Patchwork [01/20] vvfat: Fix segfault on write to read-only disk

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Submitter Kevin Wolf
Date Sept. 21, 2010, 3:21 p.m.
Message ID <1285082522-24407-2-git-send-email-kwolf@redhat.com>
Download mbox | patch
Permalink /patch/65313/
State New
Headers show

Comments

Kevin Wolf - Sept. 21, 2010, 3:21 p.m.
From: Kevin Wolf <mail@kevin-wolf.de>

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>
---
 block/vvfat.c |    5 +++++
 1 files changed, 5 insertions(+), 0 deletions(-)

Patch

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 @@  static int vvfat_write(BlockDriverState *bs, int64_t sector_num,
 
 DLOG(checkpoint());
 
+    /* Check if we're operating in read-only mode */
+    if (s->qcow == NULL) {
+        return -EACCES;
+    }
+
     vvfat_close_current_file(s);
 
     /*