libkmod-file: gracefully handle errors from zlib
zlib won't necessarily set the system errno, and this is particularly
evident on corrupted data (which results in a double free). Use zlib's
gzerror to detect the failure, returning a generic EINVAL when zlib
doesn't provide us with an errno.
diff --git a/libkmod/libkmod-file.c b/libkmod/libkmod-file.c
index 46ad8d9..8beb7e3 100644
--- a/libkmod/libkmod-file.c
+++ b/libkmod/libkmod-file.c
@@ -199,7 +199,13 @@
if (r == 0)
break;
else if (r < 0) {
- err = -errno;
+ int gzerr;
+ const char *gz_errmsg = gzerror(file->gzf, &gzerr);
+
+ ERR(file->ctx, "gzip: %s\n", gz_errmsg);
+
+ /* gzip might not set errno here */
+ err = gzerr == Z_ERRNO ? -errno : -EINVAL;
goto error;
}
did += r;