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Merge \"Zero out blocks if BLKSECDISCARD fails\" into nyc-mr1-dev

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am: d6a39dd78a

Change-Id: I7ee62f8cb0b2144f4385bd132a3d32ecf3d918d2
This commit is contained in:
Paul Crowley 2016-07-13 19:54:02 +00:00 committed by android-build-merger
commit a1b2949be2
1 changed files with 32 additions and 9 deletions
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41
secdiscard.cpp
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@ -43,11 +43,12 @@ constexpr uint32_t max_extents = 32;
bool read_command_line(int argc, const char * const argv[], Options &options);
void usage(const char *progname);
int secdiscard_path(const std::string &path);
bool secdiscard_path(const std::string &path);
std::unique_ptr<struct fiemap> path_fiemap(const std::string &path, uint32_t extent_count);
bool check_fiemap(const struct fiemap &fiemap, const std::string &path);
std::unique_ptr<struct fiemap> alloc_fiemap(uint32_t extent_count);
std::string block_device_for_path(const std::string &path);
bool overwrite_with_zeros(int fd, off64_t start, off64_t length);
}
@ -58,9 +59,11 @@ int main(int argc, const char * const argv[]) {
usage(argv[0]);
return -1;
}
for (auto target: options.targets) {
for (auto const &target: options.targets) {
LOG(DEBUG) << "Securely discarding '" << target << "' unlink=" << options.unlink;
secdiscard_path(target);
if (!secdiscard_path(target)) {
LOG(ERROR) << "Secure discard failed for: " << target;
}
if (options.unlink) {
if (unlink(target.c_str()) != 0 && errno != ENOENT) {
PLOG(ERROR) << "Unable to unlink: " << target;
@ -95,19 +98,19 @@ void usage(const char *progname) {
}
// BLKSECDISCARD all content in "path", if it's small enough.
int secdiscard_path(const std::string &path) {
bool secdiscard_path(const std::string &path) {
auto fiemap = path_fiemap(path, max_extents);
if (!fiemap || !check_fiemap(*fiemap, path)) {
return -1;
return false;
}
auto block_device = block_device_for_path(path);
if (block_device.empty()) {
return -1;
return false;
}
AutoCloseFD fs_fd(block_device, O_RDWR | O_LARGEFILE);
if (!fs_fd) {
PLOG(ERROR) << "Failed to open device " << block_device;
return -1;
return false;
}
for (uint32_t i = 0; i < fiemap->fm_mapped_extents; i++) {
uint64_t range[2];
@ -115,10 +118,11 @@ int secdiscard_path(const std::string &path) {
range[1] = fiemap->fm_extents[i].fe_length;
if (ioctl(fs_fd.get(), BLKSECDISCARD, range) == -1) {
PLOG(ERROR) << "Unable to BLKSECDISCARD " << path;
return -1;
if (!overwrite_with_zeros(fs_fd.get(), range[0], range[1])) return false;
LOG(DEBUG) << "Used zero overwrite";
}
}
return 0;
return true;
}
// Read the file's FIEMAP
@ -206,4 +210,23 @@ std::string block_device_for_path(const std::string &path)
return result;
}
bool overwrite_with_zeros(int fd, off64_t start, off64_t length) {
if (lseek64(fd, start, SEEK_SET) != start) {
PLOG(ERROR) << "Seek failed for zero overwrite";
return false;
}
char buf[BUFSIZ];
memset(buf, 0, sizeof(buf));
while (length > 0) {
size_t wlen = static_cast<size_t>(std::min(static_cast<off64_t>(sizeof(buf)), length));
auto written = write(fd, buf, wlen);
if (written < 1) {
PLOG(ERROR) << "Write of zeroes failed";
return false;
}
length -= written;
}
return true;
}
}