shaba/systemd
1
0
Fork 0
mirror of https://github.com/systemd/systemd.git synced 2024-12-25 01:34:28 +03:00
Code

basic/fileio: simplify calculation of buffer size in read_full_virtual_file()

Browse Source 
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.
This commit is contained in:
Zbigniew Jędrzejewski-Szmek 2021-03-25 11:58:35 +01:00
parent 91a96a564f
commit ca79564309
1 changed files with 11 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

18
src/basic/fileio.c
View File

@ -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)