From a647502c582981c395b5d16e52a22ac7aff0fb2b Mon Sep 17 00:00:00 2001 From: Keno Fischer Date: Thu, 7 Jun 2018 12:17:22 +0200 Subject: [PATCH] 9p: xattr: Fix crashes due to free of uninitialized value If the size returned from llistxattr/lgetxattr is 0, we skipped the malloc call, leaving xattr.value uninitialized. However, this value is later passed to `g_free` without any further checks, causing an error. Fix that by always calling g_malloc unconditionally. If `size` is 0, it will return NULL, which is safe to pass to g_free. Signed-off-by: Keno Fischer Signed-off-by: Greg Kurz --- hw/9pfs/9p.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/hw/9pfs/9p.c b/hw/9pfs/9p.c index d74302deeb..4386d69817 100644 --- a/hw/9pfs/9p.c +++ b/hw/9pfs/9p.c @@ -3256,8 +3256,8 @@ static void coroutine_fn v9fs_xattrwalk(void *opaque) xattr_fidp->fs.xattr.len = size; xattr_fidp->fid_type = P9_FID_XATTR; xattr_fidp->fs.xattr.xattrwalk_fid = true; + xattr_fidp->fs.xattr.value = g_malloc0(size); if (size) { - xattr_fidp->fs.xattr.value = g_malloc0(size); err = v9fs_co_llistxattr(pdu, &xattr_fidp->path, xattr_fidp->fs.xattr.value, xattr_fidp->fs.xattr.len); @@ -3289,8 +3289,8 @@ static void coroutine_fn v9fs_xattrwalk(void *opaque) xattr_fidp->fs.xattr.len = size; xattr_fidp->fid_type = P9_FID_XATTR; xattr_fidp->fs.xattr.xattrwalk_fid = true; + xattr_fidp->fs.xattr.value = g_malloc0(size); if (size) { - xattr_fidp->fs.xattr.value = g_malloc0(size); err = v9fs_co_lgetxattr(pdu, &xattr_fidp->path, &name, xattr_fidp->fs.xattr.value, xattr_fidp->fs.xattr.len); -- 2.39.5