From ca79564309e87f1cd92f7c79a03fccb792cca274 Mon Sep 17 00:00:00 2001 From: =?utf8?q?Zbigniew=20J=C4=99drzejewski-Szmek?= Date: Thu, 25 Mar 2021 11:58:35 +0100 Subject: [PATCH] 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. --- src/basic/fileio.c | 18 +++++++++++------- 1 file changed, 11 insertions(+), 7 deletions(-) diff --git a/src/basic/fileio.c b/src/basic/fileio.c index 6e42b60c3fe..46ab5db79f8 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) -- 2.47.3