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| author | Zbigniew Jędrzejewski-Szmek <zbyszek@in.waw.pl> | 2021-03-25 11:58:35 +0100 |
|---|---|---|
| committer | Zbigniew Jędrzejewski-Szmek <zbyszek@in.waw.pl> | 2021-03-26 15:46:44 +0100 |
| commit | ca79564309e87f1cd92f7c79a03fccb792cca274 (patch) | |
| tree | f237e32b35549b66cdd93081b88a38be3ae3e2e6 | |
| parent | 91a96a564f5fc0dbad15f1c23a0fbda157a03558 (diff) | |
| download | systemd-ca79564309e87f1cd92f7c79a03fccb792cca274.tar.gz | |
basic/fileio: simplify calculation of buffer size in read_full_virtual_file()
We'd first assign a value up to SSIZE_MAX, and then immediately check if we
have a value bigger than READ_FULL_BYTES_MAX. This wasn't exactly wrong, but a
bit roundabout. Let's immediately assign the value from the appropriate range
or error out.
Coverity CID#1450973.
| -rw-r--r-- | src/basic/fileio.c | 18 |
1 files changed, 11 insertions, 7 deletions
diff --git a/src/basic/fileio.c b/src/basic/fileio.c index 6e42b60c3f..46ab5db79f 100644 --- a/src/basic/fileio.c +++ b/src/basic/fileio.c @@ -403,18 +403,22 @@ int read_full_virtual_file(const char *filename, char **ret_contents, size_t *re return -EBADF; /* Be prepared for files from /proc which generally report a file size of 0. */ + assert_cc(READ_FULL_BYTES_MAX < SSIZE_MAX); if (st.st_size > 0) { - if (st.st_size > SSIZE_MAX) /* safety check in case off_t is 64bit and size_t 32bit */ + if (st.st_size > READ_FULL_BYTES_MAX) return -E2BIG; size = st.st_size; n_retries--; - } else - /* Double the buffer size (saturate in case of overflow) */ - size = size > SSIZE_MAX / 2 ? SSIZE_MAX : size * 2; - - if (size > READ_FULL_BYTES_MAX) - return -E2BIG; + } else { + /* Double the buffer size */ + if (size >= READ_FULL_BYTES_MAX) + return -E2BIG; + if (size > READ_FULL_BYTES_MAX / 2) + size = READ_FULL_BYTES_MAX; /* clamp to max */ + else + size *= 2; + } buf = malloc(size + 1); if (!buf) |