vvfat: Fix segfault on write to read-only disk
vvfat tries to set the readonly flag in its open function, but nowadays
this is overwritted with the readonly=... command line option. Check in
bdrv_write if the vvfat was opened read-only and return an error in this
case.
Without this check, vvfat tries to access the qcow bs, which is NULL
without enabled write support.
Signed-off-by: Kevin Wolf <mail@kevin-wolf.de>
diff --git a/block/vvfat.c b/block/vvfat.c
index 365332a..5898d66 100644
--- a/block/vvfat.c
+++ b/block/vvfat.c
@@ -2665,6 +2665,11 @@
DLOG(checkpoint());
+ /* Check if we're operating in read-only mode */
+ if (s->qcow == NULL) {
+ return -EACCES;
+ }
+
vvfat_close_current_file(s);
/*
