[libvirt PATCH 3/4] virFileReadLimFD: Limit maximum file size to INT_MAX - 1

[Tim Wiederhake]

virFileReadLimFD always returns null-terminated data. To that end, it has to
add one to the maximum file size. If the maxium file size is INT_MAX, this
triggers a signed integer overflow.

There is no instance left where a caller would call virFileReadLimFD with a
maxium file size of INT_MAX. Make virFileReadLimFD error out if the maximum
file size is INT_MAX to prevent the reintroduction of this issue.

Signed-off-by: Tim Wiederhake <twiederh at redhat.com>
---
 src/util/virfile.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/util/virfile.c b/src/util/virfile.c
index 723e1ca6e5..b5600658d5 100644
--- a/src/util/virfile.c
+++ b/src/util/virfile.c
@@ -1418,7 +1418,7 @@ virFileReadLimFD(int fd, int maxlen, char **buf)
     size_t len;
     char *s;
 
-    if (maxlen <= 0) {
+    if ((maxlen <= 0) || (maxlen >= INT_MAX)) {
         errno = EINVAL;
         return -1;
     }
-- 
2.31.1