commit 38d8cfc0bd
2 changed files with 87 additions and 1 deletions
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28
fs/incfs/vfs.c
View File

@@ -10,6 +10,7 @@
#include <linux/fs_stack.h>
#include <linux/fsnotify.h>
#include <linux/fsverity.h>
#include <linux/mmap_lock.h>
#include <linux/namei.h>
#include <linux/parser.h>
#include <linux/seq_file.h>
@@ -110,11 +111,36 @@ static const struct address_space_operations incfs_address_space_ops = {
/* .readpages = readpages */
};
static vm_fault_t incfs_fault(struct vm_fault *vmf)
{
vmf->flags &= ~FAULT_FLAG_ALLOW_RETRY;
return filemap_fault(vmf);
}
static const struct vm_operations_struct incfs_file_vm_ops = {
.fault = incfs_fault,
.map_pages = filemap_map_pages,
.page_mkwrite = filemap_page_mkwrite,
};
/* This is used for a general mmap of a disk file */
static int incfs_file_mmap(struct file *file, struct vm_area_struct *vma)
{
struct address_space *mapping = file->f_mapping;
if (!mapping->a_ops->readpage)
return -ENOEXEC;
file_accessed(file);
vma->vm_ops = &incfs_file_vm_ops;
return 0;
}
const struct file_operations incfs_file_ops = {
.open = file_open,
.release = file_release,
.read_iter = generic_file_read_iter,
.mmap = generic_file_mmap,
.mmap = incfs_file_mmap,
.splice_read = generic_file_splice_read,
.llseek = generic_file_llseek,
.unlocked_ioctl = dispatch_ioctl,

60
tools/testing/selftests/filesystems/incfs/incfs_test.c
View File

@@ -18,6 +18,7 @@
#include <zstd.h>
#include <sys/inotify.h>
#include <sys/mman.h>
#include <sys/mount.h>
#include <sys/stat.h>
#include <sys/types.h>
@@ -4057,6 +4058,64 @@ out:
return result;
}
static int mmap_test(const char *mount_dir)
{
int result = TEST_FAILURE;
char *backing_dir = NULL;
int cmd_fd = -1;
/*
* File is big enough to have a two layer tree with two hashes in the
* higher level, so we can corrupt the second one
*/
int shas_per_block = INCFS_DATA_FILE_BLOCK_SIZE / SHA256_DIGEST_SIZE;
struct test_file file = {
.name = "file",
.size = INCFS_DATA_FILE_BLOCK_SIZE * shas_per_block * 2,
};
char *filename = NULL;
int fd = -1;
char *addr = (void *)-1;
TEST(backing_dir = create_backing_dir(mount_dir), backing_dir);
TESTEQUAL(mount_fs(mount_dir, backing_dir, 0), 0);
TEST(cmd_fd = open_commands_file(mount_dir), cmd_fd != -1);
TESTEQUAL(build_mtree(&file), 0);
file.mtree[1].data[INCFS_DATA_FILE_BLOCK_SIZE] ^= 0xff;
TESTEQUAL(crypto_emit_file(cmd_fd, NULL, file.name, &file.id,
file.size, file.root_hash,
file.sig.add_data), 0);
TESTEQUAL(emit_test_file_data(mount_dir, &file), 0);
TESTEQUAL(load_hash_tree(mount_dir, &file), 0);
TEST(filename = concat_file_name(mount_dir, file.name), filename);
TEST(fd = open(filename, O_RDONLY | O_CLOEXEC), fd != -1);
TEST(addr = mmap(NULL, file.size, PROT_READ, MAP_PRIVATE, fd, 0),
addr != (void *) -1);
TESTEQUAL(mlock(addr, INCFS_DATA_FILE_BLOCK_SIZE), 0);
TESTEQUAL(munlock(addr, INCFS_DATA_FILE_BLOCK_SIZE), 0);
TESTEQUAL(mlock(addr + shas_per_block * INCFS_DATA_FILE_BLOCK_SIZE,
INCFS_DATA_FILE_BLOCK_SIZE), -1);
TESTEQUAL(mlock(addr + (shas_per_block - 1) *
INCFS_DATA_FILE_BLOCK_SIZE,
INCFS_DATA_FILE_BLOCK_SIZE), 0);
TESTEQUAL(munlock(addr + (shas_per_block - 1) *
INCFS_DATA_FILE_BLOCK_SIZE,
INCFS_DATA_FILE_BLOCK_SIZE), 0);
TESTEQUAL(mlock(addr + (shas_per_block - 1) *
INCFS_DATA_FILE_BLOCK_SIZE,
INCFS_DATA_FILE_BLOCK_SIZE * 2), -1);
TESTEQUAL(munmap(addr, file.size), 0);
result = TEST_SUCCESS;
out:
close(fd);
free(filename);
close(cmd_fd);
umount(mount_dir);
free(backing_dir);
return result;
}
static char *setup_mount_dir()
{
struct stat st;
@@ -4173,6 +4232,7 @@ int main(int argc, char *argv[])
MAKE_TEST(inotify_test),
MAKE_TEST(verity_test),
MAKE_TEST(enable_verity_test),
MAKE_TEST(mmap_test),
};
#undef MAKE_TEST