Integer overflow observed while formatting volume
While calculating volume size, get_block_device_size() returns
u64 value but the returned value is assigned in ssize_t variable.
This may cause integer overflow if the volume size is beyond
ssize_t limit.
Use int64_t instead of ssize_t in get_file_size() and explicitly check
for overflow to fix the issue.
Bug: 65001754
Test: mmma bootable/recovery
Change-Id: I91eb30bff0bf7dcc48678efc2f414d2b79af6d0d
diff --git a/roots.cpp b/roots.cpp
index fdcbfe8..26602a7 100644
--- a/roots.cpp
+++ b/roots.cpp
@@ -18,6 +18,7 @@
#include <ctype.h>
#include <fcntl.h>
+#include <stdint.h>
#include <stdlib.h>
#include <sys/mount.h>
#include <sys/stat.h>
@@ -178,16 +179,22 @@
return WEXITSTATUS(status);
}
-static ssize_t get_file_size(int fd, uint64_t reserve_len) {
+static int64_t get_file_size(int fd, uint64_t reserve_len) {
struct stat buf;
int ret = fstat(fd, &buf);
if (ret) return 0;
- ssize_t computed_size;
+ int64_t computed_size;
if (S_ISREG(buf.st_mode)) {
computed_size = buf.st_size - reserve_len;
} else if (S_ISBLK(buf.st_mode)) {
- computed_size = get_block_device_size(fd) - reserve_len;
+ uint64_t block_device_size = get_block_device_size(fd);
+ if (block_device_size < reserve_len ||
+ block_device_size > std::numeric_limits<int64_t>::max()) {
+ computed_size = 0;
+ } else {
+ computed_size = block_device_size - reserve_len;
+ }
} else {
computed_size = 0;
}
@@ -231,13 +238,13 @@
close(fd);
}
- ssize_t length = 0;
+ int64_t length = 0;
if (v->length != 0) {
length = v->length;
} else if (v->key_loc != nullptr && strcmp(v->key_loc, "footer") == 0) {
android::base::unique_fd fd(open(v->blk_device, O_RDONLY));
if (fd == -1) {
- PLOG(ERROR) << "get_file_size: failed to open " << v->blk_device;
+ PLOG(ERROR) << "format_volume: failed to open " << v->blk_device;
return -1;
}
length = get_file_size(fd.get(), CRYPT_FOOTER_OFFSET);