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Fix the overflow issue in Checkpoint

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When the partition is f2fs and the OS is 32bit, the data.f_bavail and
data.f_frsize are 32 bits in size. The product of them is also 32 bits
in size. If the available size of storage is greater than 4G, the
product may be greater than the unsigned long max value. If the product
is overflow and less than 100M. The UDC feature will be disabled.

There is also an overflow for std::strtoul when the variable content
is a very big number(more the unsigned long max value).

To avoid the overflow:
1. convert the variable data.f_bavvail to uint64_t and then compute the
multiplication.
2. use std::strtoull replace to std::strtoul.

Bug: 147118861
Change-Id: I60172ae4cb7c997e2ad4a36583be74736c25e565
This commit is contained in:
Qilin Tan 2020-01-02 19:07:47 +08:00 committed by Denis Hsu
parent f9510e3262
commit 5d0aaaf8e0
1 changed files with 2 additions and 2 deletions
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4
Checkpoint.cpp
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@ -320,13 +320,13 @@ static void cp_healthDaemon(std::string mnt_pnt, std::string blk_device, bool is
uint64_t free_bytes = 0; uint64_t free_bytes = 0;
if (is_fs_cp) { if (is_fs_cp) {
statvfs(mnt_pnt.c_str(), &data); statvfs(mnt_pnt.c_str(), &data);
free_bytes = data.f_bavail * data.f_frsize; free_bytes = ((uint64_t) data.f_bavail) * data.f_frsize;
} else { } else {
std::string bow_device = fs_mgr_find_bow_device(blk_device); std::string bow_device = fs_mgr_find_bow_device(blk_device);
if (!bow_device.empty()) { if (!bow_device.empty()) {
std::string content; std::string content;
if (android::base::ReadFileToString(bow_device + "/bow/free", &content)) { if (android::base::ReadFileToString(bow_device + "/bow/free", &content)) {
free_bytes = std::strtoul(content.c_str(), NULL, 10); free_bytes = std::strtoull(content.c_str(), NULL, 10);
} }
} }
} }